INTEGRATED
LAND USE/AIR QUALITY/WATER QUALITY
CONTROL STUDY FOR
SONOMA COUNTY CALIFORNIA
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D. C. 20460
JANUARY 1977
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INTEGRATED LAND USE/AIR QUALITY/WATER QUALITY CONTROL STUDY
FOR SONOMA COUNTY, CALIFORNIA
Prepared by
Association of Bay Area Governments
assisted by
Sonoma County Planning Department, Advanced Planning Division
Bay Area Air Pollution Control District
Contract No. 68-01-2648
Project Officers
William Lienesch
John Robson
David Healy
Prepared for
U.S. Environmental Protection Agency
Washington, D.C. 20460
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EPA REVIEW NOTICE
This report has been reviewed by the Environmental Protection
Agency and approved as satisfying the terms of the subject
contract. Approval does not signify that the contents neces-
sarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trademarks or commercial
products constitute endorsement or recommendation for use.
11
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ACKNOWLEDGEMENTS
The Association of Bay Area Governments' Sonoma Study project team
include:
Project Coordinator Gordon Jacoby
and
Principal Author
Contributing Authors Bob Frommer, Steve Goldman,
Marcine Martin, Tom Priestley
Principal Report Reviewers John McKoy, Planning Director,
George Hagevik, Assistant Planning Director
Eugene Leong, Division Chief for Air and
Water Quality Management
Technical Analysts Nickey Glidden, Dennis Wambem
Cartographer Karen Graser
Other ABAG staff that provided management direction and reviewed the draft
copies of the report were Revan A. F. Tranter, Executive Director; Dean Macris,
Associate Executive Director; Robert Goldman, Technical Services Director and
Douglas Detling, Assistant to the Public Affairs Director.
Sub-contractors who assisted the study as both contributing authors and
technical analysts were:
Sonoma County Advanced Chris Kirschner
Planning Division
Bay Area Air Pollution Richard Thuillier
Control District
Water Resources Larry Davis, Larry Roesner,
Engineers, Inc. Michael Sonnen
URS Research Company Michael Miller, Jack Jenkins
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TABLE OF CONTENTS
PAGE
EPA REVIEW NOTICE 11
ACKNOWLEDGEMENTS iii
TABLE OF CONTENTS v
LIST OF FIGURES xi
LIST OF TABLES xiii
Chapter
I SUMMARY 1-1
STUDY LIMITATIONS 1-2
CONCLUSIONS 1-3
RECOMMENDATIONS 1-5
o General Recommendations 1-5
o Spatial Pattern and Assimilative Capacity
Recommendations 1-5
o Intergovernmental Organization
Recommendations 1-6
II INTRODUCTION
BACKGROUND II-l
o Sonoma County as a case study II-2
o Study Limitations II-3
o Who participated in the study II-5
SONOMA COUNTY SETTING II-6
o Present environmental conditions II-9
o Growth dynamics in Sonoma County 11-12
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Ill PRESENT THEORIES ON INTERRELATIONSHIPS OF AIR
AND WATER QUALITY AND LAND USE III-l
RATIONALE FOR STUDYING INTERRELATIONSHIPS OF AIR
AND WATER QUALITY AND LAND USE III-l
SPATIAL PATTERN VERSUS SITE SPECIFIC MANAGEMENT
CONTROL STRATEGIES II1-3
SPATIAL PATTERN STRATEGIES II1-4
SITE SPECIFIC MANAGEMENT TECHNIQUES II1-7
o Site Specific Management Techniques
Strategies for Water Quality II1-7
o Site Specific Management Techniques
Strategies for Air Quality III-9
SUMMARY OF SITE SPECIFIC MANAGEMENT CONTROL DEVICES III-ll
SEWER SYSTEMS AS A DETERMINANT OF REGIONAL GROWTH 111-18
RESIDUAL MANAGEMENT AS AN APPROACH OF INTER-
RELATING LAND USE/AIR QUALITY/WATER QUALITY 111-21
SUMMARY . II1-22
IV GOVERNMENTAL STRUCTURE OF AIR AND WATER POLLUTION
CONTROL IN CALIFORNIA IV-1
HISTORIC PERSPECTIVE OF ENVIRONMENTAL CONTROL IV-1
STATE AGENCIES INVOLVED IN AIR AND WATER QUALITY IV-3
o Air Resources Board IV-3
o Air Pollution Control Districts IV-6
o State Water Resources Control Board IV-7
o Regional Water Quality Control Boards IV-9
o Office of Planning and Research IV-11
o Department of Fish and Game IV-12
o Energy Resources Conservation and,
Development Commission IV-13
o Department of Transportation IV-U
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REGIONAL AGENCIES INVOLVED IN AIR AND WATER
QUALITY IV-15
o Association of Bay Area Governments IV-15
o Metropolitan Transportation Commission IV-16
o Bay Area Sewage Services Agency IV-17
LOCAL GOVERNMENT LAND USE CONTROLS AND AIR
AND WATER QUALITY IV-18
o General Plans in California IV-18
o Analysis of General Plan Policies For
Air And Water Quality in Sonoma County IV-21
o Analysis of Zoning and Subdivision
Regulations For Air And Water Quality
in Sonoma County IV-25
LOCAL AGENCY FORMATION COMMISSION AND SPECIAL
DISTRICTS IV-32
o Local Agency Formation Commission IV-33
o Special Districts IV-34
DEFICIENCIES OF THE GOVERNMENTAL STRUCTURE FOR
POLLUTION CONTROL IV-37
o Lack of Policy Integration IV-38
o Minimal Local Government Involvement IV-39
o Lack of Consistent Appeal or Review Process IV-41
o Vague Policies IV-42
DESCRIPTION OF STUDY TECHNIQUES V-l
ALTERNATIVE LAND USE GROWTH PATTERNS V-l
o Santa Rosa Centered (SRC) Alternatives V-5
o Urban Centered (UC) Alternatives V-8
o Suburban Dispersed (SD) Alternatives V-8
o Rural Dispersed (RD) Alternatives V-12
o Continuing Trends (CT) Alternatives V-12
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MODELING OF WATER QUALITY V-12
o Modeling of Surface Runoff Water Quality V-13
o Relationship of Water Model Variable to
Government Policy Making V-17
AIR QUALITY MODELING V-18
o Analysis of Non-Reactive Pollutants V-22
o Oxidant Analysis V-23
o Relationship of Air Quality Modeling to
Government Policy Making V-23
VI RESULTS OF MODEL ANALYSIS VI-1
WATER QUALITY ANALYSIS VI-1
o Impacts of Development on Dry Weather
Quality VI-2
o Impacts of Development on Wet Weather
Quality VI-12
o Impact of Sewerage Plants During Wet
Weather Periods VI-22
o Site/Design Management Control Simulations VI-34
o Groundwater Impacts VI-39
AIR QUALITY ANALYSIS VI-45
o General Considerations VI-46
o Interpretation of Modeling Results VI-48
o Impacts of Development on the Emission of
Carbon Monoxide VI-48
o Impacts of Development on the Emission of
Particulates VI-56
o Impacts of Development on the Emission of
Sulfur Dioxide VI-60
o Reactive Pollutants-Oxidant VI-67
o Impacts of Development on the Creation of
Oxidant VI-67
vi ii
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VII LINKAGES BETWEEN LAND USE, AIR QUALITY AND WATER
QUALITY VII-1
GENERAL CONCLUSIONS VII-1
SPATIAL PATTERN LINKAGES VII-3
o Regional Urban-Rural Population
Distribution VI1-4
o Regional Distribution of Urban
Population and Employment VII-4
o Density and Location Characteristics
of Residential and Commercial Land Uses VII-6
ASSIMILATIVE CAPACITY LINKAGES VII-10
o Assimilative Capacity Characteristics
and Wet Weather Water Quality VII-10
o Assimilative Capacity Characteristics
and Dry Weather Water Quality VII-11
o Assimilative Capacity and Oxidants VII-11
MITIGATION MEASURE LINKAGES VII-12
o Impact of Mitigation Measures on Water
Quality VI1-13
o Impact of Mitigation Measures on Air
Quality VII-14
POLICY IMPLICATIONS OF LINKAGES VII-14
o Spatial Pattern and Assimilative Capacity
Considerations VI1-15
o Mitigation Measure Considerations VII-21
o General Governmental Considerations VI1-22
VIII RECOMMENDATIONS FOR AN ENVIRONMENTAL MANAGEMENT
PLANNING STRUCTURE VIII-1
BASIC RECOMMENDATIONS FOR AN ENVIRONMENTAL
MANAGEMENT PLANNING PROCESS VIII-1
o Integration of Air and Water Quality
Land Use Measures With Other Functional
Elements VII1-2
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o Integration of Inter-governmental Air
and Water Quality Land Use Measures VII1-3
o Involvement of Local Government VII1-3
o Creation of a Consistent Review and
Appeal System VII1-4
o Adoption of Clear and Specific Policies 'VIII-7
o Clear Assignment of the Responsibilities VIII-7
INTER-GOVERNMENTAL RESPONSIBILITY IN PREPARING
AND ENVIRONMENTAL MANAGEMENT PLAN VIII-7
o State Responsibility VIII-8
o Regional Responsibility VIII-9
o Local Responsibility VII1-12
SUMMARY VII1-13
APPENDIX
A - GLOSSARY A-l
B - TECHNICAL DESCRIPTION OF THE LAND USE ALLOCATION
SYSTEM B-l
C - TECHNICAL DESCRIPTION OF THE MODELING SYSTEM FOR
NON-REACTIVE AIR POLLUTANTS AND METEOROLOGY AND
AIR QUALITY IN SONOMA COUNTY - C-l
D - TECHNICAL DESCRIPTION OF OXIDANT MODELING D-l
E - TECHNICAL DESCRIPTION OF TRAFFIC ESTIMATION
PROCEDURES E-l
F - TECHNICAL DESCRIPTION OF THE WATER QUALITY
MODELING F-l
BIBLIOGRAPHY
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FIGURES
ML PAGE
II-l Location of Sonoma County 1n the
San Francisco bay Region II-7
11-2 Project Area Grid Map 11-10
V-l Santa Rosa Centered o 478,000 V-6
V-2 Urban Centered o 478,000 V-7
V-3 Suburban Dispersed o 478,000 V-9
V-4 Suburban Dispersed o 630,000 V-10
V-5 Continuing Trends o 478,000 V-ll
V-6 Compilation of Total Emissions by Grid Cell V-19
VI-1 Laguna de Santa Rosa and Tributaries -
QUAL-II Stream Network VI-3
VI-2 Laguna de Santa Rosa Dissolved Oxygen
Profile VI-6
VI-3 Petaluma River QUAL-II Stream Network VI-9
VI-4 Petaluma River Dissolved Oxygen Profile Vl-il
VI-5 Guide to Basin Maps & Channel Numbers VI-15
VI-6 Laguna Basin Subareas and Channels VI-16
VI-7 Channel Quality Per Growth Alternative VI-20
VI-8 Laguna Basin-Base Year Urban Washoff
and Channel Qualities VI-23
VI-9 Laguna Basin-SRC-478 Urban Washoff and
Channel Qualities VI-24
VI-10 Laguna Basin Quality Results at Channel 3002 VI-25
VI-11 Laguna Basin Quality Result at Channel 3015 VI-26
VI-12 Petaluma Basin Subareas and Channesl VI-28
VI-13 Petaluma Basin-Base Year Urban Washoff and
Channel Qualities VI-30
VI-14 Petaluma Basin-SRC-478 Urban Washoff and
Channel Qualities VI-31
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FIGURES
NO. PAGE
VI-15 Petaluma Basin Quality Results at Channel 1007 VI-32
VI-16 Petaluma Basin Quality Results at Channel 1010 VI-33
VI-17 Channel Quality Per Management/Site Design
Control VI-38
VI-18 Laguna Basin-Base Year Urbanization and Groundwater
Recharge areas VI-41
VI-19 -Laguna Basin-SRC-478 Urbanization and Groundwater
Recharges Areas VI-42
VI-20 Petaluma Basin-Base Year Urbanization and
Groundwater Recharges Areas VI~$?
VI-21 Petaluma Basin-SRC-478 Urbanization and
Groundwater Recharges Areas VI-44
VI-22 Carbon Monoxide, Base Year-1973 VI-49
VI-23 Carbon Monoxide, SRC 478 VI-52
VI-24 Carbon Monoxide, SRC 630 VI-53
VI-25 Carbon Monoxide, UC 478 VI-54
VI-26 Carbon Monoxide, SD 630 VI-55
VI-27 Carbon Monoxide, CT 478 with 1973 Vehicle Emission
Devices VI-'57
VI-28 Carbon Monoxide, CT 478
VI- 58
VI-29 Effect of Vehicle Emission Inspection/Maintenance
Program: Downtown Santa Rosa 1rr
VI- 59
VI-30 Suspended Particulates, SRC 478
VI-31 Suspended Particulates, SRC 630
V J."" DO
VI-32 Suspended Particulates, UC 630
VI- 64
VI-33 Suspended Particulates* SD 630
VI- 65
VI-34 Sulfur Dioxide, SRC 478 VT **
»•!•- 66
VII-1 Characteristics of Land Use Alternatives VII-.5
xi i
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TABLES
NO PAGE
II-l Sonoma County Population
Changes: 1960-1975 11-13
III-l Land Use Measures Designed to Improve
and Maintain Water Quality III-12
IV-2 Applicability of Design Revfew Reguirements
in Sonoma County IV-30
V-l Land Use Classification System V-3
V-2 Populations of the Land Use Alternatives V-4
VI-1 Effluent Flows and Qualities Used in QUAL-II
Simulations VI-5
VI-2 Quantity and Quality of Low Flow Discharges
to Russian River VI-7
VI-3 Effluent Flows and Qualities Used in QUAL-II
Simulations VI-10
VI-4 Quantity and Quality of Low Flow Discharges
to San Pablo Bay VI-12
VI-5 Laguna Basin Channel Quality and Pollutant
Washoff VI-17
VI-6 Petaluma Basin Channel Quality and Pollutant
Washoff VI-29
VI-7 Effectiveness of Site Design/Management
Alternatives on Total Urban Washoff VI-36
VI-8 Reduced Impervious Area Simulation Watershed
Washoff Loads VI-36
VI-9 Effectiveness of Site Design/Management
Alternatives on Peak Concentrations VI-39
VI-10 Water Runoff From Reduced Impervious Coverage
Peak Runoff, m3/sec VI-40
xiii
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NO PAGE,
VI-11 Annual Average and Maximum Anticipated
Concentration of Carbon Monoxide (ppm) VI-51
VI-12 Annual Average Concentration and Frequency
of Exceedence of State
24-Hour Standard for Particulates VI-61
VI-13 Results of the Oxidant Analysis VI-68
VII-1 Population Exposure Levels of Air Contaminants
Per Land Use Alternative VII-7
VI1-2 Washoff Characteristics of Land Uses VI1-9
VII-3 Santa Rosa Centered Growth Management Policies VII-16
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CHAPTER I - SUMMARY
The purposes of the "Integrated Land Use/Air Quality/Water Quality Control
Study for Sonoma County, California" are:
1) to assess the Influence of land use controls for attaining air
quality objectives on those for attaining water quality objec-
tives and vice versa, giving particular attention to whether the
control strategies for either medium are mutually supportive or
conflicting;
2) to analyze the impact of urban spatial patterns on air and water
quality to determine if any of the elements of spatial pattern —
population and employment size, type of land use, location of
land use or development density -- is the dominant character-
istic; and
3) to determine the relative effectiveness of other air and water
pollution control strategies, such as vehicle emission devices or
site design methods for reducing surface runoff water pollution,
in achieving and maintaining environmental objectives.
The study can be particularly helpful in assisting governmental agencies
preparing water quality management plans under Section 208 of the Federal
Water Pollution Control Act Amendments of 1972 (P.L. 92-500) and air
quality maintenance plans as required under the Clean Air Amendments of
1970 (P.L. 91-604). Its findings and recommendations should be of assis-
tance to agencies involved in preparing the plans by describing methods for
assessing the effectiveness of different air or water pollution control
strategies and in recommending an organizational framework for inter-
governmental cooperation in preparing the plans.
The approach for analyzing the linkages between air and water pollution
control strategies included three steps. The first was projecting
different population and land use patterns in Sonoma County to the year
2000 to determine their influence on air and water quality. The land use
patterns were studied for their influence on water quality during both dry
and wet weather. The second step was analyzing the land use and environ-
mental planning process conducted at different jurisdlctional levels to
determine its influence on land use and the attainment of air and water
quality objectives. The third step was examining air and water quality
simulations resulting from the various land use alternatives to determine
what development patterns or conditions represented the best arrangement
for achieving air and water quality objectives and what are the require-
ments for intergovernmental policy setting and enforcement to achieve those
objectives.
As the study progressed, attention focused on the analysis of two somewhat
separate forms of land use control:
\
1) Growth management programs — the use of alternative land use
plans and specific controls to influence the size, location and
timing of urban growth in an area and
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2) Site specific management techniques — the use of pollution
abatement strategies other than spatial pattern to reduce the
potential for air and water contamination created at a specific
location or by a particular emission source. The influence of
street sweeping, retention storage facilities and increased
ground surface capable of absorbing stormwater were measures
studied for water quality improvement. The effectiveness of
vehicle emission devices was studied as part of the air quality
analysis.
STUDY LIMITATIONS
There were a number of study limitations that the reader should understand
in reviewing the conclusions and recommendations. Discussed more completely
in Chapter II, they will likely be experienced by others preparing similar
studies, including those necessary for "208" water quality management
plans.
First, there was a lack of sufficient data, including water quality
information during rainy periods, to completely calibrate the surface
runoff model. Therefore, the surface runoff model was calibrated using
existing water quantity, with water quality determined by use of data from
other study areas. Second, there was a limited amount of information on
the type and nature of contaminants that are washed off the streets during
a rainstorm. More extensive information will be required from future
research projects to establish precise findings on surface water contaminants.
Third, the models used for both air and water pollution did not directly
simulate reactive pollutants. For example, the surface runoff model did
not make adjustments for certain chemical or hydrological forces in the
river that have varying consequences on different contaminants. The air
quality analysis did not consider in a detailed manner the chemical or
meteorological factors concerned in the creation and distribution of oxidant.
Fourth, the present surface runoff models did not precisely simulate the
influence of various control measures. This is largely because most of
the control measures have not been fully evaluated as to their effectivenss.
Therefore, some of the assumptions used in this study will need refinement
in future studies when there is greater experience to draw upon. Finally,
the present water quality standards relate more to dry rather than wet
weather conditions. For example, many of the present standards are set
as concentrations whereas one of the greatest problems associated with
surface runoff is increased sedimentation that can be better evaluated by a
total emission measurement.
Whereas the above limitations require that the study be read with appropriate
qualification, any discrepancies between the simulated and the actual data
should not be overstated because the purpose of the study is to establish
relative rather than absolute differences in the effectiveness of different
land use growth patterns or control measures in achieving air and water
quality.
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CONCLUSIONS
The environmental factors analyzed in the Sonoma Study that contribute to
or are involved in the air and water pollution process are both numerous
and complex. Natural features such as soil types, rainfall patterns, river
widths or topographical characteristics are some of these factors. Popula-
tion and employment needs, building sizes, subdivision designs and travel
patterns are a number of the man-made factors that interact with the
natural conditions.
All of these factors are known to have some influence or impact on the
amount and distribution of air and water pollution. Yet, the critical
issue being addressed in the Sonoma Study is which of these factors are the
most important in terms of their influence on pollution and which, there-
fore, should receive the most attention in preparing solutions to reduce
the pollution problem.
The general conclusions reached in the study are: 1) assimilative capacity
of air and water basins is a key determinant of future levels of population
and employment activities that can be supported within the basins without
violating environmental standards; 2) the population and employment size
and density are the most critical factors affecting both air and water
quality as compared to other variables such as location, land use type or
meteorological conditions (excluding reactive air pollutants); and 3) other
pollution control approaches such as site specific land management techniques
generally have greater influence on air and water quality than variations
in spatial configurations or intensity of land use.
Natural features of an air or water basin determine its assimulative
capacity, and therefore strongly influnce the concentration and distri-
bution of pollutants. The impact of land use and transportation alter-
natives on environmental quality objectives can be measured only by
understanding the basin's assimulative capacity, defined in this study
as the extent to which the physical enviornment can absorb pollutants
before air and water quality standards are violated.
The assimilative capacity of a basin may be significantly different for air
quality than for water quality. The Petaluma sub-basin, for example, has a
relatively high assimilative capacity for water pollutants given the
population and employment levels of the different land use alternatives.
However, it has a relatively low assimilative capacity for oxidant.
The analysis of spatial pattern characteristics, including population and
employment size, density, location and land use type, indicated that only
the first two of these variables were particularly significant influences
on levels of air and water quality. Other things being equal, the land use
alternatives which concentrated population and employment produced the
highest localized concentrations of non-reactive air pollutants and water
pollutants"! For example, the worst case situation /for both air and water
was the central section of Santa Rosa in the Santa Rosa Centered alterna-
tive, which was the largest and most densely populated pattern simulated.
In this case the particulate concentrations, carbon monoxide concentrations
and the total washoff loads entering nearby streams were the highest amounts
of any simulation. Yet, when water pollution was measured on a regional
level, in the receiving waters of an entire basin, there is very little
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difference between the quality levels produced by the various land use
alternatives. When air pollution was measured in terms of population
exposure to violations of these air quality standards, the centralized,
compact spatial patterns result in far worse conditions.
There were no profound relationships between countywide urban development
patterns to achieve air quality objectives on those to achieve water
quality objectives. The basic reason was that the hydrologic system and
meterological patterns in Sonoma County were essentially unrelated. The
water quality in a stream draining one city in the County bears little
relationship to the quality in a stream draining another city. On the
other hand, some air pollutants are subject to a high degree of transport
among cities. Air pollutants are transported not only across water
basin boundaries within Sonoma County, but they are also transported to
and from other sections of the San Francisco Bay Region. It is this
dissimilarity in the characteristics of water basins versus air basins
that resulted in the lack of well defined interrelationships.
The analysis indicated that the site design/management control measures
provide far more effective means of environmental improvement than their
spatial form counterparts. The control measures for water quality control
that proved most effective were retention storage and street sweeping. The
retention storage simulation resulted in a twelve-fold reduction in peak
concentration and total washoff over the original simulation. It was
effective because it holds the runoff from the beginning of a storm, when
urban pollutant washoff is the greatest. Street sweeping resulted in a
pollutant reduction equivalent to the frequency of sweeping (i.e., sweep
twice as often prior to potential rain period, cut the runoff pollution in
half).
The water quality control measure that did not prove effective in the
simulation was the reduction of the amount of impervious surfaces in urban
development. This measure resulted in a significantly higher pollutant
concentrations. This increase was due to a decrease in the amount of
runoff available to dilute the pollutants washing off the land.
The air quality mitigation measure studied in this report was the motor
vehicle emission control device requirements. The full implementation of
the emission device control program resulted in a 30% to 40% reduction of
the existing carbon monoxide levels by the year 2000. The failure to
implemented the program resulted in a 100% to 200% increase by the year
2000.
The conclusions reached after review of the governmental structure in
California concerned with land use, air quality and water quality were that
there are five basic deficiencies in the structure:
1) there is a lack of integration of air and water concerns with
other social and economic concerns;
2) there is a lack of integration of either air or water policies
among all agencies surveyed;
3) there is minimal participation by local government in state and
federal pollution control efforts;
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4) there is a lack of consistent review or appeal procedures on land
use decisions that can impact air and water quality objectives;
and
5) many local government policies relating to environment management
are too vague for effective enforcement.
RECOMMENDATIONS
The recommendations that follow relate both to methods of preparing environ-
mental management control strategies and the intergovernmental organization
arrangements needed to prepare and enforce those strategies.
General Recommendations
1. Water quality standards should be revised to make them more
appropriate for protecting water quality in wet weather con-
ditions. Recommendations for these revisions should be made
as part of "208" water quality management plans. The standards
should be expressed in terms of both concentrations and total
emissions.
2. Methods for projecting population and employment, including those
based on alternative governmental policies, should be consistent
for both air and water quality planning. Such consistency is
necessary in developing the assessment on the assimilative
capacity of an air or water basin.
3. Greater priority should be placed on investigating the costs and
benefits of such water quality control methods as street sweeping
and the use of retention storage. More information is required
on their effectiveness, limitations and methods and costs of
implementation. For example, model land use ordinances need
to be prepared to guide local planning agencies that want to
require retention storage in large scale developments.
Spatial Pattern and Assimilative Capacity Recommendations
1. Assimilative capacity assessment should be an initial first step
in an environmental management process. Air and water basins
need to be described in terms of their capacity to assimilate or
absorb air and water pollutants without violating environmental
standards. Such an assessment is necessary to determine the
level of growth that can be accommodated by a basin and that
determination should be used in developing growth management
mechanisms aimed at fostering particular spatial patterns.
Assimilative capacity should be described in terms of combined
population and employment levels, based on a set of assumptions
on the pollution generating potential of these two variables.
The assumptions might include wastewater production and sewage
treatment needs or vehicle trip volumes. In this manner, popu-
lation and employment provide a convenient measurement device
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against which different land use, transportation and infra-
structure strategies can be assessed for achieving an optimum
development pattern desired for air and water quality objectives.
2. With the passage of the Clean Air Act, national ambient air
quality standards became a recognized constraint in the com-
munity planning process. However, operational policies for
considering this constraint are not easy to come by. For
example, the assertion that centralized and compact urban
development is the best spatial pattern for minimizing all
types of air pollution needs some qualification. Without
effective motor vehicle emission controls, this spatial
pattern may produce high levels of localized carbon monoxide
concentrations. Since such a development pattern will best
support a mass transit program aimed at reducing the use of
cars, automobile emission controls must be closely related
to land development strategies included in an air quality
maintenance plan. Otherwise, localized concentrations of CO,
within the limits imposed by the national ambient air quality
standards, may have to be accepted to achieve broader regional
objectives.
Intergovernmental Organization Recommendations
1. Air and water quality objectives should be integrated within
the comprehensive state planning and budgeting program such
that infrastructure planning and budgeting have a common
basis.
2. State agencies with development permit granting powers should
develop a program for delegation of such powers to local govern-
ment when local planning policies and enforcement mechanisms
provide similar environmental protection. Direct state involve-
ment in local land development decisions should be avoided unless
the subject matter is so complex that a specialized form of
administrative expertise is required.
3. Regional environmental management plans should provide regional
direction to State and Federal objectives and should describe the
role local government should play in planning and enforcing air and
water quality objectives. The direction of local government
should be provided by 1) describing the assimilative capacity of
the air and water basins in which the cities or counties are
located, 2) establishing the levels of land use, transportation
and infrastructure requirements based on different population and
employment assumptions that can be accommodated by the assimi-
lative capacity and 3) describing environmental performance
criteria that reflect acceptable levels of pollutants that can be
emitted from a city or county. The performance criteria should
be expressed as the amounts of each of the various types of
pollutants that can be discharged into the air and water. The
primary use of these criteria is to suggest to local government
the types of policy actions they would need to take to reduce the
impacts of new or existing development.
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4. Local government, using the different levels of land use activities
based on varied population and employment ranges and performance
criteria provided by the regional environmental management plan,
would prepare individualized approaches to attain the regional
objectives. The local government units would be required to
adopt ordinances or other plan implementation measures. To
include local government to adopt these measures, greater auto-
nomy in air and water quality control strategies could be dele-
gated to them. Similarly, regional review or permit requirements
could be waived when local implementation plans become consistent
with regional environmental objectives.
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CHAPTER II - INTRODUCTION
BACKGROUND
It is increasingly asserted that land use planning and control provide
a supplementary strategy to technological controls in the effort to
maintain acceptable levels of environmental quality in metropolitan
regions. Both areawide water quality management plans prepared under
Section 208 of the 1972 Amendments to the Federal Water Pollution
Control Act and air quality maintenance plans prepared under Section
110 of the Clean Air Act are expected to include consideration of
land use controls as part of overall environmental management
strategies.
Yet, experience from similar limited purpose planning efforts, whether
concerned with transportation, flood control or housing, has shown that
there are often unanticipated impacts of land use controls when used
unilaterally for the improvement of a single environmental or social
condition. For example, a regional water quality plan that constrains
new development in a built-up city with an inadequate sewage treatment
system could result in directing urban growth to newly developing com-
munities with adequate sewage treatment but inadequate public trans-
portation, thereby adding to air quality problems.
The impetus for the "Integrated Land Use/Air Quality/Water Quality Con-
trol Study for Sonoma County" came from this recognition that potentially
undesired or unanticipated impacts can result from limited purpose plan-
ning. Specifically, the purposes of the "Sonoma Study" are:
1) assess the relationship of land use controls designed to
meet air quality objectives to those designed to meet water
quality objectives and vice versa, giving particular atten-
tion to whether the control strategies for either medium are
supportive or conflicting;
2) analyze the impact of urban spatial patterns on air and
water quality to determine if any of the elements of spatial
pattern — population size, location, density or land use --
is the dominant characteristic; and
3) determine the relative effectiveness of other pollution con-
trol strategies, such as vehicle emission devices or site
design methods for reducing water pollution for storm water
runoff, in achieving and maintaining environmental objec-
tives.
II-l
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Three related steps were undertaken as part of the study approach. The
first was the projection of different population and land use patterns
to determine their influence on air and water quality. The pollution
measures related to future development patterns included air pollution
emission projections based on vehicle kilometers travelled (VKT), pro-
jections of point and area source air pollutant emissions from existing
and potential land uses, projections of point source wastewater loadings
from land uses, and projections of runoff pollutant loadings from area
sources related to existing and potential land use patterns.
The second step of the study was an analysis of the land use planning
and control process conducted at different governmental levels in
California to determine what effect this process has on attaining air
and water quality management objectives. The jurisdictions reviewed
included State, regional, County, local general purpose units of govern-
ment and subcounty special purpose districts. As the study progressed,
attention focused on the use of two somewhat separate types of land use
control:
1) Growth management - the use of alternative land use plans and
policies to influence the size, location and timing of urban
growth in a region, and
2) Site specific controls - the use of conditions or "mitigating
measures" to reduce the potential for air or water pollution being
created due to the land use activities that take place at a specific
site.
The third and final step was one of examining future land use patterns,
with their resultant air and water impacts, and estimating the land use
policy decisions required of various jurisdictions to create the pre-
determined land use patterns. From such an assessment, it was possible
to understand both 1) how effective the decisions might be in improving
environmental quality and 2) under what circumstances a land use
decision aimed at attaining air quality objectives would conflict with
a desired water quality objective, or vice versa.
The study is written primarily for policy makers and planners/environ-
mentalists who are making or recommending land use decisions. People
working in agencies concerned with air or water quality, including
pollution control districts, public health departments, public utility
departments, public works departments and flood control agencies will
also find the study helpful. Finally, people living in Sonoma County,
California will find this study useful in understanding what new urban
growth will mean to the future of their county.
Sonoma County as a Case Study
It was decided that the analysis of the land use/air quality/water
quality linkages should be conducted as an applied case study. This
decision was made because many of the earlier studies on the subject
matter were of a more theoretical nature or were not applied directly
to assist a county in reshaping its planning policies.
II-2
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There were three principal reasons Sonoma County was selected for the
case study:
1) its present pressures for growth are similar to those in many
other counties that are located at the fringe of an expanding
metropolitan area. Therefore, the findings of the study may
well be transferable to those jurisdictions who hope to avoid
some of the air and water problems that have occurred over the
past decades due to urban expansion;
2) its Planning Department was in the process of preparing its
first countywide General Plan and was anxious to consider air
and water quality issues; and
3) it is within a major metropolitan area yet has well distin-
guished topographic and meteorological characteristics that
the environmental impact of urban growth both within and out-
side the study area can be readily evaluated.
The final section of this Chapter will provide a description of Sonoma
County and some of the growth dynamics it is facing.
Study Limitations
As with any case study, the selection of Sonoma County as the site
affected the study's structure. Currently, the County does not have
significant air and water quality problems. Although it is growing
rapidly, there is no city with a population over 65,000 people. There-
fore, the magnitude of its present air or water pollution problems are
small in comparison to other cities and counties in the San Francisco
Bay Region. As an example of the water quality problems the study is
not facing, Santa Rosa, the largest city in the County, does not have
a sewer system that overflows into the storm drainage system during a
heavy rain. From the air quality standpoint, the County has sufficient
vehicular travel to justify only one major freeway. Therefore, it was
not possible to analyze in the Sonoma Study all of the air or water
quality problems that may be of concern to other cities or counties in
the San Francisco Bay Region.
Of course, it was because of the limited scope of existing environmental
problems and the anticipated pressures for increased population growth
that lead to the selection of Sonoma County as the study area. It is
the intent of the study that some of the findings may assist the County
planners in their efforts of anticipating and planning for future growth
so that environmental, economic and social objectives can be met.
Because the study took place in California the discussion of govern-
mental organization is restricted to California jurisdictions or insti-
tutions. There may be, therefore, some readers who cannot readily
identify with the various governmental bodies that are concerned with
air and water quality in California and whose policies or actions may
appear unique.
II-3
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There are five other basic limitations faced in preparing this study.
Many of the limitations, particularly those concerned with the water
quality analysis, may well have to be faced by other planners or
engineers who hope to conduct similar studies. They need to be rec-
ognized in reading this study as well as in developing the work plans
for similar studies. The five limitations are:
1) lack of water monitoring information — data were only avail-
able on river and stream quantity during and following rain-
storms. However, no information was available on water qual-
ity during those periods. Therefore, the model is calibrated
for water quantity, with pollution loads determined by use of
data from other study areas with similar characteristics.
2) lack of detailed information on the type and nature of surface
pollutants ~ the information on the exact type, amount, par-
ticle size and source of surface contaminants has been studied
in United States for only the past five years. A number of EPA
studies cited in Chapter III have summarized initial research
on this subject. Yet, it still must be recognized that this
analysis is in its infancy and that much more work is needed
to establish precise findings on the nature of surface water
contaminants and the effectiveness of control measures to
remove such contaminants.
3) lack of present air pollution modeling capability to exactly
simulate reactive pollutants. The air pollutants modeled in
the study are carbon monoxide (CO), particulate matter (PM),
and sulfur dioxide ($02). Photochemical oxidant, primarily
ozone, is perhaps the air contaminant best known to the public.
It is extremely difficult to model because it is formed chem-
ically in the atmosphere when hydrocarbons and nitrogen oxides
are mixed in the presence of sunlight. Because no model was
, readily available for oxidant analysis in Sonoma County, it
is impossible to conduct a rigorous analysis of this pollutant.
The proportional rollback model, a less sophiscated method of
oxidant analysis explained in Chapter V, is used in the study.
In the surface runoff analysis, the model does not make adjust-
ments for certain chemical or hydrologic forces in the river
that have differing consequences on different contaminants.
For example, the model does not consider how different contam-
inants may settle through the sedimentation process. The model
also does not consider the chemical reactions of heavy metals
when mixed with water in the river.
'• *:
4) lack of present modeling capability to exactly simulate control
measures ~ the present surface runoff control measures are in
their preliminary stages of development. Therefore, it is
difficult to adjust or refine the model to simulate the effec-
tiveness of the measures due to lack of data on levels of per-
formance. For example, retention storage, explained in Chapter
VI, is a relatively new pollution control measure whose effec-
tiveness in reducing a]JL the various water pollution contamin-
ants has never been tested through water quality monitoring.
II-4
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It may be very capable of removing insoluable and large con-
taminants but have limited effectiveness in removing highly
soluable and small contaminants.
Moreover, the present surface runoff models give an approxi-
mation of the effect of control measures but cannot give
absolute measurements due to the nature of some of the model
variables and the manner in which they are mathematically
analyzed. For example, street sweeping is simulated in the
study assuming a particular rate of sweeping efficiency. Yet
the rate of efficiency can vary greatly according to the con-
struction material of the street surface, the design of the
curbs and gutters, the type and size of the contaminants and
the type of sweeping device. These conditions can be fairly
exactly measured but the model must generalize them due to
other model variable limitations.
5) lack of standards set specifically for wet weather water
quality — the present water quality standards are not specifi-
cally set for either dry or wet weather conditions and it must
be recognized that such conditions need to be evaluated separ-
ately. Many of the present standards are set as concentrations
whereas one of the greatest problems of surface runoff is in-
creased sedimentation that can be better evaluated by a total
emissions measurement. Therefore, this study does not relate
any of the surface runoff simulation to water quality standards
because it would be inappropriate.
To summarize the limitations of this study, particularly as it
relates to the water quality simulations, it provides a general-
ized assessment on the relative effectiveness of different con-
trol strategies in reducing contaminants but it was not possible
to provide exact water quality measurements that can be reviewed
against water quality standards. Whereas the above limitations
require that the study be read with appropriate qualification,
any discrepancies between the simulated and the actual data
should not be overstated because the purpose of the study is to
establish relative rather than absolute differences in the effec-
tiveness of different land use growth alternatives or control
measures in achieving air and water quality objectives.
Who Participated in the Study?
The five participants in the "Integrated Land Use/Air Quality/Water
Quality Control Study" include the Association of Bay Area Governments
(ABAG), Sonoma County, represented by the Advanced Planning Division of
the Planning Department, the Bay Area Air Pollution Control District
(BAAPCD), Water Resources Engineers, Inc. (WRE), and URS Research Company.
A general description of each participant and the roles they play in the
study is as follows:
II-5
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o ABAG is the areawtde comprehensive planning agency for the San
Francisco Bay Area. A voluntary association of local governments
of the Bay Area, membership includes 85 of 94 cities and 7 of 9
counties in the Bay Area. Twenty-five special districts, regional
agencies and other government agencies are non-voting cooperating
members. Serving an area of about 7,000 square miles and nearly 5
million citizens, ABAG is presently developing an Environmental
Management Plan, an element of its Regional Comprehensive Plan,
which will include surface runoff, air quality maintenance, munic-
ipal wastewater, point source, industrial wastewater, non-point
sources other than surface runoff, water conservation, reuse and
supply and solid waste. ABAG staff provided project leadership,
technical contributions, coordinated the study team and wrote the
final report.
o The Sonoma County Advanced Planning Division was preparing its
first general plan during the period of the study. This general
plan incorporates such State mandated elements as land use, cir-
culation, open space, conservation and safety as well as the non-
mandated transit, air quality, recreation and bikeway elements.
For the study, Sonoma County provided 1) population, land use, em-
ployment and transportation forecast methods and data, 2) water
quality reports including groundwater studies and 3) general li-
aison on all aspects of the study.
o The Bay Area Air Pollution Control District (BAAPCD) was created by
the California Legislature in 1955 as the first regional agency
dealing with air pollution in California. Its jurisdiction is
limited to policing non-vehicular sources of air pollution within
the Bay Area (primarily industrial emissions and open burning).
The BAAPCD, working in conjunction with Sonoma County, provided the
air quality analysis for some of the alternative land use patterns
by using air quality dispersion models.
o WRE is a consulting firm specializing in water resources and water
quality management planning. It provided most of the water quality
modeling and analysis in the study. This included adjusting various
surface water runoff and stream quality models to fit Sonoma condi-
tions and alteration of model variables to test the relative impacts
of growth management and site specific land use controls on the
water quality in the study area rivers and streams.
o URS, a consulting firm specializing in environmental research and
planning, provided the study with air quality modeling and analysis
of alternative land use patterns using the BAAPCD diffusion model.
They also forecast the future photochemical oxidants by using the
proportional rollback model technique.
Sonoma County Setting
Sonoma County is one of the nine counties that constitute the San Fran-
cisco Bay region. The County's southern boundary is 43 kilometers (27
miles) from the City of San Francisco and extends along the northern
II-6
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LOCATION OF SONOMA COUNTY
in the San Francisco Bay Region
FIG. 11-1
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boundary of Marin County and a portion of San Pablo Bay. The County
extends 80 kilometers (50 miles) north to south and varies in width from
48 to 64 kilometers (30 to 40 miles) covering an area of 4090 square kilo-
meters (1,579 square miles). It is geographically composed of roughly
equal areas of valleys, mountains and rolling hills. Figure II-l
indicates the location of Sonoma County in the San Francisco Bay Region.
The study has focused on growth potential in the Santa Rosa Plain/
Petaluma Valley and Valley of the Moon. The Santa Rosa Plain/Petaluma
Valley, in which the majority of the County's population lives, lies
roughly in the middle of the County between rolling hills on the west
and the Sonoma Mountains on the east. The cities of Petaluma, Cotati,
Rohnert Park, Santa Rosa and Healdsburg are in this valley with Sebas-
topol on its western fringe in the foothills. On the south eastern side
of the County is the narrow Valley of the Moon, sandwiched between the
Sonoma Mountains on the west and the Sonoma/Napa Mountains on the east.
The City of Sonoma is located in the southern section and small portions
of Santa Rosa extend into the northern section of the Valley of the Moon.
A complex system of rivers and streams drain Sonoma County. The Russian
River extends for 105 kilometers (65 miles) through the County, entering
from Mendocino County to the north and crossing over to the Pacific
Ocean. The major northerly tributaries include Windsor Creek and Mark
West Creek. The Laguna de Santa Rosa flows into Mark West Creek.
Sonoma Creek and the Petaluma River drain the southern portion of the
County into San Pablo Bay.
Sonoma County has a Mediterranean climate. The Pacific High, a major
high pressure area over the northern Pacific Ocean, locally affects the
directions of prevailing winds, seasonal precipitation, cloud cover,
amount of available sunshine and fog conditions. Sonoma County ex-
periences an annual cycle of rainy and dry seasons with three-fourths of
the County's rainfall occuring from November through March. Temperature
averages 8.3°C (47°F) in January to 13.90C (67°F) in July.
The 1975 population of Sonoma County was approximately 244,300. The
eight major cities and towns are Santa Rosa, Petaluma, Rohnert Park,
Cotati, Sonoma, Sebastopol, Healdsburg and Cloverdale. Santa Rosa is
the largest city and main commercial center, as well as the County seat.
Petaluma is the second largest city and the County's dairy center.
Petaluma is also growing as an industrial center as well as a place of
residence for commuters who travel to work in counties south and east
of the city. Rohnert Park is experiencing rapid development attribut-
able to commuters who take up residence there as well as it being the
location of California State University-Sonoma. Immediately adjacent
to Rohnert Park is Cotati whose factors for growth are much the same as
Rohnert Park's. The town of Sonoma is a historical and resort site.
Sebastopol is the location for most of Sonoma's apple industry. Healds-
burg and Cloverdale are locations for grapes, prunes, lumber and recre-
ation. Agriculture and wine production are found throughout the valleys
of Sonoma County.
11-8
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The main transportation route in the County is U.S. 101 which connects
Sonoma County with Marin County and San Francisco to the south and Men-
docino County to the north. It also passes through several of Sonoma
County's major cities - Petaluma, Cotati, Rohnert Park, Santa Rosa,
Healdsburg and Cloverdale. The major east-west route, Highway 12, runs
through Sevastopol to the west and Sonoma to the east of U.S. 101. Water
transport in Petaluma is available by barge and some shipping occurs via
the Petaluma River and San Pablo Bay. The Russian River is navigable
by small craft only.
Present Environmental Conditions
The study area for the air quality analysis (Figure II-2) includes the
Santa Rosa Plain/Petaluma Valley and the Valley of the Moon. The
boundary line for this study area roughly coincides with the elevation
61 meters (200 feet) above the Santa Rosa Plain. It was defined in
this manner for the following reasons: 1) it coincides with the
Petaluma/Santa Rosa air basin, an area of generally homogenous dis-
persion characteristics, (2) ninety percent of the County population
resides in this area and (3) future urbanization is expected to occur
there.
The study area for the water quality modeling effort consists of two
basins - the Laguna de Santa Rosa (Laguna) basin and the Petaluma River
basin. These two basins contain most of the urbanized land in Sonoma
County and are separated by Meacham Hill, a low divide south of Cotati.
The Laguna basin, a sub-unit of the Russian River basin, includes the
watersheds of Windsor Creek, Mark West Creek, Santa Rosa Creek, and
the upper Laguna (Copeland Creek). The Laguna drains a major portion
of the Santa Rosa Plain, including the cities of Santa Rosa, Rohnert
Park, Sebastopol and Cotati. The Laguna empties into Mark West Creek
at a point about two miles before its confluence with the Russian River.
The Petaluma River drains the southern portion of the Santa Rosa Plain,
including the City of Petaluma, and empties into the north end of San
Francisco Bay (San Pablo Bay) near the City of Novato. There are no
major tributaries in this basin.
Air quality in Sonoma County at the present time is generally good with
few violations of federal or state standards. Though the County is part
of the San Francisco Bay Area air basin, an area ringed by mountains and
subject to frequent temperature inversions,!the air quality is consider-
ably better than in the southern and southeastern portions of the basin
because: (1) the dominant windflow patterns tend to flush pollutants
from the major portion of the County while transporting pollutants in
from other areas in the basin and (2) there are no major industrial
sources or power plants in the County. Because of the absence of major
industrial sources and power plants, particulates and S02 are not a
significant problem. Petaluma does experience occasional excesses of
the State 24-hour standard for suspended particulates. A cement
batching plant is the source of a local particulate problem.
II-9
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PROJECT AREA
GRID MAP
Air Quality Study Area
Water Quality Study Area
FIG. 11-2
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Most of the air pollutant emissions in the County come from automobiles.
However, the current air quality situation is difficult to evaluate
quantitatively due to the scarcity of monitoring data. The only stations
in the County are located in Santa Rosa, Petaluma and the City of Sonoma
(begun in late 1974). Santa Rosa and Petaluma have an oxidant problem
as evidenced by the federal oxidant standard of 8 parts per hundred
million (pphm) being exceeded in Petaluma ten times in 1973 and thirteen
times in 1974, and in Santa Rosa, nine times in 1973 and six times in
1974.
Petaluma may experience one to three excesses of the primary federal
8-hour carbon monoxide standard per year in the industrial area east of
downtown. The BAAPCD believes that if these excesses do occur, they are
due to stationary rather than mobile sources.
Santa Rosa experiences one to three excesses of the carbon monoxide
standard in two locations: the downtown and Coddingtown, a major
regional shopping center in the northern section of the city. The
downtown area', including the interchange of Highways 101 and 12,
experiences both large traffic volumes at low speeds (on the surface
streets) and large volumes at medium to high speeds during morning and
evening peak hours on the freeways. The Coddingtown area, contains
three major indirect sources - the Coddingtown shopping center, Santa
Rosa Junior College and the County Administration Center, in addition
to a heavily travelled stretch of Highway 101.
The quality of the surface waters in Sonoma County is generally very
good. Yet, certain problems do exist in both the Russian and Petaluma
River basins. Algal blooms have been reported on various stretches of
the Russian River from Healdsburg to the mouth. Surveys in the Laguna
de Santa Rosa and Santa Rosa Creek have shown coliform values greater
than 50,000/100 milliters (ml), which are well in excess of standards
set by the North Coast Regional Water Quality Plan for water contact
sports. In addition, low dissolved oxygen (DO) levels have been
observed in both the Laguna and Santa Rosa Creek, and problems with
septic tanks overflowing into surface waters have been documented in
the small rural communities, including some on the Russian River.
i
The high coliform counts and low DO levels in the Laguna de Santa Rosa
and the Santa Rosa Creek were apparently caused by dry weather dis-
charges from the sewage treatment plants of Santa Rosa, Rohnert Park
and Sebastopol and from dairy operations near these streams. Since
the City of Santa Rosa has eliminated its dry weather discharges as
part of recent water quality planning and enforcement efforts, the
coliform and DO conditions have improved considerably. Because eu-
trophication in the Russian River has occurred both upstream and
downstream from sewage treatment plant discharges, it is felt that
this problem is due to non-point sources.
The estuaries of the Petaluma River are known to be eutrophic (nutrient
rich) and there have been indications of low DO levels. Data from these
areas are scarce. The City of Petaluma's domestic water supply is en-
dangered by the large quantities of dairy wastes that are discharged to
the Petaluma River upstream from the City. California's Department of
Fish and Game has expressed concern over these discharges.
11-11
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Growth Dynamics in Sonoma County
Spillover of population from the San Francisco Bay Region is transforming
Sonoma County from an essentially rural area to one that is considerably
more urbanized. The changes taking place in Sonoma County are generally
similar to those experienced by other high amenity rural areas on the
periphery of major metropolitan regions. During the last decade the
County has experienced major changes in its economic base, its popu-
lation and the appearance of its physical environment.
Between 1960 and the present, the County's economy has been changed
due to: 1) shifts Within its agricultural sector, 2) in-migration of
persons who commute to the central San Francisco Bay Region and 3)
establishment of new institutions^ offices, and production facilities.
Changes in employment patterns between 1960 and 1970 are indicative of
the economic shifts that have been taking place. During that period,
the work force increased by 59% from 46,000 to 73,000. Although there
was a general increase in employment, there were absolute declines in
employment in agriculture, forestry and fisheries (18%) and the manu-
facture of non-durable goods (6.2%). The most dramatic employment
increases were in professional and related activities (116%) and fin-
ance, real estate and insurance (112%). To some extent, these shifts
are partly explained by general changes in the nature of the economy
including more mechanization in agriculture and manufacturing and an
increased need for professional and administrative services. The
phenomenal increase in professional, and finance, real estate and
insurance activities can be primarily attributed to the location of a
number of new employers in Sonoma County. California State University,
Sonoma was established near Rohnert Park in the early 1960's and now
has approximately 7,000 students and a large staff. In the mid-60's,
State Farm Insurance Company moved its northern California headquarters
to Santa Rosa and presently employs over 600 people. A new trend emerged
around 1968 with a growing number of high technology industries estab-
lishing facilities in the County. The advantages for these industries
were inexpensive land, a large semi-skilled labor force and environ-
mental amenities necessary to attract and hold managerial and technical
personnel. Hewlett-Packard is the largest of the new employers, with
1,000 employees at present, and plans to expand to 4,500 by 1990. Be-
sides these large employers, the County has also been attracting many
small manufacturing enterprises.
The commuters who have been settling in the southern portion of the
County, have also had an effect on the County's employment statistics.
There were 10,000 out-commuters residing in the County in 1970. This
number by 1973 had grown 50% to 15,000 (or approximately 20% of the
County's work force).
The County's population in 1975 had reached 244,300, an increase of
96,925 (or 65%) over 1960. Most of the increase can be attributed to
in-migration. During that period, the County's rate of population growth
has increased by 4,000 to 13,000 persons per year. Most of the new
population was accommodated in the communities along Highway 101 from
Santa Rosa to Petaluma. Table II-l indicates the population changes ex-
perienced by each community.
11-12
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TABLE II-l
SONOMA COUNTY POPULATION CHANGES: 1960-1975
POPULATION TOTALS INCREASE % CHANGE
Cloverdale
Cotati
Healdsburg
Petaluma
Rohnert Park
Santa Rosa
Sebastopol
Sonoma
1960
2,848
1,852
4,816
14,035
-0-
31,027
2,694
3,023
1975
3,520
2,760
6,520
32,050
13,150
64,900
4,600
5,025
672
900
1,434
18,015
13,150
33,873
1,906
2,002
23%
49%
29%
128%
109%
70%
66%
The population increase has been accompanied by shifts in population
composition. The nature of the changes has varied from one part of the
County to another. In the central portions of the County where the sub-
urbanization and economic growth has taken place, the population tends
to be younger than in 1960. In Petaluma, for example, there was an
increase in the percentage of the population in the 5-14 age group,
reflecting the influx of young families. The percentage of population
65 and over has decreased in these communities and the median age has
shifted downward. In contrast, the more rural parts of the County, away
from the urbanizing Santa Rosa/Petaluma corridor, have had only slight
increases in young people and major increases in the over-65 population.
Economic development, population increase and suburbanization have all
made for visible changes in the County's landscape. The most dramatic
change has been increased urban development which has occurred along
Highway 101 from Petaluma to Santa Rosa. The development of large
tracts of single family housing for suburbanites east of the old city
of Petaluma has greatly increased that community's physical size.
More than 4,000 residential building permits, most of them single
family, were issued between 1964 and 1974.
Santa Rosa's development has been more dramatic and complicated than
Petaluma's because it had to accommodate major commercial, office and
industrial facilities. To a large extent, Santa Rosa's central business
district has been bypassed, with most of the major commercial and in-
dustrial development locating on the city's periphery with quick access
to the freeway. A new focus of activity has emerged around a freeway
interchange two miles north of the old central business district. The
County Administration Center, a regional shopping center and an in-
surance headquarters were all established there on open land in the
1960s and have since been surrounded by a heavy concentration of smaller
businesses and offices. Industrial parks established just to the north
of this area have accommodated many of the city's new warehouse and
industrial facilities. There has also been a significant amount of
commercial and industrial development in a three mile long strip paral-
leling Highway 101 just to the south of the city.
11-13
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Santa Rosa has experienced a substantially increased volume of residential
development. Between 1964 and 1974, building permits for over 11,000
dwelling units were issued. About a third of these permits were for
multi-family units. Much of the residential development during the last
15 years has taken place in the small valleys to the east of the city.
In more recent years, there has been increasing development on the plain
to the west.
One of the most dramatic changes in the County's landscape has been the
appearance of a new community halfway between Santa Rosa and Petaluma.
In 1963, large parcels of agricultural land to the east and north of
Cotati were incorporated as the City of Rohnert Park. The city now has
almost 4,000 acres within its jurisdiction and since its founding has
issued building permits for approximately 2,500 dwelling units. In
more recent years the city has also managed to attract growing amounts
of industrial and commercial activity. The City of Cotati, in contrast,
has experienced only modest growth.
Away from the Petaluma/Santa Rosa corridor, urbanization has been more
incremental in nature. Sonoma, Sebastopol, Healdsburg, Cloverdale and
the unincorporated communities have experienced some infilling and some
development of small subdivisions on their fringes. In most cases, the
amount of growth has not been large, especially when contrasted to that
of the U.S 101 corridor communities.
Historically, there have always been a great many small rural holdings
in Sonoma County used for specialized family farming operations. More
recently, many of these small farms have been split into 1 to 10 acre
parcels and sold as ranchette sites for rural residential living. Typi-
cally, ranchettes are developed with single family houses served by
wells and septic tanks. Often, they serve as home to people with city
jobs but who enjoy gardening, keeping animals, or other activities which
require ample space or a rural setting. In some areas of the County,
dense concentrations of ranchettes have emerged and strained the ground-
water supply., the ability of the soil to absorb septic wastes, and the
capacity of the old rural road network to handle the increased traffic.
Sonoma County's rapid growth and change have been accompanied by a
number of problems. They include: 1) strained capability of munici-
palities and special districts to provide services; 2) traffic conges-
tion in some areas; 3) perceptibly reduced air quality; 4) diminished
viability of some forms of agriculture; and 5) erosion of what many
people feel is the rural and small town character that made Sonoma
County attractive in the first place. As the problems have emerged,
and the awareness of them has crystallized, the local governments have
attempted to exert more control over new development in order to
reduce its detrimental effects. The best known of these efforts has
been Petaluma's Residential Development Control System, a measure
adopted in 1972 that limits the total number of dwelling units that
can be built in any one year and establishes a procedure for choosing
between the various residential development projects that might be
proposed. During the past year, Santa Rosa has also adopted a growth
management program that brings together annexation and urban extension
policies and coordinates them with the city's overall urban develop-
ment goals. The County has begun to strengthen some of its develop-
11-14
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ment control mechanisms ~ revising its zoning ordinance, rezoning
those areas of the County that are undermost severe development
pressure, and greatly restricting the use of the,lot-split .mechanism
that had facilitated the proliferation of small rural lots.
In spite of the efforts made to date, the County's development has yet
to be entirely brought under effective control. One persistent barrier
to successful growth management has been the lack of consensus among
the muncipalities, the County and the various special service districts
as to the objectives to be achieved. Consequently, the actions of one
governmental unit often run counter to the actions or desires of an-
other. An example is the conflict between the orderly expansion of
the municipalities and the urban and semi-urban development which the
County has allowed on their borders. The problem is intensified by
the existence of special service districts which permit an urban level
of development without annexation. The County's general plan program,
which is now nearing completion, has placed the growth problems in
perspective, and has outlined some common goals. Yet, intergovernmental
mechanisms to ensure that these goals are achieved have yet to be worked
out.
It is, therefore, these growth issues, and the potential air and water
problems they can create, that provided the rationale for selecting
Sonoma County as a case study for determining the linkages between
land use/air quality/water quality controls.
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CHAPTER III - PRESENT THEORIES ON INTERRELATIONSHIPS OF AIR AND WATER
QUALITY AND LAND USE
The growing awareness among planners and policy makers of the relation-
ships between air and water quality and the use of land can best be
measured in terms of the increased volume of literature on the subject.
The interrelationships that have traditionally received the greatest
attention have to do with meteorologic and hydrologic factors considered
in locating industries or sewage treatment plants, the influence of
alternative spatial patterns on the generation and dispersion of pollu-
tants, and the role of vegetation and open space in reducing pollution.
Many of the initial theories about the air and water quality relation-
ship to urban development were highly speculative or based on limited
research. In retrospect, many of the early notions were somewhat sim-
plistic and failed to provide an adequate basis for sound decision
making.
Heightened environmental awareness and the mandates of national and
state environmental legislation generated a need for more sophisticated
and operationally useful understanding of air and water quality relation-
ships. In response to this need, federal funding has spawned a new gen-
eration of environmental research. This chapter provides a survey of
recent studies with the intent of providing a background on the various
land use/air quality/water quality relationships explored in this study.
This review starts with a bibliographic essay on the rationale for
relating land use planning to air and water quality management. Next,
the land use control strategies for air and water quality are grouped
into the categories of 1) growth management measures to achieve a de-
fined spatial pattern and 2) site specific measures that can be applied
irrespective of spatial patterns. The first category discusses the air
and water relationships from a regional perspective. These studies typi-
cally examine the relationship between urban spatial form and environmental
quality. The second category focuses on the smaller-scale subregional
or site specific considerations including the influences of urban roadway
design and maintenance, runoff control measures for various types of
development and local development control ordinance changes for reducing
air or water pollution. Finally, the influence of sewer system extensions
on land development is discussed because of the importance being placed
on this form of growth control by federal, state and regional agencies.
RATIONALE FOR STUDYING INTERRELATIONSHIPS OF AIR AND WATER QUALITY AND
LAND USE
There is a growing realization that technological change and operational
controls over sources of air and water pollution may not be sufficient
to achieve desired air and water quality goals. Land use policies are
being looked to as a necessary means of supplementing source controls.
For example, it is argued that land use planning and control can be used
to prevent excessive concentration of air pollutants, to aid pollution
dispersion and to reduce the number of people exposed to high pollutant
III-l
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levels. Similarly, there is a growing awareness that water quality is
affected by stormwater runoff from urban lands and mitigation of storm-
water impacts may require some special land use controls.
Other forms of air and water controls may also have indirect land use
impacts. For example, a metropolitan transportation control strategy
for reducing the amount of automobile travel could redirect the develop-
ment of new housing, employment and commercial facilities to areas with
the best public transportation access. Effluent discharge regulations
could influence the distribution of industrial activities due to pro-
duction shifting to new plants to meet discharge requirements.
Much of the recent national environmental legislation has recognized the
influence of air and water controls on land use. EPA Authority Affecting
Land Use (Bosselman, Feurer and Callies, 1974) provides a thorough listing
of the potential land use impacts of environmental controls. The work
gives special attention to the provisions of the Clean Air Act and the
Federal Water Pollution Control Act as amended that directly or indirectly
affect Vand use.
The National Environmental Policy Act of 1969 and the 1970 Federal Aid
Highway Act also reinforce the momentum for consciously considering the
relationships between land use and air and water quality. The National
Environmental Policy Act requires the preparation of environmental impact
statements for federally funded actions with a significant effect on the
environment including considerations of air, water, and land use. The
Federal Aid Highway Act requires the issuance of guidelines to ensure that
new highways built with Federal aid are consistent with a state implemen-
tation plan (SIP) required under the Clean Air Act. A Guide for Reducing
Air Pollution Through Urban Planning (Alan M. Voorhees and Assoc., and
Ryckman, Edgerly, and Tomlinson and Assoc., 1971) has a discussion on
some of the specific legislation mandating coordination of air quality
concerns with land use.
The emphasis of the environmental legislation on interrelating land use,
air and water considerations suggests a need to work out procedures to
integrate these factors into comprehensive planning at the regional and
even local level. A strong case for efforts in this direction is made in
Promoting Environmental Quality through Urban Planning and Controls
(Kaiser et a!., 1974).
The literature on air quality planning has given greater attention to
the need for integration with land use than literature on water quality.
One of the first of reports making such a plea was one which analyzed a
local area plan in Los Angeles, Research Investigation. Air Pollution
and City Planning, Case Study of a Los Angeles District Plan, (BrancFT
and Leong, 1972). The report demonstrated the inadequacy of conven-
tional land use planning efforts in addressing air quality concerns.
The report entitled Air Quality Management and Land Use Planning (Hagevik,
Mandelker, and Brail, 1974) indicated a number of methods by which air
quality issues could be dealt with in local planning including perfor-
mance standards and spacing controls in the zoning ordinances.
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A number of reports have made observations as to why urban planning had
given only limited attention to air quality. The previously mentioned
Guide for Reducing Air Pollution Through Urban Planning felt the reasons
were:
1. Lack of knowledge of how the arrangement, design and operation
of urban land uses affect air quality.
2. Lack of procedures for incorporating air quality considerations
into the land use decision-making process.
3. Lack of land use implementation tools with the breadth and depth
necessary to affect air quality.
Interagency Cooperation in Comprehensive*Urban Planning and Air Quality
Maintenance, a nationwide survey carried out by Argonne National Labor-
atory and the American Society of Planning Officials (1974) cited the
lack of adequate information and the scarcity of personnel with appro-
priate capabilities as the most serious limitations to integrating air
quality considerations into the planning process. Although these obser-
vations were made in reference to the incorporation of air pollution
concerns in the local land use planning process, they can to a large
degree be extended to describe the treatment of water quality issues at
the local level as well.
Finally, the literature search did not turn up one report that has
examined the extent to which the interrelationships between local land
use measures designed to improve water quality and those improving air
quality conflict with or reinforce each other.
SPATIAL PATTERN VERSUS SITE SPECIFIC/MANAGEMENT CONTROL STRATEGIES
A fundamental environmental management issue that emerged from the
review of literature is whether a growth management strategy to achieve
an optimum spatial pattern for air and water quality is more effective
than the application of site specific management devices or other con-
trol methods that are applied with little regard to questions of spatial
form.
The question on the effectiveness of planning to achieve an optimum
land use pattern raises another series of questions as to which of the
characteristics of spatial pattern are instrumental in bringing about
the desired levels of air and water quality. Are such factors as popu-
lation size, geographic location or density the key determinants of the
optimal pattern? Which of the characteristics are most necessary in
supporting specific work/residence/shopping spatial relationships or
for maximizing public transit use?
The current literature does not evaluate the two different strategies in
terms of their effectiveness. Yet, an evaluation is necessary in deter-
mining the optimum combination of spatial pattern and site specific land
use measures for use in an environmental management plan. A strategy
that requires a particular section of a region to slow its rate or re-
III-3
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directs its urban growth because of anticipated environmental problems
must be technically supportable if it is to gain political acceptance.
Another equally effective strategy for reducing pollution, which may get
the support of a larger number of elected officials, could be one that
permits increased growth but requires high levels of abatement or miti-
gation measures included in new development. Because of the importance
of these different strategies, they will be discussed in greater detail.
SPATIAL PATTERN STRATEGIES
Empirically based consideration of the relationships between urban form
and environmental quality is still in its germinal stage. There has
been relatively little work on the subject and results are sketchy,
difficult to verify and often conflicting. Until recently research
on urban form and its relationship to environmental quality has focused
on air quality questions. This orientation is understandable in that
automobile travel patterns and the distribution of air pollutant sources,
two of the major air quality components, are clearly linked to urban form.
Some explorations of the air quality/urban form question are theoretical
in nature. "Air Pollution and Urban Regions", a research note by C. Peter
Rydell and Benjamin H. Stevens which appeared in the Journal of the
American Institute of Planners in January 1968, provides a good example
of the initial work in this area. The article presents a theoretical
study using a simple urban structure, direct links between travel and
pollutant generation and an uncomplicated notion of pollution dis-
persion. Using a series of equations, a hypothetical spatial form is
found that makes for an optimal mix of trip lengths and distributions,
thereby minimizing the city's exposure to pollutants.
A more recent example of this kind of hypothetical analysis is provided
in the earlier cited Guide for Reducing Air Pollution Through Urban
Planning. A hypothetical metropolitan area of 625 square miles and 2.5
million people was simulated. Varying assumptions were made concerning
overall urban form and highway and transit systems, creating eight
simplified alternatives. Using a computer, vehicles miles travelled
(VMT) were projected for each alternative and used to predict air
pollutant concentrations. A satellite cities configuration was found
to have the shortest trip lengths, and decentralized configuration with
strong radial corridors was found to allow the heaviest transit use.
The conclusion reached was that the radial corridor configuration
produces the best air quality conditions.
Several air quality/urban form studies were carried out in the late
1960's and early 1970's that were more practical in their focus. Typi-
cally, modeling techniques were applied to determine the air quality
conditions that could be expected to accompany alternative development
patterns hypothesized for a specific metropolitan region. The con-
clusions from these earlier studies are heavily oriented to generation
of pollutants and give only minimal attention to the dispersion of
pollutants by differing meteorologic conditions. In addition, many of
the findings were area specific and they cannot be readily transferable
to other metropolitan areas. The benefit of these studies lies more in
III-4
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understanding the analytical approaches for studying the impact of
spatial pattern on air quality. One of the first studies of this type
was Summary Report: Air Pollution Study of the Capitol Region an anal-
ysis by Yocum, Chisholm, and Collins (1967) of regional development
alternatives proposed for the Hartford metropolitan area. A study by
Kurtzweg and Weig (Determining Air Pollution Emissions from Transpor-
tation Systems) sought an optimal development configuration for the
Seattle area that would limit pollutant generation. The Northern
Illinois Planning Commission (NIPC) (Managing the Air Resource in
Northern Illinois, Technical Report No. 6, 1967). modelled three alter-
natives:a finger (corridor) plan, a multi-towns plan and a satellite
cities plan to test for the levels of oxides of nitrogen and particu-
lates that they would create. The NIPC study found that the finger
plan and satellite plan had the lowest concentrations of particulates,
and that the finger plan had the lowest NOX levels.
Generally similar analytic techniques were applied at a somewhat smaller
geographic or non-metropolitan scale in the following studies: A Trans-
portation Study for Montgomery and Prince Georges Counties, Maryland
(Voorhees and Assoc., 1974) and The Hackensack Meadowlands Air Pollution
Study - Task 4 Report; Air Quality Impact of Land Use Planning (WmlsT
Mahoney, and Goodrich, 1973).These studies highlight the problems of
analyzing small areas whose air quality problems are largely created by
pollution from other parts of the metropolitan area.
A revealing county level analysis, completed not too long ago for Middle-
sex County, New Jersey, is entitled Air Quality Management Plan and Pro-
gram Recommendations Middlesex County, New Jersey (TRW, Inc., 1974).Two
alternative land use plans were projected for the year 2000. One empha-
sized controlling growth to concentrate it around the county's present
urban centers; the other was a "continuation of trends" scenario that
anticipated dispersed ("sprawl") development. The air quality modeling
indicated that the concentrations of SO?, particulates, and CO would
increase for both scenarios, even thougn the effects of pollution con-
trol technology were taken into account. Of greatest interest was that
in the controlled growth alternative, high pollutant concentrations were
created in and around the intensified urban centers. Periods of highest
concentrations were considerably lower, but they spread over a wider area
in the "sprawl" alternative.
Up until now, no analogous studies have been carried out to relate
alternative regional development forms to water quality. The lack of
generalized water quality/urban form analysis may be due to the very
nature of water quality relationships themselves. Water quality is
very dependent on the characteristics of the local hydrologic system
and its ability to assimilate pollutants. These characteristics are
highly variable from one metropolitan area to another, depending on
such factors as configuration of the drainage system, flow volumes
and patterns and climatic regimes. Water quality is also sensitive
to the specific type of the wastewater collection and treatment systems
used, which does not relate directly to metropolitan structure.
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Perhaps the most comprehensive assessment of the relationship between
urban structure and overall environmental quality that has been made to
date was carried out by Brian Berry and colleagues at the University of
Chicago entitled Land Use. Urban Form, and Environmental Quality (1974).
It considers the linkages between the spatial form of metropolitan
development and a variety of environmental quality factors, including
both air and water pollution. Unlike the preceding air quality/urban
form analyses, it focuses on existing rather than hypothetical urban
systems. Data from 76 American metropolitan areas was assembled and
statistically analyzed to produce some observations about the nature of
urban structure/environmental quality relationships. Because the study
is broad in scope, and has an empirical basis, its findings are of
unusual interest.
Information on city characteristics (population factors, density and
employment) and urban form (number of degrees of arc and number of
radial and circumferential highways) were gathered for each of the 76
urban regions. Additionally, for each urban area, a standardized set of
environmental quality indicators was prepared. Using the environmental
quality data as a base, factor analysis was applied to generate a
typology of urban regions with similar environmental quality charac-
teristics. Once the typology was created, an attempt was made to
determine 1) the differences in the environmental characteristics of
each group, 2) the differences in urban characteristics and regional
form from group to group and 3) how the pollution differences and urban
characteristics vary. These objectives were achieved in a limited way
by comparing the mean city characteristics, urban form variables and
environmental variables for each of the groups. On the basis of these
initial comparisons, it was concluded that the largest metropolitan
areas with high residential densities and high levels of manufacturing
employment have the highest levels of air and water pollution and gen-
erate the greatest volume of solid wastes.
A second level of analysis was carried out, holding the major variables
of size, density, and manufacturing constant to determine what effects
urban form and land use have on increasing or decreasing environmental
pollution. One of the second stage analyses involved creating a series
of regression equations relating environmental quality indicators to the
independent variable of SMSA population, density ratio, median family
income and percentage of labor force employed in manufacturing. Equa-
tions were developed for 14 dependent variables, including aggregate
air quality, concentrations of sulfur dioxide, nitrogen dioxide, and
total suspended particulates. Water quality indices were also developed
related to aggregate water quality, drinking use, recreation use, and
industrial use.
On the basis of the relationships detected through statistical analysis,
the study concludes that when city size and manufacturing concentrations
are taken into account:
"1. The core oriented urban region with a radial transportation
network and a steep density gradient
III-6
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a. displays greater Intensity of land use, a lower per-
centage of land developed and used for residential and
commerical purposes and more open space, and
b. as a consequence of this land use mix and pattern, has a
superior air and water quality to:
2. The dispersed urban region with a less focused transport
network and lower, more uniform population densities
a. displays urban sprawl with a higher percentage of resi-
dential and commercial land use and less open space than
in the core oriented case, and
b. as a consequence of this land use mix, has inferior air
and water quality." (p. 413)
SITE SPECIFIC MANAGEMENT TECHNIQUES
In contrast to the research on spatial pattern, a much more extensive
body of literature has been written on site specific management tech-
niques for improving air and water quality. Rather than providing an
exhaustive survey of the available material, an attempt has been made
to cite the works which are the most value in meeting the informational
needs of practicing planners.
Site Specific Management Techniques for Water Quality
There is a fairly large body of recent literature dealing with the
relationship between water pollution and land use on the subregional
or site specific level. Most of this literature is authored by private
consulting firms and university research groups, largely under the
sponsorship of the U.S. Environmental Protection Agency. This liter-
ature may be classified into two basic groups - problem description-
oriented and solution-oriented. The problem description-oriented
works focus the bulk of their research on describing or quantifying
the nature of specific problems giving only minimal attention to
solutions. The solution-oriented works, on the other hand, describe
the problems rather briefly and devote most of the work to exploring
possible solutions.
An elementary primer for planners is Urban Planning Aspects of Water
Pollution Control (Grava, 1969) which covers the nature of water pollu-
tion problems, treatment systems, administrative and financial consider-
ations, and relationships to local planning. Water Pollution Aspects of
Urban Runoff (American Public Works Association, 1969) is a basic work
analyzing the pollution effects of urban runoff based on field data and
theoretical calculations. Factors considered include street refuse,
catch basins, air pollution fallout and sewer solids deposition. A more
III-7
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recent study conducted by the Regional Science Research Institute titled
Stream Quality Preservation Through Planned Urban Development (Cough!in
and Hammer, 1973) establishes relationships between amount, density,
type and location of urban development, and stream water quality and
channel enlargement.
The body of literature that deals with solving land use related water
pollution problems ranges from works dealing with regulations and
ordinances intended for planners and government officials to site de-
sign specifications intended for engineers and designers. On the former
topic, the most comprehensive document is the report prepared by ASPO
for the U. S. Environmental Protection Agency entitled Performance Con-
trols for Sensitive Lands: A Practical Guide for Local Administrators
(Thurow, et al., 1975).It identifies sensitive geographic areas and
discusses current regulatory practices and recommends programs for
regulating these areas. Also provided are examples of local ordinances,
information on where to go for technical assistance from government
agencies, summaries of pertinent state and federal legislation and legal
decisions relating to sensitive lands and an extensive annotated biblio-
graphy. The Water Resources Center at the University of Delaware has
prepared two excellent site-specific studies dealing with land use
planning and on-site measures to protect water resources. The studies
are Water Resources as a Basis for Comprehensive Planning and Develop-
ment in the Christina River Basin (Tourbier, 1973) and Water Resources"
Protection Measures in Land Development - A Handbook (Tourbier and
Westmacott, 1974).The earlier of these works defines land use controls
which can be used to direct urban land uses onto areas where they are
expected to do the least damage and outlines environmental protection
measures to incorporate into development as it proceeds. This study is
based on the assumption that the cost of solving water related problems
on-site is far less than trying to solve the resulting off-site problems,
such as flooding and siltation. The latter work is essentially a de-
tailed handbook describing measures to lessen the effects of urban
development on water quality and quantity. Measures to control in-
creases in runoff or decreases in infiltration, soil erosion, sedimen-
tation, stream bank erosion, flood damage, runoff pollution and sewage
effluent pollution are discussed. Included in such descriptions are
site characteristics, advantages and disadvantages, references, design
specifications, case study information, cost guidelines, maintenance
requirements, implementation considerations, and legal implications of
each of the recommended measures.
Three reports intended primarily for engineers and designers are Urban
Stormwater Management and Technology - An Assessment (Lager and Smith,
1974). Approaches to Stormwater Management (BeckerT"et al., 1973), and
Management of Urban Stormwater Runoff (McPherson. et al., 1974). The
Lager study is a comprehensive description and evaluation of engineering
projects and methods for the collection, retention and treatment of
Stormwater with an emphasis on major off-site facilities. The Becker
report describes fifteen basic techniques for Stormwater management,
including surface and sub-surface detention and infiltration systems
The latter volume contains eight lectures delivered at a training
111-8
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course on "Management of Urban Storm Water, Quantity and Quality"
sponsored by the Hydrologic Engineering Center of the U. S. Army Corps
of Engineers. This report covers a variety of topics including both
quantification of the problem as well as discussion of alternative
solutions.
The majority of the works reviewed deal with the problem of runoff and
non-point source pollution. Methods for Identifying and Evaluating
the Nature and Extent of Non-"Point Sources of Pollutants (U. S. Environ-
mental Protection Agency, 1973) provides detailed descriptions of four
non-point sources of pallution - agriculture, silviculture, mining and
construction. Hater Quality Management Planning for Urban Runoff (U. S.
Environmental Protection Agency, 1974) is primarily a manual of pro-
cedures for quantification of urban nonpoint source pollution problems
in local planning areas.
Works emphasizing specific solutions to runoff problems include Practices
in Detention of Urban Stormwater Runoff (Poertner, 1974) and Processes,
Procedures and Methods to Control PoTTution from All Construction Activity
(U. S. Environmental Protection Agency, 1973).The former work covers
all aspects of on site detention facilities, including planning, design-
ing, financing, regulating, operating and maintaining such facilities.
It provides detailed information of specific site-scale, engineering
measures and offers a good background for developing design-review
criteria related to runoff. In addition, references are made to ordin-
ances in effect in various communities.
Two good studies dealing with the problem of runoff from streets are
Water Pollution Aspects of Street Surface Contaminants (Sartor and Boyd,
1972) and Contributions of Urban Roadway Usage to Water Pollution
(Shaheen, 1975).The Sartor study provides a description of street pol-
lutants and cleaning practices of various cities and quantifies the effici-
ency of various street cleaning techniques. The Shaheen report details
the origin and composition of roadway dust and dirt. Both works include
recommendations regarding street cleaning practices, curb and gutter
design, roadway site selection, porous pavement and other techniques to
reduce the problem.
Site Specific Management Techniques for Air Quality
Specific ideas for use of land use control measures in air quality
planning began appearing in reports in the early 1970's. A brief
introduction to this topic is found in "Urban Planning and Air Pollu-
tion Control: A Review of Selected Recent Research" (Kurtzweg, JAIP,
1973). The article includes a discussion of land use and transporta-
tion planning measures for improving air quality along with a review
of applicable federal legislation and policies. It also presents a
number of projects initiated by the National Air Pollution Control
Administration and continued by the Environmental Protection Agency.
The projects funded were to demonstrate the value of incorporating air
quality considerations into urban planning. More specifically, the
projects dealt with land use patterns and density, site specific
structures and operations and planning and design of transportation
systems.
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A large amount of literature pertaining to the various strategies,
measures and methods for incorporating air quality into the planning
process was initiated by the Environmental Protection Agency in an
ongoing series titled Guidelines for Air Quality Maintenance Planning
and Analysis. The purpose of this series was to assist local and state
agencies in the development of Air Quality Maintenance Plans.
The third report in this series, Guidelines for Air Quality Maintenance"
Planning and Analysis - Volume 3: Control Strategies (Research Triangle
Institute, 1974) is especially valuable to local planners in the early
stages of identifying measures applicable to their areas. It defines 18
measures for maintenance of air quality standards. Nine of these mea-
sures relate to land use and planning including emphasis on indirect
emission sources. Some of the measures are density zoning, environmental^
impact statements and emission charges. The remaining nine measures
presented are concerned with existing direct emission sources.
Another report aimed at the planner with minimal technical background in
air quality analysis is A Guide for Considering Air Quality in Urban
Planning (Environmental Research and Technology, 1974).It outlines a"
five step procedure for integrating air quality considerations into the
planning framework. An excellent tool for planners is the Air Quality-
Land Use Planning Handbook for California - Part I: Planning for Air
Quality (California Air Resources Board, 1975). It gives explanations of
how and where air quality objectives can be achieved and maintained at
the local and regional level. The handbook provides background infor-
mation, specific planning mechanisms and evaluation processes for air
pollution.
There are several area specific studies of value to local planners.
The Air Quality Plan of San Bernardino County (San Bernardino County
Environmental Improvement Agency, 1975) is a example of the actions
which can be taken by local governments to reduce the generation of air
pollution. Included in this discussion of transportation and land use
strategies are various land use incentive programs aimed at reducing air
pollution generated by cars. The Plan also presented an "Air Quality
Indexing System" based on critical receptors (pollution sensitive vari-
ables) and emitters (pollution causing variables).
Development of A Trial Air Quality Maintenance Plan Using The Baltimore
Air Quality Control Region (Engineering Science. 1974) contains a useful
table of control measures with the corresponding implementation policies
for suspended particulars and hydrocarbons. Factors evaluated in the
table are economic, adnri strative, political, legal and environmental
effectiveness. The San Diego Clean Air Project: Summary Report (Goeller,
1973) reviews the procedures and findings of a research study that
evaluated the costs and effects of strategies designed to improve and
maintain air quality in the metropolitan area. In general, the results
tend to support the implementation of source controls rather than land
use and transportation controls as a best approach to the region's
air quality problems.
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In the area of air quality planning through transportation controls,
Transportation Controls to Reduce Automobile Use and Improve Air
Qua!i ty i n Cities; the Need.the Opti ons.and Effects on Urban Tcti vi ty
(Horowitz, 1974} is a summary of the rationale for transportation con-
trols, the primary methods for reducing automobile use, the revelant
control mechanisms and the consequences of reducing automobile use.
Evaluating Transportation Controls to Reduce Motor Vehicle Emissions
in Major Metropolitan Areas (Institute of Public Administration, 1972)
and Guide!ines to Reduce Energy Consumptions through Transportation
Actions (Voorhees, 1974) are good examples of the other numerous reports
detailing transportation control strategies.
SUMMARY OF SITE SPECIFIC MANAGEMENT TECHNIQUES
In the accompanying Table III-l, the locational and site design measures
most frequently proposed in the literature are summarized, and the im-
plementation devices available to effectuate them are noted. The measures
cited are described in detail in Guide to Implementation Techniques for
Air and Water Quality Management Plans a report prepared for ABAG in 1976
by the Sedway/Cooke consulting firm.Besides describing the intent and
use of each measure, the report also evaluates their potential application
in addressing air or water quality concerns. Basic principles underlying
air quality related measures are to:
1. Disperse major sources of pollutants so that the assimilative
capacity of the air is not overloaded in any one area.
2. Locate housing, schools, hospitals and other pollution
sensitive uses away from pollution sources and concentrations.
3. Buffer sources and receptors from each other.
4. Reduce the generation of pollutants by altering travel and
consumption patterns.
The principles underlying the measures suggested to protect water
quality are to:
1. Locate urban and industrial uses in areas where the waterways
are capable of assimilating the effluents produced.
2. Regulate the location and operation of agricultural resource
extraction, and other rural activities so that their dis-
charges can be appropriately assimilated.
3. Limit the generation of wastewater and surface runoff and
regulate its entry into natural waterways.
4. Reduce the waste loads carried by runoff by controlling
erosion, the use of fertilizers and pesticides and by
promoting improved urban housekeeping practices.
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TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN WATER
QUALITY
MEASURES
IMPLEMENTATION METHODS
Control of Location and Concentration of Sources
Point Sources
0 location of sewage treatment plants
where effluents can be best assimilated
by hydro! ogic and lan'd systems
0 channeling of development Into areas
that can be readily served by ap-
propriately located treatment fa-
cilities
0 holding development in sewered areas
to the design capacities of the STP's
and/or the assimilative capacities of
the receptor of their discharges
0 location of power plants, industries,
and processing plants where their
effluents can be appropriately as-
similated by natural systems
"201" plans
administrative/funding policies
environmental assessment review
zoning
capital Improvements
development moratoria
zoning district regulations
capital Improvements
permits (based on
an emissions-density
concept)
zoning
Nonpoint Sources
permit unsewered development only in
areas where soil and other environ-
mental conditions permit successful
long-term operation of septic or other
acceptable on-s1te treatment systems
set stringent regulations on the
design, construction in and main-
tenance of septic systems
ensure that densities in unsewered
areas are kept low enough to prevent
septic systems from overtaxing the
assimilative capacity of the groundwater
restrict agricultural forestry and
mining activities to areas where
discharges can be appropriately
assimilated
stage construction and development
activities so that erosion levels do
not exceed the assimilative capacity
of the watershed
zoning
special permits
public health
regulations
zoning
zoning
permit-system
capital improvements
permit system
zoning (performance standards)
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TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN MATER
QUALITY
Site Design and Resource Management Control!
Limitation on Wastewater Generation
Recycling - this Isn't a land-use
measure per se, but 1t may well have
land-use ramifications - as in re-
serving lands near treatment plants
for users of recycled water (ag-
riculture, golf courses, industries)
separation of existing storm and sani-
tary sewer collection
reduction of wet-weather flows by in-
creasing infiltration into interceptors
Reduction and Control of Runoff
0 limitations on the amount of im-
pervious surface
use of porous paving materials
creation of retention ponds
preservation or creation of
recharge areas
° modification of agriculture and
forestry practices (contour
plowing, field arrangements,
selective cutting, cutting in
mosaic patterns, etc.)
Reduction and Control of Erosion
(many of the runoff reduction measures also
limit erosin by reducing the volume and
intensity of surface flow)
0 protection of natural ground cover
111-13
zoning
capital improvements
agricultural preserves
redevelopment
capital improvements
zoning (physical form,
siting requirements)
subdivision regulations
design review
zoning (physical form, siting requirements)
subdivision regulations
design review
zoning (performance standards)
subdivision regulations
design review
capital improvements
zoning (performance standards)
subdivision regulations
design review
capital improvements
zoning (physical form, siting requirements)
agricultural preserves
flood plain zoning
subdivision regulations
design review
soil conservation
district regulations
zoning(performance standards)
hillside and soil
-------
TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN WATER
QUALITY
replanting or special treatment
of disturbed areas
protection of natural drainage ways
limitation of development on steep
slopes and highly erodible soils
conservation regulations
grading regulations
subdivision regulations
design review
soil conservation district regulations
zoning (performance standards)
hillside and soil
conservation regulations
grading regulations
subdivision regulations
design review
soil conservation district
regulations
zoning
flood plain zones
subdivision regulations
design review
capital Improvements
(purchase of stream banks)
zoning (performance standards)
hillside and soil
conservation regulations
design review
strategic capital improvements
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TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN AIR
QUALITY
MEASURES IMPLEMENTATION METHODS
Control of Location and Concentration of Sources
and Receptor?~
—• « ' ' •**' *" ™" ^ ^
Point Sources
*• , -•
0 location of industries, incinerators,
and power plants in areas where the
air system 1s capable of adequately
assimilating their emissions
0 location of indirect sources (e.g.
shopping centers, stadiums),
in areas where the air system Is
capable of adequately assimilating
the emissions associated with them.
Line Sources
0 location of major thoroughfares
where emissions can be best
assimilated
Area Sources
0 location of activities and land uses
in areas that have sufficient
assimilative capacity to maintain
acceptable air quality
Critical Receptors
0 location of sensitive receptors
(schools, hospitals, rec. facilities)
in areas that are likely to retain
superior air quality
0 restrict housing development in areas
that have, or are likely to experience
unacceptable air quality levels
Site Design and Resource Management Measures
Buffering of Sources
0 segregation of Industries, indirect
and line sources from living areas
and other sensitive receptors
emission density zoning
special permit techniques
environmental assessment review
special permit techniques
emission density zoning
environmental assessment review
capital Improvements
zoning
capital Improvements
environmental assessment review
zoning
environmental assessment review
zoning
capital improvements
(e.g. not funding sewage treatment plant
development moratoria
zoning district regulations
special zones
subdivision regulations
capital improvements
(e.g. buying open lands in
strategic locations)
design review
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TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN AIR
QUALITY
creation of artificial buffers around
sources (such as by creating heavily
planted buffer strips)
zonina
subdivision regulations
capital improvements
(e.g. buying open lands in
strategic locations)
design review
Buffering of Receptors
requirement for housing to be set well
back from freeways, major arterials,
and other significant sources of air
pollutants
requirement for planted open spaces
where subdivisions "or housing projects
abutt major roadways or other major
pollutant sources
placement of active recreation areas in
the centers of parks and school yards,
away from the surrounding thoroughfares
where possible, creating bicycle lanes
that do not run along side major
streets
zoning district regulations
subdivision regulations
design review
environmental assessment review
zoning regulations
subdivision regulations
environmental assessment review
design review
environmental impact assessment
subdivision regulations
capital improvement program
design review
Reduction of Energy Use
0 requirement for building designs and
orientations to reduce heating and
cooling energy demands
0 neighborhood designs to reduce
automobile use at the local level
(some of the notions involved here
include providing a high enough
density and mix of uses to allow
most everyday facilities to be
within convenient walking distance
from home)
Transportation Strategies
Limitations on Automobile Use
0 parking restrictions
0 reduction in the number of parking
spaces required for most land uses by
zoning regs.
building codes
subdivision regulations
zoning and design review
subdivision regulations
design review
zoning
parking ordinance
zoning changes
111-16
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TABLE III-l LAND USE MEASURES DESIGNED TO IMPROVE AND MAINTAIN AIR
QUALITY
restriction of construction of parking
garages in selected areas
creation of car-free zones, pedestrian
malls
zoning
development moratoria
zoning
redevelopment
Emphasis on Public Transit
construction and upgrading of transit
facilities
improving interface between transit
and other transportation modes
fostering densities and land-use
mixes that can support public transit
capital improvements
zoning
subdivision regulations
redevelopment
zoning district regulations
redevelopment
Reduction of the Need to Travel
(reduced vehicle trip frequency and lengths)
0 creation of multi-use centers
creation of residential areas
with high amenity levels
zoning
redevelopment
capital improvements
zoning (planned unit developments)
subdivision regulations
captial improvements
design review
111-17
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SEWAGE SYSTEMS AS A DETERMINANT OF REGIONAL GROWTH
The use of public utilities as a means of directing urban growth has
long been advocated in planning literature. More recent attention to
the subject has been initiated by EPA through efforts encouraging the
development of sewage collection and treatment facilities that will
result in urban growth patterns that do not contribute to a continued
violation of air quality objectives. However, there are a large number
of considerations other than public utilities that influence the location
and timing of urban development. A considerable amount of research has
been conducted attempting to identify the factors involved in develop-
ment and the relative roles that they play.
One of the classic works in this area is Urban Growth Dynamics in a
Regional Cluster of Cities (Chapin and Weiss, 1962), a study of urban
development processes in the Carolina piedmont. The study concludes
that the development of vacant land is encouraged or intensified by
location of major transportation routes, employment centers and the
availability of community services, and that development is discour-
aged by poor drainage conditions or proximity to non-white and/or
blighted areas.
The City Expands (Milgram, 1967) focuses on the urban expansion into
Philadelphia's northeast district. Its analysis determined that the
timing of new development was largely related to access to the central
business district. Whether the lack of sewers delayed development in
areas where builders were prepared to build, or whether the sewer lines
directed new development into areas preferred by the city could not be
clearly determined. Although there has been some success in identifying
the factors affecting development, understanding of their relative im-
portance in determining the location, timing, and form of what happens
has proven to be much more difficult. In 1972, a HUD advisory committee
concluded that: "...despite growing public concern, we know relatively
little about the import or impact of processes leading either to the
development and use of raw land, or to the changes in density and uses
of developed land." (Urban Growth and Land Development; the Land Con-
version Process (Land Use Subcommittee of the Advisory Committee to the
Department of Housing and Urban Development, 1972). The imperfect know-
ledge of the development process has made research into the sewer/growth
question highly speculative.
One of the most comprehensive and thorough reviews of the sewer extension/
urban development question is contained in Secondary Impacts of Transpor-
tation and Wastewater Investments: Review and Bibliography (Bascom et a!.,
1975).Besides providing an evaluation of the literature, the report
provides a cogent statement of the relationships between the availability
of sewer service and various kinds of development. The report observes
that the presence of sewer service has a direct effect on the location
and character of housing, and a more indirect effect on the location of
industry and commerce. It points out that the location of industry
depends the most on access to markets and labor and that the relative
influence of sewer service is fairly small. In fact, the report states
that because communities are generally anxious to attract industry, they
are often willing to make a special effort to provide the required service
111-18
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on demand, and often at a nominal cost. The situation cited for com-
mercial land users is somewhat parallel, except that these uses can also
quite frequently be seen as secondary impacts of sewer service provision -
with the housing stimulated by the new sewers attracting commerical
activities to serve it.
The Bascom report also observes that although the lack of sewer services
does not always prevent the development of single family housing (homes
on large lots served by septic tanks are often an alternative), the
construction of new sewer lines does open up new land for development.
Newly sewered land tends to develop faster than previously served areas
because developers rush to buy the land before its value shifts up the
levels normally associated with sewered land. The report goes on to
point out that:
"Generally, significant increases in single family housing con-
struction can be expected to follow new sewer investments in areas
where there is little vacant, sewered land, where vacant land prices
are low relative to the regional average, and where large tracts of
contiguous underdeveloped land exists." (p. 21)
Increases in high density housing are seen in situations where the newly
sewered land also has high accessibility. The conclusion is that ex-
tending sewer service to a new area creates increased land values and
encourages speculation. Dispersed, sprawl-like development is seen as
the consequence, a condition which is interpreted as leading to fiscal
problems and decreased water quality due to increased runoff loads.
Other case studies dealing with the sewer/urban development question in-
clude Interceptor Sewers and Suburban Sprawl: The Impacts of Construction
Grants~on Residential Land Use (Urban Systems Research and Engineering.
Inc., 1974) and Water Resources Management for Metropolitan Washington:
Analysis of the Joint Interactions of Mater, Sewage Service. Public Policy
and Land Development Patterns in an Expanding Metropolitan Area (Promise
and Leiserson, 1973).
Increased attention is now being given to consciously applying sewer
service extension policies as a means to achieve desired urban develop-
ment patterns. A good explanation for the movement in this direction is
provided by a discussion in the Fifth Annual Report of the Council on
Environmental Quality (CEQ, 1974JIThe CEQ notes that since virtually
all interstate freeways have been completed throughout an entire metro-
politan area, sewers and sewage treatment plants have become prime de-
terminants of urban growth. It points out that water pollution con-
trols have restricted the opportunities to use septic tanks and made it
more difficult to tie into overburdened sewer systems. Federal grants
of 75% of the costs have encouraged the upgrading and expansion of
community sewage treatment facilities, making it cheapest for developers
to build where they can take advantage of these systems. The report
also notes that many of the federally funded treatment plants are
regional facilities, requiring interceptor sewers to run through un-
developed land between communities, possibly encouraging sprawl along
their right-of-ways. Additionally, the plants and interceptors have
often been oversized, stimulating increased development. These factors
have already been recognized as posing problems for sound environmental
111-19
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development. In California, for example, the State Water Resources
Control Board limits the federal and state funding of local sewage
treatment plants in critical air basins to the capacity justified by
the State's low range population projections. Planning and Human
Values, an Inquiry into the Phenomenon of Urban Growth and the Possi-
bility of Its Control Through Water and Land Related Actions, (Salama,
• 1974), a recent EPA-sponsored report, suggests that infrastructure in-
vestment can be a powerful tool for influencing urban development,
especially in inner-city areas and in metropolitan areas in the early
stages of growth. The conclusion is that strategic infrastructure
investments can have the most effects where:
"...growth potential and demand for space are strong, where the
direction of that growth can be influenced by the creation of
marginal advantages,...and where the scale of intervention is
large relative to other development resources." (p. 65)
A growth control strategy that is often related to the strategic pro-
vision of sewer service is the development moratorium. The Fifth Annual
Report of the CEQ noted that in 1973-74 period, over 200 local develop-
ment moratoria were put into effect. The Sewer Moratorium as a Technique
of Growth Control and Environmental Protection (Rivkin/Carson, Inc., 1973)
identified six different forms that development moratoria can take:
"1. A freeze on new sewer authorizations (i.e., the extension of
trunklines into currently unsewered areas).
2. A freeze on new sewer connections (i.e., the actual hookup of
a building to an existing trunk or feeder line).
3. A freeze on the issuance of new building permits, or a freeze
on a class of building permits such as multi-family.
4. A freeze on the approval of subdivision requests.
5. A freeze on rezonings or zonings to higher than presently
developed densities.
6. A slowing down or a quota allocation for any or all of the
above within an affected area." (p. 2)
The Rivkin/Carson report found that so far, development moratoria have
had mixed results. On the positive side, moratoria:
1. Have in some cases possibly relieved the physical problem they
were intended to address.
2. Have provided an impetus to infilling of vacant land where
sewer connections are available.
3. When applied in suburban areas could encourage reconcentration
in the central cities where utilities are already available.
111-20
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On the negative side, moratoria have:
1. Stimulated short-term spurts of construction followed by sharp
drops in activity if facilities have not been provided promptly.
2. Caused hardships and inequities for small builders.
3. Discriminated against apartments and other efficient higher
density housing in some areas.
4. Created roadblocks to the provision of low and moderate income
housing by contributing to escalation of land costs and dis-
criminating against higher densities.
5. Encouraged urban sprawl in areas beyond the jurisdiction
imposing the moratorium by encouraging use of septic tanks
and package treatment facilities which may not provide
adequate treatment.
6. Provided a stimulus to complicated bureaucratic processes and
capital works delays.
It is clear that all the facts are yet available on the growth moratorium
question. Further monitoring and careful evaluation of actual experience
will be necessary before complete assessment of their utility and the
circumstances under which they are appropriate can be made. Special
attention will have to paid not only to the direct effects of moratoria
on growth, but their indirect effects on air and water quality as well.
RESIDUALS MANAGEMENT AS AN APPROACH FOR INTERRELATING LAND USE/AIR QUALITY
WATER QUALITY
In considering the notion of applying land use strategies to achieve air
and water quality objectives, one of the questions that arises is the
extent to which measures intended to improve air quality will conflict
with or reinforce those intended to improve water quality. This issue
has received increasing consideration by EPA. The general question of
the interrelationships of pollution control measures is given attention
in the residuals management literature. (Residuals management is used in
this context to be the very broad concern with all forms of wastes as
distinct from perhaps its more familiar reference to sludge from wastewater
treatment process.) Residuals management is an analytic approach to air
pollution, water pollution and solid waste issues that treat the questions
in a comprehensive, systemic way. The relationships between the various
types of pollutants in their receiving media are considered, and trade-
offs are made in devising the least-cost strategies for pollution abate-
ment. The residuals management approach is best described and its use
demonstrated in Environmental Quality Analysis (Kneese and Bower, 1972)
and Residuals^- Environmental Quality Management: Applying the Concept
(Bower and Basta, 1973).
A report for EPA entitled Development of Residuals Management Strategies
(Howe and White, 1975) provides a general descriptive model for identify-
ing and evaluating residuals management strategies. The report also dis-
111-21
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cusses some administrative and legal considerations in preparing the
strategies. Unfortunately, to date none of the studies on residuals manage-
ment have focused in detail on the various land use based approaches that
have been suggested for air and water quality improvement and therefore
provided little direct assistance to the formulation of the Sonoma Study.
SUMMARY
The present theories on the interrelationships of air and water quality
and land use provided strong direction to the Sonoma Study. Based on the
findings from the literature survey, the study has concentrated on three
subject areas where earlier research was either lacking or limited.
The first subject area for study is the relationship of land use controls
designed to meet air quality objectives to those designed to meet water
quality objectives. Of particular interest is whether the land use con-
trol strategies for either medium is supportive or conflicting.
The second consideration of the Sonoma Study is the impact of spatial
pattern on air and water quality. Most of the earlier studies on spatial
patterns concentrated solely on air quality. The Sonoma Study is designed
to consider both media and to determine if any of the elements of spatial
pattern -- population size, location, density or land use type -- is the
dominant characteristic and how these elements are related to each other.
Finally, the study focuses on the effectiveness of spatial pattern or site
specific management devices for achieving and maintaining environmental
objectives. The intent of this analysis is to provide direction to those
public agencies preparing environmental management plans on what would be
an optimal planning strategy in using both types of controls.
111-22
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CHAPTER IV - GOVERNMENTAL STRUCTURE OF AIR AND WATER POLLUTION CONTROL
IN CALIFORNIA
Governmental structure for air and water quality management has come
under considerable scrutiny, recently, with attention being directed
to how environmental protection programs can be made more effective.
A particularly perplexing issue is how to integrate the policies and
implementation programs of various state, regional and local agencies
into a more cohesive approach to environmental management that also
considers social and economic objectives. This chapter describes
those public agencies at the state, regional, local and special dis-
trict levels concerned either directly or indirectly with the attain-
ment and maintenance of acceptable levels of air and water quality in
the study area. This description includes: (1) the specific nature
of the jurisdiction, including its purpose, means of policy setting,
enforcement powers, intergovernmental relationships, nature of exist-
ing policies and relationship, of plan or plan enforcement to Sonoma
County, and (2) an evaluation of the air and water pollution control
structure in California.
HISTORIC PERSPECTIVE OF ENVIRONMENTAL CONTROL
This chapter presents a picture of air and water pollution control in
California that is both extensive in terms of actors but disjointed in
terms of its operation. This disjointed approach to environmental
management results in a confusion as to whether the present or poten-
tial effectiveness of either the controls of an individual agency or
the collective sum of controls by all agencies are adequate. This
confusion raises the further questions: (1) will such controls meet
the legal mandates of state and federal legislation, (2) are they
satisfactory to a continuously changing public demand and (3) can
state, regional, or local policy makers act on recommended controls
with any confidence in their effectiveness?
Much of this confusion is the result of the past six years of rapid
promulgation of environmental regulations at all levels of government.
It is therefore necessary to place this period into a historical per-
spective to better understand the reasons for such confusion.
The factual information on environmental deterioration has been well
documented for the past twenty to thirty years and had resulted in an
increased level of political awareness on the subject. California was
perhaps more sensitive to the issue than other states in that it
created (1) a state and regional water pollution control system in
1949 and (2) enabling legislation in 1947 for county level Air Pollu-
tion Control Districts (APCD) to control stationary source emissions.
The national awareness of the severity of air and water pollution pro-
blems came in the late 1960s and appears to have come in part out of
declining attention to one set of national problems - civil rights,
poverty and the Vietnam War - and 1n part from a realization that the
IV-1
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"ecology" issue had considerable merit. Environmental improvement provided
a new cause that could be attacked with the same political fervor of the
civil rights or anti-war movement, but it also had a constituency that had
not been embroiled in earlier political confrontation. The constituency
included people from such groups as fishing, naturalist, hiking or garden
clubs who had not previously been involved in the then current political
debate. The fight against pollution, therefore, provided national level
policy makers with a means of re-channeling the energies of discontent to
a subject matter that was new and genuine and that was perceived as being
less volatile. It brought to those long concerned with the environment
political support for the development of quick solutions to large and
complex problems.
Another historical event that would seem to have shaped the political
atmosphere for environmental management was the landing on the moon. This
event evoked a national pride that American engineering and technology
could solve overwhelmingly complex problems under extremely short time
periods. The impact of the moon landing on the fight against pollution
was to create a strong confidence that engineering and large project
planning could quickly clean up the nation's air or water. Such normally
vague terms as "best available technology," which has been used recently
in the federal statutory scheme to describe the desired 1983 sewage treat-
ment level, attest to the political leaders' faith that engineering in-
genuity can come up with new and yet undefined treatment methods. Im-
plicit in such a descriptive phrase is the belief that technological
advances can be made if we simply place the pressures on our economic and
governmental system to find them.
The dilemma is that much of the legally required solution to air and water
pollution cannot be provided solely by technological solutions. They
require changes in governmental organization, in land use patterns or
activities and in the way people have become accustomed to living. The
potential of short-term environmental change under these approaches is '
less than through engineering inventions. Yet, the basic federal or state
air and water pollution laws have been very specific in terms of their
desired intent, including exact timetables for compliance and penalties
against those polluters that cannot comply with the timetables.
The planning effort for air and water quality took on a whole new direc-
tion not previously seen in other federally initiated planning require-
ments. Its equivalency would have been if the 1949 Housing Act, which
stated the national intent of a "decent home and a suitable living envi-
ronment for every American family," had included the additional proviso
that the intent was to be satisfied by 1960 or the federal and state
government would become directly involved in correcting local housing
problems.
It was with this background that states, counties, cities and special
districts have hastily expanded their environmental improvement efforts.
The result is that the sense of urgency appears to have required the
compromising of a more integrated governmental approach involving all
concerned agencies in providing needed improvements.
IV-2
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STATE AGENCIES INVOLVED IN AIR AND WATER QUALITY
There are six state agencies involved directly with air and water quality
in the Sonoma study area and a number of other state agencies, such as
the State Board of Forestry and the Department of Agriculture, that are
also involved but whose activities are less direct and will not be dis-
cussed in this study. There is also a major state agency concerned with
both air and water, the Coastal Zone Conservation Commission, whose juris-
diction was not in the study area.
The different state agencies are not identical in terms of their organi-
zational structure or nature of policy setting. Some of the state agen-
cies, like the State Water Resources Control Board or the Air Resources
Board have been organized to respond in part to federal environmental
requirements, while others have been established and organized to direct
state initiated environmental programs. Some state agencies have substate
planning and enforcement agencies such as the Regional Water Quality Con-
trol Boards. Unfortunately, for the reader wishing to readily understand
the California network, the state agencies do not lend themselves to a
single classification system. Therefore, they will be discussed in a
sequential fashion based roughly on their importance to air or water
quality with those agencies with complementary substate or regional
divisions presented together.
Air Resources Board
In 1967, the California Legislature enacted the Mulford-Carrell Act, es-
tablishing the Air Resources Board (ARE) to deal with the State's air
pollution problems. The ARE has authority over motor vehicle emissions,
including responsibility for motor vehicle emission standards and certifi-
cation of devices for the extensive California used car retrofit program.
Another ARE function is to review, evaluate and change (if necessary)
local air pollution control districts (APCD) programs. While the primary
responsibility for stationary sources (including enforcement of state
standards) remains with the APCDs, the State can and does provide overall
guidance to APCDs on the State's ongoing programs to improve air quality
from stationary sources.
In the year the California Air Resources Board was established, the federal
government also responded to the increasing national concern about air
pollution by enacting the Air Quality Act of 1967. This legislation pro-
vided for a national program to control automobile emissions and larger
support of state and local programs to control air pollution from station-
ary sources. The Clean Air Amendments of 1970, which expanded the federal
government's role in air pollution, resulted in EPA requiring each state
to prepare a State Implementation Plan (SIP). Such a plan was to contain
measures to attain the nationally promulgated ambient air quality standards
established to protect public health and welfare. EPA was given the au-
thority to prepare and/or enforce the SIP should the State fail to do so.
ARB, with the assistance of the APCDs including the Bay Area Air Pollution
Control District, submitted its SIP to EPA in February, 1972, and EPA
approved it, with certain exceptions in May, 1972. One of the deficiencies
IV-3
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of the California SIP was:that it did not include adequate control strat-
egies for transportation related pollutants. This particular deficiency
was common in many SLPs around the nation.
Subsequent to a court decision on this issue, EPA directed the appro-
priate states, including California, to submit a Transportation Control
Plan (TCP) for the auto-related pollutants. The purpose of the TCP was
to develop control stratesies which would lead to a reduction in trans-
portation related pollutants sufficient to attain national air quality
standards. Among the ways in which this was to be accomplished were
reducing the number of vehicle kilometers traveled (VKT) and more ex-
tensive controls on in-use vehicles Ce.g., special maintenance, retrofit).
There were a number of control measures proposed in the TCP which would
have had definite land use impacts. They were Parking Management Plans
(PMP), used to complement the transportation and carpooling measures,
and "Indirect Source" review, aimed at more detailed studies on traffic-
inducing facilities such as shopping centers, industrial parks, or schools.
In 1973, as a result of the court decision in National Resources^Defense:
Council v. EPA, SIPs were also required to include a long-term air quality
maintenance plan (AQMP) for maintenance of air quality standards. Air
quality maintenance requires a comprehensive control strategy approach to
the long-term air pollution problems of a region. By necessity, such am
air pollution program will include land use and transportation control
measures, as well as the regular SIP application and enforcement of tech-
nological controls on stationary sources and on the car. The ARB is
currently guiding California efforts to develop AQMPs and revise the SIP
to demonstrate both attainment and maintenance of air quality objectives.
ARB Pol icy Formation and Enforcement. The State Implementation Plan is
the main Air Resource Board planning document to reflect state air pollu-
tion abatement policies. The regulations in the SIP are primarily aimed
at carrying out the elements of the federal statutory/regulatory scheme.
The SIP also includes the ongoing Air Resources Board programs of auto
emission controls and standard setting for stationary and non-vehicular
sources.
ARB's enforcement powers include:
1} assume the powers of an APCD if there is a finding that the
APCD regulations are insufficient to achieve the air quality
standards. Such, powers would include the issuance of permits
for stationary sources. The ARB can also direct the APCD to
correct deficiences in their program;
2} assess and recover a penalty for a violation of a vehicle
emission control; and
3) eliminate or reduce the amount of funding to an APCD if ARB
feels that they are not actively or effectively enjgaged in
reducing air contaminants.
IV-4
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Effect of State Air Quality Controls on Land Use. The status of the
state-encouraged air quality controls in 1975 was extremely confus-
ing. The ARB was In its fifth revision of the SIP in order to satisfy
national air quality standards. EPA over the past four years had pro-
mulgated the earlier mentioned mandatory strategies in the SIP (TCP,
PMP, Indirect Source Review) that included a number of land use related
controls. Indirect source review, for example, was to be a permit issu-
ing program, most likely administered by APCDs, aimed at eliminating the
localized carbon monoxide problem. Permits could have been denied to such
traffic generating land uses as shopping centers or industrial parks if
such facilities would cause a violation of the carbon monoxide air quality
standard. In 1975, EPA suspended the indirect source review regulation
pending further Congressional guidance. Similarily, parking management
strategies, aimed at controlling traffic generated by parking, were drop-
ped pending further guidance. Recent congressional guidance has leaned
in the direction of not requiring any mandatory land use or stringent
transportation strategies in SIPs. Instead, states would conceivably
have greater flexibility in suggesting air quality control strategies
as long as they provide proof that they could attain and maintain the
national air quality standards. However, given the stringency of the
federal standards, it is difficult to imagine a SIP being accepted that
does not include land use and transportation strategies in some form.
Since indirect source review has never been made operational, there have
been no enforcement actions to determine how its potential use would im-
pact either growth management or site specific planning activities. For
example, it is unknown whether indirect source review would result in
shopping centers being disallowed in areas exceeding the federal carbon
monoxide standards, or if only additional mitigation measures or design
changes would be required to minimize the adverse impacts. An indirect
source review that disallowed a downtown office and shopping complex pro-
posed in an area of high carbon monoxide concentration while permitting
the same facility at the fringe of the city because of lower CO concentra-
tions would encourage a dispersed employment growth pattern in the region.
This would particularly be the case in an emerging area like Sonoma County
already faced with strong sprawl pressures and whose public transportation
may not provide satisfactory service to induce new commuters or shoppers
to ride to more centralized areas.
The equity of the indirect source review to handle such issues would become
critical in determining how control affects the size and shape of a region.
The above example of high carbon monoxide concentrations would most likely
occur in an older, built-up city thereby resulting in those cities being
at a disadvantage in indirect source review when compared to with the new
and developing communities.
Parking management is aimed at being an automobile disincentive strategy.
Such controls as a parking fee structure, restrictions on time of use or
preference to multiple occupants are some of the potential elements in
this strategy. Parking has typically been controlled locally by parking
requirements in zoning ordinances and by controls placed on privately or
publicly owned or managed parking lots. Therefore, the impact on employ-
ment or population patterns depends highly on whether local governments
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agreed or were forced to agree with a region wide planning and compli-
ance approach. A regional growth strategy featuring a strong central
city concept serviced by public transit and with limits on parking would
face competitive advantage problems if a nearby city placed no restric-
tions on its own parking. Here again, the impact of parking management
on growth would vary based on the level of region-wide enforcement.
Air Pollution Control Districts (APCD)
The air pollution control district is a local government agency and
therefore somewhat out of place in a discussion on state agencies. Yet,
because of its extremely close connection with the Air Resources Board
and the federal air quality programs, it is appropriate to discuss APCDs
at this point. The county level air pollution control district was the
first state legislatively initiated system to work specifically on air
pollution. The APCDs are empowered to enforce the state stationary
source emissions standards and can set more stringent standards should
they desire. APCDs are also, as part of a basinwide effort, required
by state law to establish a coordinated air pollution control plan which
can then become part of the State Implementation Plan.
There are two APCDs involved in the Sonoma study area - the North Sonoma
Air Pollution Control District and the Bay Area Air Pollution Control
District (BAAPCD). (The BAAPCD, strictly speaking, is not an APCD. It
was specially created by the State Legislature as a regional special
district including all those sections of the nine-county Bay Area that
make up the air basin. The BAAPCD has identical powers to all the other
APCDs with the exception that it has the ability to tax.)
APCD Policy Setting and Enforcement. Policy setting by APCDs comes in
the form of:1) regulations on stationary source emissions, 2) recom-
mended control measures as part of the SIP and 3) "variances" to the
regulations.
The Board of Supervisors of the county serves as the policy making body
of the Air Pollution Control Board. The control board for the BAAPCD is
comprised of one member from the Board of Supervisors of each county and
one city councilman or mayor from within each county.
The regulations serve as the main policy of the air pollution control
boards. As an example, some of the BAAPCDs regulations cover:
1. Dump fires and trash burning;
2. Controls on particulate matter, sulfur compounds, lead, nitrogen
oxides, asbestos, mercury, odorous substances from industrial and
commercial sources, and some forms of incineration emissions. The
Ringelmann test, used in evaluating smoke, is used by the BAAPCD
for particulate matter. The Ringelmann test will be cited later in
the discussion on local planning agency zoning controls; and
3. Storage and use of solvents, paint, gasoline, and ink.
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Enforcement of the regulations conies through:
1. Orders of abatement - gives a polluter a period of time to stop a
violation;
2. Permits - includes both the authority to construct and the permit
to operate;
3. Injunctions; and
4. Misdemeanor penalties.
There is some flexibility in strict regulation enforcement to relieve
polluters from "extraordinary hardship." The hearing board, the judiciary
of the APCDs, can grant a variance to the regulations and impose other con-
ditions on the polluters - e.g., time limits for compliance, alternative
standards.
Impact of APCDs on Land Use Decisions. The potential impact of APCD
regulations on land use is their influence on the location of stationary
sources, e.g., an existing or new industry. The stationary source regu-
lations concern both the total amount of emissions permitted from any
source and the effect of these emissions on the air quality at or near
the source location. For example, a new refinery applying to locate in
an area of poor air quality could be required to attain a higher level
of emission control than if it located in an area of acceptable air
quality. If the cost of the additional emission control devices was
prohibitive or disproportionate when compared to the other locational
advantages of the area, the refinery could settle elsewhere. The land
use effect of point source regulations, therefore, can be one of disper-
sion of industries or other land uses of high emission potential.
State Water Resources Control Board (SWRCB)
California has had a state/sub-state water pollution control system
since 1949 (Dickey Water Pollution Act). It was reorganized in 1969
under the Porter-Cologne Water Quality Control Act. Because of Calif-
ornia's history of State level concern for water quality, it is not
surprising to find that its legislation was a model for the present
federal program in that it included both: 1) giving more attention
to control of discrete water discharges and 2) preparation of basin
(regional) water quality plans.
SWRCB Policy Setting and Enforcement. The SWRCB, consisting of five
members appointed by the Governor, is charged with:
1. Formulating and adopting state water quality control policy in-
cluding that on groundwater, surface water and water reclamation;
2. Determining water quality research needs;
3. Coordinating water quality related investigations of other state
agencies;
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4. Formulating, revising, and adopting general procedures for water
quality control plans as submitted by the regional board;
5. Requiring state and local agency investigations and reports on any
technical factors involving water quality control;
6. Allocating funds to regional boards; and
7. Regulating the testing, licensing, and use of materials for cleaning
up oil in state waters.
The policy setting comes in a variety of forms including: 1) statewide
policies, 2) review and revision of basin plans and 3) establishing
priorities and administering the federal and state grants for local
sewage treatment and collection systems.
The statewide policies provide guidance to the regional water quality con-
trol boards on their preparation of basin plans, and, thereby, provide the
basis for SWRCB plan review. These statewide policies include:
1. General principles for the implementation of water resource manage-
ment programs among which are: a) consolidation of sewerage facil-
ities, b) reclamation of wastewater, c) regional management of water
supply and wastewaters, d) prevention of substances not amenable to
treatment from entering the sewage treatment systems.
2. A "non-degradation" policy whereby waters of higher quality than
state standards should, to the maximum extent possible, remain
unchanged.
3. Thermal, ocean, and enclosed bays and estuaries policies aimed at
giving specialized water quality attention to the unique circum-
stances that the subject areas present.
One of the most politically sensitive policy decisions made by the SWRCB
is its setting of statewide priorities for the distribution of state
and federal sewage treatment grants. Priority setting is important
because of: 1) the limited amount of money for such improvements and
2) the linking of population expansion to the adequacy of existing or
proposed sewage treatment facilities. The basin plans prepared by each
region for the SWRCB indicate the estimated capital and operating costs
of needed facilities and the staging program for their construction.
Yet, these plans do not set priorities of funding within the region.
Priorities are instead established by state regulations to which the
regional boards adhere on a project by project basis. The priority list
is then submitted to SWRCB for its alteration and approval.
The enforcement powers of the SWRCB include its ability to review and
override point source permit decisions made by the regional water quality
control boards, and its priority setting power which can be used to
ensure modifications of basin plans and/or "201" facility plans.
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Influence of SWRCB oh Land Use. The powers provided to the State Water
Resources Control Board and its regional water quality controls boards,
make it now one of the strongest agencies at the state and regional
level in shaping regional and local land use. No other agency has the
same power to influence growth by controlling the configuration of sewer
infrastructure and sewer hook-ups, and the directing of money that con-
trols the quantity and quality of the sewage system to which individual
homes or commercial establishments are connected. For example, there
are a number of areas within the Sonoma study area that are, or will
soon be, faced with growth limitations due to inadequacies either of
their treatment plants in meeting State effluent limitations or to the
hydrologic limitations that make them unsuitable for septic tanks or
cesspools. The regional water quality control board has virtually
stopped growth in these areas. The restrictions will be removed only
when the appropriate additions are made to the sewage system.
Regional Mater Quality Control Boards
There are nine water basins in California, each of which has a regional
water quality control board providing sub-state planning and regulatory
powers. Like the State Board, regional board members are appointed by
the Governor. There are two regional water quality control boards in
the Sonoma Study area - representing the San Francisco Bay Region and
the North Coast Region.
Policy Setting and Enforcement. The regional boards serve basically as
the local water quality planning and enforcement arm of the State Water
Resources Control Board. The powers other than planning given to the
boards are:
1. The establishing of requirements for all waste discharges, in-
cluding both those by community sewer systems and point sources not
hooked to the community sewer system. Both categories of dischargers
must submit a report describing the nature of discharge, including
its character, location and volume. If the regional board finds
that a discharge violates or will violate a board requirement, it
can require the submission of intended remedial actions, including
time schedules. The board, however, is limited in its power in
that it may not specify the design, location, type of construction
or manner by which compliance with State standards may be achieved.
2. The issuing of cease and desist orders for those dischargers who
do not comply with requirements. Such an order can require immedi-
ate or phased compliance. Court injunctions and civil fines are
possible to enforce these orders. Potential discharge violations
covered by the cease and desist law include issues of volume, type
and concentration of waste.
Effect of Regional Water Quality Control Boards on Land Use. As indic-
ated with the SWRCB, the regional boards' effect on land use can be con-
siderable, particularly with respect to growth management controls.
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The effects of hook-up limitations, septic tank restrictions, and sewer
system quantity and quality restrictions were indicated earlier. In
addition, special mention should be made of the possible land use im-
pact of controls on industrial waste sources and stormwater runoff.
The basin plans for both regions do not discuss in any great depth
the impact of industrial discharges or other point discharges on the
"beneficial uses" of nearby waters. ("Beneficial uses" described in
the various basin plans include municipal water supply, fish spawning,
scientific study, marine habitat, commercial fishing, water contact
recreation, agricultural water supply.) This omission was due to the
lack of EPA effluent guidelines for most of the discrete industries
requiring permits under the National Pollution Discharge Elimination
System (NPDES). Even when these standards are completed, the regional
board could be more restrictive than the federal standards if a desired
beneficial use at the particular location warranted it. Since both water
quality and beneficial uses are locationally varied, they have the
potential for creating different regional land use patterns. As an
example, an industry located in a city that is upstream from a shellfish
bed may face controls that it would not face if located elsewhere in
the region.
The industrial point source type of problem did not present itself in
the Sonoma Study area due to the area's low level of industrial dis-
charges. Thus, it is difficult to determine how major such a growth
issue might be for other regions. Conceivably, the combination of a
"non-degradation policy," wide distribution of beneficial uses through-
out the region, and pollution abatement costs that are not prohibitive
would result in no one area having a competitive advantage over another.
Therefore, the importance of point source control in a scheme of growth
management could be minimal.
The basin plans pay only modest attention to urban surface runoff. Con-
sequently, the regional boards have no clear policy on the subject matter.
This condition was recognized by both federal legislation, and its state
and regional implementers, in the required "208" plans, which are to
address such nonpoint sources as surface runoff.
The only land use policy implication of stormwater runoff faced by
regional boards, occurs when stormwater runoff has infiltrated an
existing sewage system resulting in wet weather flows to the treat-
ment facility at levels greater than its capacity to handle them.
Unless such infiltration results in a major regional level public
health hazard, it would be classified only as medium priority on the
state priority list for funding. This priority rating would most likely
mean that federal or state money would not be immediately forthcoming
and yet still result in a limited growth situation due to the inadequacy
of the treatment facility.
A land use control/surface runoff issue of greater significance is that
the present methods of measuring dry weather water quality are inappro-
priate for wet weather. (Dry weather refers to a time period when there
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is relatively little rain while wet weather refers to the rainy season.)
First, the water quality standards for beneficial uses established in
the basin plans have been determined to protect generally the beneficial
uses during dry weather flows (e.g., 7 day, 10 year low flow). The impact
of wet weather flows on beneficial uses has not been assessed and therefore
standards setting has not been necessary. Secondly, pollutant levels in
dry weather flows are usually measured in terms of concentrations that are
measures of the amount of contaminants in a net volume of water (e.g., 5
milligrams per liter) thereby taking dilution into consideration. Surface
water runoff, however, can cause wet weather concentrations to be lower
than those for dry weather because the increase in stream flows more than
offsets the increase in contaminants washing into the stream. Yet, the
total amount of pollutants entering the water would be substantially
higher. This higher total amount of pollutants can have a considerable
impact on beneficial uses once they settle in areas of inadequate mixing
or movement such as in bays or estuaries. Therefore wet weather measure-
ments should be distinguished from those for dry weather if greater atten-
tion is paid to the impact of total pollutants (mass emissions) on beneficial
uses.
Office of Planning and Research (OPR)
The Office of Planning and Research is the designated state agency for
overall state-level environmental policy planning. Its functions in-
clude assistance to and coordination with other state departments and
agencies. Perhaps most importantly, its functions do not include any
direct implementation or regulatory power.
OPR Policy Setting. The primary activity of OPR related to policy
setting is the legislatively required Environmental Goals and Policy
Report. The purpose of this report is to provide both coordination
and information for the legislature and state agencies, and it does
this by presenting all approved state environmental goals. It also
provides a 20 to 30 year overview of state growth and development.
The report, therefore, does not set policy. Rather, it compiles the
policies from other state agencies. For example, the air and water
quality policies of the 1973 report are re-statements of policies set
forth in California's pollution legislation.
OPR Intergovernmental Relations. The major role OPR plays in state-
level planning is one of coordination and assistance to other state
departments, to regional agencies and to local governments. For ex-
ample, one of its special duties is to help the State Department of
Finance in preparing the state budget in such a way that it reflects
the statewide environmental goals.
OPR serves as the state clearinghouse for environmental impact reports
and A-95 reviews of applications for federal grants to state, regional
and local governments. It is also the state level administrator of
federal "701" comprehensive planning funds to cities, counties and
regional planning organizations.
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OPR Effect on Land Use. Because OPR lacks direct implementation or
regulatory power, it is restricted in how it affects land use patterns
in the state. It relies on altering the policies of other state agencies
through various special purpose studies, and on encouraging local govern-
ment to improve its own ability to prepare the mandatory elements required
of each city and county general plan. It has therefore to date played
only a nominal role in integrating air and water quality considerations
with land use planning.
Department of Fish & Game
Protection and enhancement of the state's wildlife resources is the
responsibility of the Department of Fish & Game. To fulfill this
responsibility, the Department carries out a wide range of activities,
including measures to protect the waters of the State from pollution.
The Department receives policy direction from its governor appointed
five member Fish and Game Commission.
Policy Setting and Enforcement. General guidance for the Department's
policies and activities is provided by the California Fish and Wildlife
Plan, which was completed in 1965. The Plan consists of a comprehensive
inventory and evaluation of the state's fish and wildlife resources, and
it then recommends goals and policies to be followed in order to achieve
them. The policies and recommendations include a commitment to actions
preserving fish habitats by protecting water quality.
The State Fish and Game Code gives the Department substantial authority
to limit water pollution. Besides listing a number of specific substan-
ces that are "...unlawful to deposit in, permit to pass into, or place
where they can pass into the waters of this State..", the law also makes
a blanket statement making it illegal to discharge "any substance or
material deleterious to fish, plant life or bird life." Additionally,
the Fish and Game Code bans the disposal of vehicle parts or other
rubbish within 150 feet of the high water mark of any water body or
water course. The Department has the authority to levy fines against
offenders and require polluters to remove the contaminating substances
from the water.
The Department also has review authority over all actions which would
divert or obstruct the flow of any water course or water body, includ-
ing streams or rivers, or use material from their beds. Further regu-
lations require government agencies, utilities and private individuals
or corporations to submit plans affecting designated water courses and
water bodies to the Department for review. If the Department determines
that the activities will affect an existing fish or game resource, it
can impose conditions on the project for their protection. The Fish
and Game Code makes special mention of salmon and steel head resources,
and directs the agency in its review of project environmental impact
reports to promote measures that expand as well as protect salmon and
steelhead resources.
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In its water quality related work, the Department of Fish and Game works
in conjunction with the various regional water quality control boards.
The Fish and Game Code specifically directs the Department to cooperate
with and work through the regional water quality control boards in
correcting pollution problems. According to interpretations of state
law by the Attorney General, the Department has authority to take in-
dependent action to apply its own criminal sanctions against polluters.
Additionally, the Attorney General has ruled that water quality control
boards cannot permit actions that would be in violation of the Code. In
the North Coast Regional Water Quality Control Board's jurisdictional
area, the fish and game employees serve as field inspectors.
Effect on Land use and Water Quality. The Fish and Game Commission's
effect on land use is largely on a site-specific, case-by-case basis.
A review of applicable literature did not reveal any cases where the
Commission has come into conflict with a regional water quality control
board. It appears that every effort has been made to avoid such a
conflict. Fish and game habitat is one of the "beneficial uses" con-
sidered in setting standards in regional water quality plans.
Energy Resources Conservation and Development Commission
The Energy Resources Conservation and Development Commission was created
in May 1974 by the State Energy Resources Conservation and Development
Act (Public Resources Code 25000) and became effective January 1, 1975.
The Commission is a state level planning and regulatory agency with
comprehensive authority to plan for electric energy needs within the
State and to preempt, with few exceptions, the certification of all new
thermal power plants or electric transmission lines. (In this case,
thermal means all those electric generating systems based on heat con-
version, which thereby includes virtually all forms of energy gener-
ation.) The Commission is part of the Resources Agency. A surcharge on
electricity rates pays for its operations.
Policy Setting and Enforcement. The main policy setting device will be a
biennial report which includes emerging trends and the level of state
and service area energy demands. These demands are then to be re-assessed
by the Commission, and it will issue its own statement on future energy
demands, taking into consideration growth and development, environmental
quality needs, maintenance of a healthy economy and protection of public
health and safety. This statement will provide guidance for certification
of new facilities.
Enforcement powers of the "Energy Commission" come in the form of a certifi-
cation program of all new electric generating sites and related facilities.
The Commission has the power to override many state and local agency decis-
ions. The override power cannot be used, however, on air or water standards,
Effects on Land Use. The "Energy Commission" was created in 1975 and thus
it has not yet developed decisions or plans by which its policies can be
assessed. Its powers most certainly can affect such growth management
issues as the timing and sizing of additional power sources to a region
or community. However, it is too early to tell, for example, if the Com-
mission's charge to seek means of conserving energy will include limits
on population until the per capita consumption drops to desired levels.
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It is certain that requiring the Energy Commission to prepare the Environ-
mental Impact Reports for all proposed new sites is a step toward ensuring
that more than just energy requirements are considered in energy planning.
Department of Transportation (Caltrans)
The Department of Transportation (Caltrans) was created in 1972, in part
to meet federal transportation planning requirements. The State Trans-
portation Board was created at the same time. The Board's functions
include:
1) review of transportation plans and the adoption of the Calif-
ornia Transportation Plan;
2) review of annual budgets for their consistency with the
California Transportation Plan; and
3) review of transportation implications of statewide and regional
comprehensive general plans, including those for air and water
quality.
Means of Policy Setting. Transportation policy for California was provided
Tn the 1972 legislation. Further elaboration on this general legislative
policy will be provided when the California Transportation Plan is completed.
The 1972 legislature made a clear policy shift towards environmental con-
siderations when it placed emphasis on:
1) urban mass transportation and interregional high-speed trans-
portation; and
2) a highway system which is compatible with statewide and regional
socio-economic and environmental goals, priorities and available
resources.
In noting past problems, the legislature stated that "it is the desire of
the state to provide a transportation system that significantly reduces
hazards to human life, pollution of the atmosphere, generation of noise,
disruption of community organization, and adverse impacts on the natural
environment" (Section 14000 of Government Code).
The following example was provided by the legislation to clarify the
direction for future transportation planning:
"In some cases, future demands, particularly in urban corridors,
may prove to be beyond the practical capabilities of a highway
solution; while in other cases, environmental conditions may rule
out a highway solution" (Section 14000, Government Code).
Effects on Air, Water and Land Use. The policy relationship of Caltrans
and the State Transportation Board to land use, air and water quality
will become clearer when the California Transportation Plan is completed
These interrelationships must be considered due to:
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1) Environmental Impact Report requirements, and
2) state transportation policy directives requiring the prepara-
tion of alternative plans which can be assessed for air and
water quality implications.
Yet, the state statute has already come under fire for not placing
sufficient emphasis on air quality issues. The Land and the Environ-
ment, a publication sponsored by the Planning and Conservation Foun-
dation, questioned if the statue went far enough in air quality issues.
The report indicates that the state statute would have been stronger and
more consistent with federal regulations if air quality served more as a
"constraint" rather than a "consideration."
This concern may have been premature, owing to the State Transportation
Board's action on the draft report of the California Transportation
Plan. The Board postponed preparation of the final plan due to inade-
quacies in the draft. The Board determined that many parts of the draft
did not comply with sections of the state statutes requiring a clear
presentation and evaluation of alternative plans. An alternative that
was not in the draft, and one which the Board wanted to see, was one
aimed at reducing auto use.
REGIONAL AGENCIES INVOLVED IN AIR AND WATER QUALITY
This next section is concerned with the regional governmental agencies
involved in land use, air quality and water quality. Two of the most
important of such agencies, the air pollution control districts and the
regional water quality control boards, were discussed previously. Two
other regional agencies active in pollution matters in the San Francisco
Bay Area, the San Francisco Bay Conservation and Development Commission
and the regional coastal zone commissions, do not have jurisdiction
inside the Sonoma Study area. The three^regional agencies that will be
discussed are the Association of Bay Area Governments (ABAG), the Metro-
politan Transportation Commission (MTC), and the Bay Area Sewage Services
Agency (BASSA).
Association of Bay Area Governments (ABAG)
ABAG was the first council of governments in California. Created in
1961, it functions as the only multi-function, comprehensive planning
agency concerned with the entire San Francisco Bay region. At present,
85 of 92 cities and 7 of 9 counties in the Bay Area are members of ABAG
as voluntary signators to a joint powers agreement.
Policy and Enforcement Powers. ABAG policy is stated in the form of 1)
the Regional Plan 1970:1990, 2) additions and amendments to the Regional
Plan, and 3) actions by agency committees reviewing grant applications.
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The Regional Plan's policies are concerned with regional growth in the
Bay Area and include a city-centered concept aimed at re-building the
existing cities and preserving open space between the cities. ABA6 has
prepared or is presently preparing a variety of regional plan elements
aimed at satisfying federal requirements; these include HUD required
housing and land use elements and an environmental management element
with AQMP and "208" sub-elements.
Effect on Land Use and Air and Water Quality. ABAG has no direct en-
forcement powers.Any implementation of its policies comes either as
voluntary action on the part of member agencies or as a result of A-95
reviews which alter the initially intended actions. For example, a 1975
ABAG initial review on a "new town" proposal in an area of current air
quality problems resulted in the project being postponed indefinitely.
Nonconformance with various Regional Plan policies provided part of the
reasoning behind-the negative comments. The review also indicated that:
1) topographical and meteorological characteristics of the area were
conducive-to air pollution, and 2) long distance car commute patterns
would result from the development due to the lack of nearby jobs and
mass transit.
The effects of ABAG air pollution policies on land use would be to en-
courage a centralized population and employment pattern in sub-regional
areas that are serviced by mass transit. ABAG policy is less clear on
water quality control and so, therefore, is its related effect on land
use. It is expected that these policies will become more specific
during the "208" planning effort.
Metropolitan Transportation Commission (MTC)
The Metropolitan Transportation Commission (MTC) was created by state
legislation in 1970. It was organized to respond to federal trans-
portation programs and to the state mandate of preparing a regional
transportation plan for the Bay Area. It is governed by a 19-member
board representing the counties, the state Secretary of Business and
Transportation, and the federal Departments of Housing and Urban
Development and Transportation.
Policy Setting and Enforcement. The principal policies of MTC are
found in its Regional Transportation Plan. This plan, adopted in 1973,
considered:
a) ecological, economic, and social impacts of existing and
future regional transportation systems; and
b) regional plans prepared and adopted by other organizations.
Its content focused attention on 1) federal, state and local highways,
2) transbay bridges and 3) mass transit systems.
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The enforcement powers of MTC are:
1) review and approval of local government and transportation
district applications for state and federal transportation
assistance to ensure compatibility with the regional trans-
portation plan; and
2) approval of various transportation construction projects -
bridges, exclusive right-of-way transit systems, bridge
expansions.
Effects on Land Use and Air and Water Quality. The effects of MTC on
land use are considerable.- It is for this reason that MTC is linked to
ABAG through a legal agreement and through a Joint Policy Committee.
Its planning and plan enforcement powers are major determinants of
regional growth In terms of size, shape and timing. A number of MTC's
Regional Plan objectives and policies place particular emphasis on land
use and environmental linkages. They include:
1) "transportation programs will be designed to reduce dependence
on the automobile as a transportation mode;
2) The speed, frequency and service efficiency of transit shall
be increased to enable it to compete with the automobile as a
feasible and attractive choice;
3) Pricing mechanisms and other economic incentives and traffic
and parking restriction shall be considered for appropriate
application to reduce automobile use and traffic congestion
and improve access in major urban areas consistent with local
and regional interest;
4) Staging of transportation facilities investment shall correspond
to staged development of the metropolitan centers in accordance
with the ABAG Plan; and
5) Transportation program designs and plans shall include estimates
of air polluting emissions, so that these plans can be evaluated
by air quality standards."
These policies place strong attention on coordinated land use/transportation
plans which are aimed at reducing air pollution levels. They also give
direction to the use of mitigation measures, including transit and traffic
restricting approaches, that could further reduce the potential for air
pollution created by the car. Finally, MTC has most recently been working
on the Transportation Control Plan portion of the State Implementation
Plan for the Air Resources Board. The agency has also been developing
parking management guidelines for the Bay Area.
Bay Area Sewage Services Agency (BASSA)
BASSA was created to ensure the implementation of the San Francisco
Regional Water Quality Basin Plan. To carry out this function, BASSA
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prepared a comprehensive water quality management plan. This plan
included:
1) a facilities plan - a system or system for conveyance, treat-
ment, reclamation and disposal of municipal and industrial
waste waters, and
2) an implementation plan - an identification of the appropriate
local agencies responsible for constructing and operating the
water quality control facilities. The implementation plan was
to include a timetable for construction and a financing plan.
Policy Setting and Enforcement. BASSA policy setting is made by its 21 -
member board. The board's policy document is its Regional Water Quality
Management Plan which was adopted in December, 1973. The policies of
this plan are generally similar to that of the San Francisco Bay Regional
Water Quality Control Board. This was to be anticipated because the
BASSA legislation requires it to comply with the policies, plans and
objectives of the State Water Resource Control Board and its regional
boards. In this manner, BASSA's planning is very similar to that of the
regional board.
The main difference between BASSA and the Regional Water Quality Control
Board relates to implementation powers. BASSA can assume responsibility
for construction and operation of a facility: 1) when asked to by one
or more sewage agencies, or 2) when there is a finding that a local
agency does not wish to proceed or cannot proceed on a proposed facility.
Effect of BASSA on Land Use. BASSA does not have any of the land use
powers of either the State Water Resources Control Board or its regional
boards. For example, it does not make findings on the quality of sewage
treatment from a particular discharge facility and place restrictions on
its further use. The only possible effect on land use would be that
which would occur as the result of BASSA taking over the construction of
a sewage treatment plant that was operating below water quality standards,
thereby removing a growth limiting cease and desist order. This event
has not yet occurred and its likelihood appears remote.
LOCAL GOVERNMENT LAND USE CONTROLS AND AIR AND WATER QUALITY
The next section on governmental structure analyses the use of land use
controls by cities or counties in achieving air and water quality. The
land use planning activities presently operating in the Sonoma Study
area will serve as the basis for analysis. The regulations studied
include General Plans, zoning ordinances, subdivision regulations and
grading regulations.
General Plans in California
The California Planning and Zoning Law provides the statutory basis for
local government planning in California. It requires each county and
city in the state to establish a planning agency whose functions include
IV-18
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the development and maintenance of a general plan. This general plan is
required to include the following elements:
1) land use,
circulation,
housing,
conservation,
noise,
scenic highway,
7) seismic,
8) open space, and
9) safety.
Each of these elements requires a statement of development policies
including objectives, principles, standards and plan proposals. The
Conservation Element is of particular importance to water pollution
because it is required to provide policy on conservation, development
and use of natural resources including water, rivers, and harbors. It
is also to cover:
(1) The reclamation of land and waters i
(2) Flood control ,
(3) Prevention and control of the pollution of streams and other
waters , and
(4) Regulation of the use of land in stream channels and other
areas required for the accomplishment of the conservation
plan.
Other general plan elements can also have significance to water pollution
control. For example, the Open Space element lists the use of open
space for the "protection of water quality and water reservoirs as well
as for the protection and enhancement of air quality."
No element is particularly adaptive to air pollution control. Because
of this problem, the California legislature in 1972, through Senate Bill
981, requested the development of guidelines for an air pollution control
element in the general plans. However, the California Air Resources
Board did not recommend such an element because: 1) the required
environmental impact report on general plan elements would accomplish
similar results, and 2) a local plan air pollution element could not
resolve the problems of interregional transport of pollutants.
A planning consultant report, prepared as part of the SB 981 request,
found similar problems with an air pollution element. For example:
1) air quality modeling or forecasting could only be accomplished
at an air basin level; and
2) interjurisdictional problems of plan development and enforcement
would not be resolved.
IV-19
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Therefore, all efforts at creating a separate air pollution element in
local general plans have been dropped. Theoretically, the air quality
consideration in general plans would come as a result of the environ-
mental impact reports (EIR) on the other general plan elements. (To
date, no EIRs for any General Plan and General Plan Element have been
submitted in the Sonoma study area.) In addition, total reliance on an
EIR fails to recognize the need for local governments to adopt policies
on methods of attaining air quality. Conceivably, such policies could
be well addressed in the land use or transportation elements. However,
because they are not specifically required, local planning agencies
have generally not adopted specific air quality policies.
Enforcement of General Plans in California. The general plan has no
direct legal effect.It must be implemented by various legal controls
including zoning ordinances, subdivision ordinances, and a variety of
other ordinances, regulations, and administrative rules. The general
plan is also implemented by capital or operating budgets.
California has taken a number of steps in tying the general plan policies
directly to implementation. First, it has required that zoning ordinances,
open space ordinances, and subdivision and building permits must be "con-
sistent" with general plans. Unfortunately, there has been no clear de-
scription of the word "consistent" as to whether it includes the process
of zoning, including the attachment of conditions, or simply consistency
of the mapped land uses of the general plan and zoning map.
An interesting portion of this legislation is that enforcement of con-
sistency can come through legal action by residents and property owners
within the city or county. •-•• -
The California legislation has required that public works budgets from
all city or county departments be reviewed by the planning departments
for their conformity with general plans. This requirement must also be •
met by special districts. While the law is limited in that it does not
include operating budgets or require budget "consistency" with general
plans, it does provide an initial step towards integrating local policy
setting with budgeting.
The Impact of New Forms of Zoning On General Plans. A number of the
recent zoning approaches in the Sonoma study area, as in the rest of the
United States, have shifted from very rigid and patterned controls to
those with increasing administrative flexibility. Planned Unit Develop-
ment zones, cluster zones, overlay zones, and performance standard zones
have shifted the administration of zoning from rigid procedures to those
with greater flexibility for reviewing environmentally or socially sensi-
tive geographic areas. This new flexibility is particularly adaptive to
the General Plan Policies in that the policies can be applied directly •
as part of mitigating conditions in the granting of zoning. More complete
data on a site can also be provided for an Environmental Impact Report
(EIR), which is required in California for most zoning decisions.
For example, a particular parcel of land may not appear to be suitable
for housing development from a water quality standpoint due to poor
natural drainage conditions which could lead to rapid water runoff and
IV-20
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greater stream pollution. Yet, an adopted general plan policy, included
in the Conservation Element, might permit development in such areas
when:
1) a detailed site investigation included in an EIR indicates
that structural means can be undertaken on the parcel to
reduce the pollution runoff problems, and
2) such structural measures (e.g., detention ponds, siltation
basins) are included as part of zoning conditions.
The importance, then, of general plans and zoning ordinances in California
is that they provide the policy making and enforcement structure by which
local level air and water quality land use issues may be addressed. To
summarize:
1) the General Plans provide policy,
2) the zoning and subdivision ordinances and building permits
provide the framework and mechanisms to enforce the policies,
and
3) EIRs provide the technical information by which flexible
zoning decisions, based on both policy and site sensitive
data, can be made.
Analysis of General Plan Policies for Air and Water Quality in Sonoma
County
A review has been undertaken of all General Plans and Plan Elements in
the study area for policy statements that are directly or indirectly
related to air and water quality.
The documents include:
Sonoma County
o Statement of goals and policies of the draft General Plan (the
statement has not been adopted as of the date of this writing)
o Plans of unincorporated communities which vary in content from
general to specific recommendations
Santa Rosa - General Plan and completed elements
Rohnert Park - General Plan and completed elements
Sonoma - General Plan and completed elements
Sebastopol - General Plan and completed elements
Healdsburg - General Plan and completed elements
Cotati - General Plan
IV-21
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General Plan Policies Related to Air Quality. Few of the plan documents
reviewed give much explicit attention to air quality concerns. Only the
County, Santa Rosa, Petaluma and Sevastopol make statements that can be
interpreted as placing a major policy emphasis on preserving air quality.
Some of the other plans make incidental policy recommendations that are
specifically tied to reducing pollution or its nuisance effects, but do
not make a general commitment to the maintenance or enhancement of over-
all air quality. All the plans include policy statements, which although
not directly related to air quality concerns, are of potential relevance
for improving air quality conditions.
Of all the planning documents reviewed, the Sonoma County goal and policy
statement puts the strongest emphasis on air quality concerns. It in-
cludes a series of well articulated proposals directly addressing the
question of air quality maintenance. Its suggestions include support
for a land use pattern that minimizes the number of trips and vehicle
kilometers travelled, promotion of a transportation system that reduces
the number of vehicles, improvement of the efficiency of traffic control
systems, regulation of point sources, control of indirect sources and
support of emission control device programs.
Some of the General Plan air quality policies of the various cities are
quite general. Santa Rosa's Composite General Plan simply calls for,
without further elaboration, the application of appropriate zoning
standards to control sources of pollution. Sebastopol's Open Space
Element recommends cooperation "...with other public agencies in the
development of agricultural, industrial, and transportation systems
which will minimize air pollution and not result in economic hardship."
Air pollution caused by industries receives the most attention in
General Plan policies. Rohnert Park's plan calls for protecting resi-
dential areas from the air pollution and other nuisances associated with
industrial uses. Healdsburg's plan also recommends reducing industrial/
residential land use conflicts, and calls for a solution to the air
pollution problems associated with sawdust burning at the sawmills.
Petaluma's Ecologic Resources Element, which is a combination of a
number of the required Plan Elements, calls for locally adopted per-
formance standards for minimizing smoke, fumes, gases, dust, and par-
ticulate matter.
One unique feature of the Petaluma Ecologic Resources Element is the
stress it puts on the role of reoxygenation in air quality maintenance.
The policy calls for the preservation of water and vegetated areas, and
the creation of planted buffer strips along major thoroughfares and
around industrial areas for the purpose of absorbing air contaminants.
Policies aimed at reducing the dependence on the car through the arrange-
ment of land uses can also be related to air quality. The City of Sonoma
recommends that neighborhood convenience centers be allowed in order to
reduce automobile use. Santa Rosa places a great deal of emphasis on
creating a strong central activity center and providing housing in close
proximity to it. The plan for the Sonoma State University environs
includes a variety of policies that emphasize the creation of a high
density, pedestrian-oriented community around the new Sonoma State
campus. None of these policies, however, were specifically tied to
reducing air pollution.
IV-22
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Although only the County explicitly relates its transportation policies
to the maintenance of air quality, most of the other planning juris-
dictions also make recommendations in these areas that could contribute
to the achievement of air quality goals. Both Petaluma and Santa Rosa
suggest the expansion and improvement of local bus systems. Rohnert
Park recommends that access to arterial streets be controlled in order
to improve traffic flow. Virtually all the plans call for the creation
of networks of pedestrian ways and bicycle paths.
General Plan Policies Related to Water Qua! 11tv. On the whole, water
quality-related factors receive more attention in the local general
plans than do air quality considerations. There is more emphasis on
acceptable water quality as a generalized goal and as a result of
specific policies. Additionally, the plans recommend a variety of
measures that could potentially support water quality maintenance and
improvement objectives without explicitly linking the actions to water
quality goals. The County and most of the cities identified the
preservation of water quality as a general goal to be achieved. The
County, Santa Rosa and Petaluma tie the general goal of^preserving water
quality to the more specific objective of protecting aquatic life in
local waterways.
Petaluma, Rohnert Park, Sebastopol and Healdsburg, which are wholly or
partially dependent on local wells and reservoirs for their municipal
water supplies, stress the need to maintain water quality in order to
protect their municipal sources. Petaluma recommends that the land
surrounding its reservoirs be kept in open uses and managed to prevent
erosion and pollution. In order to do this, the plan suggests use of
easements and land use control measures to prevent urbanization.
Additionally, management techniques to regulate grazing and control
drainage are recommended. Because the watershed lands are beyond the
city's own jurisdiction, it is further recommended that all governmental
actions affecting the watershed area be carefully evaluated for their
impacts. Sebastopol proposes that the area surrounding it be zoned for
large agricultural parcels in order to protect groundwater quality and
to ensure recharge. The county calls for protection of groundwater and
recharge areas, but the specific means of doing so have not been spelled
out.
Although none of the plans for unincorporated areas of the County men-
tion the preservation of water quality as a general goal, they do pay
attention to the problems of failing septic tanks and the need to pro-
tect the groundwater sources of domestic and agricultural water supply.
In serai-urbanized areas with concentrations of failing septic tanks, the
plans recommend the expansion of community sewage collection and treat-
ment systems. Many of the plans propose that proof of adequate per-
colation be required as a condition of new rural lots.
Few of the plans reviewed considered the management of natural resources
and resource extraction as factors in water quality maintenance. Only
the County, Petaluma and Healdsburg specifically recommend forbidding
disposal of wastes in streams, floodplains or other areas where water
contamination might occur. The County suggests that measures be taken
IV-23
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to regulate forestry, agriculture, and mineral extraction to reduce
erosion and protect water quality. The plans for unincorporated areas
in forested portions of the County recommend regulation of forestry to
prevent land instability and erosion including one proposal that the
timing of fertilization be controlled to protect water quality.
Although the increased runoff and soil erosion that often accompany land
conversion and development affect water quality, these problems receive
no attention in most of the plans. When they are considered, it is
often in a somewhat limited way. Santa Rosa, for example, simply calls
for the preservation of natural vegetation. Petaluma's Ecologic Re-
sources Element is the only plan with a fairly complete set of recom-
mendations in this area. Beside suggesting replanting and grading
plans, it recommends that development be regulated to reduce runoff and
that projects that would produce excessive erosion be forbidden.
The plans devote little attention to the potential role of site design
factors in contributing to improved water quality. Only the county and
Healdsburg call for site plans that minimize runoff. Only the county
mentions the provision of on-site drainage improvements, including on-
site ponding of runoff in cases where a development would create major
increases. The county and Rohnert Park suggest reducing requirements
for pavement widths in residential areas, although the intent is to
improve the aesthestics, rather than reduce runoff. Many of the plans
recommend planned unit development concepts to allow clustering and the
preservation of open space, but the water quality benefits are seldom
mentioned.
Somewhat more attention is paid to the special problems associated with
hillside development, and the implications for erosion and water quality
are occasionally cited. The Petaluma and Sebastopol plans, as well as
virtually all the plans for the unincorporated areas, call for large
lots or otherwise reduced densities in the hillside areas. Santa Rosa,
Petaluma, Sebastopol and a few of the unincorporated areas recommend no
development at all in areas of especially unstable slopes. Petaluma and
Sebastopol suggest that street improvement requirements be modified to
reduce cuts and fills. Sebastopol's plan is the only one that makes
specific site engineering suggestions by recommending that energy dis-
sipators be required to reduce erosion.
Virtually all of the plans reviewed devote a great deal of attention to
the preservation of natural stream channels. In only a few cases is
water quality protection mentioned as an objective. Generally, the
intent seems to be to preserve the aesthetic qualities of the streamside
vegetation. Most of the plans recommend building setback and floodplain
regulations to achieve their objectives. Only Petaluma and Santa Rosa
go so far as to suggest the purchase of land or easements along the
streams.
Evaluation of General Plan Air and Water Quality Policies. Given the
recency of the idea that local planning and land use control authority
can be applied to the solution of air and water quality problems, and
the lack of detailed direction in this area in the state's local plan-
ning law, it is no surprise that the plans reviewed tend to be deficient
in their treatment of air and water quality issues.
IV-24
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Most of the plans considered here treat air and water quality concerns
tangentially, if at all. In few cases do the plans discuss the nature
of the local meteorological and hydrological systems, levels and sources
of air and water degradation, implications of air and water quality con-
ditions for the community, or the rationale for taking steps to maintain
air and water quality. Because the dimensions of the air and water
concerns are not treated in a systematic way, the goals and policies that
are suggested tend to be quite inconsistent, and there is no basis for
determining that they present a coherent program for environmental
management.
Similarly, since the specifics of local air and water quality issues
are not identified, there is no framework for evaluating the appropri-
ateness of any goals and policies that might be recommended. For ex-
ample, the plans do not provide enough information to determine whether
or not the preservation of streamside vegetation is especially critical
for the maintenance of water quality or if other measures would deserve
a higher priority.
When the plans did set goals for air and water quality they were most
often stated in vague terms such as "maintain air quality" or "preserve
the quality of surface and groundwater." In only a few cases is there
an attempt to make the goals specific by relating them to tangible objec-
tives such as preserving aquatic life or reducing view-obscuring smog.
Even these attempts fail to go far enough, because they do not provide
the qualitative or quantitative standards necessary to guide policy
selection or measure goal achievement.
In most cases the air goals are not supported by well-defined policies
needed to effect their achievement. Most of the policies that are sug-
gested are very general goals, seldom spelling out the specific public
actions or changes in procedures, administrative guidelines and regu-
latory ordinances that might be required.
Air and Water Quality Provisions of the Zoning and Subdivision Regulations
in Sonoma County
Local development control regulations can potentially play an important role
in mitigating impacts on environmental quality. To determine the extent to
which this potential is now realized in Sonoma County, an analysis was made
of the zoning, subdivision and grading ordinances and the special growth
regulations of the County and each of the municipalities in the study area.
It was found that these local regulations can apply to either air and
water quality concerns including some that can be applied concurrently
to improve both media. The regulations reviewed include:
o regulation of the magnitude of development
o regulations on the location of new development
o regulations on the intensity of development
o regulations of land uses
IV-25
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o regulation of site development practices
o regulation and review of site design
Regulation of the Magnitude of Development
Communities can reduce the potential for additional air and water pollu-
tion merely by restricting the total amount of new construction. Limited
development could result in fewer cars or industries, with an attendant
lower air pollution emissions level or with less urban runoff, erosion
and wastewater. Such a limitation is an extreme action which most com-
munities are very reticent to exercise. However, development moratoria
and other forms of building permit limitation are becoming more common-
place because of restrictions initiated by regional or state water
quality control boards due to inadequacies of the sewage treatment
systems. Most cities in the study area have been slow in integrating
such anticipated limitations into their zoning ordinances. Petaluma,
however, has attained nationwide attention for its efforts in inte-
grating growth restrictions into its local planning controls.
Petaluma has reduced its growth rate by'means of its residential devel-
opment control system. In addition to limiting new residential develop-
ent to 500 units per year, the system also apportions the development
among the various sectors of the city. This spatial allocation is of
interest from both an air and water quality point of view because it
disperses each year's construction activity, preventing the erosion,
dust and runoff associated with the development process from being
concentrated in any one particular location.
Regulations on the Location of New Development
Sonoma County and each of the municipalities control the location of new
development with zoning district regulations and annexation and utility
extension policies. These regulations and policies can directly or in-
directly guide development away from areas where it would be undesirable
from a water and air quality point of view. For example, the county,
Santa Rosa, Petaluma, Rohnert Park and Healdsburg have special district
regulations governing hillsides which establish density levels lower
than those permitted in most residential areas. Presumably, one effect
of these regulations is to discourage development in hillside areas
because they involve high per unit costs for building and infrastructure
construction. Because the hillside building that is allowed is guided
to the least steep slopes, runoff speeds and the associated erosion are
lessened. Additionally, the lowered intensities of permitted develop-
ment reduce the need for vegetation removal, grading, and the creation
of impervious surface thereby reducing the amount of runoff, erosion and
dust. Similarly, some of the land use regulations locate new residentia1
growth away from air pollution sources. Zoning ordinances throughout
the county do this in a general way by segregating industrial and com-
mercial zones. For example, Petaluma's subdivision regulations extend
the principle a bit further, requiring non-residential subdivisions to
provide buffering along lot lines bordering existing or potential resi-
dential uses.
IV-26
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Regulations Oh the Intensity of Development
Density and intensity of development are of primary concern to water
quality due to the manner in which they influence the amount and quality
of urban runoff. Generally speaking, the lower the density and the less
the allowed lot coverage, the greater the amount of water available to
transport pollutants. The reduction of "impervious surface" — those
surfaces such as roofs, streets or parking lots where there is little
rainwater absorption — is one method to reduce surface runoff pollution.
The residential densities permitted in Sonoma County and its communities
vary greatly. In Cotati, Sonoma and Healdsburg, there are residential
districts that require an acre or more for a dwelling unit. In Santa
Rosa, densities of up to 108 dwelling units per acre are possible. The
densities allowed in most residential districts, though, range from 3 to
16 units per acre.
Zoning ordinances of Sonoma County and all the communities except Cotati
explicitly regulate the percentage of lot area allowed to be covered by
structure. All the jurisdictions considered have provisions in their
ordinances that establish minimum building setbacks and yards for most
districts. Lot coverage regulations do not provide an absolute limit on
the lot area devoted to impervious surfaces because they do not limit
such facilities as parking lots, malls, walkways and patios. In
practice though, there is a relationship between the permitted percentage
of lot coverage and the ratio of pervious to impervious surface in a com-
pleted project.
Regulation of Land Uses
The control of specific land uses as a method of reducing contaminants or
limiting the exposure of people to pollution has been largely confined to
efforts to improve air quality. For example, Petaluma, Cotati and Sebas-
topol have included special provisions in their zoning ordinances limiting
the number of service stations at any intersection to two, and establish-
ing 500 feet as the minimum distance between stations that are not at the
same intersection. These regulations have an indirect effect on air quality
in that they limit the local concentrations of exhaust gases and evaporated
hydrocarbons. Cotati supplements these provisions with a statement indic-
ating that all gas stations must comply with the regulations of the BAAPCD.
A performance standard approach is also used in the review of zoning decis-
ions on industrial land uses. Petaluma has simply adopted by reference the
current emissions regulations established by the BAAPCD. The county uses
a similar approach in general industrial districts but authorizes the Board
of Zoning Appeals to adopt its own standards in light industrial districts.
Rohnert Park, Cotati, Sonoma and Healdsburg establish emission standards
in terms of Ringelmann numbers which reflect smoke density. In a few com-
munities, the zoning ordinances also establish performance standards for
non-industrial uses and districts. Healdsburg's ordinance is the most
thorough, including a provison for each land use zone district forbidding
uses objectionable because of fumes, dust, smoke, cinders or dirt.
IV-27
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Regulation of Site Development Practices
A number of ordinances of the various jurisdictions in Sonoma County
require site development practices that can be used to reduce air or
water pollution. They include requirements affecting the land both
during and after it is prepared for development.
Efforts to reduce erosion and runoff during development receive
attention by most cities, either through grading ordinances or through
adoption of the excavation and grading chapter of the Uniform Building
Code (1973). All the ordinances require that grading plans must be
submitted for review, and they establish standards for excavation, fills
and drainage. Some of the ordinances require soil engineering and
engineering geology reports. None give any attention to erosion due to
wind and its resultant dust as a source of air pollution.
The need to maintain vegetation or replant disturbed areas is also
recognized by most ordinances. Replanting is mandated by Cotati's and
Sevastopol's subdivision regulations as well as included as a consider-
ation in Sonoma County's site plan review section of the zoning ordinance.
Planting is also required on major arterials to buffer or insulate
residential structures from noise and high concentration of air pollutants
associated with heavily travelled thoroughfares.
Review and Regulation of Site Design
All the jurisdictions include design review provisions in their zoning
ordinances. These provisions provide an extra measure of control over
the details of building and site design because they require plan review
and approval as a condition on obtaining a zoning or building permit is
applied for. Typically, the planning staff is authorized to review
routine proposals and suggest modifications in design. More significant
proposals must generally be referred to a special design review committee
or to the planning commission for review. Where there are design review
committee, their decisions can be appealed to the planning commission.
Planning commission decisions, in turn, can be appealed to the city
council (or board of supervisors in the case of the county).
There is wide variation in the kinds of design information required to
be submitted, and the criteria established for evaluating proposals.
Generally, the requirements and standards set reflect the purposes the
design review provisions are intended to achieve. In most cases, the
primary objective is to promote design which harmonizes with the project's
surroundings. The design review procedures, although at present used
almost exclusively for aesthetic considerations, do provide sufficient
breadth for site conditions that could improve air and water quality.
For example, Santa Rosa'a, Petaluma's, Rohnert Park's and Sebastopol's
design review criteria touch on water quality related factors only to
the extent that they require landscaping plans, tree preservation and
consideration of impacts on natural groundcover. The City of Sonoma's
IV-28
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design review provisions are also primarily aesthetically oriented, but
they do leave the way open for evaluation of water quality factors in
that they call for consideration of "...the effect on trees, water
courses, and other natural features of the site." 'Of all the design
review provisions, the County's is most specific in its regulations
requiring bicycle paths to be created. The design review requirements
of the zoning ordinances could be used to improve the arrangements for
pedestrian circulation. The County, Santa Rosa and Healdsburg ordin-
ances, in fact, specifically require applicants to indicate the pro-
visions being made for pedestrian circulation.
•
The planned unit development concept, which is authorized by most of the
zoning ordinances in the study area, also.contributes to reducing auto
dependency. Sonoma County's and Petaluma's planned unit development
requirements specifically call for integrated planning of vehicular and
pedestrian traffic. In Santa Rosa and Petaluma, the planned unit devel-
opment regulations allow for mixed land uses, which could reduce the
need to travel. Santa Rosa's ordinance makes it clear that one of the
intentions of the PUD option is to allow residential and commercial uses
to be located in proximity to one another.
Santa Rosa, Rohnert Park and Cotati allow developers of planned unit
developments density bonuses of 10% to 35%. Besides encouraging the use
of the PUD concept, these density increases also contribute to the
creation of pedestrian oriented and transit supporting environments.
Evaluation of Zoning, Subdivision and other Land Use Regulations. Because
the general plans of the various jurisdictions do not contain a systematic
and comprehensive strategy for air and water quality improvement, it is
no surprise that such an approach is not reflected in the ordinances.
To a large extent, the ordinance provisions that affect air and water
quality are primarily oriented to some other purpose. For example, the
controls over development intensity are generally intended to regulate
density and prevent crowding and congestion. Their use as a means of
reducing runoff is only a side-effect. Similarly, street design prin-
ciples included in the subdivision ordinances are primarily intended to
insure safe, smooth traffic flow rather than to reduce vehicular emis-
sions.
Because air and water quality factors remain secondary considerations in
the ordinances, they often receive only cursory treatment. For example,
the hillside regulations contained in many of the zoning ordinances
emphasize reduction of densities, but do not go into detail in specify-
ing design measures to be taken or standards to be met in limiting
runoff and erosion. The grading and drainage related ordinances which
incorporate the Uniform Building Code grading provisions are very
thorough and detailed, while others are considerably less complete in
their coverage and provide fewer technical standards to guide their
application.
IV-29
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TABLE
APPLICABILITY OF DESIGN REVIEW
IV-2
REQUIREMENTS IN SONOMA COUNTY
JURISDICTION
Sonoma County
WHEN DESIGN
REVIEW
REQUIRED
at time of ap-
plication for
zoning permit
or building
permit
DISTRICTS
Unclassified
Agricultural
Residential
Recreational
USES IN DISTRICT
FOR WHICH DESIGN
REVIEW REQUIRED
apartment development
with 4 or more units
Santa Rosa
Petaluma
Rohnert Park
Cotati
Sonoma
zoning permit,
use permit,
building permit
zoning permit
building permit
building permit
zoning permit
building permit
construction
permit
Commercial
Manufacturing
all districts
all districts
all districts
Architectural
Design
Control combining
Districts
all districts
single family
duplex residential
multiple family
intensive multiple
family
all uses
all uses except single
family dwelling units
and their accessory
units
all uses except a
single family dwelling
unit or a single parcel
all uses
all uses
"certain uses... which
would have ...substantial
adverse effect upon the
surrounding environment
and character of the
city..."
all conditional uses
all projects with 2 or
more units
IV-30
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TABLE IV-2 continued
JURISDICTION
WHEN DESIGN
REVIEW
REQUIRED
DISTRICTS
USES IN DISTRICT
FOR WHICH DESIGN
REVIEW REQUIRED
Sonoma
(continued)
Sebastopol
building permit
Healdsburg
zoning permit
building permit
residential hill-
side preservation
mobile home park
industrial park
wine production
all commercial
districts
historic conserva-
tion combining
duplex residential
high density
mulitple residen-
tial
low density
multiple residen-
tial
administrative
and professional
office
all commercial
industrial
all agricultural
districts
all residential
districts
all commercial
and industrial
districts
all uses
duplex or apartment
buildings
any commercial
building
all conditional
uses
all uses except single
family dwellings,
duplexes, and multi-
family dwelling with 6
or fewer units, unless
more than 3 permits are
to be requested for a
single block during the
course of the year
all uses
IV-31
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Some concerns that are of potential importance for air and water quality
are left virtually unregulated. For example, although urban runoff is
increasingly seen as a significant source of water pollution, none of f
the ordinances reviewed set specific limits on the amount or character
of runoff from a site during construction or after completion. Other
considerations that have been neglected by the ordinances include:
o tying approval of direct and indirect sources of air pollution
to an emission density analysis
o relating the approval of critical receptors (e.g. hospitals, rest
homes, housing for the elderly) to expected air quality conditions
o developing special design criteria for activity centers to en-
courage the creation of high intensity pedestrian and transit-
oriented environments
Setting performance standards for emissions from industrial uses is one
of the few areas where the communities have directly addressed air
quality concerns. Ironically, many of these standards are somewhat
meaningless. Some of the standards are in conflict with State law and
the regulations of the BAAPCD. The State establishes Ringelmann number
two as the maximum permitted opacity for smoke emissions, and the BAAPCD
is even more restrictive, establishing Ringelmann number one as a maximum.
In spite of these limits, a few local ordinances in Sonoma County state
that emissions as opaque as Ringelmann numbers three and four are permis-
sible. Many of the provisions governing emissions are expressed in
broad terms (e.g.: "No use...which creates any emission which endangers
human health, can cause damage to animals, vegetation, or other pro-
perty..."). Because these provisions have no explicit operational
definition, they are difficult to administer and enforce. The primary
utility of these blanket statements is to serve as a record of public
intent that can be cited when legal action is taken to abate nuisances.
One of the features of the ordinances that has a great potential for
dealing with land use related air and water quality controls is the
design review procedures established by all the zoning ordinances. As
the earlier description notes, the primary orientation of these pro-
cedures is most often to ensure improved aesthetic qualities. However,
some of the communities have begun to apply them to achieve functional
and environmental objectives as well. This is a trend that could be
developed in a way that enables design review to address air and water
quality related factors in a direct and meaningful way. The fundamental
charge that is needed to guide design review in this direction is to
develop the underlying understanding of the local air and water quality
relationships; in this manner, broad community policy and guidelines
can be developed, the information needed for review can be specified, and
the criteria to be used for project evaluation can be identified.
LOCAL AGENCY FORMATION COMMISSION (LAFCO) AND SPECIAL DISTRICTS
This section on governmental structure reviews the role of the Sonoma
County LAFCO and special districts in air quality, water quality and
land use control.
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Local Agency Formation Commission
The Local Agency Formation Commission is a county-level independent
regulatory body responsible for controlling the formation and expansion
of local governmental units in all areas of a county. Creation of the
commission was mandated by the Knox-Nisbet Act, and its powers were
expanded by the District Reorganization Act of 1965. The intent of the
legislation was to reduce sprawl and promote the orderly provision of
services. The Sonoma LAFCO is composed of five members: two members of
the County Board of Supervisors, two members of the city councils (chosen
by the mayors of the cities in the County), and one member representing
the general public (chosen by the other four members.)
The Commission reviews and approves (with or without amendments) or dis-
approves all proposals for:
Cities
- incorporation
- exclusion of territory
- disincorporation
- consolidation of two or more cities
- development of new communities
- annexation of territory
Districts
- formation of special districts
- detachments
- dissolutions
- mergers
- reorganizations
- consolidations
- annexation of territory
In reviewing proposals submitted to it, the Commission is required by law
to consider a wide range of factors including:
- population, land use, assessed valuation, drainage patterns
potential for growth
- need for organized community services, present cost and adequacy
of governmental services and controls in the area, future needs
for such services, probable effects
- conformity with comprehensive, sub-area and functional plans
- sphere of influence.
Under State legislation passed in 1972, all LAFCOs are required to
designate "spheres of influence" for governmental units in each county
in the State. Essentially the spheres of influence are intended to
IV-33
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define the ultimate physical boundaries of the various cities and
special districts. To accomplish this, "ultimate" spheres of influence
will define entities that'are physically separated from each other by
areas of unincorporated territory.
Effects of LAFCO's on Air and Water Quality. Because the Sonoma County
LAFCO has no written criteria for decision-making, it is difficult to
make a definitive assessment of the implications of its activities for
air and water quality. Based on the kinds of authority the LAFCO does
have, it can be hypothesized.that it influences air and water quality to
the extent to which it:
- promotes orderly urban expansion that creates compact communities
which minimize travel demands
- directs municipal and service district expansion to the most
appropriate lands, avoiding areas of steep slopes and easily
eroded soils
- permits annexations or allows formations of special districts
in areas where community sewer service is needed to correct
water quality problems due to concentrations of malfunctioning
septic systems
- relates the expansion of municipalities and special districts
to their capacity to treat the wastes associated with the in-
creased development that could result.
The Sonoma County LAFCO's present operating style is strongly oriented
to coordination. The existence of unresolved conflicts between city and
county development policies and the fact that the County's General Plan
has not yet been adopted account for the reason that the LAFCO has yet
to define spheres of influence but has focused on coordination instead.
One of the primary strategies being used to promote coordination between
the various governmental units is the creation of a city-county Plan-
ning Policy Committee (PPC), a mini council of governments, to serve as
a forum for the discussion of development issues. The County and local
planning directors have been organized by the LAFCO to serve in an
advisory capacity to the PPC.
The Sonoma LAFCO has also started to carry out studies aimed at rational-
izing the provision of government and services in sub-areas of the
County that are now served by complicated overlays of service districts.
Special Districts
The governmental picture in Sonoma County, as in other California
counties, is complicated by the existence of a multitude of special
service districts. These districts are essentially limited purpose
governments established to carry out specific functions within their
jurisdictions. Under state law, districts can be established for a wide
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variety of purposes. Examples of the types of districts authorized
include community services districts, water districts, fire protection
districts, sanitary districts, flood control Districts, recreation and
parks districts, hospital districts and mosquito abatement districts.
The districts have the authority to accept grants and contributions,
issue bonds, impose charges and taxes, provide services, construct
improvements, and in a few cases, issue use permits and regulate land
use activity.
Because of their ability to affect water quality and the general
pattern of growth, the degree to which the policies of various dis-
tricts are compatible with those of other governmental units is of
critical interest. To some extent, the sensitivity of a district to
the policies and concerns of other governmental entities is determined
by the composition of its board of directors. Presumably those dis-
tricts governed by a Board of Supervisors or boards composed of county
supervisors and municipal officials are the most attuned to the larger
countywide regional policy issues. Boards that are appointed or
directly elected are less likely to identify quite so closely with the
concerns of the other governmental bodies.
The composition of a district's governing body is determined by the
state enabling laws. Under the state codes, County Service Areas are
always governed by the board of supervisors while Community Service
Districts can either be governed by the supervisors or by an elected
board. The various water districts tend to have boards that are
separate from the board of supervisors: the Municipal Water Districts
and the California Water Districts have elected boards; the boards of
County Water Districts can either be appointed by the supervisors or
elected, and County Water Works Districts are given the option of
having the board of supervisors act as their board or having an
elected board. Two of the sewer districts (Sanitation Districts and
Sewer Maintenance Districts) have governing bodies consisting of
either the board of supervisors or the supervisors and other elected
officials. The boards of County Drainage systems always consist of
either the board of supervisors or a mix of supervisors and city
councilmen. Water Replenishment and Resource Conservation Districts
both have elected boards.
In Sonoma County, the special districts vary in size from maintenance
districts serving a single subdivision to the County Water Agency
which encompasses the entire county. For the most part, Sonoma
County's districts provide services in unincorporated areas, although
there are a few districts that do include incorporated territory
within their boundaries. Each of the districts has a governing body
to establish policy. The composition of this body varies from dis-
trict to district. In a large percentage of the districts in Sonoma
County, the Board of Supervisors serves as the Board of Directors. In
the other cases, the governing boards are either appointed by the
supervisors, or directly elected.
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The procedures to establish the various districts are generally sim-
ilar. In most cases, application must be made to the Local Agency
Formation Commission and its approval obtained. Generally, formation
proceedings can be initiated by petitions signed by a percentage'of
registered voters or land owners in the area being considered for
inclusion in a proposed district. If a sufficient number of sig-
natures is obtained, the County Board of Supervisors convenes a public
hearing to allow discussion of the matter. Based on the hearing, the
Board can either terminate the formation proceedings or give the
boundaries and functions of the proposed district precise definition
and put the question up to a vote. The most common procedure is to
allow the voters or property owners in the area within the proposed
district to vote on the matter, although in some cases the Board can
decide the question for itself. If a district wishes to take on new
functions, approval by the Board of Supervisors is mandatory.
Effects on Air and Water Quality. The special districts have a
variety of potential effects on air and water quality. In providing
sewage service, controlling storm and waste water, replenishing ground-
water, restricting use of on-site sewage disposal and providing for
street sweeping, some of the districts have a direct effect on water
quality. Many of the districts provide services such as water and
sewer which make possible urban levels of development in unincorpor-
ated areas, indirectly affecting air quality. A brief discussion is
provided here of those districts authorized under California statutes
to carry out these functions. Not all of the districts described
exist in Sonoma County.
Sanitary Districts and County Sanitation Districts focus most sharply
on water quality issues. Besides being able to construct and operate
systems for the collection and treatment of storm waters, these two
districts can also: 1) establish refuse disposal systems, 2) make and
enforce regulations for street cleaning, 3) compel connection with the
district's sewers and storm drains and 4) prohibit the use of cess-
pools, septic tanks, and private drainage systems. The last two of
these powers provide the special district with a form of land use
control that can shape the urban pattern in that particular section of
the county.
County Service Areas and Community Service Districts have a consider-
able amount of potential for addressing water quality problems. Yet
this aspect of their operation is not particularly well focused be-
cause of the wider spectrum of functions they are to provide for an
unincorporated area. Of the two, the County Service Areas have the
broadest authority, in that they are allowed to provide the same
services as the county. Both district types can collect and treat
sewage waste and stormwater, provide for drainage, and collect garbage
and refuse. However, unlike the Community Service Districts, County
Service Areas can also carry out street sweeping and soil conservation
activities.
There are four different types of water districts in California. Each
is allowed to establish and operate facilities for the collection,
treatment, and disposal of sewage, waste, and stormwaters. On the
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whole, the legislation which established these districts does not
emphasize pollution-related concerns. The primary exception is the
California Water Districts, which have the authority to declare cess-
pools and septic tanks to be public nuisances, and to require their
abandonment in favor of hookup to public sewer systems. The Calif-
ornia Water Districts and the County Water Districts also have power
to prevent actions that interfere with the natural flow of water - a
factor that could be related to water quality in some specific situ-
ations. Therefore, some water districts are vested with land use
controls aimed at protection of water quality.
There are several other types of districts that are not involved with
sewer service or otherwise explicitly linked to water pollution con-
cerns, but that do have some authority that could affect water quality.
Water Replenishment Districts are established to replenish groundwater.
They can buy and sell water, distribute it, and spread, sink, or inject
it. County Drainage Districts are established to control storm and
waste waters and protect property from storms. They can conserve
storm and waste waters or cause it to percolate. County Flood Control
districts can provide for the improvement of rivers, prevent their
obstruction, and protect and preserve their banks.
Resource Conservation Districts (RCD) deserve some special attention.
These districts were formerly known as Soil Conservation Districts,
but 1971 amendments to the California enabling legislation broaden
their scope. These districts are required to develop plans and
programs concerned with soil and water conservation, farm irrigation
and land drainage, erosion control and flood prevention, and community
watershed protection. An interesting part of the RCD legislation is
that the plans that are required must be "consistent" with County
general plans. This is the only case where the activities of special
districts are required to be integrated with local government planning.
Cooperating land owners can have the district pay for conservation
improvements on their land, but they must abide by specific cropping,
tillage, and range practices identified in the plans and programs.
DEFICIENCIES OF THE GOVERNMENTAL STRUCTURE FOR POLLUTION CONTROL
If looked at in its aggregate, the California governmental structure
for resolving air and water pollution problems would appear to be most
laudable. It is so vast in terms of agencies and legal mechanisms
that it would appear that no pollution problem can go undetected or
unabated. Yet the structure has many shortcomings due to its com-
plexity and its failure to recognize the roles which all levels of
government can play in environmental protection.
The major deficiencies in the area of governmental structure are:
1) lack of integration of air and water policies and actions
with those of other functional planning elements, e.g.
transportation, urban design, natural resources, housing,
agriculture,
IV-37
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2) lack of Integration of policies and actions by the different
governmental agencies that affect air and water quality,
3) minimal involvement of local government in the federal and
state schemes for planning and enforcing pollution control
strategies,
4) lack of consistent review or appeal procedures, and
5) frequent policy setting that is too vague for judicious
enforcement.
Lack of Policy Integration
The reasons for the lack of both functional and jurisdictional policy
integration relate to the nature of governmental structure in California
concerned with environmental quality. The creation of unilateral air
and water quality planning entities at both state and substate/regional
levels, without sufficient attention to their relationships to other-
forms or levels of planning, is the main reason for the lack of policy
integration.
Local government is the only level of government in California in which
there is multi-functional planning combined with enforcement. The
state mandated general plans require cities and counties to formulate
policies that implicitly require compromises between the potentially
competing functional elements that are also mandated as part of the
general plans. For example, the land use element policies are devel-
oped under the same planning framework as those for circulation or
water quality. Once the element policies are created and adopted,
local government is required to enforce them with consistent sets of
zoning or subdivision controls.
Multi-functional, comprehensive planning does occur in California at
the regional level through councils of government like ABA6. Yet,
the councils of government have only minimal enforcement powers and
are therefore less effective in accomplishing integrative plan en-
forcement.
At the state level, the Office of Planning and Research has a general
charge to conduct and coordinate comprehensive planning but has a very
explicit constraint on enforcement powers.
Other state and regional agencies, including those concerned directly
with air and water quality, have wide ranging and very powerful en-
forcement powers, including those that can greatly change land use
patterns. However, their policy setting is quite narrow. (It is
interesting to note that the recent state legislation for the his-
torically older state transportation function requires more in-
tegrative and comprehensive planning than that for many of the more
recent state environmental agencies.) Hence, it is not surprising to
find that the more narrow perspective filters down to some of the
IV-38
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detailed project planning as represented in the following quote from
an EIR for an expanded treatment plant in Sonoma Valley under the
"201" program:
"Growth inducement has frequently been misinterpreted with
regards to wastewater treatment facilities. Inducement implies
stimulus or incentive to promote development and its associated
population growth. Treatment facilities do not in themselves
promote growth. However, if the treatment facilities are in-
adequate either due to capacity or treatment level, they can be
growth-limiting."
The above comment on the growth-related effects of a treatment facil-
ity presents a correct picture when read in isolation of regional and
statewide planning and budgeting considerations. But when read in
light of the large regional demands for limited state and federal
financial assistance, this passage reveals a lack of recognition that
growth inducing and growth limiting are one and the same.
The absence of policy and enforcement integration has two impacts.
First, it makes it extremely difficult for policy makers to assess the
combined effect of all expenditures or controls on the achievement of
air or water quality objectives. It becomes difficult to answer
questions about cost-effectiveness of the different steps being taken
when one cannot adequately assess the effect of overlapping or counter-
productive actions. Secondly, it makes government vulnerable to charges
from industry or commerce that additional costs are being borne by the
private sector without adequate justification. Additional, needed con-
trols could well become politically unacceptable because their benefits
cannot be adequately substantiated.
Minimal Local Government Involvement
Previous federally-initiated air and water quality planning efforts
have often been described as "bottom-up." This refers to the pre-
paration of detailed regional plans which are then forwarded to the
State for statewide consideration prior to being submitted to the
federal level.
Unfortunately, this form of planning did not really start at the
bottom because it neglected the role of local government during the
development of environmental quality strategies. The rationale for
the omission, although not readily apparent, might possibly be that:
1) the problems of air and water pollution are traditionally
classified as "regional" in nature-,
2) the involvement of numerous counties, cities, and special
districts in environmental strategies would present far too
complex a management system for planning and enforcement
within the statutory timetables; and
IV-39
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3) the lack of the appropriate level of staff expertise at the
local governmental level to cope with either the technical
subject matter of pollution or the complicated elements of
the federal regulatory scheme.
Based on this study's review, it is apparent that the failure to
include local government specifically in the federal and state plan-
ning and regulatory scheme has resulted in a number of negative con-
sequences .
First, this omission failed to recognize adequately the strength of
local government in comprehensive planning and plan enforcement.
Comprehensive planning is, an area of local government activity which,
since the days of urban renewal, has been given considerable federal
encouragement. The local level is also the jurisdictional level where
some of the greatest innovations have been made in both the content
and the form. Certainly, the Petaluma growth control efforts give
evidence to integrative planning of such concerns as population growth,
environmental improvement and housing considerations. The current
emphasis on developing new methods for site-sensitive, environmental
policy interpretation again demonstrates the advances local govern-
ment is making on land use planning. Therefore, any new regional or
state environmental planning and regulatory scheme which deals with
land use decisions and does not directly involve local government can
be both duplicative and irritating to local planning efforts. Some of
the present federal guidance for the preparation of "208" plans has
recognized this importance of local government involvement and has
encouraged those preparing the plans to give priority attention to
resolving intergovernmental issues.
Secondly, the usurping of local government land use control powers can
and has alienated local government. When this condition is combined
with earlier frustrating pollution abatement efforts, as has been the
case in much of the municipal involvement of "201" facilities planning,
it is not surprising to find the following quote from "Problems of
Municipal Doers in Implementing P.L. 92-500" Report to the National
Commission on Water Quality (September, 1975):
"Many municipal doers, from large but especially small municipal-
ities, are baffled and sometimes angered by the new coordinative
mechanisms, administrative burdens and constant form-filling and
scheduling involved. They find that the roles of each level of
governmental - Federal, EPA regional, State, substate regional
and local — which are different for each major water pollution
control function, are frequently overlapping and constantly
changing. For these reasons alone, some municipalities have
concluded at this point in time, as one municipal doer in Knox-
ville, Tennessee, that "the passage of P.L. 92-500 has been a
decidedly mixed blessing." (p. V-14)
Third, the lack of a structured yet flexible system of local government
involvement with state and regional levels has resulted in self-initiated
but Incomplete environmental planning efforts by local government. The
IV-40
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Sonoma study certainly points to the desire on the part of local
planning to respond to the public concern for environmental improve-
ment., It also highlights the fact that a number of creative efforts
have been undertaken to solve pollution problems. Yet, this desire is
hampered by the lack of overall guidance as to the amount and type of
land use control effort that is necessary to satisfy both regional and
local contaminant abatement needs. A uniformity or consistency of
effort by all local jurisdictions in the region is also lacking.
Lack of Consistent Appeal or Review Process
Another finding from the study is that the environmental decisions
lack a consistent review, appeal or adjudicatory process. The main
concern because of this lack is that the decisions that emanating from
review or appeal process often form a new level of policy.
There are a number of different types and reasons for the existing
review or appeal process. First, there is the review/appeal process
of the state agency over its subordinate regional agency. This is the
case with both the Air Resources Board and the State Water Resources
Control Board over the air pollution control districts and the regional
water quality boards, respectively. The state boards' powers allow
them to override a regional boards' decision on a regulation or a
permit issuance if it does not meet state standards or if a variance
is inappropriate.
A second type of review authority is that of ABAG's A-95 responsibility.
Policies that guide this review include those found in ABAG's Regional
Plan and those developed on an ad hoc basis if not adequately covered
in the comprehensive regional plan.
A third review comes through the environmental impact report process.
EIRs are available for both public and private groups and individuals
to review. The limitations of this process are well known. Basically,
environment impact reports simply report conditions and are not statu-
torily required to alter the proposed plan or project based on the
report findings.
A fourth form of appeal/review comes in the form of hearing boards
that can grant variances to the normal regulations. The main reason
for appeals is that a particular control brings about an alleged
hardship. The zoning boards of appeal and the air pollution control
district hearing boards have this form of review.
A final form of appeal/review is through the courts. Traditionally,
appeals through the legal system on planning decisions have been on
issues of due process and compliance with particular planning legis-
lation or ordinances. However, the recent requirement of consistency
between general plans and zoning may lead to direct judicial inter-
pretation of general plan policies to ensure consistent enforcement
actions.
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Vague Policies
A final conclusion that can be drawn from the review of agencies con-
cerned with air and water quality is one that can be directed at many
other agencies involved in planning. Many of the present policies
that have been adopted at all jurisdictional levels and pursuant to
various land use and environmental issues do not offer the decision
makers - and the communities they serve - a clear set of enforceable
choices. Too frequently they are stated in such general terms that
they offer little guidance for directing improvement actions. The
policies described earlier under the local general plans provide
numerous examples of environmental policies so vague that their
effectiveness cannot be measured. The result of such general policy
setting is:
1) confusion and inconsistency in enforcements
2) appeals or law suits because enforcement is either too
•severe or too lax, and
3) inability to determine whether the policy can be realis-
tically used to achieve some quantifiable end.
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CHAPTER V - DESCRIPTION OF STUDY TECHNIQUES
Based on the review of the earlier environmental studies described in
Chapter Three, the Sonoma Study directs its attention to determining
1) the influence of urban spatial patterns on air and water quality
and 2) the relative effectiveness of specific urban spatial patterns
and the corresponding land use controls necessary to create such
patterns, in attaining and maintaining air and water quality objec-
tives. The analytical approach used to address these questions is the
development of alternative land use patterns that can be evaluated by
simulation models for their air and water pollution impacts.
This chapter presents a description of the methods used in: 1) devel-
oping alternative land use growth patterns, 2) predicting water quality
conditions and 3) predicting air quality conditions. The study tech-
niques are presented in an abbreviated format. A more technical dis-
cussion on the air and water modeling efforts is presented in Appendices
B, C, D, E and F.
ALTERNATIVE LAND USE GROWTH PATTERNS
The primary purpose for developing the land use alternatives is to
present a range of growth patterns for testing the relationship be-
tween land use configuration and intensity and the resulting air and
water quality (Appendix B).
Nine growth alternatives are developed to represent different combin-
ations of population size, urban spatial pattern, land use density and
land use type. These alternatives are described later in the chapter.
Two different County populations are used, based on projections to the
year 2000. The 1973 County population of 226,000 provides a benchmark
for further analysis and is therefore described as Base Year. The
California Department of Finance D-100 projection (assumes a fertility
rate of 2.45 children per woman and a net in-migration of 100,000
persons per year to California) of 478,000 population for the year
2000 in Sonoma County, is used as one level. The second projection
figure is 630,000, based on ABAG's "Gronorth" alternative which assumes
major regional development in the northern counties of the San Francisco
Bay Area.
Total county employment estimates were derived, by the University
Research Center consultants, as part of the Sonoma County General Plan
process. The total employment figures were disaggregated by employment
sub-categories (e.g. basic industry - agriculture, manufacturing,
basic insurance, local serving - retail, services, local finance and
1nsurance, constructi on).
V-l
-------
The population and employment totals are then converted into their
area! equivalents in the form of hectares of residential, commercial
and industrial land use. The categories and densities of land uses
are selected in a manner that ensures compatability with the existing
County land use information and the air and water model requirements.
Table V-l indicates the categories used in the study and their County
land use equivalents.
The next step in creating the different growth patterns is to distribute
the land uses according to different assumptions on regional and urban -
development, including:
1) single, central city development versus multi-city develop-
ment,
2) concentrated development in the core of the city versus
development spread throughout the city, and
3) high density development versus low density development.
The General Plans of the Sonoma County cities were used to the fullest
extent possible in determining probable future land use locations.
The final step in the preparation of the growth alternatives is the
overlaying of a one kilometer grid pattern on the development patterns
to determine the percentage of each land use in each cell. There are
a total of 920 grid cells in the study area. The land use information
for each grid cell was then transferred to a computerized file system
for use in both the air and water quality modeling.
There are a variety of reasons that a one kilometer grid pattern was
selected. First, since area-source air quality models use a square
(or rectangular grid), the square grid cell provides the advantage of
easy conversion to model needs that could not be provided by other
data units such a census tracts or traffic zones. Secondly, the size
is a maximum unit for carbon monoxide analysis because averaging of
pollution concentrations over larger cells has the effect of diluting
the emissions from certain traffic areas. Thirdly, the one kilometer
grid cells can easily be combined to make up the larger hydrologic
sub-areas that serve as the basic units for the study's surface runoff
modeling. The number of grid cells per hydrologic sub-areas in the
study area range from seven to forty. The need to combine many cells
means that the detailed land use information derived per grid cell is
frequently generalized when used in the runoff model, a point that is
important for those wishing to undertake similar studies. A land use
system that provides for many land use categories and great spatial
detail can provide for far greater resolution than is required for
surface runoff modeling.
The following section of the chapter provides descriptions of each of
the alternative land use growth patterns. Table V-2 indicates the
population distribution in the different land use alternative. Figures
V-2
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Table V-l
Land Use Classification System
Base Year (1973) Land Use
1
Land Use Alternatives
Single dewlling
Multi-dwell ing
Commercial
Industry, non-urban industry,
transportation and sand
Open Space
Agriculture: orchards and
vineyards
Agriculture: field crops and grain
Wetlands
Residential-Low Density
12.3 DU/hectare (5 DU/acre)
Residential-Medium Density
36.9 DU/hectare (15 DU/acre)
Residential-High Density
78.7 DU/hectare (32 DU/acre)
Commercial - City Centered2
2
Commercial - Suburban
Industrial
Grazing/Open Space
Agricultural - orchard/vineyard
Agricultural - truck crops/field
crops
Wetlands
4
U.S. Geological Survey, Geographic Applications Program, land use map of
Sonoma County, 1:62,500, 1972 (from unpublished open file)
2
The "City Centered" versus "Suburban" distinction is made for water model
purposes. The assumption is that the "Suburban" Commercial land will have
less impervious surface coverage due to locational and costs advantages not
shared by "Centered" Commercial.
V-3
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TABLE V-2 POPULATIONS OF THE LAND USE ALTERNATIVES (in thousands)
County Total
Santa Rosa
Petaluma
Rohnert Park
Healdsburg
Sonoma
Sebastopol
Cotati
Other County Cities
(not in study area)
City Total
Community Total
Rural Total
% of County in Cities
% of County
in Communities
% of County in Rural
% of City Total
in Santa Rosa
Base Year
(1973)
226
60
30
9
6
5
4
2
3
119
22
85
53
10
38
50
Santa
Cent*
(20(
478
215
60
42
11
12
11
9
5
365
28
85
76
6
18
59
Rosa
ired
X))
630
306
79
55
14
16
14
12
8
504
32
94
80
5
15
61
UrbE
Cente
(20C
478
110
92
40
33
27
33
15
15
365
28
85
76
6
18
30
in
;red
10)
630
151
126
55
45
35
45
20
27
504
32
94
80
5
15
30
Subui
Dispe
(200
478
150
79
48
21
25
21
13
8
365
28
85
76
6
18
41
rban
>rsed
0)
630
250
91
55
25
30
25
18
10
504
32
94
80
5
15
50
Rural
Dispersed
(2000)
478
75
38
12
7
6
5
3
4
150
28
300
31
6
63
50
Con tin
Tren
(20(
478
145
65
48
9
10
7
8
8
300
48
130
63
10
27
48
luing
tds
x»
630
196
97
60
15
15
10
12
9
414
76
140
66
12
22
47
-------
V-l to V-5 are schematic representations of a selected group of the
land use alternatives. The shaded circles show the populations of
each of the cities and rural areas in the study area. The larger
circles surrounding the population circles indicate the area of each
city occupied by residential land. By comparing the relative sizes of
the two circles, one can get an indication of the density in each city
in each alternative. The larger the white circle is, relative to the
shaded circle, the lower the density. The density is high when the
two circles are similar in size, as in the Urban Centered illustration.
It must be emphasized that these are only schematic illustrations.
The actual land use alternatives consist of very detailed sets of land
use data specified in the form of hectares of each of 10 land use
types in each of over 900 grid cells for each alternative. The loca-
tions of the circles shown on Figures V-l to V-5 are only rough ap-
proximations of where the cities are and should not be taken literally.
Santa Rosa Centered (SRC) Alternatives; 478,000 and 630.000
The intent of the Santa Rosa Centered alternatives is to create a
growth pattern in the County which is dominated by the City of Santa
Rosa and where most of the growth is urban and compact in nature.
Santa Rosa is the center of both population and economic activity in
the County in these alternatives. Figure V-l indicates the growth
pattern of Santa Rosa Centered 478.
Overall Spatial Appearance. These two alternatives are characterized
by a very large, dense and spatially extensive Santa Rosa. The
physical dimensions of the city are large, even though the densities
are high, because of the large Santa Rosa population and the consider-
able number of jobs located in that city. The other cities in the
County have roughly 2 to 3 times their Base Year populations, but are
essentially contained within their 1973 boundaries. High density
residential areas in these cities are more extensive than in the Base
Year, but far less extensive than in the Urban Centered Alternatives.
These high density areas are located near the centers of each of the
cities. The rural areas of the County and the communities remain
essentially the same as in the Base Year.
All the cities generally appear as a series of roughly concentric
rings with city-centered commercial and high density residential
located near the center, surrounded by medium density residential. A
moderate amount of low density residential is located at the outer
ring. Interspersed among the low and moderate density residential are
several clusters of suburban commerical. Industry is located primarily
along the U.S. 101 corridor or near the rail lines. Much of it is
within present city limits and the rest is located on the periphery of
the residential areas. Vacant land within city limits is minimal.
Only land currently used as a public park or for an institution (such
as a school, church, or hospital) is left unaffected.
V-5
-------
SANTA ROSA
CENTERED
• 47aooo
©Population based an a total
of 478,000
Hectares of land covered
by residential development
FIG.V-1
-------
URBAN
CENTERED
•47aooo
Population based on a total
of 478,000
Hectares or tend covered
by residential development
FIG. V-2
-------
Urban Centered (UC) Alternatives: 478.000 and 630,000
These two alternatives concentrate growth in all of Sonoma County's
incorporated cities, while maintaining distinct spatial separations
among these urban areas. Employment opportunities grow in each of the
cities and Santa Rosa becomes less of a center of economic activity in
the County. As in the Santa Rosa Centered growth pattern, development
is dense and compact. Figure V-2 displays Urban Centered 478.
Overall Spatial Appearance. In these alternatives, all the cities are
large and compact, and the rural portions of the County remain essen-
tially the same as they are now. Cities that were 4,000 in 1973
become cities of 30,000 and 40,000, and Petaluma grows from 30,000 to
92,000 and 126,000, respectively, in UC 478 and 630. Santa Rosa, on
the other hand, only doubles in population over the Base Year. The
Urban Centered alternatives are differentiated from those of Santa
Rosa Centered in that all the cities except Santa Rosa have a much
larger and denser core area and require more land for development.
Santa Rosa, in contrast, is about half the size. Commercial and in-
dustrial locations follow the same assumptions as in the Santa Rosa
Centered alternatives, but the amount of land devoted to these uses is
much greater in all the cities except Santa Rosa. The rural population
remains the same as in the previously discussed alternatives.
Suburban Dispersed (SD) Alternatives: 478.000 and 630.000
The intent of the Suburban Dispersed alternatives is to create a
sprawling, urban fringe-oriented growth pattern where the heaviest
development takes place on the periphery of the existing cities, and
the predominant housing type is a single-family detached home.
Figures V-3 and V-4 illustrate spatial extent of Suburban Dispersed
478 and 630.
Overall Spatial Appearance. These alternatives have, by a large
margin, the greatest amount of developed land. For example, Santa
Rosa stretches to the floodplain of the Laguna de Santa Rosa on the
west and into the Valley of the Moon on the east. By comparison,
Santa Rosa in Santa Rosa Centered 630, with a population of 306,000,
contains approximately the same residential acreage as the Santa Rosa
in Suburban Dispersed 478, with a population of 150,000. Petaluma
sprawls outward to the foothills both to the west and to the east.
Strips of commercial and apartment house development stretch out along
major roads. Commercial development is also placed into large shopping
centers and neighborhood shoppping areas scattered throughout the new
residential areas. The commercial growth of the existing downtown
areas is relatively minor. Industrial development, as in the other
alternatives, occurs primarily near the highways and the railroad.
The rural areas remain the same as in the alternatives described
earlier.
V-8
-------
SUBURBAN
DISPERSED
•4?aooo
Population based on a total
of 478,000
Hectares of land covered
by residential development
FIG. v-3
-------
SUBURBAN
DISPERSED
•630,000
Population based on a total
of 630,000
Hectares of land covered
by residential development
FIG.V-4
-------
CONTINUING
TRENDS
• 478,000
Population based on a total
of 478,000
Hectares of land covered
by residential development
FIG.V-5
-------
Rural Dispersed (RD) Alternative: 478.000
This land use alternative Is designed to demonstrate the effect of
developing the rural portions of the county with low density resi-
dential developments and "ranchettes" one to ten acre parcels with a
house, farm animals and garden or small plot of cultivated land.
Overal1 Spatial Appearance. In this alternative the Santa Rosa Plain
is carpeted with three acre rural residential lots. Development
extends to the mountains on both the east and west sides of the PIariln
and there is virtually no land left untouched within this area.
Cities and communities experience only a 25% increase in population
and remain essentially the same size as they are now. Commerical and
industrial development is similar to that of the Suburban Dispersed
478,000 alternative with new commercial shopping located at the
fringes of the cities.
Continuing Trends (CT) Alternatives: 478.000 and 630.000
The Continuing Trends alternatives are developed to show what would
happen if the present growth patterns continued to the year 2000.
Since Sonoma County Planning Department had already completed growth
trend projections for the County at the population levels 478,000 and
630,000, these alternatives essentially were a conversion of the
County's projections into a form comparable with the study's other
alternatives. Figure V-5 illustrates Continuing Trends 478.
Overall Spatial Appearance. These land use patterns are typified by
having a large amount of development along the U.S. 101 corridor with
Santa Rosa, Rohnert Park and Petaluma all experiencing considerable
growth. Cotati, Rohnert Park and Santa Rosa virtually grow together
and Santa Rosa expands northward towards Healdsburg. Residential
densities increase only slightly over what presently exists, thereby
requiring a continued conversion of present day agricultural land into
new urban development. Commercial development expands primarily
around its current locations and industrial growth is heavily corridor-
oriented. Unlike the other alternatives, existing small unincorporated
communities throughout the County grow substantially and the rural
areas increase in population by about 50% over the Base Year.
MODELING OF WATER QUALITY
Two separate forms of water quality simulation are conducted in the
Sonoma Study. QUAL-II is used to study the impacts of the different
land use alternatives on dry weather water quality. A Runoff-Quality
model is used to evaluate water quality impacts during periods of
storm runoff. Both models are described in detail in Appendix F.
The modeling analysis for dry weather conditions varies only according
to the population size being served by the various sewage treatment
plants that discharge treated effluent in the study area rivers. As
V-12
-------
such, the other growth alternative characteristics of spatial pattern,
land use density or land use type are not critical in the analysis. In
contrast, wet weather water quality conditions are influenced by all
of these characteristics. Consequently, this section of the chapter
will concentrate on the surface runoff modeling techniques. (A brief
description of QUAL-II will be provided in Chapter VI as part of the
explanation of the results from the dry weather water quality analysis.)
Model i ng of Surface Runoff Hater Qua! i t.y
Two models, the Urban Runoff and Agricultural Runoff Models, are
combined to provide a runoff and quality model. These two models are
variants of the EPA's Storm Water-Management Model (SWMM). This
Runoff-Quality Model predicts the storm water runoff, including its
pollutant washoff, for different urban and non-urban land use cate-
gories during a selected storm event and routes the runoff from the
watershed through major drainage and river channels.
The main steps in predicting surface runoff include:
1) Geographic definition of hydrologic sub-areas in the study
area.
2) Physical description of the sub-areas ~ land uses, percent
imperviousness, soil infiltration characteristics, depression
storage, average slope, hydraulic roughness.
3) Description of channel characteristics — width, depth,
slope, length and roughness.
4) Selection of pollutant loadings to wash off with storm
water.
5) Selection of appropriate storm conditions for testing.
Geographic Definition_of Hydro!ogic^Sub-Areas. Two major basins were
chosen to be modeled for water quality ~ the Laguna de Santa Rosa and
the Petaluma River Basin. (The Valley of the Moon did not receive
water modeling attention because the information derived from the
other two basins was felt to be sufficient for study purposes.) The
watersheds of the main rivers (the Laguna and Petaluma River) are
termed "basins" and the watersheds of the major tributaries are termed
"watersheds." These watersheds are, in turn, broken down into smaller
hydrologic units called "sub-areas."
Sub-areas are defined using the following criteria:
1) areas of homogeneous slope,
2) areas either predominantly developed or undeveloped, and
3) comparable flow path lengths from points along the perimeter
of a sub-area to the tributary draining the sub-area.
V-13
-------
Each sub-area contains one or more tributaries or parts of tributaries.
For modeling purposes, in cases where more than one tributary drains a
sub-area, a single tributary is chosen to represent the drainage
channel.
After all the watersheds and sub-areas were defined in both basins,
their hydrologic boundary lines were translated into 1-km grid cell
lines. Thus, all sub-areas were described in terms of grid cells,
making them compatible with the land use data system.
Physical Description of the Sub-Areas. The physical description of
the various sub-areas provides the key to understanding the impact of
urban growth and related land use control measures on water quality.
The various land uses, discussed earlier as part of the alternative
growth pattern description, are the key variables in the sub-areas.
The land use categories were reviewed for their imperviousness to rain
water absorption and thus to greater amounts of storm water runoff.
The impervious surface coverage percentages that are used in the study
are:
Percent
Land Uses Impervious
Low Density Residential 35
Medium Density Residential 65
High Density Residential 80
Commercial - City Centered 95
(retail/office)
Commercial - Suburban 90
Industrial 98
Grazing and Open Space 6
Agriculture - Orchard/Vineyard 6
Agriculture - Truck/Field crops 6
Wetlands 100
The procedures used in determining these impervious percentages were:
1) review of existing zoning codes in Sonoma County for lot
coverage requirements,
2) application of professional experience from researching
similar areas,
3) review of literature on impervious surface and
4) review of aerial photo maps of Sonoma County.
The surface infiltration rates for soils within Sonoma County were
determined using information from the United States Department of
Agriculture Soil Conservation Service. The slope, hydraulic roughness,
and depression storage of the sub-areas were also determined from soil
survey maps or other studies.
V-14
-------
Description of Channel Characteristics. Having defined the two major
basins in the study area, Laguna de Santa Rosa and Petaluma River, and
the runoff characteristics for the sub-areas, the next step is to
describe the hydraulic properties of the drainage or stream channels
draining the sub-areas. The sub-areas are represented in the model as
idealized rectangular areas having uniform groundcover and slope.
However, because real catchment areas do not experience uniform over-
land flow, average values must be assigned to each sub-area.
Actual channel site examinations were necessary in order to determine
the specific characteristics of channels represented in the model.
Eighty-one stations were chosen for observation in the Laguna and
Petaluma Basins. Each station provided a representative cross-sectional
area at a portion of a channel. Stations were located at the headwaters,
near the middle of channels, and at downstream locations.
Data collected at each station included channel width, depth and slope
of the channel banks. Special note was taken of the debris in the
channel so that a hydraulic roughness factor could be assigned to each
channel.
Selection of Pollutant Loadings. Pollutants in developed areas accumu-
late in gutters or on other impervious surfaces and are washed off
during the next storm. The key variable in the Runoff-Quality Model
accounting for the pollution load in urban areas available for washoff
is the accumulation of dust and dirt. The daily rates of the buildup
of dust and dirt per unit length of curb and gutter vary by land use.
All water quality pollutants are expressed as a function of the accumul-
ation of dust and dirt. They were derived from past studies in other
geographical areas and not from a sampling program conducted as part
of the Sonoma Study. Time and budget considerations precluded the
latter approach. The pollutants considered are total suspended solids,
nonsettleable solids, biochemical oxygen demand (BOD), oil and grease,
fecal coliforms, total nitrogen, total phosphorus and total heavy
metals.
Pollutant loadings for urban land use categories are adopted from
WRE's recently completed work in Seattle. Environmental Management for
the Metropolitan Area Cedar-Green^Rivef Basins (.U.S. Army Corps of
Engineers, 1974).The original EPA Storm Water Model used pollutant
loading rates determined in a separate study in the Chicago area.
These rates did not seem applicable for the Seattle area in light of
data obtained from additional studies recently performed in the local
area. Based on the EPA report titled, Water_Pollution Aspects of
Street Surface Contaminants, dated November 197Z, an average loading
factor for total dust and dirt of 0.72 pounds per day per 100 feet of
curb was adopted. This rate of 0.72 is less than one half of the
average loading used in the original model. Relationships of water
quality parameters to total dust and dirt were determined from samples
taken in Seattle. Quality data was obtained for a few select storms
at the gaging manholes of the calibration areas. The quality data
V-15
-------
consisted of the analysis of the manhole grab samples for a total of
28 water quality parameters. The grab samples were taken at a minimum
interval of 15 minutes for the duration of the rainfall event.
The loading rates, developed in the Seattle study and used for the
Sonoma Study, may be compared to the ratio of BOD, nitrogen, phos-
phorus, oil and grease and total heavy metals emissions to emission
of total suspended solids estimated in the San Francisco Bay Basin
Plan. These comparisons are given in the chart.
Basin Flan (Sonoma County) Sonoma Study Rates
Parameter/Total Suspended Solids, Parameter/Total Suspended Solids,
mg/g mg/g
BOD
TST
N
TBT
P
T5T
Oil and Grease
URBAN
126
19
3.4
71
Residential
Light
106
22
3.1
132
Residential
Heavy
212
20.4
,4.3
314
Commercial
80
14
1.4
67
TSS
Total Heavy
Metals 14 6.3 9.1 5.0
TS"S
Urban land use categories were not presented in detail in the Basin
Plan. Consequently, only general comparisons can be made. However,
the Basin Plan ratios of mass emissions to total suspended solids
appear to fall within the range of loading values used in the Sonoma
Study.
The washoff from the non-urban areas is predicted by use of the Universal
Soil Loss Equation. The same pollutants used for urban areas are used
for non-urban areas. They were determined as a ratio of the anticipated
soil erosion washing off the non-urban land uses (e.g. grazing and
open, orchard and vineyard agriculture, and truck/field crop agriculture),
Selection of Appropriate Storm Conditions. The selection of a storm
event to be used in runoff simulations is important .depending on the
type of land use impacts or runoff management techniques to be studied.
The types of storms that may be of interest include:
V-16
-------
1) first significant storm of the winter season
2) "typical" winter storm
3) storm with a 1-year recurrence interval
4) storm with greater than 1-year recurrence interval.
The first event described above will probably produce the greatest
pollution during the wet season. The second event should represent
"average" wet weather quality. The third and fourth events are of
interest mainly from a flood flow design standpoint.
The "typical" winter storm was used for simulation purposes in the
study. The intensity of the storm was determined by a review of
historical rainfall records in Santa Rosa.
Since there is little historical wet weather water quality data for
Sonoma County streams, verification of the water quality portion of
the runoff model was not possible. Various storms will produce quite
different quality results depending on a number of factors, such as
preceding weather conditions, rainfall intensity, and total rainfall.
Because the model is unverified, it was decided to use a single storm
event for analytical purposes. The simulations for a single event are
useful for comparing the overall water quality impacts of alternate
land use configurations and for evaluating the relative accomplishments
of certain runoff management techniques. More detailed evaluations of
runoff management techniques should consider other storm events and
varying antecendent conditions (e.g. number of dry days proceeding the
storm).
Relationship of Hater Model Variables to Government Policy Making
There are basically four approaches to control pollutants from storm
water runoff: 1) preventing contaminants from reaching a ground
surface, 2) improving street cleaning or soil practices where con-
taminants may be present, 3) detaining and treating runoff prior to
discharge into the streams and 4) reducing storm runoff through land
use controls. The study has used the modeling techniques to assess the
effectiveness of these different approaches in the following manner:
1) preventing contaminants from reaching the surface - model
runs based on two different frequencies of dust and dirt
build-up periods have been made in the study. The use of
different build-up periods, ten days and twenty days,
simulates the relative importance of requiring and actively
enforcing health ordinances whereby certain contaminants are
either not used or not permitted to wash off into areas that
are part of the storm drainage system, as in the cases of
oil and grease from service stations;
2) improving street cleaning or soil practices where contaminants
may be present - the use of different frequencies of dust
and dirt build-up in the streets can simulate the frequency
V-17
-------
of street sweeping. A ten day build-up reflects a ten day
sweeping cycle. This approach of varying the build-up rate
can be used to determine the optimum pattern and frequency
of sweeping;
3) detaining and treating runoff prior to discharge into the
streams - one of the model variables can be altered to
reflect storm water detention such as on a slightly dep
pressed parking lot, a catchment basin on a rooftop or a
pond in a residential development. Detention devices can be
required as part of building regulations or conditions of
zoning; and
4) reducing storm runoff through land use controls - the arrange-
ment of land uses in the sub-areas, as in the case of the
various alternative land development patterns, or the use of
measures that result in less impervious surfaces in new
developments, can be tested by the model for their effec-
tiveness. Examples of the latter would be requirements for
more open space in subdivisions, use of porous pavements for
streets and parking lots or use of smaller curb, gutter and
road widths in subdivision regulations.
AIR QUALITY MODELING
Two separate types of air quality modeling are used in the Sonoma
Study. Non-reactive pollutants -- carbon monoxide, total suspended
particulates and sulfur dioxide, were simulated by use of a dispersion
model based on climatological phenomena. Photochemical oxidant, which
is a reactive pollutant, is modeled by a modified proportional roll-
back, a technique which assumes that the maximum concentrations of
oxidant in an sub-basin (such as the Santa Rosa Plain) are directly
related to emissions of non-methane hydrocarbons in that sub-basin as
well as emission from other areas in the air basin. Average wind
patterns were used to determine the import of non-methane hydrocarobns
from outside the sub-basin. Nitrogen dioxide is not analyzed because
of the limited modeling techniques available for this pollutant.
The Sonoma County Advanced Planning Division and the Bay Area Air
Pollution Control District had agreed to perform air quality analysis
of the alternative plans developed in the County General Plan program
prior to the inception of this study. The BAAPCD was to provide
technical advice and assistance to the County on the preparation of a
emission inventory and conduct mathematical modeling to determine
pollutant concentrations and violations of air quality standards. The
County prepared the alternative plans and directed transportation
studies capable of being assessed for their contribution to pollution
emissions. Figure V-6 provides a graphical description of how the
emissions were compiled.
The Sonoma County/BAAPCD work was delayed with the creation of this
study in order to determine if there were any modifications necessary
to the data such that they would be easily used for joint air and
water quality investigations. In particular, the question of land use
V-18
-------
COMPILATION OF TOTAL EMISSIONS BYGWDCEU
PERSONS
GRID CELL
vo
TfeAFRc
-------
emission factors was explored to determine if appropriate types and
amounts of air emissions or water pollutant loadings could be associ-
ated with particular land use activities. Review of the literature
yielded limited information on this subject, especially for the
relatively low population and employment levels that are character-
istic of Sonoma County. The air quality analysis then proceeded by
preparing an emission inventory and modeling pollutants from three
different types of sources: 1) stationary, 2) area and 3) mobile.
Stationary Source Emissions. The Bay Area Air Pollution Control
District maintains a detailed inventory of total emissions for each
county in its jurisdiction. This inventory provided the basis for
calculating the stationary source emissions in the study area.
Estimates of future emissions are made by the BAAPCD for each of its
105 stationary source categories in the Bay Area through projections
of demand for products associated with each category and availability
of materials such as natural gas and low sulfur fuel oil. Cement
patching plants in Petaluma and a food processing plant in Sevastopol
are examples of stationary sources in the study area. The emission
factors are based on compliance with current BAAPCD regulations. The
possibility of significant technological advances in emission control
devices or new, more stringent-regulations are not reflected in
emission estimations.
This projection method is then applied for each grid cell which pre-
sently has stationary sources. The year 2000 stationary source pro-
jections, which were specifically associated with the Continuing
Trends 478,000 alternative, are used for all other land use alter-
natives. The intent of this method is to-keep stationary source
emissions constant throughout all alternatives in order that their
impacts did not obscure those created by non-stationary sources (e.g.,
cars, trucks) and population related sources (e.g. home furnaces). It
should, therefore, be noted that the use of the Continuing Trends 478
stationary sources in the other land use alternatives may understate
the amounts of pollution from those sources. This may be particularly
true in Santa Rosa, in the Santa Rosa Centered alternatives, and all
of the alternatives at the 630,000 population levels. This problem is
expected to be minor due to the limited number of stationary sources
presently in the study area.
Area Sources. As explained earlier, the use of land use emission
factors was determined inappropriate due to the lack of available
information. Therefore, it was decided to distribute area emissions
(e.g., emissions from home heating, house painting, neighborhood dry
cleaning establishments) proportional to county-wide activities such
as population, employment or retail trade or combinations of these
activities. Because it was necessary to produce these emissions at a
grid cell level, it was decided to use population per grid cell as the
means of distributing nonpoint stationary source. A drawback of this
technique is that per capita emissions factors from high density
structures associated with compact development may well differ from
those in low density, single-dwelling developments. In the absence of
any empirical data on the subject, a strict proportioning of non-point
stationary emissions to population was used.
V-20
-------
The per capita emission factors are determined in a straightforward
manner by:
1) subtracting point source emissions and vehicular emissions
from the BAAPCD estimates of 1973 Sonoma County total emis-
ssions based upon fuel consumption and economic indices, and
2) dividing the difference from the first step by the county
population to arrive at the per capita non-point stationary
source emission factors for each pollutant.
The same emission factors are used for 1973 (the Base Year) and the
year 2000 due to the uncertainties in anticipating control regulations
for these sources.
Mobile Emissions. A major section of the Sonoma County General Plan
is a Transportation Element. This element was prepared by the Advanced
Planning Division and the Department of Public Works, Office of County
Roads, with consultation by JHK and Associates. Two of the products
of this effort are traffic-loaded road networks based on the existing
(1973-Base Year) and Continuing Trends 478,000 land use patterns. The
road network loading consists of an average daily traffic (ADT) for
most of the roads in the county. The ADT is prepared by traditional
transportation modeling based on "productions" and "attractions" of
different land uses. Socioeconomic variables in the model include
population, employment, land use, income and dwelling units. Trans-
portation variables include route locations, road service levels and
speed. Travel is expressed in numbers of trips which the model separ-
ates into different travel modes such as vehicle driver, vehicle
passenger and transit passenger. External travel, trip patterns that
start and/or end outside of the County, are also calculated into the
traffic scheme.
The ADT is then translated to a grid cell level by overlaying the grid
cell pattern on the road network. This enables the computation of
gridded vehicular emissions by use of the table of speed dependent
emission factors developed by the BAAPCD, which considers different
mixes of cars on the road for 1973 and 2000. (The BAAPCD emission
factors are modified versions of the Supplement No. 2 Compilation of
Air Pollutant Emission Factors. Second Edition prepared by EPA in
September, 1973.Supplement No. 5 is not used in this study because
it was issued after the initial air modeling analysis was completed.)
A procedure other than detailed traffic modeling had to be developed
to predict vehicular emissions for the other eight land use alter-
natives (Appendix E). This was necessary because the budget limitations
did not permit traffic modeling for each alternative. As a consequence,
a regression formula was developed by deriving correlation coefficients
between the different emissions and socioeconomic and traffic charac-
teristics per grid cell. The transportation analyses of the Base Year
and Continuing Trends 478,000 provided the basis for the regression
formula.
V-21
-------
This procedure limited' the variety of model analyses that could be
conducted. The regression formula mathematically explains a series
of complex land use and transportation interactions by simple co-
efficients. In this manner, it obsures the various land use and
transportation policy actions that would result in different travel
patterns and vehicular emissions estimations. Therefore, it is not
possible to test different transportation policy actions. For example,
it is impossible to reduce the capacity of a particular road, as a
means of testing an air quality strategy of reducing the road network
to discourage the use of the car, and be assured that the resultant
travel effects are accurately predicted by the formula. Similarly, it
is impossible to change the modal split (car vs. mass transit) or the
commuter pattern because their impact would be obsured by the formula.
Analysis of Non-Reactive Pollutants
The emissions from the stationary, area and mobile sources are dis-
persed over the study area by use of a "gaussian plume" model, as
described in Appendix C. This model simulates the existing clima-
tological conditions, including wind speeds and directions, at both a
regional and local scale. There are three steps in determining the ''
calculation of the concentrations. First, the entire 9-county Bay Area
is considered in estimating background concentrations from distant
sources. Using wind pattern frequency information and an average wind
speed, a factor is developed to represent the contribution to the
background pollutant concentrations in the detailed study area from
the rest of the 9-county region.
Secondly, the contribution from each grid cell within the study are on
the others is computed. This is accomplished by considering all
upwind squares as point sources and assuming uniform horizontal dif-
fusion within a certain angle of the wind direction and vertical
diffusion as a function of distance.
Thirdly, the local contributions of a grid cell to itself are computed
by calculating the average emission density (mass/area/time) and
assuming uniform distribution over the grid cell. Then the contri-
bution of each point within a cell is measured on the other points
within the same cell, again taking into consideration vertical dif-
fusion and wind direction. The average of the concentrations at all
the points within a cell is then assigned as the concentration in the
cell.
The annual average concentrations calculated by the above procedure
are then analyzed for frequency of violations of air quality standards
through the use of the statistical model developed by Dr. Ralph Larsen
of EPA. This model converts average concentrations to expected maximum
concentrations and expected geometric mean concentrations for various
averaging times (e.g. 1 hour, 8-hour). By relating the violations of
standards or concentrations of air pollutants to the land use alter-
natives, it is possible to derive a linkage betwen land use and air
quality.
V-22
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Oxldant Analysis
A rollback approach is used to analyse oxidant concentrations. The
analysis is described in detail in Appendix D. Briefly, rollback is
based on the premise that the total amount of non-methane hydrocarbons
(NMHC) emitted in an air basin is proportional to the maximum oxidant
value in that basin. For example, if 100 tons/day of NMHC were emitted
in 1973 resulting in a peak hour oxidant value of 16 parts per hundred
million (pphm) then a 50 tons/day of NMHC in another year would produce
a peak hour of 8 pphm. The above statistical procedures developed by
Dr. Larsen are then used to determine how many violations of standards
in a year would be expected given the peak hourly oxidant value.
Refinements of the procedure used in the study were breaking down the
county into three sub-basins: Santa Rosa, Petaluma, and Sonoma (Valley
of the Moon), and considering inter-basin transport. This separation
resulted in the analytical ability to distinguish between areas primarily
affected by pollutants from other areas versus those originating
within the study area.
Relationship of Air Quality Modeling to Government Policy Making
The utility of the air quality modeling in assessing the effectiveness
of land use control tools lies in the relationship developed between
pollutant emissions and population and employment distribution and
density. The degree of population or employment exposure to air con-
taminants estimated in the different land use alternatives enables the
setting of zoning densities, the sizing and structuring of sewage
collection and treatment facilities, or the enforcement of other
growth directing mechanisms based upon desired air quality objectives.
It also assists in decision making of site selection for schools or
hospitals that require high air quality.
The second use of the air model to test the impact of government
policy is the analysis conducted to determine the effect of partial
implementation of vehicular emission control device regulations. This
was done by using BAAPCD's average vehicular emission factors for the
1973 vehicle mix, rather than the year 2000 vehicle mix, in assessing
the Continuing Trends 478,000 emissions in the year 2000. The impact
of the treatment levels created by the different emission devices was
dramatic.
Finally, a pilot area analysis was conducted by the Sonoma County
Advanced Planning Division to determine the relative effects of
differing levels of emission device inspection and enforcement. This
examination was aimed at finding what would happen if the latest
devices where placed on the car, but later not checked for their
adequacy and/or replaced when necessary.
The next chapter will describe the results of the different model
simulations.
V-23
-------
CHAPTER VI - RESULTS OF MODEL ANALYSIS
The results of the various model analyses provide a number of findings
useful for developing environmental management strategies. The water
quality analysis emphasizes the influence of watershed characteristics
on both dry and wet weather pollution. The air quality analysis
emphasizes the impact of both spatial land use patterns and meteoro-
logical conditions on the quantity and distribution of air contami-
nants. The water and air quality modeling analysis, as well as some
qualitative findings on related pollution problems, is organized into
two sections:
1) water quality analysis
a) dry weather quality
wet weather quality
groundwater impacts
b)
c)
2) air quality analysis
a) non-reactive pollutants (e.g., particulates)
b) reactive pollutant (I.e. photochemical oxidants)
WATER QUALITY ANALYSIS
Development in Sonoma County will impact the quality of both the
streams within the study area and the receiving waters outside the
study area. Increased population levels will result in a greater
demand for water and a corresponding increase in wastewater to be
treated and discharged. The discharge of municipal wastewater is of
particular concern in the Laguna de Santa Rosa and the Petal uma River
during low flow periods when the assimilative capacity of the streams
is low because of its seriously impacts on the quality of the Russian
River and the San Pablo Bay. Urbanization impacts water quality
during wet weather periods primarily through increased washoff of
pollutants which accumulate in urbanized areas. The analysis also
indicates that the impact of development in the county on groundwater
resources will be the reduction of natural recharge of groundwater
basins and degradation of groundwater quality resulting from the use
of septic tanks in rural and low density residential areas.
This section of the report presents the results and analysis of the
impacts of the ten alternative urban growth patterns on water quality
in the Laguna and Petaluma Basins. Water quality impacts that were
not modeled are also briefly discussed. To evaluate the effects of
the different growth patterns on the quality of streams within these
basins, two separate mathematical models were used: QUAL-II for
studying the impacts during low flow periods and a Runoff-Quality
Model for evaluating water quality impacts during periods of storm
runoff. These models are described in Chapter Five and in Appendix F.
Also described in Appendix F are the key model variables unique to
VI-1
-------
Sonoma County, how they were developed and a description of the work
necessary to calibrate the models for use on the Sonoma County water
sheds and streams.
The Sonoma Creek watershed is also a part of the study area, but there
were insufficient funds to permit modeling of this watershed and
stream network. However, some of the conclusions reached in the
analysis of model results for the Laguna and Petaluma Basins can be
extended to the Sonoma Creek watershed.
Impacts of Development on Dry Weather Quality
The stream quality model QUAL-II was applied to the Laguna de Santa
Rosa and the lower reaches of its major tributaries including Santa
Rosa Creek, Mark West Creek, and Windsor Creek. In the Petaluma
Basin, QUAL-II was applied to the Petaluma River from one kilometer
upstream of the confluence of Lichau Creek and the river to 29.5
ki1ometens downstream.
Simulations of water quality for low flow conditions were made in both
the Laguna and Petaluma Basins for Base Year (1973) conditions and
most of the land use alternatives. (Some alternatives were npt studied
because their findings would have been essentially the same due to
similar population levels being served by the sewage treatment plants.)
The greatest impact of development on low flow quality in both basins
is caused by the discharge of treated wastewater from municipal sewage
treatment plants. The loads on these plants are a function of the
populations served by the sanitary districts. Consequently, the
population distributions for the Base Year and each alternative are
allocated to the sanitary districts under present and future conditions
of treatment plant configurations to arrive at the magnitude and
location of treated discharges. Under future conditions, the treatment
plant configuration is the same for all land use patterns.
Laguna Basin
In 1973, there were three sewage treatment plant discharges to the
Laguna de Santa Rosa and two discharges to Santa Rosa Creek. These
discharges and the QUAL-II stream network are shown schematically on
Figure VI-1. (The diagram should be read from the top to the bottom
of the page for the directional flow of the various tributaries to the
Laguna de Santa Rosa, which in turn drains into the Russian River.
The diagram is drawn to indicate how the simulation model receives
information for each section or "element" of the tributaries.) Accord-
ing to the North Coastal Water Quality Control Plan, a consolidated
treatment plant at the existing Laguna STP location will serve most of
Santa Rosa, Rohnert Park, Cotati, and Sebastopol, thereby eliminating
the Sebastopol and Rohnert Park-Cotati plants. The College Avenue
plant will remain in service but it will be limited to a capacity of
220 liters/second (I/sec) (5 mgd). Under future conditions, with the
exception of Oakmont, College Avenue will treat up to 220 I/sec of
municipal waste flow and the consolidated Laguna plant will treat all
the remaining wastewater originating in the Santa Rosa area.
VI-2
-------
Hinebough Ck./
Rohnert Park-
Colati STP ^
143
3
Element Number
.Reach Number
*— = Point Source Input
Scale: Schematic, but 1 element -0.5km
FIG.VI-1
LACUNA DE SANTA ROSA AND TRIBUTARIES
QUAL-II STREAM NETWORK
-------
The effluent was assumed to be discharged as follows under all alter-
natives in accordance with the Basin Plan proposals:
Oakmont - treated and discharged to Santa Rosa Creek
College Ave. - treated and land disposal
Laguna - treated and discharged to Laguna de Santa Rosa
Treated effluent at the consolidated Laguna plant may be discharged to
land during summer months in the future similar to the current disposal
of effluent from the College Avenue plant. Discharges to the Laguna
de Santa Rosa may be allowed only during wet weather when the Laguna
has a high assimilative capacity. However, for purposes of this study
the entire Laguna plant effluent was assumed to be discharged to the
Laguna de Santa Rosa.
Wastewater Flows and Characteristics. For the Base Year simulation,
the quality of treated effluent was set to that observed in September
1973 at each of the operating treatment plants. Under future conditions
the effluent quality was set at or better than the quality defined by
the EPA as secondary treated effluent. Table VI-1 shows the concen-
trations of key constituents used to characterize the quality of
effluent discharge to Santa Rosa Creek and the Laguna de Santa Rosa.
Flows at each treatment plant were estimated by multiplying the popu-
lation served by the historic per capita water use for that area, ;
varying by city from 454 liters (120 gallons) to 303 liters (80 gallons)
per day.
The EPA definition of secondary effluent calls for BOD concentrations
not to exceed 30 mg/1. At the population levels envisioned for several
of the growth alternatives BOD concentration of 30 mg/1 depressed
dissolved oxygen concentrations to zero in the Laguna de Santa Rosa.
Consequently, advanced treatment was assumed in terms of BOD removal
at the Laguna plant for most of the alternatives.. The effluent BOD
concentration at the Laguna plant was set at 30 mg/1 for the Rural
Dispersed alternative, 7.5 mg/1 for the Continuing Trends, and at 5.0
mg/1 for all remaining alternatives. Even with reduced BOD concen-
trations, dissolved oxygen levels were still depressed in the prelim-
inary simulations. In order to maintain some dissolved oxygen in the
Laguna de Santa Rosa, it was necessary to reduce ammonia concentrations
at the higher STP discharge rates. Table VI-1 shows NH3 concentra-
tions ranging from 5.0 mg/1 at the Laguna plant for the land use
alternatives resulting in high discharge rates to 20.0 mg/1 in the
base year.
Simulation Results. Figure VI-2 shows dissolved oxygen concentrations
along the Laguna de Santa Rosa for Base Year conditions and for four >?
of the land use alternatives, each at a County population of 478,000.
There is a pronounced DO sag downstream from the Laguna plant for 1973
conditions and the Rural Dispersed and Continuing Trends alternatives.
Another smaller sag in the Base Year simulation is noticeable down-
stream from the confluence of Santa Rosa Creek and the Laguna de Santa
Rosa. This sag is caused by the discharge to Santa Rosa Creek in 1973
VI-4
-------
TABLE VI-1
EFFLUENT FLOWS AND QUALITIES USED IN QUAL-II SIMULATIONS
Land Use Alternative
Base Year (1973)
Oakmont
College Avenue
Rohnert Park-Cotati
Sebastopol
Laguna
Continuing Trends
Oakmont (478)
Laguna (478)
Santa Rosa Centered
Oakmont (478)
Oakmont (630)
Laguna (478)
Laguna (630)
Urban Centered
Oakmont (478)
Oakmont (630)
Laguna (478)
Laguna (630)
Rural Dispersed
Oakmont (478)
Laguna (478)
Flow
(I/sec)
8
280
39
16
80
16
770
24
34
1130
1640
12
17
620
1020
25
200
Constituent
BOD
(mg/i)
24.0
24.0
60.0
26.8
5.6
30.0
7.5
30.0
30.0
5.0
5.0
30.0
30.0
5.0
5.0
30.0
30.0
NH3
(mg/1 )
20.0
0.5
20.0
20.0
20.0
20.0
13.8
20.0
20.0
5.0
5.0
20.0
20.0
5.0
5.0
20.0
13.8
N03
(mg/1 )
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
P04
(mg/1)
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
20.0
VI-5
-------
annual D.O. objective
10 15 20
Kilometers, Laguna de Santa Rosa
FIG. VI-2
LAGUNA DE SANTA ROSA
DISSOLVED OXYGEN PROFILE
(478,000 population level)
-------
from the College Avenue plant. Dissolved oxygen under the Continuing
Trends alternative never recovers from the sag whereas, under the Base
Year, Rural Dispersed, Santa Rosa Centered and Urban Centered alter-
natives, dissolved oxygen concentrations do recover. The reason for
this appears to be the NH3 concentration of 13.8 mg/1 at the high
discharge rate of 770 liters/sec. From a fish habitat point of view,
the DO levels shown in Figure VI-2 are unsatisfactory for 1973 con-
ditions and the Rural Dispersed and Continuing Trends alternatives.
The North Coastal Basin Water Quality Control Plan shows a minimum DO
mean annual objective of 7.0 mg/1 for the Laguna de Santa Rosa.
Generally, DO levels below 5.0 mg/1 are not sufficient to support
healthy populations of most species of warm water game fish. The
Santa Rosa Centered and Urban Centered DO levels, while below the 7.0
mg/1 minimum, appear to be satisfactory for maintaining a fishery in
the Laguna. If tertiary treatment (effluent BOD of 5.0 mg/1) were
applied to the waste flows at the Laguna treatment plant in both the
Rural Dispersed and Continuing Trends alternatives, dissolved oxygen
concentrations in the Laguna would be very similar to those shown in
Figure VI-2 for the Urban Centered and Santa Rosa Centered alternatives.
The main point to be made here is that tertiary treatment would be
required at the Laguna plant by al_l_ alternatives if the effluent is to
be discharged to the Laguna de Santa Rosa during summer months and if
the DO objective is to be satisfied.
The quality of water discharged to the Russian River from the Laguna
de Santa Rosa is of concern from the standpoint of its impact on the
Russian River's important recreation and fishery uses. Table VI-2
shows the quantity and quality of water discharged to the Russian
River for Base Year conditions and the land use alternatives shown in
Figure VI-2.
TABLE VI-2
QUANTITY AND QUALITY OF LOW FLOW DISCHARGES FROM
LAGUNA TO RUSSIAN RIVER
(478,000 population level)
FTow DO BOD NHT^N NO^N NOpNP04-P
Land Use q
Alternatives (nT/sec)(mg/1) (mg/l)(mg/l) (mg/1) (mg/1) (mg/1)
Base Year
Continuning
Trends
Santa Rosa
Centered
Urban Centered
Rural Dis-
persed
0
1
1
1
0
.88
.21
.58
.06
.65
6.86
0.60
5.03
7.08
7.78
3.32
1.49
1.32
0.91
1.88
1.
4.
2.
1.
2.
90
58
22
71
27
0
1
0
0
0
.45
.11
.52
.41
.55
14
19
19
16
11
.87
.98
.75
.49
.54
10.25
12.94
14.58
11.93
6.89
VI-7
-------
All land use patterns in Table VI-2 show high nutrient concentrations.
Early in the Basin Planning Program, preliminary nutrient objectives
were established for the Russian River. These preliminary objectives
were 2.0 mg/1 nitrate and 0.4 mg/1 phosphate. In the summer months
the flow of the Russian River at its confluence with Laguna de Santa
Rosa may be as low as 3.5 m3/sec. Obviously, flows from the Laguna on
the order of those shown in Table VI-2 would result in nutrient concen-
trations well above the old objectives for the Russian River. Conse-
quently, nutrient removal is indicated at the Laguna treatment plant
to produce a high quality flow in the Laguna that will come close to
meeting the quality of the Russian River. It should also be pointed
out that while the BOD removal down to 5.0 mg/1 was sufficient to
achieve minimum acceptable steady state concentrations of DO in the
Laguna, the nutrient load would undoubtedly result in biostimulation
within the Laguna itself. The Basin Plan (1) contains an objective
stating that waters shall not contain biostimulatory substances in
concentrations that promote aquatic growths to the extent that such
growths cause nuisance or adversely affect beneficial uses.
A simulation, using the Santa Rosa Centered 478 alternative, was made
assuming a very high level of treatment at the Laguna plant. The
quality of the effluent was:
BOD - 1.0 mg/1
NH3 - 1.0 mg/1
N0« - 0.0 mg/1
NO, - 1.0 mg/1
P0| - 0.05 mg/1
The BOD concentration of 1.0 mg/1 maybe a little lower than that which
is achieveable with current treatment technology. The design standards
for the future Santa Rosa STP suggests 3.0 mg/1 BOD as a median level
of performance.
The resultant quality of the Laguna at its confluence with the Russian
River was as follows:
DO BOD NH3-N NOo-N POd-P
(mg/1) (mg/1) (mg/l) (mg/1) (mg/1)
7.29 0.09 0.25 0.05 0.09
This quality compared to the preliminary objectives for the Russian
River suggest that tertiary treatment, including nutrient removal, at
a consolidated Laguna treatment plant would be required for the in-
creased population levels.
Petalurna Basin
Under Base Year conditions, the Petaluma municipal sewage treatment
flows were discharged to the Petaluma River near the City of Petaluma.
A new plant was built after 1973 and is presently discharging to the
Petaluma River about 4-1/2 kilometers downstream from the location of
VI-8
-------
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Element Numbers For Stream Quality Model
FIG.VI-3
PETALUMA RIVER
QUAL-II STREAM NETWORK
-------
the old plant. The new plant is designed for secondary process with a
discharge permit attached requiring higher specified treatment for BOD
and suspended solids. These discharges and the Petaluma River QUAL-II
network are shown in Figure VI-3.
Wastewater Flows and Characteristics. For the Base Year simulation,
the quality of treated effluent was set to that observed in September
1973 at the old plant. Under future conditions, the effluent quality
for the alternative growth patterns that were simulated was controlled
by the mass emission limitations established by the Regional Water
Quality Control Board. This was accomplished by estimating the flow
rate associated with the population to be served in each alternative
and calculating the concentration of the effluent necessary to stay
within the maximum emissions allowed by the Board for BOD, suspended
solids and coliforms. Table VI-3 shows the concentrations of key
constituents used to characterize the quality of effluent discharges
to the Petaluma River.
TABLE VI-3
EFFLUENT FLOWS AND QUALITIES USED IN QUAL-II SIMULATIONS
Constituents
Land Use
Alternatives
Base Year
Continuing Trends (478)
Urban Centered (478)
Urban Centered (630)
Flow
(I/sec)
120
300
400
550
BOD
(mg/1)
17.0
5.0
4.2
3.0
NH3
(mg/1)
22.0
22.0
22.0
22.0
N03
(mil}
8.0
8.0
8.0
8.0
P04
(mg/1)
20.0
20.0
20.0
20.0
The alternatives shown in Table 3 result in the full range of populations
that may be served by the new Petaluma treatment plant. The quality
Df the Petaluma River resulting from intermediate population levels
associated with those alternatives which were not simulated may be
interpolated from the results of the simulations.
Simulation Results. Figure VI-4 shows the dissolved oxygen concentrations
along the Petaluma River for Base Year conditions and for the land use
alternatives. The DO sag is caused by the discharges from the old
jlant in the Base Year case and by Petaluma's new plant in the new
land use patterns. The sag increases as the flow rate increases, with
the Urban Centered alternative resulting in the greatest discharge to
the Petaluma River. Interestingly, Figure VI-4 shows the low point of
the sag upstream from the location of the new plant. The Petaluma
liver is influenced by tidal fluctuations and an upstream salinity
jradient from San Pablo Bay. Dispersion caused by the salinity gradients
md tidal fluctuation appears to move a significant portion of the BOD
md ammonia discharged by the treatment plant upstream.
VI-10
-------
/
#
Mean annual 0,0. objective
Minimum 0.0. objective
0 v
0
10 15 20
Kilometers, Petalumo River
FIS. V\-4
PETALUMA RIVER
DISSOLVED OXYGEN PROFILE
25
30
-------
The steady state low flow condition in the Petaluma River, as pre-
dicted by the QUAL-II simulations, results in the DO sag near or even
upstream from the discharge locations. The differences in concen-
trations of DO among the land use alternatives or population levels
are most reflective of ammonia demands, because the BOD mass emission
rates were nearly constant, as constrained by discharge limitations.
The San Francisco Bay Basin Plan states that dissolved oxygen concen-
trations in Petaluma River shall not be less than 6.0 mg/1 on a mean
annual basis and never below 5.0 mg/1. Both Urban Centered alter-
natives result in DO concentrations below the mean annual requirement,
implying that mass emissions from the Petaluma plant may have to be
further restricted at population levels equal to or greater than those
assumed for Urban Centered 478 or alternatively, the population in the
basin should be restricted.
The quality of water discharged to San Pablo Bay is reflected in the
values shown in Table VI-4. These values are reflective primarily of
the tailwater (San Pablo Bay) concentrations used in all simulations,
rather than differences in waste discharge conditions.
TABLE VI-4
QUANTITY AND QUALITY OF LOW FLOW DISCHARGES FROM
PETALUMA RIVER TO SAN PABLO BAY
Land Use Flow DO BOD NHa-N N02-N N03-N P04-P
Alternatives (m3/sec) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Base Year
Continuing Trends
(478)
Urban Centered (478)
Urban Centered (630)
0
0
0
0
.30
.48
.58
.73
6.47
6.46
6.45
6.44
0.
0.
0.
0.
17
17
17
17
0.
0.
0.
0.
13
13
13
13
0.03
0.03
0.03
0.03
0.
0.
0.
0.
26
30
32
35
0.14
0.17
;
0.18
0.20
There is almost no difference between the alternatives in the quality
of water discharged to San Pablo Bay. It is not likely that discharges
to San Pablo Bay with the quality shown in Table VI-4 would cause a
degradation of the Bay with respect to oxygen depletion or biostimu-
lation.
Impacts of Development on Wet Weather Quality
Two models, the Urban Runoff and Agricultural Runoff Models, were
combined to provide a runoff and quality model used on the Sonoma
County study. This Runoff-Quality Model predicts the runoff and
VI-12
-------
pollutant washoff from seven categories of urban land uses and three
categories of nonurban uses for any selected storm event and it routes
the runoff and pollutant washoff from the watershed through major
channels, providing a time history of channel flows and qualities for
the duration of the storm.
To facilitate preparation of the data needed for the Runoff-Quality
Model,,,a data preprocessor was developed to create watershed character-
istics from from land use information. The type of information developed
by the preprocessor by subarea is as follows:
1. Percentage of subarea devoted to each land use category,
2. Percentage of subarea with impervious surface, and
3. Maximum and minimum infiltration rates by subarea
The percentage of each grid cell devoted to specific categories of
land use was provided for each land use alternative. The Runoff-
Quality Model is set up on a subarea basis with each subarea con-
taining several one kilometer grid cells. Consequently, it is nec-
essary to aggregate the land use information and this is done by the
preprocessor. A primary use of the land use information by the model
pertains to determining the type and rate of buildup of pollutants on
urban areas, and the soil loss (erosion) potential in nonurban areas.
As indicated in the Chapter V description of the Runoff-Quality Model,
it was next necessary to determine other key variables such as 1)
imprevious area percentages per land use, 2) soils and their infiltration
rates, 3) watershed characteristics (length, width, slope and roughness),
4) typical storm characteristics, and 5) pollutant loads for both
urban and non-urban areas.
•i
For purposes of comparing the impacts of the land use alternatives on
wet weather quality, a typical winter storm was used in the model.
Historical precipitation in Santa Rosa was reviewed and on the basis
of precipitation in 1966 and a "typical" year insofar as total annual
rainfall and monthly distribution, a typical winter storm was developed
and used in the wet weather simulations. In those portions of the
Laguna and Petaluma watersheds with mean annual rainfall of 76.2 cm
(30 in), the winter storm produced 2.5 cm of precipitation over a 4-
hour period. Five hyetographs were prepared based on mean annual
rainfall and the appropriate hyetograph was assigned to each subarea.
Pollutant washoff was computed using the Universal Soil Loss Equation
in nonurban areas. In the urban areas, pollutants were assumed to
accumulate at specified daily rates, the amount of pollutant load on
urban areas available for washoff was directly proportional to the
number of dry days proceeding the storm. In the simulations, 20 dry
days were assumed to preceed the typical winter storm. Eight types of
water pollutants were modeled, including total suspended solids,
nonsettleable solids, BOD, grease and oil, fecal coliforms, total
nitrogen, total phosphorus and total heavy metals.
VI-13
-------
In addition to the simulations using the typical winter storm for each
growth alternative, other simulations were made. Certain measures
have been mentioned in the literature which are concerned with reducing
pollutant washoff. Included are such measures as frequent street sweep-
ing, the requirement of on-site detention storage to capture a portion
of the runoff washoff load and the requirement of less impervious
area per development to reduce runoff. Simulations representing these
measures were made for the Santa Rosa Centered 478 alternative.
Since the pollutant load in urban areas available for washoff is a
function of the number of dry days proceeding a storm and washoff from
nonurban areas is not affected by this, care must be taken in making
judgments about the significance of the contribution of pollutant
loads from urban areas versus nonurban areas. For a given rainfall
event, the washoff from urban areas could be far greater than that
from nonurban areas when a long dry period proceeds the storm. For
the same event with no dry period, the washoff from the nonurban
areas, which would be the same as in the first case, could be far
greater than that from the urban areas. More detailed evaluations
of runoff management techniques must consider different storms and
various antecedent conditions if the overall effectiveness toward
pollution abatement of the techniques is to be evaluated.
Laguna Basin
Figure VI-5 provides a guide map to both the Laguna and Petaluma
Basins. The Laguna Basin covers 668 square kilometers and is repre-
sented in the Runoff-Quality Model by four watersheds and 45 channels.
The watersheds are further broken down into subareas. In the Windsor
Creek, Mark Nest Creek, Santa Rosa Creek, and Laguna de Santa Rosa
watersheds there are 6, 7, 12 and 15 subareas, respectively, with an
average area of 16.7 sq. km. Figure VI-6 shows the subareas and
channels represented in the model for the Laguna Basin.
As mentioned previously, eight types of pollutants were modeled for
each of ten land use patterns. However, for purposes of comparing
the relative impacts of the different patterns on water quality, only
total suspended solids parameters is used. In rural areas, the model
computes the total suspended solids washed off the watershed by the
Universal Soil Loss Equation. The other seven pollutants are computed
as a constant fraction of total suspended solids but are variable by
land use type. In urban areas all pollutants are computed as frac-
tions of total dust and dirt. Consequently, the amount of total
suspended solids washed off the watershed or the concentration of
total suspended solids in the channel are good indicators of the
relative pollution load.
Table VI-5 shows the peak concentrations of total suspended solids for
each channel in the Laguna Basin and the total suspended solids washed
off the subareas tributary to the channels. Washoff from the subarea
is presented as urban and nonurban washoff. The urban load is the sum
of all residential, commercial and industrial uses and the nonurban
load is the sum of all open and agricultural uses. Figure VI-7 in-
dicates stream quality in various channels as a result of the dif-
ferent patterns.
VI-14
-------
GUIDE TO BASIN MAPS
& CHANNEL NUMBERS
Channel Location and Number
FIG.VI-5
-------
Watershed Boundary
Subarea Boundary
Subarea Number
(4004)
Channel Number
(4003)
FIG.VI-6
LAGUNA BASIN
SUBAREAS AND CHANNELS
-------
TABLE VI--5
LAGUNA BASIN
CHANNEL QUALITY AND POLLUTANT WASHOFF
Channel
Number
Peak Conccntration-TSS,
BY CT* SRC* UC* RD*
mg/1
SO*
Subarea
Number
BY
Urban NonUr
Total
CT
Urban NonUr
Washoff
Load -
SKC
Urban NonUr
TSS. kilograms x 10*
UC
Urban NonUr
RD
Urban NonUr
SO
Urban NonUr
Windsor Creek Watershed
1001
1002
1003
1004
1005
1006
1007
Mark West
2001
2002
2003
2004
2005
2006
2007
2008
202 208
548 SSO
63 129
1S4 197
165 223
195 230
39 39
213
563
109
182
208
212
39
207 118
SSO 379
109 117
227 236
288 294
212 230
39 39
207
s:o
109
227
288
212
39
1001
1006
1004
--
1002
1003
1005
TOTALS
0.8S
6.46
0.55
1.01
2.13
0.00
11.00
25
1.33
0.49
3.30
2.73
3.99
2.27
14.11
r1
.11
0.87
6.53
1.43
1.67
2.79
0.00
13.29
^
27
1.33
0.49
3.38
2.76
4.01
2.27
14.24
.53
0.87
7.72
1.08
1.40
2.31
0.00
13.38
27.
1.33
0.48
3.26
2.70
3.84
2.27
13.88
26
0.87
6.55
1.08
2.05
2.31
0.00
12.86
26.
1.33
0.57
3/26
2.70
3.84
2.27
13.97
83
0.02
2.83
1.20
2.26
2.79
0.00
9.. 10
23
1.33
0.63
3.32
2.75
4.00
2.27
14.30
.40
0.87
6.55
1.08
2.05
2.31
0.00
12.86
26.
,1.33
O.S7
3.26
2.70
3.84
2.27
13.97
83
Creek Watershed
271 295
512 514
170 177
51 51
64 64
50 SO
51 51
298 302
283
475
136
51
64
SO
51
281
298 297
SIS 140
88 113
51 51
64 64
SO 50
51 51
299 211
298
515
88
51
64
SO
51
299
2002
2001
2003
2004
2005
2006
2007
--
•fciiMI>> m • JW
1.80
12.81
2.14
0.00
0.00
0.00
0.00
16..75
3.46
1.01
3.78
10.24
12.98
18.20
18.91
68.59
2.28
13.45
2.24
0.00
0.00
0.00
0.00
17.97
3.51
1.04
3.72
10.24
12.98
18.20
18.91
68.60
2.10
11.35
1.69
0.00
0.00
0.00
0.00
15.14
3.51
0.94
3.78
10.24
12.98
18.20
18.91
68.56
2.25
12.91
l.OS
0.00
.0.00
0.00
0.00
16.21
3.51
0.95
4.06
10.24
12.98
18.20
18.91
68.85
2.37
1.01
1.39
0.00
0.00
0.00
0.00
4.77
3.46
1.15
4.04
10.24
12.98
18.20
18.91
68.98
2.25
12.91
l.OS
0.00
0.00
0.00
0.00
16.21
3.51
0.90
4.06
10.24
12.98
18.20
18.91
68.80
85.34
86.57
83.70
85.06
73.75
85.01
•Court/ Population of 478,000
-------
CO
TABLE yj-S
(Continued)
Channel Peak
Nunber BY
Laguna
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
Concentration-TSS, ntg/1
CT* SRC* UC* RD* SD*
Subarea
Number
BY
Urban NonUr
Total
CT
Urban NonUr
Washoff Load -
SRC
Urban NonUr
TSS, kilograms
UC
Urban NonUr
x 103
RD
Urban NonUr
sb
Urban NonUr
do Santa Rosa Watershed
166
219
217
417
314
165
557
171
320
96
111
337
29
163
176
236
297
468
161
186
602
229
420
69
78
360
29
168
174 165
237 214
243 262
413 562
161 161
189 203
452 489
178 201
354 368
56 96
63 111
373 391
29 29
175 169
157
229
262
491
76
138
530
155
216
64
72
295
29
109
172
132
288
519
161
196
500
324
395
106
122
379
29
169
4002
4003
4004,4005
4006,4007
4008
4009
4010
4011
4013
--
4014
4012
4015
4001
TOTALS
BASIN TOTALS
(478,000 pop.)
BASIN TOTALS
(630,000 pop.)
0.70
0.43
0.99
22.52
5.58
1.12
11.44
0.12
8.44
0.86
16.20
0.00
0.37
68.77
"V
119.
356.
4.33
2.73
8.64
9.12
7.06
0.94
0.57
0.99
7.24
1.18
5.37
0.24
1.95
50.36
13
26
0.70 4.33
0.43 2.73
8.63 8.23
26.24 9.09
1.91 4.70
1.12 0.94
16.40 0.65
0.87 0.93
17.11 0.68
0.60 1.20
24.12 4.98
0.00 2.38
0.37 1.95
98.50 42.79
141.29
401.11
445.50
0.70 4.33
0.43 2.88
5.17 7.89
25.57 8.39
1.91 4.70
1.12 0.94
11.52 0.64
0.24 0.77
12.83 4.88
0.46 1.30
26.27 2.69
0.00 2.38
0.37 1.95
81.59 43.74
130.33
395.25
44S.50
0.70
0.43
5.03
37.44
1.91
1.12
11.06
0.59
12.40
0.86
30.17
0.00
0.37
10.2.08
150.
382.
414.
4.33
2.73
8.65
8.70
4.70
0.94
0.54
0.95
6.65
1.18
4.45
2.38
1.95
48.15
23
43
10
0.00 4.38
0.00 2.78
5.71 8.34
24.83 9.37
0.00 4.67
0.00 0.92
10.82 0.70
0.72 0.91
4.84 7.27
0.55 1.22
13.84 S.96
0.00 2.38
0.00 1.95
0.70 4.33
0.43 ( 2.73
7.56 8.34
31.57 8.45
1.91 4.70
1.12 0.94
13.96 0.63
2.61 0.83
16.03 6.19
0.96 1.18
26.58 4.83
0.00 2.38
0.37 1.95
60.77 50.85 103.80 47.48
111.62 151.28
339.73
(no simulation)
400.06
453.50
-------
10
TABLE VI -€
(Continued)
Channel Peak
Nunber BY
Santa
3001
3002
3003
3004
3005
3006
3007
3008
3009
spio
3011
3012
3013
3014
301$
3016
Goncentration-TSS. me/I
CT* SRC* UC* RD* SD*
Subarea
Nunber
BY
Urban NonUr
Total
CT
Urban NonUr
Washoff
Load -
SRC
Urban NonUr
TSS, kilograms
UC
Urban NonUr
X 103
RD
Urban NonUr
SD
Urban NonUr
Rosa Creek Watershed
324
614
' 441
461
587
.247
457
363
235
80
343
58
58
64
57
268
353
541
491
520
588
212
492
303
235
136
323
58
58
194
57
233
367 304
503 489
466 448
549 546
627 583
259 198
359 316
318 321
275 186
209 128
355 246
58 58
58 58
260 154
57 57
256 230
337
618
453
476
571
243
480
327
140
47
210
58
58
148
52
228
332
505
524
533
675
200
340
352
203
163
263
58
58
224
57
250
3001
3004
--
3003
3002
3009
3008
3005
--
3007
3006
--
3012
3011
3010
..
2.87
28.82
8.44
7.69
4.47
9.59
6.98
0.73
4.13
0.00
0.92
0.55
1.86
0.75
1.26
2.86
1.76
0.99
0.96
3.36
1.57
24.05
7.22
4.85
4.27
26.78
13.55
18.37
4.06
11.55
6.44
1.63
4.79
0.00
3.07
0.55
1.91
0.99
1.39
2.50
1.77
1.01
1.16
3.11
1.52
24.05
6.40
4.85
5.85
29.80
12.15
24.66
5.72
8.08
6.74
2.60
5.38
0.00
4.17
0.55
2.18
0.52
1.31
1.82
1.74
0.81
0.95
3.03
1.44
24.05
5.56
4.85
2.95
21.89
10.26
14.98
3.03
5.00
5. SO
1.23
2.85
.0.00
2.42
O.SS
1.87
0.71
1.34
2.28
1.80
0.86
0.91
3.02
1.60
24.05
6.36
4.85
2.75
31.72
9.55
10.35
4.33
9.55
5.04
0.34
2.01
0.00
2.31
0.00
1.95
1.28
1.39
3.07
1.78
0.92
1.02
3.61
1.68
24.05
7.05
5.21
3.34
23.43
13.92
22.45
3.15
5.47
6.41
1.89
3.13
0.00
3.59
0.55
2.01
0.58
1.36
2.66
1.81
0.91
0.90
3.00
1.59
24.05
5.84
4.85
TOTALS
75.19 51.49 95.06 50.66 10.5.70 48.26 70.66 49.65 77.95 53.01 87.58 49.56
126.68
145.72
153.96
120.31
130.96
136.94
-------
CHANNEL QUALITY
PER GROWTH ALTERNATIVE
Peak Concentrations-TS&mg/l
1973 12000-478000 Fhrailatirm
FIG.VI-7
-------
The peak concentrations in Table VI-5 are highest in those channels
which drain subareas with the largest urban development concentrations
and hence the largest urban washoff loads. The pollutant load in
urban areas is picked up early in the storm causing the concentration
of total suspended solids in channels draining urban areas to peak
faster and higher than those draining rural areas. In the rural areas
the intensity of rainfall and slope are major determinants of how much
material is eroded off the watershed. The storm used in these simu-
lations has a peak intensity at 1-1/2 hours after the storm begins.
Consequently, the majority of erosion occurs when flows are highest,
resulting in lower peak concentrations at a later time in the storm
for channels draining rural areas.
The washoff loads in the Laguna Basin under Base Year conditions are
distributed between urban and nonurban areas as follows:
Percent Washoff Load
Windsor Creek 50% urban 50% nonurban
Mark West Creek 20% urban 80% nonurban
Santa Rosa Creek 60% urban 40% nonurban
Laguna de Santa Rosa 60% urban 40% nonurban
In terms of the overall impact of the different growth patterns on wet
weather quality, Table VI-5 indicates the following for a County
population of 478,000:
Windsor Creek - All alternatives have about the same impact
Mark West Creek - Rural Dispersed results in the lowest wash-
off load because it has the lowest amount
of urban development for that watershed of
any alternatives
Santa Rosa Creek - Urban Centered results in the lowest wash-
off load because it has the lowest amount
of development for that watershed of any
alternative
Laguna de Santa Rosa - Rural Dispersed results in the lowest
washoff load because it has the lowest
amount of urban development for that water-
shed of any alternative
For the entire Laguna Basin, Table VI-5 shows the Rural Dispersed
alternative producing the lowest washoff load. The greatest impact on
Russian River wet weather quality, at the 478,000 population levels,
would result from the Continuing Trends pattern, although it is vir-
tually the same as Santa Rosa Centered and Suburban Dispersed and only
five percent greater than Urban Centered. Population levels of 630,000
for Sonoma County produce loads about 10 percent greater than the
478,000 level. Urban Centered results in the lowest total suspended
solids load at the 630,000 level.
VI-21
-------
Some caution is necessary when reviewing the Rural Dispersed figures.
Their relative position to the other growth alternatives is correct
but their exact quantities, particulary when measured against Base
Year, can cause confusion. This is due both to slightly different land
use categorizations between Base Year and the growth alternatives and
the way the runoff model treats the pollution runoff from the "ranchette"
residential uses that dominated Rural Dispersed. Because the "ranchettes"
are built at one unit per three acres and would have a very low percentage
Impervious coverage, the model treats them as open space. Unfortunately,
there was no information from which to determine an appropriate pollutant
load for ranchettes, and the open space load may be too low for particular
pollutants.
Figures VI-8 and VI-9 illustrate the impact of urban land uses on the
peak concentrations of total suspended solids in the channels. The
figures for Base Year and Santa Rosa Centered 478 show the impact of
urban washoff loads on peak concentrations of total suspended solids
in channels and the dilution effects of rural runoff as these streams
are combined with flows from urban areas. In order to characterize
quality in channels draining urban and nonurban areas, Figures VI-10
and VI-11 are copies of the simulations for Santa Rosa Centered 478
for channel 3002 (Santa Rosa Creek in downtown Santa Rosa) and channel
3015 (upper reach of Matanzas Creek). The quality of channel 3002
reflects the influence of urban development and channel 3015 runs
through an open area unaffected by urban development.
Without exception, the peak concentrations of all eight water quality
parameters are higher in those cjhannels affected by urban runoff than
those draining rural areas.. Also, on the recession limb of the storm,
(the last part of the storm following the peak), concentrations are
higher in the urban channel 3002 than in the rural 3015.
Impact of Sewage Treatment Plants During Met Weather Periods
The discharges from sewage treatment plants are not included in the
Runoff-Quality Model. During peak runoff periods, the impact of these
point discharges would have very little effect on the channel qualities.
The peak flow in the Laguna de Santa Rosa at the proposed consolidated
Laguna sewage treatment plant (STP) discharge location was 20 m3/sec
compared to a dry weather flow of 1.13 m3/sec for the consolidated
Laguna STP.
However, after the channel flows have peaked and are receeding, the
STP flows become significant due to infiltration into the sewer lines
and interceptors serving the plant. In order to assess the impact of
wet weather flows from the Laguna STP, a simulation was made with
QUAL-II using the channel flow and quality on the recession limb of
the storm from the Runoff-Quality Model as input to the QUAL-II Model.
The flow at the STP was assumed to double during wet weather. This
assumption is based on comparisons of dry weather flows to wet weather
flows at existing STP's in the Santa Rosa area. The quality of the
VI-22
-------
Watershed
Boundary
Subarfto
Boundary
Urban wosnoff load, total suspended
solids In kg/hectare
Peak concentration of lotof suspended
sol/di (n stream In ma/1
FIG.VI-8
LAGUNA BASIN - BASE YEAR
URBAN WASHOFF AND CHANNEL QUALITIES
-------
Urban washoff load, total suspended
solids in kg/hectare
0-1.0
::::::: 5.1-10.0
1.1-2.0
>IO.O
WKmn
IJ57] Peak concentration of total suspended
FIG.VI-9
LAGUNA BASIN - SRC-478
URBAN WASHOFF AND CHANNEL QUALITIES
-------
BASIN
SAMTA ROSA CENTERFO
I
ro
01
OF QUANTITY AND QUALITY RESULTS AT LOCATION 300?
FLO* IN C«S AND OUALITV IN (MG/L) EXCEPT CflLIFORVS IN (NUMBERS/I OOML)
TIME
0 .00
0 15.00
0 50.00
0 OS. 00
1 .00
1 IS. 00
1 30.00
1 05.00
2 .00
2 IS. 00
2 30.00
2 05.00
3 .00
3 15.00
3 30.00
3 as. oo
a .00
0 IS. 00
0 30.00
D.O
25.3
20.7
?o.1
23.5
SOD
.0
.0
.0
.0
16.7
37.8
02.9
02.5
36.0
31.7
25.0
19.7
15.6
1?.5
10.0
8.1
6.5
5.3
0.3
3.5
3.0
?..5
2.2
.0
.7
.6
.0
.3
.2
.?
.1
.0
1.0
.0
.9
.9
.8
GREASE
,.00
.00
.00
.00
20.53
06.05
52.62
52.09
07.00
38.68
30.38
23.81
18.82
15.00
12.0?
9.66
7.79
6.30
5.13
0.22
3.52
2.99
2.59
2.28
2.03*
.80
.67
.50
.0?
.V
.20
.17
.11
.05
1.01
.97
.93
F-CflLI
0.00
0.00
o.oo
0.00
.1.85 + 00
a. ?i + oo
0. 81+00
0.80+00
0.37+00
3.65+00
2.90+00
2.36+00
1.91+00
1.56+00
1.27+00
1 .00+00
8.61+03
7.15+03
6.01+03
5.12+03
0.05+03
3.90+03
3.56+03
3.27+03
3.03+03
2.80+03
2.68+03
2.50+03
2.01+03
2.31+03
2.21+03
2.12+03
2.05+03
1.08+03
1.01+03
1.85+03
1. 60+03
TOT-N
.00
.00
.00
.00
33.37
75.61
sb.eo
"85.13
76.90
63.61
50.20
. 30.70
31.60
25.02
20.55
16.70
13.62
11.18
9.27
7.78
6.65
5.70
5.10
0.60
0.24
3.01
3.60
3.01
3.21
3.00
2.80
2.76
2.60
2.50
2.05
2.36
2.29
TOT-P
.00
.00
.00
.00
0.20
0.73
11.05
10.96
0.91
8.19
6.07
5.11
0.06
3.?6
2.63
2.13
1.73
1.01
1.16
.96
.82
.70
.62
.55
.50
.06
.02
.30
.37
.30
.33
.31
.30
.28
.27
.26
.25
HVY WET
.00
.00
.00
.00
11.77
26.6?
30.13
29.8]
26.89
22.10
17.30
13.57
10.7?
8.55
6.85
5.52
0.06
3.6?
2.96
2.05
2.05
1.76
1.53
1.35
1.2?
1.10
1.01
.93
.87
.81
.76
.72
.60
.65
.63'
.60
.58
FIG.VI-10
LAGUNA BASIN
QUALITY RESULTS AT CHANNEL 3002
-------
LACUNA B4SIN
SANTA ROSA CENTF.RFD 078
SUMMARY OF QUANTMY AND QUALITY RESULTS AT LOCATION 3015
FLOW IN CMS AMP OU&LITY TM C^G/D EXCEPT COLIFORMS IN (NUMBEPS/100ML)
TIME
0 .00
0 15.00
0 30.00
0 05.00
1 .00
1 15.00
1 30.00
1 U5.00
2 .00
2 15.00
2 30.00
2 05.00
3 .00
3 15.00
3 30.00
3 US. 00
u .00
U. 15.00
U 30.00
« 05.00
S .00
5 15.00
5 30.00
5 US. 00
6 .00
6 15.00
6 30.00
6 05.00
7 .00
7 15.00
7 30.00
7 05.00
8 .00
8 15.00
8 30.00
.8 45.00
9 .00
FLOW
.000
.000
.000
.002
.328
.970
1.79?
3.796
8.300
11.388
10.73?
9.599
9.087
8.765
8.520
8.274
8.009
7.3«7
6.211
0.939
3.908
3.083
2.012
1.861
1.010
1.007
.765
.559
.020
.530
.263
.213
.176
.107
.125
.107
.092
TOT-SS
.0
.0
.0
15.9
36.5
02.7
03.6
08.0
55.6
57.2
5U.5
51.9
50.1
09.0
OR. 2
07.5
06.9
05.7
03.0
00. U
37.2
33.9
30.5
27. 1
?0.o
?2.7
22.1
22.0
21.8
21.6
21.5
21 .0
?1 .?
21.1
21.0
20.9
20.8
NON-SET
.
.
.
10.
23.
27.
27.
30.
30.
30.
33.
31.
30.
?9.
29.
?K.
28.
27.
26.
20.
22.
20.
18.
16.
1 o.
13.
1 J.
13.
15.
13.
12.
12.
12.
12.
12.
12.
12.
0
0
0
2
5
2
7
1
2
9
0
3
2
5
0
5
1
u
1
3
3
3
3
3
6
6
3
2
1
0
9
a
7
7
6
5
5
BOD
.0
.0
.0
1.1
2.0
2.5
2.3
1.9
1.0
.9
.6
.5
.0
.3
.2
.2
.2
.2
.2
.1
.1
.1
.1
.1
.1
.1
.1
—
.
.
.
.
.
.
.
.
.
GNEASE
.00
\oo
.00
2.09
0.5?
0.75
0.39
3.63
?.5t
1.57
1.05
.73
.50
.36
.27
.21
.17
.15
.13
.12
.10
.09
.08
.07
.07
.06
.06
.06
.06
.06
.06
.06
.06
.06
.06
.06
' .06
0
0
0
2
u
0
0
u
3
2
2
1
1
1
1
9
8
7
6
6
5
5
5
5
5
5
5
5
5
5
5
F-COLI
.00
.00
.00
.03+03
.00+03
.78+03
.52+03
.00+03
.35+03
.65+03
.17+03
.86+03
. 6 n + 0 3
.50+03
.01+03
.30+03
.30+03
.25+03
.18+03
.09+03
.P-0 + 03
.13+0?
.20+02
.30+02
.56+02
.12+02
,«6+02
.91+02
.87+0?
.83+0?
.79+0?
.76+0?
.72+02
.69+02
.66+02
.63+02
.60+02
TOT-M
.00
.00
.00
2.90
6.02
6.85
6.03
5.59
0.39
3.27
2,56
2.10
1.79
1.59
1.05
.37
.31
.25
.1 7
.08
.99
.90
.61
.72
.65
.60
.59
.58
.58
.58
.57
.57
.57
.56
.56
.56
.55
TOT-P
.00
.00
.00
.03
.90
1.00
.93
.79
.58
.00
.29
.22
.18
.15
.13
.12
.11
.10
.09
.09
.08
.07
.06
.06
.05
.05
.05
.05
.05
.05
.05
.00
.00
.00
.00
.00
.00
HVY MET
.00
.00
.00
1.08
2.35
2 . « 8
2.30
1.9?
1.37
.90 .
.63
.06
.35
.28
.23
.20
.18
.16
.15
.13
.12
.11
.10
.09
.08
.07
.07
.07
.07
.07
.07
.07
.07
.07
.07
.07
.07
FIG.VI-11
LAGUNA BASIN
QUALITY RESULTS AT CHANNEL 3015
-------
effluent from the Laguna plant was set to reflect a lower level of
treatment to approximate a condition of plant overloading during wet
weather. The dissolved oxygen concentrations of the headwaters were
set at 5.0 mg/1 and, as explained previously, other headwater quality
parameters such as BOD, were specified at those concentrations result-
ing from the Runoff-Quality Model simulation of the Santa Rosa Centered
478 pattern.
The QUAL-II "wet weather" simulation shows that the Laguna plant would
cause a noticeable impact on the quality of water in the Laguna de
Santa Rosa during storm periods when the plant was discharging at a
wet weather flow rate of 2.3 m3/sec with effluent quality of 50 mg/1
of BOD and 150 mg/1 or suspended solids. A DO sag was observed
beginning at the plant discharge and extending to the confluence of
Santa Rosa Creek and the Laguna. DO was 5.62 mg/1 at the discharge
location and declined to 3.95 mg/1 at Santa Rosa Creek.
Petaluma Basin
The Petaluma Basin is represented by an area of 189 square kilometers
in the Runoff-Quality Model. The drainage area of the river down-
stream from the City of Petaluma was not included in the model. Since
no growth was allowed in this area in any of the land use alternatives,
there will be no change in the quality of runoff to the Petaluma River
below the downstream limit of the model.
The Petaluma Basin is broken down into 15 subareas and 18 channels
which are shown in Figure VI-12.
Table VI-6 shows the peak concentrations of total suspended solids
for each channel in the Petaluma Basin and the total suspended solids
washed off the subareas. Rural Dispersed results in the lowest total
suspended solids washoff. However, it was pointed out earlier that
the way in which rural residential development was treated by the
model calls for care to be taken in drawing conclusions about the
impacts of this pattern on wet weather quality. The washoff from
Santa Rosa Centered alternative is so close to that of Rural Dis-
persed that Santa Rosa Centered is likely to have a lesser impact on
wet weather quality. Also, at the 630,000 population level, the Santa
Rosa Centered alternative results in the lowest total suspended
solids washoff load.
Figures VI-13 and VI-14 show the impact of urban land uses on peak
concentrations of total suspended solids in the Petaluma Basin
channels and the dilution effects of rural runoff where these streams
are combined with runoff from urban areas. Figures 15 and 16 illustrate
the quality of runoff in a channel draining an urban area and a channel
draining an area unaffected by development. Channel 1007 is the
Petaluma River at the City of Petaluma and channel 1010 is the head-
water reach of Washington Creek. There is no urban load affecting the
quality of runoff in channel 1010.
VI-27
-------
Channel Number
Suborea Number
Watershed Boundary
Subarea Boundary
KlUMETEM
FIG.VI-12
PETALUMA BASIN
SUBAREAS AND CHANNELS
-------
TABLE
PETALUMA BASIN
CHANNEL QUALITY AND POLLUTANT WASHOFF
Channel
Ntniber
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
BY CT*
152 179
61 61
58 58
375 392
109 157
45 .45
630 623
562 542
130 163
41 41
381 416
127 130
88 88
88 88
246 255
228 91
200 200
187 198
nitration*
SRC* UC*
141 158
61 61
58 58
280 247
161 198
45 45
547 573
416 436
207 239
41 41
432 427
127 103
88 88
88 88
247 190
137 137
294 200
221 230
•County Population of 478,
rss, *g/i
RD* SD*
163 153
61 61
SB 58
399 269
99 190
45 45
683 582
541 587
164 243
41 41
248 446
85 103
91 88
91 83
83 190
94 137
40 280
48 428
Subarea
Niriber
--
1002
1006
1001
1003
1009
1004
1005
1007
1010
1008
--
--
1014
1013
1015
1012
1011
BASIN TOTALS
(478,000 pop.)
°°0' BASIN TOTALS
(630,000 pop.)
BY
Urban NonUr
0.00
0.00
2.37
1.Q7
0.00
9.03
12.70
1.70
0.00
4.83
0.37
2.43
1.52
2.95
2.01
41.00
91
.
1.75
4.35
0.21
1.09
3.84
0.61
0.31
1.42
6.39
1.59
9.66
5.42
7.70
3.58
2.28
SO. 2,0
.20
Total
CT
Urban NonUr
0.29
0.00
3.17
2.37
0.00
10.90
12.75
2.78
0.00
8.51
•*.?
0.37
2.70
0.23
2.95
2.13
49.10
' >
98
112
1.36
4.35
0.24
0.98
3.84
0.78
0.45
1.38
6.39
1.64
9.66
5.12
6.97
3.58
2.21
49.00
.10
.59
Washoff Load - TSS, kilograms
SRC UC
Urban NonUr Urban NonUr
0.02
0.00
1.52
2.35
0.00
9.63
8.38
4.32
0.00
7'. 86
.,0.37
2.53
0.88
4.37
2.39
44.60
91
95
1.72
4.35
0.20
0.94
3.84
0.54
0.35
1.31
6.39
1.59
9.66
4.22
6.53
3.09
2.13
46.90
.50
.02
0.04 1.69
0.00 4.35
1.18 0.20
3.30 0.77
0.00 3.84
12.10 0.56
11.20 0.35
5.38 1.34
0.00 6.39
12.10 1.10
0.37 9.66
1.90 5.49
0.88 6.53
2.95 3.58
2.48 2.05
53.80 47.90
101.70
116.64
XlO3
RD
Urban NonUr
-
0.00
0.00
2.77
0.97
0.00
11.40
11.30
2.59
0.00
9.29
0.00
0.20
0.00
0.00
0.37
3S.90
1.75
4.35
0.23
1.11
3.84
0.98
0.41
1.43
6.39
1.64
10.10
6.51
7.32
4.58
3.00
53.70
89.60
(no simulation)
SD
fWklhAM UTrmftr-
UJL uJUA XvUvHU*
0.65 1.12
0.00 4.35
1.69 0.21
3.31 0.71
0.00 3.84
9.57 0.65
10.50 0.41
5.44 1.26
0.00 6.39
11.80 1.39
0.37 9.66
1.90 5.49
0.88 6.53
4.15 3.11
4.64 1.46
54.90 46.60
101.50
106.57
-------
Urban washoff load, total suspended
solids in kg/hectare
5.1-10.0
| > 10.0
Peak concentration of total suspended
solids in stream in mg/l
FIG.VI-13
PETALUMA BASIN - BASE YEAR
URBAN WASHOFF AND CHANNEL QUALITIES
-------
Urban washoff load, total suspended
solids In kg/hectare
0-1.0
1.1-2.0
Z.I-5.0
5.1-10.0
>IO.O
Peok concentration of total suspended
solids In stream In mg/l
FIG. VI-14
PETALUMA 3ASIN - SRC-478
URBAN WASHOFF AND CHANNEL QUALITIES
-------
BASIN
SHC-478
I
OJ
OF QUANTITY AND QUALITY RESULTS AT LOCATION 1007
IN CMS AND QUALITY IN (MG/L) E*CEPT COLIFORMS IN (NUMBERS/1 OOML)
0
0
0
0
1
1
1
I
21
2
2
2
3
3
3
3
u
4
<|
4
5
5
5
5
fc
6
6
6
7
7
7
7
a
8
8
8
9
TI^E
.00
15.00
30,00
45.00
,00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
15.00
30.00
45.00
.00
FLOW
.000
.000
.000
.000
.000
.006
.033
.173
.806
2.361
4.801
7.952
11.821
16.397
21.521
26.875
32.0«0
36.677
40.215
42.520
43.646
43.721
42.934
41.502
39.629
37.488
55.216
32.910
30.641
28.45?
26.374
24.421
22.601
20.915
19.357
17.920
16.595
TOT-SS
.0
.0
.0
.0
207.6
470.3
538.9
547.2
513.4
446.9
375.2
313.3
262.0
220.5
187.3
161.2
140.8
125.0
112.8
103.6
96.5
90.9
"6.5
63.0
80.1
77.7
75.6
73.7
72.1
70.6
69.2
68.0
66.8
65.6
64.4
63.3
62.3
NON-SF.T
.0
.0
.0
.0
125.4
263.8
324.6
32H.8
307.3
266.0
221.7
183.6
152.6
128.0
108.6
93.7
8?. 1
73.2
66.5
61.3
57.4
5<4.3
51 .8
49.8
46.1
46.7
45.5
44. a
43.5
42.6
41.8
41 .0
40.3
39.6
38.9
38.2
37.6
BOD
.0
.0
.0
.0
15.9
36.0
41.3
42.1
39.5
34.6
29.2
24.6
20.5
17.1
14.2
11 .7
9.7
8.1
6.0
5.9
5.1
4. a
3.9
3.5
3.1
2.6
2.6
2.4
2.2
2.1
1.9
1.8
1.7
1.6
1.5
1.4
i.a
GREASE
23
52
60
60
56
48
39
32
26
21
17
14
12
10
8
7
6
5
5
u
4
3
3
3
' 3
2
2
2
2
2
2
2
1
.00
.00
.00
.00
.24
.60
.16
.75
.41
.42
*95
.68
.68
.82
.9?
.82
.37
.43
.90
.69
.73
.95
.31
.78
.34
."6
.64
.36
.12
.90
.71
.54
.39
.25
.13
.01
.91
F-COLI
0.00
0.00
0.00
0.00
1 .80+04
4.08+04
4.70+04
4.79+04
4.51 +04
3.97+00
3.38+04
2.86+04
2.40+04
2.01+04
1.67+04
1.39+04
1 . 15+04
9.64+03
8,15+03
6.98+03
6.07+03
5.34+03
4.77+03
4.30+03
3.93+03
3.62+03
3.36+03
3.15+03
2.96+03
2.80+03
2.66+03
2.53+03
2.42+03
2.32+03
2.23+03
2.15+03
2.07+03
TOT-N
.00
.00
.00
.00
36.42
62.49
90.53
•95.79
69.43
77.41
64.57
53.43
40.10
36.39
30.09
25.02
20.96
17.74
15.20
13.20
11.62
10.35
9.32
8.08
7.78
7.19
6.68
6.25
5.87
5.54
5.25
4.98
4.75
4.53 •
4.34
4.16
3.99
TOT-P
.00
.00
.00
.00
4.69
11.06
12.66
12.81
11.9?
10.27
8.52
7.00
5.75
4.72
3.88
3.22
2.69
2.27
1.94
1.68
1.47
1.31
1.17
1.06
.97
.89
.82
.77
.72
.67
.63
.60
.57
.54
.51
.49
.47
HVY MET
.00
.00
.00
.00
13.25
29.98
34.30
34.65
32.20
27.66
22.65
18.72
15.30
12.53
10.31
8.55
7.15
6.04
5.17
4.48
3.93
3.49
3.1.3
2.83
2.57
2.36
2.17
2.01
1.88
1.75
1.64
1.55
1.46
1.38
1.31
1.24
1.18
FIG.VI-15
PETALUMA BASIN
QUALITY RESULTS AT CHANNEL 1007
-------
I
co
CO
PETALUMA BASIN
SRC-078
SUMMARY OF QUANTITY AND QUALITY RESULTS AT LOCATION 1010
FLOW IN CMS AND QUALITY IN (MG/L) EXCEPT COLIFOPMS IN (NUMBERS/1OOML)
TIME
0 .00
0 15.00
0 30.00
0 «S. 00
1 .00
1 IS. 00
1 30.00
1 05.00
? .00
2 15.00
2 30.00
2 «5.00
3 .00
3 15.00
3 30.00
3 05.00
0 .00
0 15.00
0 30.00
a as. 00
5 .00
5 15.00
5 30.00
5 05.00
6 .00
6 15.00
6 30.00
6 05.00
7 .00
7 15.00
7 30.00
7 05.00
8 .00
8 15.00
8 30.00
8 4S. 00
9 .00
FLOW
.000
.000
.000
.100
.003
.850
1.3U1
2.871
7.052
11.236
13.311
10.769
15.639
15.888
15.763
15.329
10.710
13.008
11.198
8.918
7.070
5.576
a. 365
3.381
2.5»1
1.956
1.023
1.020
.731
.533
.002
.312
.208
.201
.165
.138
.116
TOT-SS
.0
.0
.0
2.3
5.3
6.8
8.3
15.3
27.1
30.3
37.2
•39.0
00.1
00.7
00.8
00.7
00. U
39.5
38.0
36.0
33.9
31.7
29.5
?7.2
25.0
23.0
21.2
20.2
19.9
19.9
19.9
19.9
19. R
19.8
19.8
19.8
19.8
NON-SET
.0
.0
.0
1.0
3.2
0.1
5.0
9.2
16.2
20.6
22.3
23.0
20.1
20.0
20.5
2o.o
20.2
23.7
22.8
21.6
20.3
19.0
17.7
16.3
15.0
13.8
12.7
12.1
11.9
11.9
1 1.9
11.9
11.9
11.9
11.9
11.9
11.9
BOO
.0
.0
.0
.0
.0
.0
.0
.0
.
t
.
.
.
.
.1
.1
.1
.
,
.
.
.
.
.
.
.
.
.
.1
.1
.1
.1
.1
.1
.1
.1
.1
GPEASE F-COLI
• ,00
.00
.00
.01
.01
.02
.02
.03
.06
.08
.08
.09
.09
.09
.09
.09
.09
.09
.08
.08
.07
.07
.06
.06
.06
.05
.05
.00
.00
.00
.00
.00
.oa
.00
.00
.oa
.oa
O.oo
0.00
0.00
5.90+01
1.35+02
1.73+02
2.10+02
3.87+02
6,85+02
8.69+02
9.02+02
",88+02
1.02+03
1.03+03
1 .03+03
1.03+03
1.02+03
1.00+03
9.61+02
9.1 1+02
8.58+02
8.02+02
7.06+02
6.89+02
6.30+02
5.81+02
5.36+02
5.10+02
5.03+02
5.03+02
5.03+02
5.02+02
5.02+02
5.02+02
5.02+02
5.01+02
5.01+02
TOT-N
.00
.00
.00
.06
.10
.18
.22
.ao
.70
.89
.97
1.01
.00
.06
.06
.06
.OS
.03
.99
.90
.88
.82
.77
.71
.65
.60
.55
.52
.52
.52
.52
.52
.52
.52
.52
.52
.52
TOT-P HVY MET
.00
.00
.00
.00
.01
.01
.02
.03
.05
.07
.07
.08
.08
.08
.08
.08
.08
.08
.08
.07
.07
.06
.06
.05
.05
.05
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.01
.02
.02
.02
.05
.08
..10
.11
.12
.12
.12
.12
.12
.12
.12
.11
.1.1
.10
.10
.09
.08
.08
.07
.06
.06
.06
.06
.06
.06
.06
.06
.06
.06
.06
FIG. VI-16
PETALUMA BASIN
QUALITY RESULTS AT CHANNEL 1010
-------
Site Design/Management Control Simulations
The results of the simulations for all land use patterns clearly show
that the urban areas are the major contributors to pollution during
wet weather. It also dramatically shows that the growth management
approach of varying population levels, locational and density factors,
as reflected in the case of different alternatives, did not have a
significant effect on the total washoff load in the basin.
As was described in the review of literature, there are a variety of
site design/management controls that can be applied to reduce pollution
from surface runoff. Three of these measures were simultated, using
the Santa Rosa Centered 478 pattern, to determine their relative
effectiveness against the growth management approach implied by the
different land use alternatives. The three measures were: 1) street
sweeping, 2) retention storage and 3) reduction of impervious surface
coverage. The last two measures can be included in zoning ordinances.
Street Sweeping - It was mentioned earlier that all simulations were
made assuming that 20 dry days preceded the storm. Since the Runoff-
Quality Model assumes the buildup of pollutants increases in a linear
fashion on a daily basis in urban areas, one technique for reducing
urban washoff loads would be to sweep streets more frequently. Urban
loads are computed on the basis of length of curbs and gutters. The
easiest way to simulate this management alternative is to simply
reduce the number of dry days preceding the storm to approximate more
frequent street sweeping. To illustrate the effectiveness of street
sweeping, a simulation was made assuming 10 dry days preceded the
storm.
For purposes of simplicity, a 100% of sweeper efficiency was used in
the simulation. However, rates of sweeping efficiency can vary greatly
depending on such factors as method of street sweeping (manual, vacuum
sweepers, vehichles sweepers), the type of vehicle sweeper, the pattern
of sweeping (once over, twice over), roadway paving material, design
of curb and gutter and type and size of the contaminant particle
being swept. The EPA reports Mater Pollution Aspects of Street Surface
Contaminants (Sartor and Boyd, 1972) and Contributions of Urban Roadway
Usage to Water Pollution (Shaheen, 1975) provide greater detail on
botn the nature of street contaminants and the efficiency issues of
different street cleaning practices.
Retention Storage - Since the urban pollutant load is likely to be
picked up early in the storm, a possible management technique would be
to provide storage to capture a percentage of the initial urban runoff.
The Runoff-Quality Model was programmed to do this and a simulation
was made for the SRC-478 scenario in which the first 6 mm (.25 inches)
of urban runoff was stored.
No specific facility was envisioned for this management technique
since economic feasibility was not a consideration at this level of
study. The purpose of simulating retention storage was to gain an
insight into the potential for reducing the urban washoff load through
VI-34
-------
stormwater retention and disposal at a later time. One possible
concept for accomplishing this would be a reservoir designed to store
runoff up to some capacity after which excess runoff would be bypassed
to the storm drainage system. The outlet of the reservoir could be
connected to a sanitary sewer so that the reservoir could be drained
after the storm to a treatment plant. The stormwater pollutant load
would be treated and disposed along with sanitary flows.
Reduction of Percent Impervious Area - A simulation was made in which
the percentage of impervious area associated with urban uses was
reduced from those values used throughout the study. The purpose of
this simulation was to determine what effect, if any, the reduction
would have on runoff which would in turn effect washoff loads and
channel qualities. The reduced percent impervious values compared to
the original values are shown below:
Original % Reduced %
Land Use Category Impervious Value Impervious Value
Low Density Residential 30 20
Medium Density Residential 65 40
High Density Residential 80 40
Commercial Centered 95 40
Commercial Suburban 90 40
Industrial 98 40
The reductions in percent impervious values shown above do not reflect
actual reductions in paved areas and hard surfaces associated with
urban land uses. They represent the "effective" percent of impervious
area with respect to generating direct runoff. The reductions may be
accomplished in a number of ways, most of which involve detention of
urban stormwater runoff on the site where it originates. The follow-
ing methods may be used to reduce runoff:
1. temporary ponding on ground surfaces,
2. temporary ponding on paved areas,
3. temporary ponding on roofs of buildings,
4. storage in permanent ponds having provision for variable
depth,
5. treatment of groundwater surfaces to absorb and/or detain
water,
6. routing of runoff to infiltration pits to both recharge
groundwater supplies and reduce total flows to drainage
systems,
7. collection of stormwater for supplementary water
supplies, and
8. pervious pavement.
Fffectiveness of Site Design/Management Control Simulations. Tab!e
VI-7 presents the urban washoff for the Laguna Basin comparing street
sweeping and retention storage to the original Santa Rosa Centered 478
simulation. (The reduction of the percent impervious factor effects
urban washoff differently and will therefore be presented separately).
VI-35
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TABLE VI-7
EFFECTIVENESS OF SITE DESIGN/MANAGEMENT ALTERNATIVES
ON TOTAL URBAN WASHOFF
Total Urban Washoff Load-TSS. Kilograms x
Watershed
Windsor Creek
Mark West Creek
Santa Rosa Creek
Laguna de Santa Rosa
Basin Total
Original
Simulation
(SRC 478)
13.4
15.1
105.7
81.6
H578~
Street
Sweeping
6.7
7.6
52.9
40.8
ISO"
Retentioi
Storage
3.4
4.1
14.8
6.8
29.1
The street sweeping alternative, due to the method of simulation,
results in a washoff load of exactly one-half the original urban
load since the number of dry days were halved. The retention storage
alternative produces a dramatic decrease in the urban washoff load.
For example, when retention storage is used, the washoff in Santa Rosa
Creek, which is impacted by Santa Rosa, will reduce some 400% from
1973 conditions.
Table VI-8 shows the urban and rural washoff resulting from the reduced
impervious coverage from each of the Laguna watersheds. It indicates
only sightly lowered washoff loads from the Santa Rosa Centered 478
alternative which used the higher percent impervious values.
TABLE VI-8
REDUCED IMPERVIOUS AREA SIMULATION
WATERSHED WASHOFF LOADS
Watershed
Original SRC-478 Total r
Washoff-TSS, Kilograms x 10J
Reduced
Impervious Area
Windsor Creek
Mark West Creek
Santa Rosa Creek
Laguna de Santa Rosa
Total
27.3
83.7
154.0
130.3
39573
24.9
81.1
145.4
113.2
36O"
VI-36
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The reductions in washoff loads shown in Table VI-8 are entirely the
result of the reduction of washoff from rural subareas, adjacent to
urban areas, which had less water runoff to erode the soil surface.
The urban surface loading rates are based on the buildup of pollutants
in curbs and gutters, which the model treats as a function of the area
devoted to urban uses. Since the total areas devoted to urban uses
were not reduced, the lengths of curbs and gutters remained the same
and, consequently, the amount of urban loading available to runoff did
not change. This model assumption is considered realistic in light of
evidence provided by Contributions of Urban Roadway to Water Pollution
that traffic-related contaminants and roadway surface material are the
main components of street surface pollution buildups. Since neither
of these two sources of contaminants would be greatly affected by the
change of impervious surface conditions, it is felt preferable to keep
the buildup loads constant. However, the exact numbers need to be
viewed with some caution as some contaminants not associated with
traffic-related activities or street surface materials, like pesti-
cides or fecal coliform, might to absorbed or detained because of the
increased pervious surface. This simulation did raise a question for
further model refinement research. There has been little testing to
determine how much of the pollutant (dust/dirt) accumulation in the
street is due to street generated sources (rubber residue from tires,
oil and grease, heavy metals, etc.) versus washoff from adjacent
properties.
Table VI-9 and Figure VI-17 show the effects of the different site
design/management control measures on the peak concentrations in
various river channels. As before, both street sweeping and retention
storage provide major improvements. Retention storage would again
enable stream water to achieve a quality far higher than that of the
present. However, the reduction in impervious area coverage could
well have a negative impact of major proportions. The reduced runoff,
the same urban washoff load and a slightly reduced rural washoff load
resulted in increases in the concentrations of total suspended solids
in channels draining urban areas. The water that is retained by the
new pervious area reduces the amount of water available for diluting
the pollutants which are washed off thereby resulting in the higher
concentrations. Table VI-10 indicates the reduction in peak flow
when the new impervious surface coverage standards are used.
This rather startling finding has a number of implications. First, a
number of zoning and subdivision approaches have been designed to
reduce the impervious area coverage through requirements for greater
amounts of open space per development. Secondly, the decreased im-
pervious surface approach can be applied to solve a variety of plan-
ning issues including groundwater recharge, reduce flood potential and
hopefully reduce pollution. Therefore, there is real potential for
conflicting impacts from such a design approach. Unless it can be
combined with retention storage, street sweeping or other means of
eliminating the pollutants, the reduced impervious area approach can
be counter productive.
VI-37
-------
"V Ftetaluma
t
s
CHANNEL QUALITY'V-s
PER MANAGEMENT/SITE DESIGN
CONTROL
Peak Concentrations-TSS,mg/l
FIG.VI-17
-------
TABLE VI-9
EFFECTIVENESS OF SITE DESIGN/MANAGEMENT ALTERNATIVES
ON PEAK CONCENTRATIONS, TSS, mg/1
Watershed/Channel
Original
Simulation
(SRC 478)
Street
Sweeping
Retention
Storage
Reduced
Impervious
Area
Windsor Creek
Channel 1002
Mark West Creek
Channel 2002
Santa Rosa Creek
Channel 3002
3004
3005
3007
3008
3011
Laguna de Santa Rosa
563
475
503
549
627
359
318
355
281
237
252
229
314
180
160
178
105
85
41
34
142
43
50
37
1097
908
934
703
1306
531
451
498
Channel 4004
4005
4007
4012
413
161
452
373
209
90
226
188
81
72
37
42
622
180
725
557
Groundwater Impacts
The previous discussion concerns the impacts of development on surface
water quality. Groundwater supplies can also be impacted by urbaniza-
tion in terms of both quantity and quality.
There are three primary problem areas associated with urbanization
which could lead to a degradation of groundwater quality in Sonoma
County. First, urbanization can reduce the areas of natural ground-
water recharge. This would result from replacement of open, highly
pervious areas which serve to recharge the groundwater basin with the
impervious surfaces of development. A reduction of natural recharge
would lead to lowering of the groundwater table and a corresponding
degradation in the mineral quality (total dissolved solids) of the
groundwater. The degradation of quality in this case would result
from concentrating the basin salt load in a smaller volume of ground-
water.
VI-39
-------
TABLE VI-10
WATER RUNOFF FROM REDUCED IMPERVIOUS COVERAGE
PEAK RUNOFF, m3/sec
Watershed/Channel
Peak Runoff, m3/sec
Original Reduced %
(SRC 478) Impervious Area
Windsor Creek Watershed
Channel 1002
Mark West Creek Watershed
Channel 2002
Santa Rosa Creek Watershed
Channel 3002
3005
Laguna de Santa Rosa Watershed
Channel 4004
4009
6.8
80.0
88.4
11.8
32.3
14.1
3.5
78
78.6
7.3
22.6
10.7
Secondly, the salt load to the groundwater basin could increase as
open areas are urbanized depending on the use made of the open areas
prior to development. Application of fertilizer to lawns In areas
that were previously fallow and unused would tend to increase the
total salt load available for infiltrating the underlying groundwater
basin.
Third, groundwater problems can arise through the use of septic tanks
in areas with unsuitable soil characteristics for septic tank leach
fields. The Rural Dispersed alternative anticipates the further devel-
opment of very low density residential areas such as three-acre ranch-
ettes. Sparse development results in very high unit costs of sewering
and the potential demand for septic tank use for wastewater disposal.
While the scope of this study did not permit a detailed quantitative
analysis of impacts on groundwater quality, land use information from
the preprocessor together with a map of the recharge areas can be used
to illustrate the potential impacts of the alternatives on groundwater.
Figures 19 through 21 show the percentage of land devoted to urban
uses in the Base Year case and Santa Rosa Centered 478, superimposed
VI-40
-------
Subarea
Boundary
Percenfoge of land area in urban use
10-5.0
5.1-15.0
::::: 15.1-25.0
125. (-35.0
! >35.0
K Areas of natural
' groundwafer recharge
FIG.VI-18
LAGUNA BASIN - BASE YEAR
URBANIZATION AND GROUNDWATER RECHARGE AREAS
-------
Watershed
Boundary
i^.AylllPliilliyiiiziiiiii;/
Percentage of land area In urban use
25.1-35.0
0-5.0
5./-I5.0
I5.I-25.D
KILOMETERS
[ >35.0
. Areas of natural
groundwafer recharge
FIG. VI-19
LAGUNA BASIN - SRC-478
URBANIZATION AND GROUNDWATER RECHARGE AREAS
-------
Percentage of land area In urban use
25.1-35.0
>35.0
Areas of natural
groundwafer recharge
FIG. VI-20
PETALUMA BASIN - BASE YEAR
URBANIZATION AND GROUNDWATER RECHARGE AREAS
-------
Percentage of land area in urban use
0-5.0
5.1-15.0
15.1-25.0
25.1-35.0
>35.0
, Areas of natural
groundwafer recharge
FIG. VI-21
PETALUMA BASIN - SRC-478
URBANIZATION AND GROUNDWATER RECHARGE AREAS
-------
on the areas of natural groundwater recharge in the Laguna and Petaluma
Basins. By comparing Base Year to Santa Rosa Centered 478, it can be
seen that the percentage of impervious areas in several subareas
around Santa Rosa will increase due to urbanization. Such increases
will reduce the ability of the affected recharge areas to maintain
existing water levels in the underlying groundwater basins. On the
other hand, the recharge areas in the Sebastopol, Rohnert Park and
Cotati areas will not be developed by the Urban Centered or Continuing
Trends alternatives. In the Petaluma Basin, the primary recharge
areas are northwest of the City of Petaluma. Land use patterns con-
centrating growth by increasing densities in existing urban areas
would tend to have less impact on recharge areas than the patterns
that disperse growth.
A recent report by the Department of Water Resources discusses ground-
water problems in Sonoma County associated with septic tanks. The
report concludes that most of the rural areas in Sonoma County are
unsuitable for the construction and operation of septic tank and leach
field systems. The soils of Sonoma County are all classified as
unacceptable with the exception of small areas around Santa Rosa,
north of Santa Rosa and Petaluma. The above mentioned exceptions are
considered generally to have permeability constraints and the report
recommends that on-site testing must be done to demonstrate that soil
characteristics are indeed acceptable. Land use alternatives invol-
ving scattered low density residential development are going to pre-
sent greater problems of how to provide economical sewerage services
than those scenarios which tend to concentrate urban development.
AIR QUALITY ANALYSIS
The air quality results of the study highlighted a number of growth
management issues which pose some contradictory planning consider-
ations. Higher population levels and more concentrated population and
employment patterns result in higher localized air pollution concen-
trations of carbon monoxide and particulates. Yet, an alternative —
lower population levels and a more dispersed development pattern —
would make it more difficult to support a public transportation
program, thereby continuing the reliance on the private automobile.
(Such a development pattern can also have other negative impacts
including increasing the cost of municipal services or reducing the
quantity of valuable agriculture land.) Finally, a population pattern
that distributes population and employment more evenly throughout the
County could provide the "worst case" alternative for oxidant due to
conditions that may exist outside the control of Sonoma County officials.
The Urban Centered alternative presents Petaluma and the City of
Sonoma with high levels of oxidant because of both increased population
in the cities and oxidant transport from other sections of the Bay
Area. The air quality results are described in two sections: non-
reactive pollutants (i.e., carbon monoxide, particulates) and oxidant.
The discussion on carbon monoxide focuses on the importance of auto
emission devices and an inspection and maintenance program.
VI-45
-------
General Considerations
While extensive air monitoring activities have been conducted by the
BAAPCD in the Bay Area for many years, the air quality measurements in
the study area are limited. In Sonoma County, measurements are taken
on a routine and complete basis at three sites — Santa Rosa, Petaluma
and Sonoma. Measurements from these locations are of value in monitor-
ing current air quality in cities considered to have the highest air
pollution levels. However, because they do not provide any information
on the variability of air quality throughout the County an air pollutant
dispersion model was used to provide an projection of future air quality.
The simulation model is based both on theoretical considerations and
actual measurements in the atmosphere, which approximate the extent to
which pollutants are diluted by mixing with the air as they travel
with the wind from the pollutant source (smoke stack, automobile,
etc.) to any site where the air quality is to be determined. (Such a
modeling effort was not used for oxidant analysis). Because the
dispersion model estimates are directly related to the source con-
figuration of a given land use pattern and because the estimates can
be made at many points throughout a given study area, the spatial
variability of air quality may thereby be assessed for a variety of
future land use patterns.
In the application of dispersion modeling to the problem of air quality
estimation, the modeling results themselves are considered only as a
tool to aid the air quality analyst in drawing meaningful conclusions
with the results subject to interpretation. The accuracy of modeling
results varies greatly with the pollutant of concern, the type of
model and the quality of information regarding source emissions and
meteorology.
Compiling an Emissions Inventory. A detailed emissions inventory was
made to ensure the highest possible degree of validity. The inventory
was made for four of the pollutants for which federal ambient air
quality standards have been promulgated: carbon monoxide, non-methane
hydrocarbon, sulfur dioxide and particulate. To provide a maximum of
spatial detail within reasonable limits, an estimate was made of the
rate of emission of each pollutant in each study-grid cell covering
the currently and potentially urbanized portions of Sonoma County from
Healdsburg to the southern County boundary and from Sebastopol east-
ward to Sonoma.
t
In each of the grid squares for which an emission rate was computed,
emissions from five separate source categories were summed to provide
a total emission from the square:
1) Emissions from motor vehicles were computed for portions of motor
vehicle trips identified as occurring within each grid square;
2) Emissions from stationary sources such as industrial sites with
identifiable locations were assigned to the grid square containing
their locations;
VI-46
-------
3) Emissions from airports were assigned uniformly to the grid squares
containing the boundaries of ground-based aircraft activity;
4) Emissions from agricultural activity were assigned to grid squares
within which polluting agricultural activity such as burning is
presumed to occur;
5) Emissions from stationary sources for which specific locations
cannot be determined were distributed proportional to population
among the grid squares.
Meteorological and Climatological Considerations. The model used for
non-reactive pollutants requires:1) knowledge of wind speed and
direction characteristics in the study area and over the nine county
region as a whole and 2) information on the characteristics of the
temperature inversion and information on atmospheric stability or the
ability of the atmosphere to dilute pollutants by mixing. Details of
the incorporation of this information in the dispersion model are
presented in Appendix B.
Model Calibration. The non-reactive modeling system, as explained in
Chapter V and outlined in Appendix C, is a combination of the "gaussian
plume" and lognormal statistical formulae. An annual average value
for a pollutant concentration is obtained for each grid square using
a gaussian plume dispersion model in conjunction with the emissions
inventory associated with a given land use distribution (e.g., Contin-
uing Trends 478). Estimates of the frequency with which air quality
standards are exceeded are then obtained statistically on the basis of
historical air monitoring information. This modeling procedure is
strictly applicable only to those pollutants such as carbon monoxide
that are not subject to significant chemical transformation or physical
removal within the study area. Other pollutants may be analyzed with
due consideration for the limitations of the modeling technique.
First, the simulation model was calibrated using observed air quality.
In the case of this study, an analysis was done in the study area for
Base Year (1973) and results compared with 1973 air quality data at
the Santa Rosa air monitoring station. Data from years other than
1973 at Santa Rosa and Petaluma were also considered. Modeling re-
sults for carbon monoxide in this study as well as in studies con-
ducted in other areas of the Bay Area Air Pollution Control District's
jurisdiction support the validity of the modeling approach. These
results are within 20% of measured .station values for the annual
average. Suspended particulate modeling has proven similarly success-
ful. Non-methane hydrocarbon results are usually less satisfactory,
due in part to the reactive nature of the pollutant and a greater
uncertainty in the rate of emission and source distribution. Sulfur
oxide estimates by this model are not directly comparable to station
values because such measurements are not available in Sonoma County.
To reduce all pollutant estimates to a common basis for comparison of
land use alternatives, Base Year estimates in all grid squares are
given a constant adjustment based upon the difference between model
VI-47
-------
estimates and observed levels in the grid squares containing the
monitoring stations. The model was thus calibrated in the monitored
grid squares to the Base Year values with the assumption that such
calibration will remain valid in future years and throughout the study
area.
Interpretation of Modeling Results
Both theoretically and on the basis of direct comparison with obser-
vation, the results of the carbon monoxide analysis are the most
accurate. Carbon monoxide concentrations are related almost exclu-
sively to the use of-the automobile and vary directly with the density
of vehicle travel and inversely with vehicle speed. For this reason,
the distribution of carbon monoxide concentrations associated with
alternative plan strategies is a good indicator of the relative effect
of transportation alternatives or the lack thereof upon the air pollu-
tion problem. By estimating carbon monoxide pollution with and without
auto emission control devices for the same growth alternative, as is
done in this study, the importance of motor vehicle pollution control
is graphically revealed.
Particulate pollution on the other hand is an excellent indicator of
non-vehicular, population-related pollution because it is primarily
associated with a wide range of industrial, commercial, construction
and other human activities essentially unrelated to the use of the
automobile. Because technological and regulatory control of particu-
late sources has fairly well reached its limit in the Bay Area, par-
ticulate pollution estimates are good indicators of the air quality
impact of general population growth and alternative population density
configurations.
Sulfur dioxide pollution is an indicator of the impact of industrial
activity which accounts for the bulk of sulfur oxide emissions.
Generally speaking, sulfur dioxide pollution in Sonoma County is
negligible at present due to a minimal industrial base. Locally
impacted areas, however, are readily identified from the analysis,
and the effect of projected increases in the use of fossil fuels is
evident. (As a point of interest, the geysers in northern Sonoma
County, located outside the study area, are another source of
sulfur dioxide.)
Impacts of Development on the Emission of Carbon Monoxide
Comparison among land use alternatives is made in two ways: (1) direct
observation from the isopleth maps of which areas are most greatly
affected by pollution and (2) using a system of ranking on the basis
of frequency of violations of the Federal CO standard.
Figure VI-22 shows the modeling estimate of carbon monoxide (CO)
annual average concentration distribution for Base Year (1973)
throughout the study area. The model was calibrated by increasing
VI-48
-------
CARBON MONOXIDE
BASE YEAR -1973
WTTH 1973 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
1.5-2.0 ppm (1718-2290
8-hour Federal Standard exceeded 1-3 times per year
1.0-1.5 ppm (1 MS -1718 jig/ml
No Standard Exceedances
0.75-1.0 ppm' (ess • 1
No Standard Exceedances
Tfl 0.5-0.75 ppm (673- 888 M
No Standard Exceedances
Based on 1973 emission factors.
FIG.VI-22
-------
predicted concentrations by 20 percent to" provide Base Year agreement
with air monitoring data. The figure indicates an estimated non-urban
background concentration of between 573 and 859 micrograms per cubic
meter of air (yg/m3) or 0.5 and 0.75 parts per million (ppm). This
background results from emissions in Sonoma County as well as from
emissions outside the County. It is estimated that only some 229
vig/nr of CO as an annual average is derived from outside the County.:
In the urban areas where highest vehicle trips and reduced vehicle
speeds create high densities of CO emissions, levels of carbon mon-~
oxide are considerably elevated above the non-urban background; ,
Occassional violations of the primary 8-hour Federal standard for
carbon monoxide are projected for the Santa Rosa and Petaluma areas.
No violations are observed or projected predicted for the 1-hour CO
standard. The significance of the findings on carbon monoxide is that
the emissions are almost exclusively related to the distribution and
density of motor vehicle activity. The carbon monoxide problem is
therefore an indicator of the impact of the automobile on the quality
of the air. Mitigation of carbon monoxide pollution may therefore be
accomplished either by technological control of motor vehicle emissions
or by regulating the extent and distribution of vehicular activity to
decrease the density of motor vehicle emissions.
The projected carbon monoxide annual average concentrations for all
growth alternatives dropped substantially from their 1973 level. They
were below the 1973 level for all cities at --both the 478, OQQ and
630,000 county population levels. The reason for this drop was the
assumed full and effective implementation of both the stationary
source controls as envisioned and the currently promulgated Federal
Motor Vehicle Emission Control Program. The projected impact of
vehicle control devices (catalytic converters, etc.) is anticipated to
offset any increases in vehicular activity so that no violations of
carbon monoxide air quality standards are projected for the county
regardless of the land use alternative.
However, as noted in Table VI-11, each urban area will be affected to
differing degrees depending upon the scenario. The most consistently
low land use alternatives in terms of annual average and maximum
concentrations are Rural Dispersed, Continuing Trends and Suburban
Dispersed for the 478,000 population level. On the other hand, Santa
Rosa in the Santa Centered 630 alternative, wHh the combination of
the highest population and employment and the greatest land use
densities, will have the highest CO concentrations. Similarly, all
other cities have their highest CO counts in the Urban Centered 630
alternative, which gives them also the largest and most concentrated
population and employment pattern.
Figures VI-23 through VI-26 are the isopleth maps for some of the
growth patterns. (Because the alternatives shown in the figures in-
dicate the full range of pattern variations, not all nine alternatives
are diagramed.) A number of conditions are apparent from the maps:
1) the downtown or commercial areas of all cities have the
highest concentrations;
VI-50
-------
Table VI-11
ANNUAL AVERAGE AND MAXIMUM 8-HOUR ANTICIPATED CONCENTRATION
FOR CARBON MONOXIDE '(v9/m3
LAND-USE ALTERNATIVE
SRC
SRC
UC
UC
SO
SO
RD
CT
BY
478 An.
An.
630 An.
An.
478 An.
An.
630 An.
An.
478 An.
An.
630 An.
An.
478 An.
An.
478 An.
An.
An.
An.
Avg.
Max.
Avg.
Max.
Avg.
Max.
Avg.
Max.
Avg.
Max.
Avg.
Max.
Avq.
Max.
Avg.
Max.
Avg.
Max.
SANTA ROSA ROHNERT PARK-COTATI SONOMA
1260
8015
1580
10305
927
5725
1088
6870
1168
6870
1318
8015
1099
5725
962
5725
2313
13740
698
4580
847
5725
607
4580
802
5725
721
4580
779
5725
687
4580
664
4580
1191
8015
573
3435
561
3435
698
4580
859
5725
504
3435
550
3435
573
3435
595
3435
1099
5725
PETALUMA
1214
8015
1237
8015
1305
8015
1431
9160
1145
6870
1156
6870
1202
8015
1111
6870
1969
17595
VI-51
-------
CARBON MONOXIDE
SRC 478-FTOJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
1.0-1.5 ppm (1145-1718 uy/m>)
Maximum Annual 8-ho'ur Concentration 6.5-9.0 ppm {7443 -10305 jig/m»)
0.75-1.0 ppm (859-1145 (ICJ/m») \
Maximum Annual 8-hour Concentration 5.0-6.5 ppm (5725 -7443 uy/m
0.5-0.75 ppm (573 - 859 |/(//m>)
Maximum Annual 8-hour Concentrations 3.5-5.0 ppm (4008-5725ji"c//m>)
0.25-0.5 ppm (Z86-573(i3/m>)
Maximum Annual 8-hour Concentration 2.0-3.5 ppm (2290-woe(j(j/m>>
No Standard Exceedances
8 KM
FIG. VI-23
-------
CARBON MONOXIDE
SRC630-PRQJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
1 .0-1 .5 ppm (1145 - 1718 /ig/m»)
Maximum Annual 8-hour Concentration 6.5-9.0 ppm (7443 - 10305
wSiSSSj 0.75-1.0 ppm (869-1145Jig/m») \
WtffffSSi Maximum Annual 8-Tiour Concentration 5.0-6.5 ppm (5725 - 7443 ug/m*t
0.5-0.75 ppm <573-859K3/m>) )
Maximum Annual 8-hour Concentrations 3.5-5.0 ppm . iiooe - 5725 (ig/m>)
0.25-0.5 ppm (286 - 573 «g/m»)
Maximum Annual 8-hour Concentration 2.0-3.5 ppm (2290 -
K>
FIG.VI-24.
-------
CARBON MONOXIDE
UC630-PRCUECTION'YEAR 2QOO
•WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
1.0-1.5 ppm (1718-2290 Mff/m3)
Maximum Annual 8-hour Concentration 6.5-9.0 ppm (7443 • 10305
0.75-1.0 ppm (859 -1145 p g/ m3) \
Maximum Annual 8-hour Concentration 5.0-6.5 ppm (5725 - 7443 ng/m*i
0.5-0.75 ppm (573 - 859 ug/m3) )
Maximum Annual 8-hour Concentrations 3.5-5.0 ppm <4oo8 - 5725
I I 0.25-0.5 ppm (286 - 573 M
-------
CARBON MONOXIDE
SD 630 -PROJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
OH3
Annual Average Concentrations
1.0-1.5 ppm (1146 -1718 pg/m'l
Maximum Annual 8-hour Concentration 6.5-9.0 ppm (7443 -10305 ng/m=i
0.75-1.0 ppm (859-1146 ng/mt \
Maximum Annual 8-hour Concentration 5.0-6.5 ppm (5725 - 7443 «g/m»)
0.5-0.75 ppm (573 - 859 pg/m9)
Maximum Annual 8-hour Concentrations 3.5-5.0 ppm (4oos - ST.
0.25-0.5 ppm (286 • 573 tig/""')
Maximum Annual 8-hour Concentration 2.0-3.5 ppm. (2290 •
No Standard Exceedances
4 8 KM
5 MILES
FIG.VI-26
-------
2) the CO pattern follows the roadway pattern;
3) the more dispersed population patterns, such as Suburban
Dispersed 630, has the greatest spread of CO for Santa Rosa;
and
4) the meteorlogical patterns do not have a substantial effect
in dispersing the CO concentrations.
All of these findings simply verify the impact of motor vehicle travel
on carbon monoxide problems.
Vehicle Emission Controls. Figure VI-27 and VI-28 illustrate the
critical role of vehicle emission controls in offsetting the effect of
growth on carbon monoxide pollution. The analysis illustrated by the
figures is the CO levels for Continuing Trends 478,000 using the 1973
vehicle emission factors. This situation is equivalent to a complete
breakdown of the motor vehicle emission control program beyond 1973
including no further improvements in the emission control devices and
elimination of the inspection and maintenance program. The simulation
results in multiple excesses of air quality standards for carbon
monoxide and a 100-200 percent increase in the annual average levels
of this pollutant.
The carbon monoxide analysis reveals the importance of the Vehicular
Emission Standards. Yet, one must ask "what happens if they are not
actively enforced through an inspection and maintenance program?" The
Sonoma County Advanced Planning Division concerned themselves with
this question by conducting an impact analysis of different levels of
enforcement on downtown Santa Rosa.
Figure VI-29 provides the effects of 1975, 1980 and 1990 levels of
enforcement of emission control device requirements for the years
1980, 1990 and 2000. It shows, for example, what the concentration of
CO would be in 1990 if both the inspection and maintenance program and
the improvement of emission control devices are stopped in 1975 or
1980 or 1990. In the case of this example, the elimination of the
emission control device programs in 1975 would result in the violation
of the Federal 8-hour standard. Yet, the concentrations would be well
below the standard if the programs were stopped in 1980. This finding
shows the importance of the emission device control programs as compared
to other air pollution abatement programs such as limiting the number
of cars in a particular area. However, what should also be noted in
Figure VI-29 is that beyond 1990, when the emission device control
programs are estimated to reach their peak effectiveness, pollution
concentration will again start to increase due to increased number of
cars (due to population and employment increases) in the study area.
At this time period, land use growth and public transportation strat-
egies will become increasingly important as a means of reducing car
travel, and hence population emission.
Impacts of Development on the Emission of Particulates. Suspended
particulate is a good indicator of growth impact.SJhTle carbon mon-
oxide strongly reflects the impact of autos, particulate matter is
VI-56
-------
CARBON MONOXIDE
SRC 478-PROJECTION YEAR 2000
WITH 1973 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
3.0 ppm (3435ng/m»)
8-hour Federal Standard exceeded more than 20 days per
2.0-3.0 ppm (2290 • 3435 (|J/ rt!J)
8-hour Federal Standard exceeded 3-20 days per year
1.5-2.0 Ppm (1718-2290MS/ml
8-hour Federal Standard exceeded 1-3 days per year
1.0-1.5 ppm (1145-1718 Ji
No Standard Exceedances
0.7S-1.0 ppm (859 -1145 ti
No Standard Exceedances
FIG. VI-27
-------
CARBON MONOXIDE
SRC 478-PRQJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
-0-1.5 ppm
0.75-1.0 ppm (859
0.5-0.75 ppm (573 - 859
No Standard Exceedances
FIG.VI-28
-------
EFFECT OF CHICLE. M55ION INSPEGON/miNTEN^CL PROGRAM-
DOWNTOWN SANTA fcDSA
ORBON MONOXIDE AT 478,000 ft>WlATroM t£VEL
EKKSION PEVlC£REQUVRJ=.MEms NOT
BEYOND 1973
BEYONP
BEYOND
BEYOND l
-------
more closely related to non-vehicular pollutant sources such as in-
dustrial and commercial activity and the dust and dirt associated with
everyday human activity. Beyond existing stationary source controls,
little is envisioned at present of a technological nature in control-
ling particulates. Therefore, increased growth will tend to be assoc-
iated with increased particulate pollution.
Particulates in Sonoma County may pose a major problem in the year
2000 due to the increased population using heating fuels. Frequent
excesses of standards are anticipated for each land use alternative.
Table VI-12 shows the projected annual average maximum concentrations
at four selected urban areas and the frequency with which the 24-hour
State standard of 100 micrograms per cubic meter can be expected to be
exceeded. It should be noted that the peak annual averages do not
always occur in the same grid cells due to the varying pattern of
emissions between scenarios.
From the regional growth perspective, Rural Dispersed 478 and Contin-
uing Trends 478 have the lowest concentrations of particulates and
Santa Rosa Centered 630 and Urban Centered have the highest.
Figures VI-30 to VI-33 illustrate the isopleths of particulates. The
maps show:
1) the highest concentrations in locations of high density
residential
2) the widest dispersion when residential development spreads
This, therefore, highlights that particulate concentrations will
follow population concentrations as distinct from vehicle trips.
Impact of Development on the Emission of Sulfur Dioxide
There is presently little sulfur dioxide being emitted from man-made
sources in Sonoma County. However, a potential conversion to sulfur-
containing fuels, an .increased population, and enhanced industrial
activity will substantially raise future SO? levels over present
conditions. However, State 24-hour SOg standard in the year 2000 is
not expected to be exceeded except for isolated situations near
Petaluma where large point sources — primarily industrial
boilers — will cause localized elevated levels that may occasionally
exceed standards.
Figure VI-34 illustrates the output from the diffusion model for SRC
478 which shows that standards will be exceeded up to 35 days per year
for portions of Petaluma and Santa Rosa. However, by comparing the
output of the model with the very limited monitoring data available,
and in evaluating sulfur dioxide elsewhere in the Bay Area, it is felt
that these figures may be as much as 50 percent too high. This would
drop the maximum anticipated annual average concentration down to 0.01
ppm and therefore cause the 24-hour standard to be exceeded only 1 to
4 days per year.
VI-60
-------
TABLE VI-12
)N (yg/m3) M
OF STATE 24-HOUR STANDARD FOR PARTICULATES
ANNUAL AVERAGE CONCENTRATION (yg/m3) AND FREQUENCY OF EXCEEDANCE
LAND-USE
SRC 478
SRC 630
UC 478
UC 630
SD 478
SD 630
RD 478
BY
CT 478
ALTERNATIVE
An. Avg.2
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
An. Avg.
No. Days
Std. exceeded
SANTA ROSA
89
(116)
126
(167)
85
(97)
91
(124)
68
(53)
71
(61)
65
(46)
48
(12)
65
(46)
ROHNERT PARK-COTATI
65
(46)
72
(65)
68
(53)
74
(66)
59
(32)
60
(35)
58
(29)
41
(7)
58
(16)
SONOMA
49
(14)
56
(26)
77
(80)
80
(90)
52
(23)
59
(32)
40
(5)
31
(0)
42
(9)
PETALUMA3
65
(46)
75
(70)
75
(70)
80
(90)
60
(35)
70
(58)
60
(35)
50
(16)
60
(35)
1 3
Annual average (yg/m ).
2 3
Number of days 24-hour State Standard (100 yg/m ) will be exceeded.
3
Calibrated concentration based on Petaluma monitoring and monitoring
of similar cities in the San Francisco Bay Area.
VI-61
-------
SUSPENDED RETICULATES
SRC 478-PROJECTIQN YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations v. v
>100 jug/m3
Annual Maximum 24-hour Concentration >375 /ug/m3
24-hour State Standard exceeded more than 160 times per year
75-100 /ug/m3
Annual Maximum 24-hour Concentration 270-375
24-hour State Standard exceeded 75-160 times per year
60-75 //g/m3
Annual Maximum 24-hour Concentration 215-270//g/m3
24-hour State Standard exceeded 35-75 times per year
Annual Maximum 24-hour Concentration 180-215 jug/m3
24-hour State Standard exceeded 15-35 times per year
Annual Maximum 24-hour Concentration 145-180 jug/m3
24-hour State Standard exceeded 4-15 times per year
4 8 KM
I
FIG. VI-30
-------
SUSPENDED PARTICULATES
SRC630-PROJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations v
Annual Maximum 24-hour Concentration >375 /ug/m3
24-hour State Standard exceeded more than 160 times per year
75-100 pgtm3
Annual Maximum 24-hour Concentration 270-375 jug/m3
24-hour State Standard exceeded 75-160 times per year
Annual Maximum 24-hour Concentration 215-270//g/m3
24-hour State Standard exceeded 35-75 times per year
Annual Maximum 24-hour Concentration 180-215 /ug/m3
24-hour State Standard exceeded 15-35 times per year
40-50 //g/m3
Annual Maximum 24-hour Concentration 145-180 fig/m3
24-hour State Standard exceeded 4-15 times per year
FIG.VI-31
-------
SUSPENDED PARTICULATES
UC 630-PROJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
Annual Maximum 24-hcur Concentration >375 uglm3
tir
24-hour State Standard exceeded more than 160 times per year
Annual Maximum 24-hour Concentration 270-375 jig/m3
24-hour State Standard exceeded 75-160 times per year
Annual Maximum 24-hour Concentration 215-270/tg/m
24-hour State Standard exceeded 35-75 times per year
50-60
Annual Maximum 24-hour Concentration 180-215
24-hour State Standard exceeded 15-35 times per year
Annual Maximum 24-hour Concentration 145-180 ftglm1
24-hour State Standard exceeded 4-15 times per year
FIG. VI-32
-------
SUSPENDED PARTICULATES
SD 630 PROJECTION YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
>100
Annual Maximum 24-hour Concentration >375 //g/m3
24-hour State Standard exceeded more than 160 times per year
75-100 jig/m3
Annual Maximum 24-hour Concentration 270-375 jig/m3
24-hour State Standard exceeded 75-160 times per year
Annual Maximum 24-hour Concentration 215-270 #g/m3
24-hour State Standard exceeded 35-75 times per year
50-60 #g/m'
Annual Maximum 24-hour Concentration 180-215 ig/m3
24-hour State Standard exceeded 15-35 times per year
40-50 0g/m3
Maxi
Annual Maximum 24-hour Concentration 145-180 jtg/m3
24-hour State Standard exceeded 4-15 times per year
FIG. VI-33
-------
SULFUR DIOXIDE
SRC478-PROJECT1ON YEAR 2000
WITH YEAR 2000 VEHICLE EMISSION REQUIREMENTS
Annual Average Concentrations
.015-.OZ ppm (39.3 - 52.4 ng/mj)
Annual Maximum 24-hour Concentration .09-. 12 ppm (238-314 ng/m»)
24-hour State Standard exceeded 15-35 days per year
.01 -.015 ppm (26.2 - 39.3 (ig/ms
Annual Maximum 24-hour Concentration -06-.09 ppm ' (157
24-hour State Standard exceeded 4-15 days per year
.0075-.01 ppm (19.7 - 26.2 (ig/m")
Annual Maximum 24-hour Concentration .05-.06 ppm (131 -i57|ig/m>)
24-hour State Standard exceeded 1-4 days per year —*.
FIG.VI-34
-------
Ambient S02 concentrations are predominantly caused by major point
sources, and not so much by changing land use plans. Therefore,
because the locations of the major point sources are predominately
near Petaluma and they overwhelm other pollution sources, little if
any difference can be seen among land use alternatives. Consequently,
only the analysis on Santa Rosa 478 was made. Near the Santa Rosa and
Rohnert Park urban areas, the pattern of concentration would change
among alternatives similar to that for particulates because each
pollutant is generated primarily by population.
Reactive Pollutants - Oxidant
The oxidant analysis applied a modified proportional rollback technique
to determine the effect of future growth-pattern changes on oxidant
concentrations. Although the shortcomings of proportional rollback
techniques are well-known, it was the only method judged feasible for
this study. The modification of using inter-basin transport calculations
with the usual rollback analysis has made its application to this
study reasonable and useful.
A basic problem in applying the rollback approach to a specific area,
such as Sonoma County, is that oxidant concentrations are not only a
function of emissions in Sonoma County but of emissions in other sec-
tions of the Bay Area. Furthermore, different areas in Sonoma County
are affected differently by transported emissions. On one extreme,
oxidant concentrations in various areas of Sonoma County can be assumed
to be proportional to County emissions only. On the other extreme,
oxidant concentrations in various areas of Sonoma County can be assumed
to be proportional to emissions of the entire San Francisco Bay Area
Basin. A weighting approached, developed by the BAAPCD, was used to
estimate the transport of emissions from each County to Sonoma.
Impact of Development on the Creation of Oxidant
Nine separate future land use patterns were evaluated for their effect
on oxidant concentrations in the year 2000. Non-methane hydrocarbon
emissions for each of the scenarios were derived from grid cell infor-
mation. Emissions for each of the other counties and for the base
year (1973) were calculated by the Bay Area Air Pollution Control
District.
Table VI-13 presents the results of the oxidant analysis. This is
presented in terms of the Santa Rosa basin, Petaluma basin and Valley
of the Moon (Sonoma). The severity of oxidant pollution is repre-
sented by annual maximum hourly concentration and number of times the
1-hour National Ambient Air Quality Standard is exceeded.
The present oxidant situation in Sonoma County is presented in the
first row. Although Santa Rosa has the largest population (and
emissions), it has the least severe oxidant problem at present.
Conversely, Sonoma has the smallest population and experiences the
most severe oxidant problem. The primary reason for this difference
VI-67
-------
TABLE VI-13
ANNUAL MAXIMUM HOURLY CONCENTRATIONS (yg/m3) AND ,
FREQUENCY OF EXCEEDANCE OF FEDERAL 1-HOUR STANDARD FOR OXIDANT
Land-Use
Oxidant Pollution
Alternative At Santa Rosa
BY
SRC 478
SRC 630
SD 478
SD 630
UC 478
UC 630
RD 478
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Annual Max.
No. of times
Std. exceeded
Cont. Trends
478 Annual Max.
No. of times
Std. exceeded
Cont. Trends
630 Annual Max.
No. of times
Std. exceeded
235
9 hours
274
29 hours
353
100 hours
235
9 hours
333
88 hours
235
8 hours
294
48 hours
196
2 hours
255
11 hours
294
35 hours
At Petal Uma
274
22 hours
274
29 hours
333
66 hours
294
48 hours
353
134 hours
333
88 hours
412
306 hours
255
14 hours
294
33 hours
353
96 hours
! T
At Sonoma Ov
333
96 hours
333
88 hours
372
149 hours
372
166 hours
412
219 hours
392
202 hours
451
438 hours
353
105 hours
333
88 hours
392
202 hours
otal Hours
er Standard
127
146
315
223
441
298
792
121
134
333
1
Calculated annual maximum
close to actual monitored
and number of times standard exceeded — very
values.
VI-68
-------
is the amount of transport to each area. The analysis estimates
that present oxidant concentrations in the Santa Rosa area caused
mostly by local sources, with an estimated three percent caused by
transport on the average. Forty percent of Petaluma's oxidant con-
centrations are caused by transport while sixty-three percent of
Sonoma's oxidant is caused by transport. These figures are for the
present situation and represent estimates based on analysis of the
wind-flow patterns. These results should be viewed with caution
since the nature of the oxidant transport phemonena is not well
understood and subject to considerable uncertainty and variation.
The last column in Table VI-13 presents estimates of the total hours
over the oxidant standard for all three locations and all nine alter-
natives. These estimates are seen as the most valid comparison of
alternatives based on the analysis conducted for this study. In all
cases the 478,000 population level alternatives produce substantially
less oxidant than the 630,000 population level alternatives. In
fact, the 478,000 alternatives typically resulted in less than half
the number of hours over the oxidant standard compared to the 630,000
alternatives.
Rural Dispersed 478,000 is the only alternative that is estimated to
cause fewer days over the oxidant standard than at present. It,
therefore, is the most favorable alternative from an oxidant pollution
standpoint. (It should be noted that detailed traffic modeling was
not done on the Rural Dispersed Alternative.) A look at the rest of
the alternatives shows that the Santa Rosa Centered and Continuing
Trends are the next most favorable at both population levels, while
Urban Centered causes the most oxidant pollution at both population
levels. Suburban Dispersed falls in between the least and most
desirable alternatives.
Examination of Table VI-13 shows that although the above conclusions
are applicable county-wide, specific areas do not always follow the
general trends. For example, the Santa Rosa Centered alternatives
cause the most oxidant pollution in Santa Rosa while being favorable
county-wide, and the Urban Centered is one of the most favorable in
Santa Rosa while being the least favorable county-wide. This obser-
vation is a direct result of the substantial amount of transported
oxidants to Petaluma and Sonoma and the lack of appreciable transport
to Santa Rosa.
The analysis conducted suggests that development in Petaluma or Sonoma
is less desirable than development in Santa Rosa. Although increased
hydrocarbon sources in Santa Rosa will increase oxidant pollution in
that basin proportionately more than the other air basins, the magni-
tude of the effect on oxidants will be smaller than in Petaluma or
Sonoma. For example, the estimated increase between Base Year and
Suburban Dispersed 630, as measured in hours over the standard, is 79
hours in the City of Santa Rosa. This increase is associated with a
38 percent increase in hydrocarbon emission. The same land use alter-
native shows an increase of 112 hours and 123 hours over the standard
in Petaluma and Sonoma, respectively, with the associated hydrocarbon
VI-69
-------
increases of 28 percent and 4 percent. Due to the fact that Santa
Rosa receives less transported oxidants, a proportionately greater
increase in hydrocarbon emissions in Santa Rosa creates a lesser
increase in the number of hours over the standard than in either
Petaluma or Sonoma.
A final point to be noted in Table VI-13 is that the maximum concen-
trations shown are directly proportional to the total hydrocarbon
burden causing the local and transported oxidant concentrations. The
number of hours over the standard, however, are not directly propor-
tional but increase at a faster rate than emissions. This observation
is due to the log-normal type frequency distribution and is an important
observation to note when assessing the different future land use
alternatives.
VI-70
-------
CHAPTER VII - LINKAGES BETWEEN LAND USE, AIR QUALITY AND WATER QUALITY
The air modeling confirms the findings from earlier studies that
regional and urban form influence the distribution of air pollutants.
Conversely, the water modeling results, particularly those associated
with surface water runoff, demonstrate that spatial pattern of land
use has only a modest impact on water quality in the entire basin
although it may have significant impacts on particular stream seg-
ments.' "Therefore, since there were clear correlations between spatial
form and the distribution of air pollutant concentrations but only
minimal correlations between spatial pattern and water quality, it is
no surprise that there was only a minimal correlation among spatial
patterns to promote air quality and those to promote water quality.
The study also establishes that the land use/air quality/water quality
linkages can vary with the pollutant being measured and the location
where the measurement is made. This chapter describes the linkages
that were investigated in the study and defines some of the policy
considerations that are implied from the findings.
GENERAL CONCLUSIONS
The basic conclusions reached in this study are: 1) the assimilative
capacity of air and water basins are key determinants of future levels
of population and employment activities that can take be supported
within basins without violating environmental standards; 2) the popu-
lation and employment size and density are the most critical factors
affecting both air and water quality as compared to other variables
such as location, land use type or meteorological conditions (excluding
reactive air pollutants); and 3) other pollution control approaches
such as site specific land management techniques generally have greater
influence on air and water quality than variations in spatial configu-
rations or intensity of land use.
The combination of the natural features in an air or water basin,
whether hydrological or meteorological, are critical factors in de-
termining the concentration and distribution of pollutants in the
basin. The concept of assimilative capacity, defined in this study as
the ability of the physical environment to absorb pollutants without
violating air and water quality standards, is an excellent mechanism
by which planners can measure the influence of differing levels of
land use or transportation activities on environmental quality
objectives.
The assimilative capacity of a basin may be significantly different
for air quality than for water quality. The Petaluma sub-basin, for
example, has a relatively high assimilative capacity for water pollu-
tants given the population and employment levels of the different land
use alternatives. However, it has a relatively low assimilative
capacity for oxidant.
VII-1
-------
The analysis of spatial pattern characteristics, including population
and employment size, density, location and land use type, indicated
that only the first two of these variables are particularly signific-
ant influences on levels of air and water quality. Other things being
equal, the land use alternatives which concentrated population and
employment produced the highest localized concentrations of non-
reactive air pollutants and water pollutants. For example, the worst
case situation for both air and water is the central section of Santa
Rosa in the Santa Rosa Centered alternative, which is the largest and
most densely populated pattern simulated. In this case the particu-
late concentrations, carbon monoxide concentrations and the total
washoff loads entering nearby streams were the highest amounts of any
simulation. Yet, when water pollution is measured on a regional
level, in the receiving waters of an entire basin, there is very
little difference between the quality levels produced by the various
land use alternatives. When air pollution is measured in terms of
population exposure to violations of these air quality standards, the
centralized, compact spatial patterns result in far worse conditions.
There are several reasons why the interrelationships between air and
water quality are not pronounced. The basic reason is that the hydro-
logic system and meteorological patterns in Sonoma County are essen-
tially unrelated. The water quality in a stream draining one city in
the County bears little relationship to the quality in a stream drain-
ing another city. Most obviously, the pollution washoff from Rohnert
Park does not affect Santa Rosa because the two cities are not con-
nected by a river. What may not be apparent, however, is that pollu-
tion from upstream cities is not always the important cause of pollu-
tion in downstream cities. As was seen in the surface runoff water
quality analysis, pollution concentrations may be lower in downstream
cities that those upstream due to the combined consequence of all the
various characteristics that make up a hydrologic area including dif-
fering rainfall patterns, topography, soils or intervening land use.
The pollution washoff from a 100 hectare (247 acres) orchard one kilo-
meter (.621 miles) upstream from a city may have far greater impact
than a 1,500 hectare city three kilometers further upstream.
On the other hand, some air pollutants are subject to a high degree of
transport among cities. Air pollutants are transported not only across
water basin boundaries within Sonoma County, but they are also trans-
ported to and from other parts of the San Francisco Bay Region. It is
this dissimilarity in the characteristics of water basins versus air
basins and the methods by which the pollutants are transported that
results in the lack of linkages between land use patterns that support
air quality as opposed to those which support water quality.
The combined effect of both of these findings — the importance of
assimilative capacity and population/employment levels — provides
the key to developing an environmental management strategy. For land
use planning purposes population and employment levels provide a
mechanism for relating assimilative capacity to urban growth. Assimi-
lative capacity can be defined in terms of a combined population and
VII-2
-------
employment level, based on a clearly defined set of assumptions on the
population generating potential of each of these variables. These
assumptions would include wastewater generation,,sewage treatment
levels, compliance with auto emission standards and vehicle trip
volumes. In this manner, population and employment provides a con-
venient measure to use in evaluating differing land use, transpor-
tation and infrastructure strategies aimed at achieving development
patterns that aid in the achievement of air and water quality objec-
tives. If the assumed requirements or influences of population and
employment produce pollution levels in a basin that exceed either its
air or water assimilative capacity, then different growth management
efforts or mitigation measures would need to be considered.
The next sections of the chapter will describe in some detail the
various linkages which were observed. "They are classified in terms of
spatial patterns, assimilative capacity and mitigation measures.
SPATIAL PATTERN LINKAGES
The influence of spatial patterns on air and water quality linkages
are determined by comparing the air and water modeling results from
the different land use alternatives. For this purpose it is first
helpful to re-classify the land use alternatives in terms of their
basic properties.
1) Population growth distribution
Regional urban - rural population distribution (highly urban
population vs. highly rural population)
Regional distribution of urban population (high population
in a single city vs. population divided more evenly
among several cities)
Regional distribution of urban employment (high employment
in a single city vs. employment divided more evenly
among several cities)
2) Land use intensity distribution
Residential density (high vs. low percentage of high density
dwelling units)
Commercial densities (high vs. low number of employees per
acre in city center)
3) Land use spatial distribution (local)
Residential location (high vs. low percentage of dwelling
units located close to city centers)
Commercial locations (high vs. low percentage of businesses
located close to city centers)
VII-3
-------
Figure VII-1 is designed to illustrate the relative position of each
of the alternatives in relation to the growth characteristic listed
above. The extremes for each characteristic are at either end of a ,.
line. These are extremes in relation to each other and not to some
absolute standards. For example, in the case of the regional dis-
tribution of urban population (second diagram in figure VII-1) the-
Santa Rosa Centered alternatives are found to concentrate 60% of the
County's urban population in Santa Rosa, while the Urban Centered
alternatives locate only 30% of the County's urban population there.
Santa Rosa, in the other three alternatives, contains about 501 of the
County's urban population, so these alternatives are shown just to the
left of the midpoint of the line.
Regional Urban-Rural Population Distribution
The alternative with a high rural population and low urban population
(Rural Dispersed) produces the lowest levels for most air and water
pollutants. There are several reasons for this result:
1) The population of all the cities are lowest of all the alternatives;
thus traffic volumes, population-based air emissions (e.g., space
heating emissions) and water pollutant loadings were the lowest
in each city.
2) Population and employment densities are low in both cities and
rural areas, resulting in lower concentrations of pollutant
generators.
3) The rural residential land use has the lowest water pollutant
loadings of all the residential land uses.
4) Rural residential land use, at one house per three acres, is the
housing pattern that provides the smallest amount of impervious
surface coverage thereby permitting more water to be absorbed in
the open space rather than running off into the nearby streams.
In the case of oxidant, the Rural Dispersed alternative is actually
better than in 1973 for two of the air basins (Santa Rosa and Petaluma).
This improvement occurs because the reduction in the year 2000 hydrocarbon
emission rates due to emission control devices more than offsets the
population increase in this alternative.
Regional Distribution of Urban Population and Employment
The effects of centralizing or decentralizing population and employment
are discussed together because both of these variables are treated the
same in the land use alternative and their effects are not separated
by the modeling analysis.
VII-4
-------
FIGURE M-1
CHARACTERISTICS OF LAND USE ALTERNATIVES
REGIONAL URBW-RURAL POPULATION DISTRIBUTION
uc
£
L/RBAN P6FVIATION
W6H RURAL
REGIONAL DISTRIBUTION OF URBAN POPULATION
SRC
•
HIGHW CENTRAU ZEP (K ONE CITY
HI6H\X
SEVERAL
REGIONAL DISTRIBUTION OF URBAN EMPLOYMENT
Uc
i»J OME OlY
PBNSriY
uc
CT RD
VtlSHLY
PEKENWiE OF MUITI-
'N ernes
COMMERCIAL DENSITY
uc
LOW PERCENTAL OP MUtTl
IN
CT
HIGH NUMBER OF
PER ACRE.
RESIDENTIAL AND COMMEKm. LOCAPON
uc
SRC
UW
ACRE.
CT
SD
WI6HW
FIG. VII-1
-------
Concentrating high population and employment in one city in the County
(the Santa Rosa Centered alternatives) produces both high air and
water pollution levels in that one city. Decentralizing urban popula-
tion among several cities (the Urban Centered alternatives) produces
high air and water pollution levels in each of those cities, but the
peak air pollution levels in each of the cities are lower than the
peak levels encountered in Santa Rosa in the one-city concentrated
alternative. Table VII-1 presents the population exposure rates in
the study area in four of the land use alternatives.
The following is a summary of the general findings concerning the
above variables:
1) The one-city centralized alternatives, SRC 478 and 630, produce
the highest County peak concentrations of air pollutants, exclud-
ing oxidant.
2) The one-city centralized alternative produces very high population
exposure levels for all non-reactive air pollutants in that city.
3) The total air pollutant population exposure in the County is
comparable for both the centralized one-city alternatives and the
decentralized multi-city alternatives.
4) In terms of exposure to high oxidant concentrations, the one-city
centralized alternatives in the study area are far better than
the multi-city centralized alternatives. This result is due to
the transport phenomenon that brings Bay Area pollutants to
Petaluma and Sonoma in much greater concentrations than to Santa
Rosa. Even though the number of reactive hydrocarbons that are
transported to Sonoma and Petaluma represent a small fraction of
those produced throughout the San Francisco Bay Region, they are
still enough to cause oxidant levels that exceed the standard.
If Petaluma or Sonoma had been chosen as the site of the one-city
centralized alternatives, then these alternatives would have been
found to have been far worse than the multi-city decentralized
alternatives.
5) The streams that drain Santa Rosa have high wet weather pollutant
concentrations in the Santa Rosa Centered alternatives, and the
streams that drain the other major cities in the county have high
wet weather pollutant concentrations in the Urban Centered alter-
natives.
6) When water quality is measured at the outlet of the Laguna basin,
there is little difference between the one-city centralized
regional pattern (SRC) and the decentralized, multi-city pattern
(UC).
Density and Location Characteristics of Residential and Commercial
Land Uses
Because density and locational characteristics of residential and com-
mercial uses are distributed similarly in the alternatives, it is not
possible to separate the effects of each. Both Santa Rosa Centered
VII-6
-------
Table VII-1
Population Exposure Levels of Air Contaminants
Per Land Use Alternative
Santa Rosa Santa Rosa Urban Cen- Suburban
Centered 478 Centered 630 tered 478 Dispersed
478
Carbon Monoxide
Population Exposure R 6 g fi
Index2 1.15 x 10° 1.90 x 10 1.17 x 10 .95 x 10
Population Exposure to
Standard Violation
Indexl None None None None
Particulate
population txposure
Index2
Population Exposure to
Standard Violation
Index1
101 x 106
c
5.6 x 10b
155 x 106
c
22.5 x 10b
103
6.1
6
x 10
c
x 10b
91.3 x 101
c
.34 x 10°
The key assumption in the Population Exposure to Standard Violation
Index (PESVI) is that the degree of health hazard cause by an air
pollution level is linearly related to the total population exposed
to concentrations in excess of the standard and that pollution
levels below the standard are not harmful. The PESVI is based on
the Regional Population Exposure Level concept developed by the
Rand Corporation in The Regional Impacts of Near-Term Transportation
Alternatives: A Case Study of Los Angeles (Mikolowsky. 1974).The
units of the population exposure3indices used are person-parts per
million for CO and person - yg/m for particulates.
The PESVI is intended only to provide an estimate of the relative
difference among the land use alternatives and should not be treated
as a precise calculation. While the pollutant concentrations can
be estimated with reasonable accuracy, there is a potential for
greater relative error when the value of the standard is subtracted
from the projected concentrations.
The PESVI is determined by the summation per air basin of the products
of grid cell population and the difference between the 8-hour maxima
for CO and 24-hour maxima for particulate concentrations and the pollu-
tant standard per grid cell. As follows:
VII-7
-------
and Urban Centered alternatives are concentrated (e.g., densities were
high and locations favored the city centers). The Suburban Dispersed
alternatives have both low densities and locations favoring the periphery
of cities. There are no alternatives that test dispersed high density
residential within a city.
The following summarizes the conclusions relating to density and
location. The reader is reminded that the air quality analysis did
not take into consideration the possible changes in trip frequency or
means of transportation that could occur with different centralized
versus decentralized land use activity.
1) Concentrated development produces high localized concentrations
of both air and water pollution.
2) Dispersed low density development results in relatively low
pollution levels being spread over a large area.
3) Concentrations of commercial and industrial land uses produce the
highest amount of water pollutants from surface runoff.
4) The population exposed to carbon monoxide or particulates, when
measured in absolute terms (persons-yg./m3), is 1.2 times as
large under the centralized and concentrated alternatives (SRC
and UC) as the dispersed alternative (SD).
5) The population exposure to particulate levels above the State 24-
hour standard is under the concentrated and centralized patterns
(SRC and UC) than the dispersed alternative (SD).
The influence of the location of different land uses requires a de-
tailed explanation. As was indicated in the chapter that described
the surface water runoff model, both the amount of pollutant loadings
and the percentage of land surface covered varies according to land
use. Table VII-2 shows the washoff of total suspended solids from
each land use. The last column in the table shows the concentrations
(total pollutant emissions per volume of water) of total suspended ..
solids in the runoff from the different land uses relative to low
density residential.
z Pop (Pollutant Concentration - Pollutant Standard)
1=1 cell i cell 1
>
The summation in the study area of the products of grid cell population
and predicted 8-hour maxima for CO and 24-hour maxima for particulate
concentrations per grid cell.
I Pop (Concentration of Pollutant)
i=l cell i cell i
VII-8
-------
Table VII-2
Washoff Characteristics of Land Uses
Land Use
% Impervious
Coverage
Pollutant
Loads1
Relative
Pollutant
Loads2
Relative
Pollutant
Concen-
trations3
(compared to low density
residential)
Low Density Residential
Medium Density Residential
High Density Residential
City Commercial
Suburban Commercial
Industrial
30
65
80
95
90
98
6.0
13.7
24.6
63.8
63.8
36.8
1.0
2.3
4.0
10.5
10.5
6.0
1.0
1.0
1.5
3.3
3.5
1.9
1. Kilograms of total suspended solids (TSS) per hectare (20 days of
accumulation).
2. Kilograms of TSS per hectare divided by kilograms of TAS per hectare
of low density residential.
3. TSS concentrations in runoff divided by TSS concentrations in runoff
from low density residential.
It can be seen from Table VII-2 that the total pollution load from
commercial land is nearly eleven times greater than that from low
desnity residential and almost twice as great as the industrial
washoff load. The industrial pollution load is six times greater than
that of low density residential but only 50% more than the pollutants
from high density residential.
The effects of these high pollutant loads on the contaminant concen-
trations in streams is lessened by the dilution caused by the higher
volume of runoff from the higher intensity land uses. The first
column of the table again gives the percent impervious coverage which
indicates the relative volume of water that would run off from each
land use.
When the water quality impact of the different land uses is measured
in terms of the concentrations of total suspended solids, commercial
land is about three and one-half times as high as single family resi-
dential. Industrial land use generates about twice the concentrations
of single family housing and only 26% more than higher density housing.
VII-9
-------
As can be seen in Table VI1-2, commercial land in a watershed or sub-
area of a watershed can be the most critical land use in terms of the
water quality in the streams which drain it. Industrial land is next
in importance. Therefore, a plan which concentrates commercial devel-
opment in a particular sub-area can clearly expect a far higher quantity
of total suspended solids in the nearby streams than if a mixture of
land uses were planned.
ASSIMILATIVE CAPACITY LINKAGES st .,,
The results of the modeling show that certain pollutants or pollution
conditions are much less dependent on urban spatial patterns than
others. Both the dry weather and'wet weather water quality conditions
are highly variable depending on the assimilative capacity of the
watershed or hydrologic sub-area being studied. The volume of water
flow in a particular section of a stream and the amount of contam-
inants entering the stream at a specific site are the critical factors
in water quality.
The oxidant analysis indicates a similar relationship to assimilative
capacity issues rather than urban spatial form. Wind-flow patterns,
other meteorological characteristics and topographical features are
the dominant influence on the distribution of oxidant. The linkages
of assimilative capacity to these pollutants or pollution conditions
will be described in the next sections.
Assimilative Capacity Characteristics and Wet Weather Water Quality
In general, urban development in small watersheds produces greater
local pollution impact than development in large watersheds. For
example, the wet weather water quality in the segment of Santa Rosa
Creek that runs through downtown Santa Rosa is much higher than that
in the stream that drains the northwest section of Santa Rosa, even
though the highest concentration of urban development is in the
downtown area. The reason is that the Santa Rosa Creek is longer and
has a larger watershed that includes a substantial amount of open land
in its upper reaches which provides relatively clean water to dilute
the heavy washoff load from the center of Santa Rosa. The creek that
drains the northwest section of Santa Rosa is short and has a small
watershed with a small amount of open land. It therefore has only a
minimal amount of water to dilute its urban runoff.
Other things being equal, it can be concluded that to attain a higher
level of water quality, it is better to locate the greatest amount of
urban development in large watersheds. If some development must occur
in small watersheds, it would be best to limit it to those activities
with the least potential washoff, such as a low density residential.
VII-10
-------
Assimilative Capacity Characteristics and Dry Weather Water Quality
Water quality in rivers during dry weather is essentially dependent on
the population in the basin, the level of sewage treatment*and the
dry weather flow in the receiving water. It is this last variable
that is linked to the assimilative capacity of the watershed. Because
the dry weather model routed the effluent from homes, businesses,
industries and other point sources to the sewage treatment plants, as
is presently the case in the Sonoma study area, there was little
difference in dry weather water quality from the alternatives due to
variations in land use types or patterns. The differences that do
appear are due to the impacts of the higher populations served at the
various sewage treatment plants and, consequently, the higher effluent
volumes.
The dry weather analysis indicates that the treatment plant at Petaluma
can adequately accommodate higher levels of population due to both its
treatment capability and to the assimilative capacity of the Petaluma
River basin. The characteristics that combine to create the relatively
larger assimilative capacity are 1) the high year-round river flow due
to tidal influx from the Bay and 2) the large dilution capability of
San Francisco Bay once the pollutants from the river are discharged
into it.
The Laguna Basin, on the other hand, has a lower assimilative capacity
to receive treated effluent during the dry weather periods. This is
due to the complete lack of natural water flow in the rivers on which
the sewage treatment plants were situated.
The major conclusion that can be drawn from the linkage between assimi-
lative capacity and dry weather water quality is that the problems
created by point source discharge, including both quality and quantity,
can only be determined after the volume of the dry weather stream flow
is first determined. The extent to which the stream flow is increased
or decreased is determined by the totality of hydrologic characteristics
(e.g., rainfall, land use, slope, channel characteristics, upstream
impoundment and release, etc.). Therefore it is necessary to assess
how the hydrologic characteristics of a watershed can vary or be
altered before developing strategies for population size or sewage
treatment faci1i ti es.
Assimilative Capacity and Oxidants
Oxidant concentrations and urban spatial patterns in Sonoma County are
largely unrelated due to the nature of oxidant formation. Oxidant
forms in the presence of sunlight after its precursor emissions (non-
methane hydrocarbons and oxides of nitrogen) have thoroughly mixed in
the atmosphere. Additionally, oxidant levels in two of the three
basins in the study area are influenced by transport from other parts
of the San Francisco Bay Region. If the effects of transport are
removed from consideration, as is the case using the "rollback"
technique the resulting oxidant levels are related only to the total
emissions created in each of the three air basins (Santa Rosa, Petaluma,
and Sonoma).
VII-11
-------
The Santa Rosa basin~has the lowest oxidant levels of all the alter-
natives, except SRC 630, even though its population was between
three and five times greater than that of the Petaluma basin and six
to ten times that of the Sonoma basin (Valley of the Moon). The
results suggest that the Santa Rosa air basin has a greater assimi-
lative capacity than either the Petaluma or Sonoma basins. The three
reasons for this greater capacity are 1) the topography of the Santa
Rosa basin blocks the winds blowing up from the south but permits wind
to blow in from the west 2) the distance is greater from the Santa
Rosa basin to the major sources in the Bay Area and 3) the winds that
blow into the basin from the west and north come from nominal source
areas.
In contrast, the Petaluma basin is closer to the major sources from
the south and does not have any protective barriers. The Sonoma basin
is even more accessible to the sources of oxidant and has the added
disadvantage of being a very narrow valley vulnerable to frequent
inversions.
Determining the assimilative capacity of an air basin for oxidant is
therefore a necessary first step in determining appropriate levels of
population or employment and the various pollution generating activ-
ities they create. The use of the rollback technique, while of
limited sophistication, does help to highlight the influence of the
different topographic and meteorologic conditions on the level of
oxidant. It provides planners with a first step toward determining
whether growth limits may be necessary in particular sections of a
region or the necessity of using different management control tech-
niques when additional growth is permitted.
Similarly, the assessment of the assimilative capacity of a water
basin compared to that of the air basin helps to define the areawide
growth parameters in a planning strategy. Planning in those areas
with a large assimilative capacity for both air and water could then
proceed to reflect other issues related to growth distribution or
environmental, quality. The areas with limited assimilative capacity
would need to focus on how to compensate for that restriction.
MITIGATION MEASURE LINKAGES
The modeling analysis which tested the effectiveness of site design/
managementreontroT measures provides some of the most significant
findings of the study. For water quality, the control measures in-
clude street sweeping, retention storage, and change in the amount of
land covered by impervious surfaces. The air quality control measures
tested are different levels of implementation of the car emission con-
trol devices. Both the air and water analyses indicate that site
design/management control measures provide far more effective means
of environmental improvement in the Sonoma study area than their
spatial form counterparts. Because the site design/management con-
trol devices can be implemented to minimize or reduce the amount of
pollutants created as a result of urbanization, they are termed
mitigation measures.
VII-12
-------
Impact of Mitigation Measures on Water Quality
The mitigation devices tested by the model provide a strong indication
of which devices are more effective than others in improving water
quality. Retention storage appears to be the most effective control
device, resulting in up to a twelve-fold reduction in peak concentra-
tion and total washoff over the original simulation. Retention storage
is effective because it holds the runoff from the beginning of a
storm, when urban pollutant washoff is the greatest. There are still
many unanswered questions on precisely how effective retention storage
can be based on such variables as: 1) size and solubility of the
contaminants, 2) length of time for the contaminants to washoff the
surface and 3) size, duration and intensity of the storm. These
factors would need to be assessed to determined the size and cost of
retention storage.
Street sweeping ranks behind retention storage in effectiveness as a
water pollution mitigation measure. This pollution abating technique
was simulated by reducing the total number of days of dust and dirt
accumulation prior to the test storm from 20 to 10 days. Consequently,
the model treats it exactly as a .50% reduction in total washoff and
peak concentration of total suspended solids. The actual reduction in
the total dust and dirt accumulation would depend on the characteristics
of the sweeping processes. Present sweeper operations remove about
50% of the dust and dirt fraction of street contaminants. With multiple
cleaning cycles of slower sweeping speeds efficiency can be improved
to as high as 90% with present equipment. Thus, if the sweeping were
conducted every five days and were operated at between 95 and 100
percent efficiency, its effectiveness would be twice that indicated in
the sweeping simulation. It would thus approach the effectiveness of
retention storage in improving water quality in many of the subareas.
However, this extensive sweeping could be determined to be prohibitive
from a cost effective standpoint.
Reduction of the impervious coverage for each urban land use type
created an increase in the peak concentrations of total suspended
solids in the rivers. This increase was due to a decrease in the
amount of runoff available to dilute the pollutants washing off the
land. The simulation assumed that the same amount of pollutants would
wash off a given area of urban land use. These results suggest that a
strategy of reducing the amount of impervious surface in an urban
development is not enough by itself to improve water quality. A
reduction of the amount of total suspended solids washing off this
urban land is also required.
Though increasing the amount of surface for water absorption or deten-
tion decreases the volume of runoff available for dilution of pollutants,
it can reduce peak flood flows. It can also be effective in recharging
groundwater storage and contributing to higher stream base flow conditions
from groundwater supplies during dry periods. Therefore, effort to
provide more pervious surface, such as greater open space requirements,
needs to be combined with efforts to either remove, retain or detain
contaminants to prevent degradation of water quality in nearby streams.
VII-13
-------
Impact of Mitigation Measures on Air Quality
The motor vehicle emission control device requirements are the air
quality mitigation measures studied in this report. Different levels
of implementation of the emission device program were tested for their
effectiveness.
The simulated effect of the emission devices on future levels of
carbon monoxide provide dramatic results. In the Continuing Trends
478 alternative, the only alternative for which both the 1973 and 1990"
vehicle emission factors were modelled, the results showed that when
the 1990 factors were used, there was about a 30 to 40% decrease below
the 1973 annual average carbon monoxide concentration in the urban
areas and there are no violations of standards. With the 1973 factors,
there was a 100 to 200% increase in the annual average CO concentra-
tions over most of the urban portions of the County with up to 20 8-
hour standard violations per year.
The results of this analysis point to the importance of an effective
motor vehicle emission device program. The simulations indicate that
the devices could keep the carbon monoxide levels below the federal
eight hour standard for all land use patterns, even at the 630,000
population level. Although this condition will vary greatly from city
to city based on their traffic pattern and population size, the find-
ing does establish the importance of the motor vehicle emission device
program relative to other methods for reducing carbon monoxide. In
this case, the emission device provides a far more effective method
than altering the spatial pattern of land uses.
POLICY IMPLICATIONS OF LINKAGES
The influence of the existing state, regional, and local policies on
land use is described in Chapter Four. The descriptions indicate the
wide variety of policies and enforcement actions that are presently
being used in California. Most of these policies can have a direct or
indirect influence on the future pattern of urbanization in a region.
As was pointed out in Chapter Four, there is presently a lack of de-
tailed knowledge as to which of the different agencies or policies has
the greatest impact on guiding growth or whether other forces, includ-
ing those more connected to the private market place such as housing
preferance or land cost have a greater influence on urban spatial
patterns.
However, if the various governmental agency policies were integrated
based on a consistent set of planning objectives, and the private
market were clearly guided by such a plan, then a particular growth
pattern could be achieved that could result in the air and water
quality patterns described by the earlier modeling analysis. Such a
condition can more easily be understood when presented in the form of
an example. For this purpose, appropriate policy actions have been
determined for the Santa Rosa Centered land use pattern. This example
was selected because it comes nearest ABAG's concept of a "city-
centered" region. Table VI1-3 provides a cross reference of the
VII-14
-------
policy actions required by the different state, regional, local and
special district jurisdictions to create the Santa Rosa Centered
pattern. Using Table VII-3, it is possible to draw a variety of con-
clusions on the implications of land use decisions on air and water
quality based on the model findings.
The policy implications of the land use/air quality/water quality
interrelationships can be categorized into 1) spatial form and assimi-
lative capacity considerations, 2) mitigation measure considerations,
and 3) governmental considerations.
Spatial Pattern and Assimilative Capacity Considerations
A number of important implications for policy planning emerged from
the analysis of the impact of spatial form on air and water quality.
First, both the air and water basins need to be described in terms of
their capacity to assimilate or absorb air and water pollutants. Wind
patterns, topographic features, upwind land uses and transportation
patterns will be the major determinants to the concentration of oxidants
in a sub-regional area. Watershed size, wet and dry weather flow,
rainfall characteristics and channel shape are key features in de-
scribing the assimilative capacity of a river. The impact of popu-
lation size, pattern of urbanization or land use activities on air and
water quality can vary greatly according to the assimilative capacity
of the subregional area. Therefore, a plan which intends to use
growth management mechanisms, such as sizing of sewage collection and
treatment system, to promote a particular land use pattern aimed at
ensuring high air quality must first determine the level of growth
that can be accommodated by the assimilative capacity of the sub-
region. It is also possible that the air and water sub-regions have a
substantially different capacity to accommodate additional population
and employment. The Petaluma River, for example, can accommodate the
treated effluent from an increased population but would have greater
oxidant problems associated with growth due to its lower air pollutant
assimilative capacity. Therefore, the policy implication is that
assimilative capacity asssessment is an initial step in the environ-
mental management planning process prior to subsequent decisions on
location and timing of growth.
A second policy implication is that population and employment size
should provide the essential link, between air and water quality plan-
ning. Therefore, methods of population and employment forecasting,
including those based on alternative policy actions, should be uniform
for both air and water quality planning. With the assumptions clearly
defined, the forecasted figures can then be translated into their
influences on pollution creating activties and assessed against the
assimilative capacity of a sub-region to determine appropriate levels
of growth controls and/or types and amounts of required mitigation
measures.
A third policy implication is that some compromise may be necessary to
achieve optimum air quality, however defined. As was seen from the
study, concentrations of reactive and non-reactive air pollutants are
VII-15
-------
TABLE VI1-3
SANTA ROSA CENTERED GROWTH MANAGEMENT POLICIES
Description:
Regional: - concentrated regional population
- concentrated regional employment
- high urban population
- highly centralized population within city
- highly centralized employment within city
- high population density within city
- high employment density within city
Air and Water Quality: - highest CO concentrations
- highest particulate levels
- low County oxidant levels
- highest concentration of pollution in Santa Rosa streams
- no major difference at receiving waters
Agency
STATE
Policy Action
Possible Conflict
Department of Transporta-
tion
Energy Resources Conserva-
tion and Development
Commission
Office of Planning and
Research
Department of Fish and
Game
State Water Resources
Control Board
Air Resources Board
strong central transit support
region wide parking commuter constraints
approval on regional energy supply
necessary for population expansion
- limited policy influence
- limited policy influence
approval of full funds
for expanded STP capacity
and appropriate collection
system
designating minimum
"beneficial uses" for
urban waterways
active enforcement of hook-
up restriction in other
cities or rural areas when
applicable
high priority rating for
Santa Rosa STP
approve SIP and AQMP
that supports city
centered concept, even
with short term poten-
tial of localized air
pollution concentrations
approve a Parking Manage-
ment and Indirect Source
approach that provides
flexibility for city cen-
tered facilities and
greater restrictions for
suburban and other cities
projects
- support to regional transit
energy transmission to all
parts of region
designating Santa Rosa River
as of fish and game concern
with attendant permit restrictions
approval of funds for over-
sizing of STP and collection
systems in other cities
VII-16
-------
Table VII-3 (con't)
REGIONAL
Agency
Association of Bay Area
Governments
Bay Area Air Pollution
Control District
Policy Action
- develop 208 and AQMP's that
emphasize city centered
concept.
- A-95, EIR's which support
ABAC city centered concept
consistent with regional
plan
- flexible or non-restrictive
point source review per-
mitting continued employment
expansion in Santa Rosa, even
if some point sources may
exceed some standards (e.g.
particulate)
Possible Conflict
Regional Water Quality
Control Board
Metropolitan Transportation
Commission
develop Basin Plan
establishing "beneficial
uses" compatable with an
urbanized Santa Rosa
hook-up restrictions
other parts of the
County
in
stringent septic tank and
cesspool restrictions in
rural areas
flexibility in "remedial
actions" to dischargers in
Santa Rosa
expansion and quality Im-
provement of SIP and
collection system in
Santa Rosa
approve funds for mass
transit
approval of regional road
system to support the
Santa Rosa growth pattern
minimal approval of roadway
network In Santa Rosa to
curtail suburban growth
stringent and uniformly
"remedial actions" in com-
pliance applied to point
sources that have dispropor-
tionate effects on Santa Rosa
point discharge
approve full regional highway
network
Bay Area Sewage Services
Agency
no jurisdiction in
Santa Rosa
- actions to facilitate
disproportionate growth
in Petaluma
VII-17
-------
Table VII-3 (con't)
LOCAL
Agency
City of Santa Rosa
Policy Action
- establish general plan policies
favoring increased and compact
growth
- enforce subdivision regulations,
zoning, and permit issuance con-
sistent with policies of compact
growth in General Plan
- increase capacity of sewer and
water services, but minimize
spatial expansion
- design road network and
traffic management pro-
gra"1 for increased
population but sensitive
to transit promoting
techniques
- transit program expansion
- use density zoning regula-
tions, including bonuses to
achieve more dense, compact
developments
- create urban renewal agencies
to promote redevelopment and
intensification of land use
in city center
- use advance acquisition of
land through eminent domain
powers as a measure for re-
development of downtown
- use growth sequence zoning
through timing permits to pre-
vent urban sprawl
- nonconforming use regulations
to eliminate or prevent ex-
pansion of uses which are in
conflict with planning and
zoning for compact, dense
growth
- continue stringent limitations
on lot splits
Possible Conflict
use agricultural zoning to
confine urban development
acquisition of full or
less-than-full interest
in land to preserve open
space surrounding city
to encourage compact
growth
- too great an effort to force
compact pattern may discourage
residential and commercial
growth away from Santa Rosa
VII-18
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Table VII-3 (con't)
Agency
Other Cities and County
Policy Action
- general plan policies
favoring limited growth
- enforce regulations and
ordinances consistent
with General Plans
- limit sewer expansion
- limit expansion of road
networks
- support intra-reglonal
transit program
- stringent County limita-
tions on lot splits
- agricultural zoning to
encourage urban develop-
ment 1n Santa Rosa
- acquisition of full or
less-than-full Interest
in land to preserve open
space surrounding city
to encourage compact
growth
Possible Conflict
- too great an effort to force a
compact pattern may discourage
residential and commercial
growth away from Santa Rosa
VII-19
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Table VII-3 (con't)
SPECIAL DISTRICTS
Agenc
Local Agency Fonnatlon
Comjnission
Sanitation Districts
County Water District
Resource Conservation
Districts
Policy Action
- limit annexation in Santa
Rosa to permit total
population increase but
still restrict sprawl and
thereby support high density
development
- restrict annexations in
other cities
- limit formation of special
districts when they are
population and employment
inducing
- limit size of collection and
treatment facilities in all
areas outside Santa Rosa
- prohibit septic tanks
ancl cesspools in rural
areas
- establish sewer "hook-up"
restrictions
- limit size of sewage
collection and treatment
facilities in all areas
outside Santa Rosa
- design water distribution
system to achieve population
and employment in Santa
Rosa and not in the other
cities
- limited influence
Possible Action
- annexation restrictions
limiting high density de-
velopment
VII-20
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dispersed in dissimilar patterns. A population dispersed through the
region may create the lowest CO concentrations but produce an increased
oxidant problem in a particularly sensitive area. Therefore, it may be
necessary to study each air contaminant separately and base land use
recommendations on strategies aimed at those air quality standards judged
the most difficult to achieve and maintain.
A fourth policy implication concerns the conjecture that centralized
and compact urban development is always the best spatial pattern for
meeting the objective of minimizing air pollution. There is a risk in
developing a compact urbanization pattern on the assumption that it
will facilitate a lower dependence on the car and a higher use of mass
transit. The study demonstrates that highly centralized and dense
spatial forms, that are auto-dependent, will result in the highest CO
and particulate levels of any of the land use patterns. This is due
to the concentration of car use in a small area where the combination
of a high number of cars and the confined road network result in
congestion and high localized production of contaminants. This air
pollution condition means that there is a greater need for adopting
adequate levels of mitigation measures including mass transit and
parking limitations. Inadequate political or economic support for
such measures would mean that the long-term commitment to the compact
development could well include the long lasting existence of high
population exposure to certain air contaminants. The centralized
spatial pattern presents a potential risk situation unless air quality
planning is closely related to land use and transportation planning
decisions that will mitigate the undersirable impacts associated with
compact growth.
Unfortunately, the policy implications of centralized versus dispersed
development receive contradictory and somewhat ambivalent treatment in
the present air quality regulations. As indicated by the Santa Rosa
Centered policy actions required by the Air Resources Board and BAAPCD
(Table VII-3), some flexibility in regulation administration may be
required if new businesses or apartments are to be permitted in the core
of Santa Rosa. A new office complex would not want to locate in the
downtown if it knew "indirect source" requirements would restrict its
parking while permitting offices located outside the downtown, where the
air is cleaner to have more parking. Either a more lenient position on
downtown parking or strict parking limitations on suburban office
zoning would be needed to attract and protect centralized offices.
Mitigation Measure Considerations
A second category of policy implications is that associated with the
use of mitigation measures for minimizing air or water pollution.
Perhaps the most significant policy implication is that mitigation
measures, particularly those associated with stormwater runoff,
provide far more effective methods of pollution abatement than the
control of spatial form.
This policy implication is important to federal, state and local
levels of government. To the Environmental Protection Agency, it
highlights the need for further study on the usefulness and limita-
tions of the different measures. Information concerning implemen-
VII-21
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tation of the measures including cost, staffing expertise, and legal
constraints are of particular importance for study. To the state's
regional water quality control boards, its importance relates to the
funding implications related to both existing sewage treatment grants
and possible future assistance in creating retention storage. For local
government, the significance of the mitigation measures is both how they
can be used in new development conditions and the financial and legal
implications of implementing them.
There are a variety of unanswered questions about the effectiveness of
the different devices to reduce surface runoff water pollution. The
aspects of retention stprage requiring further study include:
1) ways to build retention storage into presently developed areas,
2) application of different retention measures for different land
uses,
3) methods for determining the most cost effective sizing of deten-
tion storage facilities,
4) costs and legal implications of cleaning and maintaining reten-
tion facilities following storms, and
5) treatment versus discharge of retained stormwater.
Street sweeping, although generally more straightforward than retention
storage, can also benefit from further study. The review of literature
in this report discussed the previous research on street sweeping. One
dimension that the earlier research did not cover is optimum sweeping
patterns or frequencies within different cost levels. For example, a
commercial area, with its higher pollutant loading and higher percent-
age impervious surface coverage, may require extremely frequent sweep-
ing during the rainy season. Sweeping in residential areas, on the
other hand, might have a cost effective pattern of infrequent sweeping
except just prior to the first storm in the wet season.
Cities and counties should also consider the implications of street
sweeping to the creation of special districts. If a particular area,
such as an industrial park, is anticipated to have a higher pollutant
washoff rate, it may be appropriate to create a special assessment
district for that area to provide for the costs related to a greater
frequency of sweeping.
General Governmental Considerations
A third category of policy implications from this linkage finding is
concerned with the need for improved governmental policy setting.
None of the implications that will be discussed will be particularly
new or startling. The importance in listing them is that they be
recognized in preparing planning strategies and openly addressed in
the developing of an environmental management strategy.
VII-22
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First, the orchestration of a proper mix of land use policies to
achieve specific spatial patterns or mitigation measures presents a
major challenge. The Santa Rosa Centered example given in Table VII-3
lists some 55 policy actions necessary to be adopted and implemented
by the various state, regional and local jurisdictions to encourage a
spatial pattern for environmental enhancement. These actions do not
reflect the many other possible policy implications emanating from
housing, flood control, historic preservation, economic development
or seismic safety requirements. The importance of this implication is
that-policy must be integrated into the far broader issues of urban
and regional development to achieve a regionwide strategy for environ-
mental management. ».
Second, some policy flexibility is required if compromises are to be
made in environmental planning. As pointed out earlier, air quality
policies may require some modification if a particular spatial pattern
is desired as part of a long-term strategy. Localized pockets of CO
or particulate concentrations—up to limits imposed by mandatory stan-
dards—may have to be accepted to achieve regional air quality objec-
tives.
An acceptable tradeoff in a regional water quality strategy might
allow a particular segment of a stream or river to have higher amounts
of pollutants than desired for the entire river while still protecting
the beneficial uses in other sections of the river. The strict enforce-
ment of a non-degradation policy could be counter-productive to this
overall approach and may need some interpretive flexibility in its
implementation.
i*t
The importance of this policy implication is that it is far better to
recognize the need and set limits on flexibility at the outset of
planning rather than ignore the need or permit it to be applied
through a potentially more erratic appeal or judicial process.
Third, growth control strategies at a regional level may require a "
two-sided approach of encouraging new development in one area while
constraining it in others. Such an approach will require the re-
solving of many contradictory issues involving both environmental
quality and political and economic equity. An example of a dichot-
omous situation exists in the Valley of the Moon where the collection
and sewage treatment capacity of areas planned for minimal growth is
being expanded and extended to get the existing homes off the use of
septic tanks. In this example, a growth and environmental management
mechanism, the sewer system, can be working at cross-purposes. It
can improve the environment by reducing the dependence on the water
polluting septic tanks. Yet, it will provide the basic infrastructure
by which further population growth can eventually be permitted, there-
by increasing the potential for reduced air quality.
Similarly, a rural section of the county may have a bus service
extended to it which could reduce the dependence on the car but also
make the area more accessible for further residential expansion.
VII-23
-------
The policy issue that these linkages highlight is one of balancing the
need for a basic level of governmental services throughout the region
against the growth inducing effects of these services. The debate
will become particularly difficult when an area totally lacks the
basic services such as the above example in the Valley of the Moon.
The resolution of the issue needs to be made at both a local and
regional level based on a debate on the type and quantity of the
service, the specific demands it is trying to satisfy, and the extent
of potential environmental damage that may result should the costs of
population inducement outweigh the benefits of the particular service.
This form of assessment should guide the policy makers by providing an
evaluation system that highlights the trade-offs.
The policy implications from the findings on linkages between land
use/air quality/water quality should provide real assistance to those
jurisdictions that are preparing to undertake environmental management
planning efforts. The conclusions on spatial form and assimilative
capacity indicate some direction in which initial regionwide planning
studies could be pointed. The effectiveness, and therefore importance,
of mitigation measures should encourage local jurisdictions to look
further into the more detailed issues of how the measures might be
carried out. The governmental implications are more complex and
potentially most elusive. Chapter Eight contains a number of recom-
mendations on the manner by which some of these policy implications
could be addressed.
VII-24
-------
CHAPTER VIII - RECOMMENDATIONS FOR AN ENVIRONMENTAL MANAGEMENT
STRUCTURE
The conclusions of Chapter VII suggest that land use controls can be
used as part of an overall plan for achieving desired air and water
quality objectives. The section on the deficiencies of the pollution
control structure provided in Chapter IV indicates that a new direc-
tion is necessary in the application of land use controls through a
more integrated and effective environmental management program. The
primary problem of the present structure as it relates to the use of
land use control measures to reduce environmental pollution is that
there is the lack of an adequate role for local government. The
efforts that EPA has made to employ land use related factors in
individual environmental management programs (e.g., parking manage-
ment, indirect source review, sewage treatment sizing based on en-
vironmental impacts) have emphasized controls to be imposed by state
and regional levels of government. The failure of these measures to
win acceptance can be partially attributed to the lack of effective
involvement with the land use planning process at the city and county
level. This chapter will suggest strategies for improving govern-
mental sensitivity to environmental needs. Further study will be
required to provide further elaboration on the proposed measures.
If land use measures are to be successfully used to support air and
water quality objectives, a structure for environmental management has
to be devised that connects the intent, concerns and funding of the
federal and state programs with the institutions and the expertise for
comprehensive land use planning and control that already exists at the
local level. The potential advantages of an approach that involves
local government are that it makes use of administrative organiza-
tions, powers and implementation devices that already exist, thereby
avoiding duplication and the imposition of additional administrative
and enforcement procedures. It has the important added advantage of
relating the achievement of air and water quality to the attainment of
other community objectives, thus permitting appropriate tradeoffs to
be made and a determination of the most publicly acceptable implemen-
tation strategies.
BASIC REQUIREMENTS FOR AN ENVIRONMENTAL MANAGEMENT PLANNING PROCESS
The overview of the present pollution control system highlights five
basic deficiencies that need to be remedied. When restated as neces-
sary components of a regional environmental management plan, the five
are:
1) integration of air and water policies and actions with other
functional elements required in comprehensive planning* e.g.
transportation, conservation of natural resources, housing,
urban design, agriculture,
2) integration and consistency of the policies and actions by the
different governmental agencies that influence air and water
quality,
VIII-1
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3) involvement of local government in the preparation of environ-
mental management plans and the enforcement of controls that
are required by the federal and state schemes,
4) creation of a consistent review or appeal system at both the
regional and sub-regional level, and
5) adoption by regional and local government of clear and
specific policies that are capable of judicious enforcement.
An additional component of a clear understanding of responsibilities
for each jurisdictional level is also necessary for environmental
management planning.
Integration of Air and Water Quality Land Use Measures with Other
Functional Elements.Air and water strategies should be treated in
the context of comprehensive planning, with their associated costs and
benefits measured against other social, economic and environmental
objectives. The Sonoma Study illustrates a number of instances where
the need for such a comprehensive planning approach is apparent.
There are a number of air quality/land use control strategies that
will place an important emphasis on major transportation improvements.
The failure of a General Plan transportation element to adequately
reflect that emphasis and provide direction to subsequent traffic
management techniques or budgeting for mass transit purchases would
defeat the air quality strategy.
From the water quality perspective, the storm runoff modeling indicates
that a flood control strategy for reducing the amount of impervious
surface coverage can have a counter-productive impact on water pollution.
The failure to consider the objectives of both flood control and water
quality under the same planning framework and make necessary adjustments
could well result in some undesired and unintended impacts.
The present local planning framework in California provides for such
comprehensive planning through the general plan program. However, as
pointed out, air quality policies are presently not required and water
quality planning, under the conservation element, is vague. Therefore,
any requirement for the inclusion of air and water quality considerations
in comprehensive planning needs to be more specific as to the subject
matter of anticipated policies.
Regional planning also requires a comprehensive approach to ensure
air and water quality objectives are integrated with those of other
functions. An example of such an approach is that currently being
initiated by ABAG in developing its Environmental Management element
to its Regional Plan. The element will have sub-elements that con-
sider air quality, water quality and solid waste disposal. The air
quality sub-element is being prepared to satisfy the air quality
maintenance plan requirements of the State Implementation Plan and the
water quality planning comes under the Section 208 requirements of the
Federal Water Pollution Control Act Amendements of 1972.
VIII-2
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Integration of Intergovernmental Air and Water Quality Land Uses
Measures.There is a need to make consistent the planning process of
both 1) agencies at the same jurisdictional level and 2) agencies at
different jurisdictional levels. Integration of inter-agency policy
setting will come about only when the policies of one level of govern-
ment (e.g. state, regional, local) are presented and debated as a more
unified whole. Compromises among the policies of the different depart-
ments or commissions are necessary and must be based on a particular
comprehensive planning strategy. This strategy must then have sufficient
legal and administrative support to provide for a unified enforcement pro-
gram. The problem with inter-departmental coordination in California,
particularly at the State level, is that 1) the efforts to integrate
policies are not based on a particular statewide comprehensive plan and
2) the coordination that does take place is not followed by a uniform
enforcement program. Therefore, department budgets, policies and plan
review powers tend to be conducted as separate exercises.
Another improvement necessary to bring about policy integration is a
clearer hierarchical structure of plan development involving state,
regional and local agencies. This structure will be discussed later
in the chapter under the section on "assignment of responsibilities."
The hierarchical framework would provide a system whereby the environ-
mental objectives of the higher level of government are addressed in
greater detail at the lower levels of government. For example, the
State air pollution control program would provide the framework for
local application, but would not dictate the land use and transpor-
tation control measures by which local government would achieve the
standards.
Air and water quality strategies developed at the regional level
should provide guidance on land use and transportation controls and
expenditures to cities, counties and special districts in developing
their individual approaches toward implementing the strategies. For
example, an older city may choose to conduct more intensive street
sweeping in its downtown commercial area rather than undertake the
provision of retention storage facilities. However, a new and devel-
oping city might decide retention storage is preferable because it can
require such storage in new development.
Cities that failed to propose policies consistent with regional
policies would be vulnerable to regional or state sanctions in the
form of regional permit reviews or restricted financial assistance.
Conversely, cities that amended the'ir General Plans to be consistent
with regional objectives, and that adopted new ordinances to implement
the policies, would be delegated responsibility for complete permit
issuance powers. For example, regional level concerns on indirect air
pollution sources could be delegated to local planning commissions
when the General Plan is amended to include an approach for shopping
center location review that is consistent with regional policy.
Involvement of Local Government. The overview of the present govern-
mental structure indicates that local government has the best developed
comprehensive planning program of any jurisdictional level, particularly
because it is combined with wide ranging and flexible enforcement
VIII-3
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mechanisms. The design review procedures provide specialized consider-
ations for selected land uses or locations. Implementation or enforce-
ment measures including conditions to zoning or performance standards
provide wide administrative flexibility to ensure mitigation measures
or growth management considerations are implemented. The principle
element local government lacks is a regional perspective on the impact
of the pollution generated within its boundaries on other cities or
counties in its region. When this perspective can be provided in a
regional environmental planning framework, local government can direct
its established planning and enforcement ability to carry out both
local and regional air and water quality objectives.
•
Cities in the study area like Santa Rosa or Petaluma have sufficient
staff capability to conduct or direci planning studies aimed at devel-
oping a set of air or water quality policies. However, the smaller
municipalities would have difficulty in preparing sophisticated en-
vironmental approaches. Similarly, the new enforcement review methods
that require a considerable knowledge of air or water pollution impacts
are presently beyond the expertise of the staff in smaller cities.
Therefore, state and regional planning agencies must provide an admin-
istrative alternative for these small cities. Staff and/or financial
assistance for providing the local approaches Would need to be available.
Local planning agency staff training programs in air and water quality
planning and enforcement are necessary. Experience of local adminis-
trators may indicate that a state certification program, similar to
that for sanitary engineers in the local public health departments, is
necessary and desirable to ensure competence in implementing the
control measures.
Creation of a Consistent Review or Appeal System. As stated earlier,
the main improvement needed in the review or appeal process is assur-
ance that the review decision is consistent with the intent of the
environmental planning policies. There are presently two levels of
review. The first is that which occurs when a general plan or a
functional plan (e.g., transportation plan, water quality plan) is
developed. This review needs to provide a check to ensure that a plan
prepared by a local jurisdiction is consistent with the plan of a
regional or state agency. For example, a circulation element prepared
for a local government general plan would be reviewed by the regional
transportation agency for consistency with regional transportation
objectives. Quantitative measures of the anticipated effectiveness of
the different local transportation strategies and a program of implemen-
ting the strategies including capital or operating expenditures would
need to be provided.
At present, the environmental impact report review requirements attempt
to provide for this form of review. Yet, the deficiencies of the EIRs
point to the need to place some sanctions against those plans that are
inconsistent with local, regional and state comprehensive plans. For
example, a local air quality control approach that is not consistent
with the regional strategy would not be delegated indirect source
review powers.
VIII-4
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The second level of review is that for individual capital works
projects or individual land use changes, e.g., zoning, subdivision
approvals. This level presently has the greatest number of different
reviews, including those made by zoning appeal boards, A-95 reviews,
regional and State regulatory agencies and, potentially, the court.
Consequently, the decisions made by these various bodies have the
greatest opportunity for divergence or inconsistency. For example, a
lenient decision by an air pollution hearing board that permits an
industry to locate at a particular site may not be viewed by either
a zoning appeals board or the court as consistent with the general
plan policies. Similarly, a regional water quality control board or
sewage service agency may approve the size or configuration of a
sewage collection and treatment system that is inconsistent with the
growth objectives of regional or local comprehensive plans.
This second level of review requires more focus as to what the zoning
appeal or project is being judged against. Is it consistency with a
general plan's policies as in the case of a zoning or subdivision
court case? Is it the secondary growth impacts of a "201" treatment
facility?
The answer to these questions lies in the development of an integrated
environmental management plan that provides for consistent intergovern-
mental policy setting. Such a plan should provide policy guidance on
matters of growth inducement or location of dischargers. The plan
therefore would provide the basis for an appeal judgment on consis-
tency between the environmental policies and the individual project.
If environmental management plans successfully integrate other func-
tional elements and local general plans are made consistent with
regional plans, then there would exist a body of local government
policy that provides for treatment of land use and capital budgeting
decisions that is uniform with the state and regional environmental
strategies.
For example, a regional environmental planning program would:
1) establish the beneficial uses -- i.e., protect shellfish beds
2) establish standards for the protection of beneficial uses, or
procedures necessary to determine such ~ i.e., measurements
in both concentrations and sedimentation levels for different
contaminants necessary to protect the shellfish
3) establish the potential control methods to reach the standards —
i.e., street sweeping, retention storage, in-system storage and
treatment
4) establish which jurisdiction would be most necessary and most
effective in implementing the control for a particular beneficial
use
VIII-5
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Both the regional and local agencies would assess the various control
methods for 1) their relative ability to achieve the standard, 2)
their financial and institutional consequences and 3) their impacts on
other functional elements such as land use and housing. For example
the cost of a control method like retention storage, which might be
passed on to new residential development, would need to be assessed
against the objectives of regional and local housing element. Once
both the local and regional assessment is completed and the necessary
compromises and alterations are made, the local government would adopt
the water pollution control strategy as an amendment to their general
plan. The local agency would then develop or amend the various ordi-
nances to provide the implementation methods to carry out the strategy.
The next step would be to ensure that implementation actions are con-
sistent with the policies. The existing general plan legislation,
providing for court review of consistent planning policy enforcement,
provides a useful model for an improved appeal process. First, the
purpose of the review is very explicit — determination of consistency.
Secondly, the court review encompasses the entirety of all elements of
the general plan rather than the limited scope of a single function
hearing board. (It should again be pointed out that the breadth of
the court review is not yet firmly established as to whether it in-
cludes the consistency of the act of rezoning or, more restrictively,
the consistency of zoning maps to general plan maps.)
The determination of consistency requires judgment on a case-by-case
basis. Such judgment would be based on the intent of the policies.
It requires clarity of planning objectives, including priority of one
objective over another. For example, a central city may want to
manage its downtown parking in such a manner as to discourage peak
hour commuter traffic as part of its effort to improve air quality.
Yet, it may want to permit some additional retail parking as an effort
to keep its downtown economically viable. This priority of one form
of parking over another would need to be clearly established in the
transportation policies. Then, a new downtown building, whose zoning
permit did not include parking management conditions (e.g., propor-
tionally higher fee after the first two hours, opening the lot after
10 a.m.) could be challenged as inconsistent with the general plan
transportation policies.
The major drawback of the court review system is that it can be
expensive and create a new burden on the judicial system. Therefore,
new forms of appeals need to be considered such as semi-judicial
appointed appeal tribunals at the regional or sub-regional level.
Such tribunals could be empowered to review appeals made by residents
or property owners on local or regional decisions as to their con-
sistency with the planning policies. The tribunals would concern
themselves with the content or substance of,the consistency issues
(e.g., the intent of the policy) while the court would continue its .
role in judging if the procedure by which the content was evaluated
meet constitutional due process safeguards.
VIII-6
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Adoption of Clear and Specific Policies. The adoption of clear and
specific planning policies becomes critically important when enforce-
ment actions are legally required to be consistent with policies.
The present condition in some municipalities of vague policies com-
bined with highly discretionary enforcement mechanisms can lead to
frequent challenges on consistency. Instead, jurisdictions need to
adopt explicit statements of air and water policies whose impacts are
capable of being measured. As an example, policies that require re-
tention storage should indicate the relative quantity of water runoff
that the new development should retain. Similarly, management policies
should be based on specific range of population or employment size
assumptions for the future and indicate the conditions under which
this growth would occur. A regional plan may determine that the
assimilative capacity of a watershed could permit a combined work
force and resident population of 100,000 people in a particular basin
given the existing level of sewage treatment and methods to reduce
surface runoff. However, it could accommodate an additional 50,000 if
retention storage were required in all new development, the capacity
of the treatment facility was expanded, and more frequent and effec-
tive street sweeping were undertaken. All three of these measures
should be explicitly stated as policies and assumptions and tested for
their impact in achieving regional and local environmental objectives.
C1ear Assi gnment of Resppnsi bi1i t ies. Each of the governmental
entities involved in air and water quality planning should be given a
clear responsibility for specific aspects of plan preparation, plan
review or appeal and plan enforcement. Such clarity in assignment is
necessary to ensure that all environmental management issues are
treated in a comprehensive, systematic manner and that the public has
a better understanding of whom they must deal with on matters of new
development or in appealing recent decisions. Implied in the need for
a clearer assignment is the elimination of duplicative planning or
plan enforcement.
The nature of the assignment of responsibilities should be related to
the agency's perspective and abilities. For example, it would be
appropriate for a regional agency to determine the assimilative
capacity of each watershed in the region and determine the cause and
effect relationships of pollutants that travel across jurisdiction
boundaries. It would then be the responsibility of the local juris-
diction to develop alternative management approaches to prevent the
assimilative capacity in a particular area from being exceeded. The
final section of this chapter will outline the responsibilities of
jurisdiction levels in developing and enforcing an environmental
management plan.
INTERGOVERNMENTAL RESPONSIBILITIES IN PREPARING AN ENVIRONMENTAL
MANAGEMENT PLAN
The question of the appropriate governmental framework to provide for
the required environmental analysis, policy setting and implementation
raises some complex issues. The framework must be adjusted to the
VIII-7
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existing governmental institutions in the particular state and region
and the state and local laws that guide land use and environmental
planning. It is therefore difficult in this study to specify a de-
tailed institutional framework that would fit the needs of all areas
in the country. Therefore, the following recommendations will present
a generalized outline of the different jurisdictional levels concerned
with environmental planning and enforcement and will relate most
specifically to California and the San Francisco Bay region. The
recommendations may appear to be less useful to those states whose
regional or local planning laws and institutions are not as strong or
complex as those in California. The state authorities may have to
play a more direct role in both the planning and enforcement of
environmental management controls. However, the importance of the
recommendations is that it highlights the components of a cooperative
approach between the different levels of government in preparing the
plans and it provides the beginning of a more direct role that local
government can play in environmental management.
State Environmental Planning Requirements
The existing environmental management planning responsibilities of the
various State agencies provide for an effective planning program. The
only significant change required at the State level is a better system
for integrating their policies into a more cohesive set of State
comprehensive planning objectives. The improvement most needed in the
area of state level enforcement of environmental objectives is the
delegation of some permit issuance to the local level when proper
assurances can be made that state objectives will be effectively
implemented.
Planning Requirements. The existing State level planning responsi-
bilities have been discussed earlier and should continue to include:
1) making State plans consistent with federal environmental
objectives,
2) establishing more stringent State objectives when the
existing environmental conditions warrant it,
3) integrating with other State functional elements,
4) monitoring and evaluating the effectiveness of State and
regional policies, and
5) establishing State and regional financial assistance prior-
ities in line with state objectives.
The State planning responsibility that requires the greatest attention
is the integration of the planning efforts of the various state agencies
The chapter on the existing State governmental structure indicates the
substantial influence the State Water Resources Control Board has in
VIII-8
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determining growth within a region. Similarly, the Department of
Transportation and Energy Resources Conservation and Development
Commission have a strong control on the location, size and timing of
basic regional service infrastructure. The method by which the in-
frastructure decisions are made or state financial priorities are set
requires a more comprehensive approach. This comprehensive planning
approach must provide guidance to regional and local government on the
earlier discussed issue of a basic level of governmental services
throughout the state versus the growth inducing effects of those
services. It must also provide the methods to resolve governmental
conflict when intra or inter-governmental policies work at cross-
purposes.
Plan Review and Enforcement Requirements. The existing roles of state
agencies in the review and enforcement of air and water quality plan-
ning objectives include: 1) establishing ambient air or water quality
standards, 2) establishing emission levels from point and mobile
sources, 3) setting expenditure priorities, 4) approving plans and
projects and 5) replacing or voiding the actions of regional, single,
purpose boards (e.g. air pollution control districts, regional water
quality control boards). In contrast to these enforcement powers is
the review authority of the Department of Fish and Game which reviews
and issues permits on individual development actions that take place
on or in a water body. It is this form of policy enforcement that is
duplicative of local policies and enforcement controls. This is a
case where local planning policies could be made consistent with the
policies of the California Fish and Wildlife Plan and the State
enforcement powers delegated to local government when there are
adequate guarantees of local staff capability. Direct state involve-
ment on local development decisions should be avoided unless the
subject matter is so complex that only a specialized form of admin-
istrative expertise is required.
Regional Environmental Planning Responsibilities
The regional responsibilities in environmental management planning are
to provide regional direction to state and federal objectives and to
describe the role local government should play in planning and enforcing
air and water quality objectives.
Planning Requirements. There are nine planning requirements that
regional governmental agencies should undertake:
1) making plans consistent with federal and state environmental
objectives,
2) integrating with other regional, functional plans,
3) establishing more stringent regulations than those of the
federal or state government if existing environmental con-
ditions warrant them,
VIII-9
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4) setting regional financial priorities on the use of state
and federal assistance,
5) monitoring the environmental conditions in evaluating the
effectiveness of planning policies,
6) describing the assimilative capacity of the region's sub-
basins
7) identifying population and employment level assumptions per
sub-basin.in line with assimilative capacity,
8) describing the land use control or capital expenditure
options available for local government, and
9) describing the regionwide spatial patterns of development
that might provide optimal air quality conditions.
The first five of these responsibilities need little explanation in
that they have been discussed above. The remaining responsibilities
do require some description.
A major means of meshing air and water quality planning is through the
allocation of future population and employment levels that can be
accommodated within the environmental quality standards established by
the federal and state legislation. The central task of this require-
ment would be the identification of each of the region's air basins
and watersheds and the evaluation of their assimilative capacity.
Beside establishing the general ranges of population and employment
appropriate for analysis at each sub-region, the regional body should
establish environmental performance criteria for each sub-region. The
performance standards would reflect acceptable levels of pollution
that could be emitted from a particular area. These pollution levels
would be associated with both locally and regionally established
beneficial uses that are to be protected. Implied in the setting of
performance criteria is that pollutant emissions could be variable,
based on the nature of activities that are desired near the emission
sources and the related consequences of such contaminants on other
sections of the region. For example, the total suspended solids
concentrations running off into the Petaluma River may be very low
when measured in nearby water permitting a wide variety of activities
at that point in the river. However, the total emissions or washoff
may have a considerable impact on the crab beds 15 kilometers down-
stream where the emissions reach the receiving waters and finally
settle. As a consequence, more stringent runoff measures would be
required in the City of Petaluma for the purpose of protecting region-
ally designated beneficial uses. Therefore, the performance standards
must reflect 1) the concentrations of pollutants that can be tolerated
by the population in nearby areas and 2) the total emissions that will
be transported and impact other areas in the region.
VIII-10
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These standards could be expressed both as ambient levels of pollution
that should not be exceeded and as effluent or emission limits for the
various types of pollutants which can be discharged into the air and
water of the sub-region during a given time period.
The primary utility of these standards, besides providing a means of
measuring goal achievement, would be to suggest to local government
the types of policy actions they could take to reduce the impacts of
existing or new development. For example, in an area with a severe
limit on the amount of total suspended solids permitted to enter local
water courses, local government would have to take steps to limit the
pollutant loadings carried by urban runoff. A variety of means are
available to do,this and it would be up to the local government to
choose those methods that would be most appropriate for its particular
circumstances. The regional body could develop an assistance program
to provide local governments with the specialized information and
expertise necessary to evaluate alternatives.
As pointed out earlier, establishing a particular regional or citywide
spatial pattern-to attain optimal air quality conditions presents some
perplexing issues. The modeling analysis projects that concentrated
residential and commercial development can lead to the worst alternative
in terms of population exposed to air quality conditions exceeding the
governmental standards. On the other hand, a concentrated pattern is
thought to be the best pattern for encouraging the use of mass transit
and the disuse of the car. This theory is based on the premise that
concentrated land use patterns 1) can make transit routes more avail-
able to a large number of people and 2) facilitate shorter trips
between home and work or shopping facilities. The importance of
shorter trip lengths is currently being questioned as to its impor-
tance to air quality.
Unfortunately, the usefulness of the Sonoma Study is that it raises
questions on spatial pattern and air pollution that need further
study and debate rather than providing conclusive evidence as to the
best spatial land use strategy.
Regional Review and Enforcement Requirements. The existing methods
for enforcing air and water measures at the regional level, including
1) issuance of discharge permits for sewage treatment plants or in-
dustries, 2) air pollutant emission permits for stationary sources, 3)
sewer hook-up moratoria 4) plan and project review by various regional
agencies, and 5) assistance in setting budget priorities provide
sufficient means of ensuring environmental quality.
Their main inadequacies are those discussed earlier including the lack
of integration and consistency of air and water quality objectives
with those of other agencies. Regional governmental agencies can
improve on the administration of these measures through a more focussed
review of plans and projects. The plan review can be directed through
the same mechanisms - e.g. A-95 reviews, environmental impact report
reviews - but greater attention needs to be placed on reviewing for
consistency of local plans and projects with regional objectives.
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The regional level of government can play a new role in environmental
management by providing an improved system of appeals to local and
regional decisions that are challenged as being inconsistent with
regional and local plans. A series of regional or sub-regional appeal
tribunals could relieve the court system of the potential burden of
determining planning implementation consistency. The tribunals could
also ensure that the actions of separate local or regional boards were
reviewed as a part of a whole rather than as separate or unrelated
events as is presently the case with the existing appeal boards.
Local Responsibilities
The basic role of local government, including cities and counties, is
the preparation of local planning approaches to implement the regional
and local environmental management strategies and to use their varied
land use controls powers and expenditure programs to carry out their
approaches.
Local Planning Requirements. Local planning departments and commissions
would be guided by the regionally determined population and employment
range assumptions and environmental performance criteria in preparing
their individualized approaches to attaining and maintaining air and
water quality objectives. Their planning would require local-scale
analysis of the air and water quality impacts of specific plans and
projects, with an emphasis on identifying the most appropriate mitiga-
ting measures. The local plans could enable higher population or
employment objectives if their approaches indicated a willingness and
capability of undertaking higher degrees of mitigation measures or
spatial organization to reduce pollution emission. Higher treatment
levels at the sewage treatment plants, increased bus service, or
shifting of housing or office densities to promote the use of mass
transit are such measures.
Local Enforcement Requirements. The local governmental units could be
encouraged to adopt ordinances and other plan implementation control
mechanisms that incorporate a combination of development guidance and
mitigation measures that would ensure compliance with the performance
standards set by the regional body.
In order to induce the local government to adopt the enforcement
devices, greater autonomy in air and water quality related matters
could be delegated. For example, those governments that adopt plans
and ordinances that are consistent with the regional strategy could
have regional review or permit requirements waived or reduced for some
classes of projects. They would also receive quicker or higher
priority use of state and federal assistance.
This increased role of local government in environmental planning will
place an added burden on existing staffs and budgets. To some cities
or counties, the additional costs will be worthwhile in that they will
ensure some local autonomy in policy planning and decision making.
Other municipalities may find that the added costs are prohibitive and
VIII-12
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the regional agencies will need to provide an alternative for this
situation. Regional staff assistance and simplified policy and
ordinance packages should be available in such circumstances.
SUMMARY
The recommendations contained in this chapter provide the basis for
the more detailed organization that is required in preparing a re-
gional environmental management plan and in establishing the govern-
mental structure for its implementation. Arrangements among different
departments or jurisdictions require a highly individualized approach
based on the nature of the existing institutions. The logic behind
each of the recommendations may require more localized and extensive
justification to convince the policy makers of their rationale.
The findings and recommendations of the Sonoma Study are timely in
that they can assist regional planning agencies in directing their
present air quality maintenance and "208" planning efforts.
The conclusions on the linkages of land use, air quality and water
quality demonstrate that there are some mutual influences. Air and
water quality objectives need to be integrated through land use
controls by an environmental management strategy. Yet, the linkages
are less complex than initially anticipated and the influences of
other regional or community objectives such as transportation re-
quirements, housing preferences, energy conservation or agricultural
protection may play a more significant role in deciding the nature of
compromises that are necessary in developing the environmental manage-
ment plan.
Consequently, the governmental structure elements of a plan may require
considerably more attention than the selection of the proper urbaniza-
tion pattern or mitigation measure. Added emphasis given to developing
institutional cooperation will be an important key in the success of
developing an integrated environmental management program.
VIII-13
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APPENDIX A
Glossary
-------
APPENDIX A - GLOSSARY
air quality standard - The maximum concentration of a specified air
pollutant averaged over a specified time period (e.g., one hour, eight
hours, one day, a year) that may not be legally exceeded.
ambient air - That portion of the atmosphere, external to buildings,
to which the general public has access.
average daily traffic (ADT) - A term used to describe the average
number of vehicles passing a specified point on a roadway during a
24-hour period.
basic employment - Employment in industries that produce goods and
services mainly for export out of the County. In this study basic
employment includes agriculture, forestry, fisheries, mining; in-
dustrial - manufacturing, long distance transportation and wholesale
trade; and office - insurance carriers, holding companies, business
services and large Federal and State installations.
biochemical oxygen demand (BOD) - A measure of the consumption of
dissolved oxygen in water by the oxidation of organic materials. In
general terms, a high BOD suggests a water burdened with organic
wastes and thus likely to be deficient in oxygen and inhospitable for
most plant and animal life.
biostimulation - A water quality condition that promotes the growth of
aquatic plants.
carbon monoxide (CO) - A colorless, odorless, toxic gas produced by
the incomplete combustion of carbon-containing substances. One of the
major air pollutants, it is emitted in large quantities in the exhaust
of gasoline-powered vehicles.
central business district (CBD) - The primary center of economic
activity in a city; usually considered the "downtown" area.
coliforms - A large and varied group of bacteria. Fecal coliform
bacteria, commonly found in the intestines and feces of warm blooded
animals (including man), apparently does not cause disease, but its
presence in water suggests that disease causing organisms may be
present. Coliforms are used as indicators of pollution because they
are abundant and their presense is fairly easy to detect.
dissolved oxygen (DO) - The concentration of oxygen dissolved in water
(measured in mg/1). Non-living organic matter and various chemicals
react with oxygen in water, depleting its concentration and causing
stress (from lack of oxygen) on fish and other aquatic life. DO
saturation levels are greater in cold water than in warm, and at sea
level (high atmospheric pressure) than at high altitudes (low atmo-
spheric pressure).
A-l
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effluent - The liquid discharged by a sewage treatment plant or
industry.
emission factor - An estimate of the amount of a specified air pollu-
tant emitted from a source per unit time, or per unit of fuel consumed,
per unit of distance traveled (e.g., grams of CO per mile) or per some
other unit.
eutrophication - The condition in which a body of water is rich in
dissolved nutrients, frequently leading to the proliferation of algal
growth.
groundwater recharge area - The portion of a land surface through
which the groundwater receives its replenishment by the percolation of
water through the soil and intermediate zone.
groundwater - Subsurface water that fully saturates the pore spaces of
the rock in which it is located.
heavy metals - Metals that can be precipitated by hydrogen sulfide in
acid solution. For example, lead, silver, gold, mercury, and copper.
hectare - A metric unit of area equal to 10,000 square meters (.01
square kilometers, or 2.47 acres).
hydrocarbon - Any of a class of compounds containing only carbon and
hydrogen in various combinations, found especially in fossil fuels.
Some of the hydrocarbon compounds are major air pollutants. They may
be active participants in the photochemical process. They also may
be carcinogenic.
hydrograph - A graph of the flow in a stream during the time period of
a rainstorm.
hyetograph - A graph of rainfall intensity versus time during the
period of a storm.
inversion - The atmospheric condition in which a layer of warm air
overlays a layer of cooler air, thus preventing contaminants in the
bottom layer from dispersing into the upper air layer.
isopleth - A line on a map connecting points of equal value (e.g., an
equi-pollution contour).
leach field - A system of open pipes within covered trenches allowing
the effluent from a septic tank to enter the surrounding soil.
link - A specified stretch of roadway (e.g., U. S. 101 from Todd Road
to Hearn Avenue).
link loading - The average number of vehicles per day on a link of a
transportation network.
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local-serving employment - Employment in those businesses that serve
the population. In this study, local-serving employment includes
retail trade and services; local finance, insurance and real estate;
local government; and construction, transportation, communication and
utilities.
low flow - The period, during the course of a year, when the flow in a
stream is at a minimum. In California, low flow usually occurs in
late summer or early fall, at the end of the dry season.
NH3 - Ammonia (see "total nitrogen").
NHg-N - The amount of ammonia expressed as equivalent nitrogen.
NOg - Nitrite (see "total nitrogen").
NO~-N - The amount of nitrite expressed as equivalent nitrogen.
NOj - Nitrate (see "total nitrogen").
NO ~N - The amount of nitrate expressed as equivalent nitrogen.
0
nonpoint source (air pollution) - A term used to describe air pollutant
emissions from groups of minor stationary sources, such as furnaces in
private homes and small commercial establishments. Also referred to
as "area source."
nonppint source (water pollution) - A term used to describe the con-
tribution of water pollutants from sources that do not emanate from
pipes or other man-made conduits. Examples of non-point sources are
runoff from agricultural land, runoff from urbanized land and runoff
from slopes that have been logged.
non-sett!eable solids - That matter in wastewater that will stay in
suspension during a pre-selected settling period.
nutrients - Substances or ingredients essential to biological growth.
oxidant - A major air pollutant, primarily consisting of ozone with
small quantities of nitrogen dioxide and peroxyacetylnitrate (PAN),
formed by a photochemical process between hydrocarbons and oxides of
nitrogen..
particulates - Particles of solid or liquid matter, usually suspended
in the air: dust, soot, ashes, aerosols, mists.
photochemical process - The chemical changes brought about by the
radiant energy of the sun acting on various polluting substances in
the atmosphere; the process by which oxidant is created.
PO. - Orthophosphate, a hydrolyzed form of inorganic phosphate (see
"tQtal phosphorus").
A-3
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P04-P - The amount of orthophosphate expressed as equivalent phosphorus.
point source - A discrete place of object (such as a smokestack or out-
fall from a sewage treatment plant) from which relatively large quanti- >
ties of air or water pollutants are emitted.
pollutant loading - An estimation of the amount of a given pollutant
washing off a land surface of a given type, usually after a rainfall.
primary treatment - A series of mechanical treatment processes, in-
cluding screening, skimming and sedimentation, that remove most of the
floating and suspended solids found in sewage, but that have a limited
effect on colloidal and dissolved material. y1
. -' „' •• '•
reach - A stream segment, used in the model QUAL-II, comprised of
several elements with homogeneous hydraulic properties. ;
•i '•
receiving water - A natural watercourse, lake or ocean into which
treated or untreated wastewater is discharged.
recession limb - The falling portion of a hydrograph in which water is
being withdrawn from storage in the drainage area. ;
recurrence interval - A term referring to the frequency and intensity
of storm. A storm with a 100-year recurrence interval has a 1% chance
of occurring in any given year. , ? ,
retention storage - The temporary storage of stormwater runoff in a
device such as a pond or basin.
secondary treatment - A series of biochemical (trickling filters or
activated sludge), chemical (coagulation), and/or mechanical (sedi-
mentation) treatment processes, that remove, oxidize, or stabilize
non-sett!eable, colloidal and dissolved organic materials found in
sewage, following primary treatment.
stationary source - A non-vehicular source of air pollutants, such as
a smokestack or chimney.
sub-area - A watershed of a small stream or creek or a portion thereof;
the smallest unit of analysis in water modeling, defined using the
criteria of homogeneous slope, homogeneous land use (hydraulic roughness),
and uniform width, measured perpendicular to the direction of flow.
sulfur oxides - Pungent, colorless gases formed primarily by the
combustion of fossil fuels. Considered major air pollutants, they may
damage the respiratory tract as well as vegetation.
tertiary treatment - Any sewage purification process that has the
capability to remove over 98 percent of the pollutants from sewage,
following secondary treatment.
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total nitrogen - The total amount of the element nitrogen, a principal
nutrient required for biological growth, in all Its chemical forms.
Four forms of nitrogen are of main Interest in water quality manage-
ment. These are ammonia, nitrite, nitrate, and various compounds of
organically-bound nitrogen. These forms are all normalized and ex-
pressed as total nitrogen.
total phosphorus - The total amount of the element phosphorus, a
principal nutrient required for biological growth, in all its chemical
forms. Phosphorus may exist in wastewater as ortho, poly, and organic
phosphorus.
total suspended solids - All particulate matter in a water sample that
1s removable by laboratory filtering.
vehicle kilometers traveled (VKT) - A measure of the total amount of
motor vehicle usage on a specified stretch of roadway or in a specified
area (the metric equivalent of VMT).
"201" - Refers to Section 201 of the Federal Water Pollution Control
Act Amendments of 1972 (PL 92-500). Section 201 calls for detailed
planning for the wastewater treatment facilities needed to achieve the
goals of the Act.
"208" - Refers to Section 208 of the Federal Water Pollution Control
Act Amendments of 1972 (PL 92-500). Section 208 provides for the
designation of state and areawide agencies for the purpose of devel-
oping effective water quality management plans for areas that, be-
cause of "urban-industrial concentrations" or other factors, have
"substantial water quality control problems." The approach is aimed
at integrating controls over municipal and industrial wastewater,
storm sewer runoff, nonpoint source pollutants and land use.
A-5
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APPENDIX B
Technical Description of the
Land Use Allocation System
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APPENDIX B - TECHNICAL DESCRIPTION OF THE LAND USE ALLOCATION SYSTEM
REQUIRED CHARACTERISTICS OF THE LA^D USE INFORMATION SYSTEM
The selection of a land use information system for the study demanded
careful attention because of its relationship to the analytical require-
ments of the air and water quality models. The land use information system
had to satisfy three key elements:
1) capable of bejng used by the various air and water models,
2) capable of being used in the predictive methods used in allocating
future land uses and
3) capable of being related to the existing county and city land use
systems in Sonoma County such that the study findings could be
transferable.
The most important of the three elements was its adaptability to air and
water quality modeling requirements. From the air modeling perspective,
the land use system had to provide for the model variables used in distri-
buting area and mobile emission sources. Area sources were distributed
according to the population in £he residential land uses. (They could also
have been distributed by employment in the industrial and commercial land
uses.) Mobile emissions were determined as a function of the average daily
traffic (ADT) on the road network. The ADT was projected using traditional
but somewhat dated transportation modeling variables of "productions" and
"attractions" of various land uses. Planning agencies wishing to conduct
similar analysis should recognize that transportation modeling is contin-
uously in a state of change and improvement. Recent transportation models
have been developed that are more sensitive to such variables as structure
of household, family size, accessibility functions (time and costs) and
auto availability. Therefore, any new program aimed improving on the
Sonoma Study should give particularly attention to reviewing new trans-
portation models and should consider adapting their land use classification
systems to the needs of those new models.
In relationship to surface runoff model needs, the principle importance of
the land use information system is its adaptability to the impervious
surface and pollutant loading descriptions. A key consideration is how
precise the land use classification must be with respect to model require-
ments. Because information on pollutant loading is no more refined than
such basic land use categories as residential, industrial or commercial
(Mater Pollution Aspects of Street Surface Contaminants, Sartor and Boyd,
1972), greater detail in the classification system is not warranted.
Similarly, the information on impervious surface characteristics, because
the model generalizes it for a wide geographic area, requires only a simple
classification system. Furthermore, the surface runoff model does not
require a system that provides for a high level of spatial resolution. The
model adds all the land use categories within a hydrologic sub-area and
computes for a total sub-area impervious surface factor or a total pollu-
tant load for all land uses. Therefore, a land use classification system
that provides for great resolution is not required.
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The steps to be learned from the study in developing or adapting a land use
classification system for air or water quality modeling are:
1) determine the governmental policies that are to be investigated
2) determine the capability of the various air and water models to
assess the effectiveness of the policies and
3) determine the characteristics of the land use classification
necessary as inputs to the models. r :
Future planning efforts should avoid selecting land use information systems
that require great spatial resolution or highly detailed land use categories
when they are not warranted for the water or air quality models unless, of
course, the systems can and will be used for other planning purposes.
REVIEW OF ALTERNATIVE METHODS FOR ALLOCATING GROWTH
Several methods for allocating future residential, commercial and industrial
growth were reviewed at the outset of the study. It was initially decided
to use a computerized system for allocating future land uses because of the
extremely large amount of information to be evaluated. The following land
use projection and allocation techniques were examined:
1. PLUM (Protective Land Use Model)
The PLUM model distributes future population and basic and local
service employment into subregional zones and computes accompany-
ing land use changes. It was developed by ABAG and the Metropol-
itan Transportation Commission (MTC) and has been used in the Bay
Area Simulation Study, the Bay Area Transportation Study and as
part of ABAG's ongoing regional projections program.
2. ZAP (Zonal Allocation Procedures)
ZAP is a series of programs that allocate broad-area projections
to smaller sub-units. Developed by Peat, Warwick and Mitchell,
it is used in conjunction with EMPIRIC, an equivalent to PLUM.
ZAP has been applied to several areas of country including
Atlanta, Central Puget Sound, Washington, D.C. and Denver.
3. DYLAM/Lakewood
DYLAM/Lakewood is designed to allocate land uses based on the
"attributes" of each sub-regional measurement units and the
relative desirability of this "attributes" to each land use. It
projects land uses for each of approximately 1,000 40-acre grid
cells. The City of Lakewood, Colorado in conjunction with Parsons,
Brinckerhoff, Quade and Douglas, developed this model.
4. Modification of PLUM
The modification of the PLUM model to include some of the same
attractiveness factors as the DYLAM/Lakewood was also considered.
B-2
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The attractiveness factors considered were: travel to employment
centers, distance to major roads, presence of sewer system and
other infrastructure, distance to service areas and presence of
usual or recreational amenties.
All of the above methods for allocating growth were finally considered too
complex or costly for the purposes of the study. Instead, future residential,
commercial and industrial growth were allocated by locating the appropriate
land areas needed for projected development according to the land use
patterns established by the existing general plans of the cities in Sonoma
County. The following sections of this appendix will describe the steps in
that allocation process.
STEPS IN ALLOCATING FUTURE GROWTH
A seven step process was used for allocating future land use in Sonoma
County. The end product of this process was distributed land uses, associ-
ated with projected population and employment, in a manner compatible with
the air and water quality simulation models.
Step One - Determine Population and Employment Projections for the County
The Sonoma County Advanced Planning Department, as part of the General Plan
preparation effort, had population and employment projections made per
census tracts for two year 2000 population levels. These projections are
contained in Baseline and Gronorth Projections, University Research Center,
July, 1974.
The total county population figures of 478,000 and 630,000, both for the
year 2000, were used in the study. The California State Department of
Finance (DOF) projection figure of 478,000 people served as one level.
This figure is derived from the DOF-100 series which is a population
projection model (cohort survival) using a non-constant growth rate ranging
from 4.0% to 1.7% between 1975 and 2000. The second population level of
630,000 is derived from ABAG's Regional Plan gronorth assumptions whereby
there is a shift of population ana employment towards the North Bay Area.
The population growth rate varies between 4.3% and 2.6% between 1975 and
2000.
The number of residents in the labor force was next determined by multiplying
a labor force participation rate by the different total population levels.
An assumed number of unemployed are subtracted to obtain the number of
employed residents. Adjustments were also made for both in-commuters and
out-commuters. Finally, total employment was broken down according to
different industrial categories including "basic employment" (e.g. agri-
culture, manufacturing, basic finance or insurance) and "non-basic" or
"population-serving" (e.g. retail services, local finance, construction).
The output of this first step was total population and employment by
industrial category that could be distributed to the various cities or
unincorporated areas of the county in a manner consistent with the study's
hypothetical development patterns.
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Step Two - Select the Land Use Categories
Ten land use categories — low density residential, medium density
residential, high density residential, centered commercial, suburban
commercial, industrial, grazing/open, orchard and vineyard agriculture,
truck crop and field crop agriculture and wetlands — were selected because
they approximated the categories used by the various planning agencies in
the county and they fit the needs of the simulation models.
Of particular importance to the selection of the land use categories was
their similarity to the land use categories used in the basic surface
runoff research on both pollutant loading rates and impervious surface
coverage. For example, the two commercial categories -- centered and
suburban ~ were selected to permit a lower percentage impervious coverage
for suburban shopping centers, which have an opportunity to cover less of
their development areas than do their downtown counterparts.
One improvement that should be considered in future studies is a wider
range of low density residential categories. The impervious surface
characteristics can change as much as 50% between 10.8 dwelling units
(d.u.) per hectare (5 d.u. per acre) and 6.5 d.u. per hectare (3 d.u. per
acre). Similarly, the impervious surface coverage in older residential
neighborhoods is about 10-15% lower than that for the new residential
neighborhoods. Therefore, the land use categories should be carefully
selected to reflect variables tested in the water quality models.
Step Three - Translate Population and Employment into Land Use
The third step was to transform the county population and employment totals
into hectares of land use for the categories established in Step 2. An
initial step in developing the amount of residential hectares was to divide
a 2.5 persons per dwelling unit factor into the total population to get
the number of future dwelling units in the county. The 2.5 factor was
used in the study to maintain consistency with the county planning program.
However, it would have been preferable to have varied a person per unit
rate for each housing density to better approximate current or anticipated
conditions.
A density average of 12.3 d.u. hectare (5. d.u. per acre) was assigned to
the low density class because it approximates the gross density resulting
from 6,000 square foot lots — the present minimum single family lot size
for much of the county. While the present average density of single family,
dwelling units in Sonoma County cities is probably lower than 10.8 d.u. per
hectare, the trend is toward higher densities. A high percentage of new
single family subdivision developments have been built at this higher density
in recent years.
The medium density class was assigned a density of 36.9 d.u. per hectare
(15 d.u. per acre) because it represented an average density for the
multi-family dwelling units being constructed currently in the county.
Structural types in this category represent a range from 2 story townhouses
with a high floor area ratio to 2 and 3 story apartments with moderate
to low floor area ratio.
B-4
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The high density category was assigned a density of 78.7 d.u. per hectare
(32 d.u. per acre) for the following reasons:
1) it was the highest density obtainable in three story apartment
units;
2) it represented a flexible range in multi-family structural
types - from three story walk-ups to four, five, and six story
apratment buildings with respectively lower floor area ratios; and
3) it was determined from initial calculations that a very high
level density class would be necessary to accommodate the popu-
lation growth in the cities without unreasonably expanding their
boundaries or making the spacial patterns among the various
development alternatives too similar.
The process of translating employment to land use required first the
correlation of the various industrial employment categories to their
comparable commercial and industrial land use classifications. This was
achieved simply by allocating to the commercial land use category those
"basic" or "local serving" employees most likely to be located in offices
or stores. For example, employment in "basic" finance and insurance and
"local serving" banking was assumed to be located in commercial land uses.
The amounts of land used by either the industrial or commercial land use
categories were then derived by the use of an employee per hectare factor
determined for each category. These factors were developed from:
1) the 1970 Federal Highway Administration report by Edward A. Ide,
Estimating Land Use and Floor Area Implicit in Employment
Projections, (Federal Highway Administration, July, 1970) Table
2.1, pp. 11-13 to 11-17 and
2) the comparisions of Sonoma County's 1971 land use inventory to
the 1970 Census of Employment.
The factors were adjusted according to the density configurations desired
for a particular growth pattern tested in the study or to particular
industrial activities for which the single factor was inappropriate. The
commercial employee per hectare factors ranged from 314.8 employees per
hectare (145 employees/acre) in suburban commercial locations. The in-
dustrial factors ranged from 43.4 employees per hectare (20 employees/acre)
for more labor intensive industrial categories to 26.1 employees per hectare
(12 employee/acre) for less intensive industries such as transportation or
storage.
Step Four - Designate Land Unsuitable for Development
A number of geographical sections of the County within the study area were
determined to be unsuitable for urban development. The criteria used for
defining such areas were those areas with slopes greater than 30% and
existing park land. Other criteria were considered including land
within a flood plain and land outside a sewer district. These were
dropped because the existing local policies do not uniformly preclude .
development in those areas.
B-5
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Step Five - Determine Intent of Each Growth Alternative
The fifth step was to determine the land use allocation assumptions to be
used in each growth alternative. The purpose of these assumptions was to
provide a method by which the countywide land use category totals could be
allocated to the cities in the study area. The desired growth patterns are
described in Chapter V.
The assumptions included:
1) the relative size of the various cities to the total county
population, e.g., 80% of the County's population will be urban;
50% of the total County population will live in Santa Rosa, 25%
in Petaluma, etc.
2) the residential density configurations within each city, e.g.,
10% will be high density, 40% medium and 50% low.
3) the location of residential development, e.g., all of the high
density development will be located in general plan, high density
category that is most centrally located.
4) the relative size of employment in the various cities to the
total county employment, e.g., 70% of "basic" commercial will
be located in Santa Rosa; 60% of "non-basic" commercial and
industrial will be located in Santa Rosa.
5) the location and density of the different commercial and industrial
categories, e.g., 100% of "basic" commercial at 314.8 employees
per hectare will be located in the center of Santa Rosa; 50% of
"local-serving" commercial at 130.3 employees per hectare will be
located at the suburban or fringe commercial districts of Santa
Rosa.
Step Six - Allocate Land Use to Each Grid Cell
Based on the allocation assumptions established in Step 5 and the required
number of hectares for each land use category as established in Step 3, it
was next possible to calculate the land use categories for each city and
locate them according to the development pattern established by the various
general plans. When the general plans were not consistent with the study
allocation assumptions, the study assumptions predominated. Next the one
kilometer grid pattern was laid over the allocated land uses and the per-
centage of each land use category per grid cell was determined.
Step Seven - Translate the Land Use Information Per Grid Cell to a Computer
Format
The final step in the land use allocation process was to translate the
percentage of each land use per grid cell into a computer format useable by
both the air and water model. The computerized data from all the grid
cells was tabulated for the study area to verify that it conformed with the
initial county population and employment control totals.
B-6
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APPENDIX C
Technical Description of the Modeling
System for Non-reactive Air Pollutants
and
Meteorology and Air Quality in Sonoma County
(Modeling Input and Calibration)
-------
APPENDIX C
PART I - DESCRIPTION OF MODELING TECHNIQUES
MODELING PHILOSOPHY
The BAAPCD modeling techniques are designed to address a variety of
considerations. First, they are designed to provide answers to the
questions most frequently asked by local and regional planning
agencies including air quality impacts of various projects that are
being evaluated. Secondly, the modeling techniques consider the
more general regional, nature of the air pollution problem and the
relationship of primary air quality standards to the pollutant con-
centrations throughout the various geographical sectors of the San
Francisco Bay Area. On the basis of these considerations, the
modeling approach was developed with the following characteristics:
1. It should consider the contributions from all sources,
local as well as regional and background.
2. While regional in nature, it should have the capacity of
resolving the impacts of local sources.
3. It should provide information on transport of pollutants
from remote sources.
4. It should provide the basis for statistical estimates of
the probability of exceeding air quality standards.
5. It should reflect an ambient impact in keeping with the
mobility of the population and the resolution limitations
of modeling techniqes.
To meet these requirements, a regional, climatological, gaussian
dispersion model was developed and coupled with a statistical con-
centration frequency estimation model. The dispersion model was
split into two separate sub-models: a regional, low resolution
sub-model and a local high resolution sub-model. The complete
model was designed to yield the following information on a resolu-
tion of one square kilometer:
1. The annual arithmetic mean concentration for each con-
taminant.
2. The number of times per year an air quality standard is
violated.
3. The portion of the problem derived from local sources
versus the portion imported from outside the immediate
study area.
C-l
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Use of a climatological model on an area averaged basis has the effect
of smoothing or averaging out the large random error fluctuations in-
herent in short term, point by point modeling applications. Residual
error in the climatological model (which can with care be reduced to
20% or less of the true climatological average) is amendable to
further reduction through model calibration, if a long-term record of
contaminant and meteorological data is available. The same data
record may be used as the basis for a statistical recovery of spatial
and temporal detail lost in the climatological smoothing process. The
output is a modeled probability distribution of contaminant concen- -
trations which is a function of local and regional climatology and any
assumed geographical distribution of emissions. The form of the
output is quite useful for planning and design applications.
MODEL DETAIL
The Dispersion Model
In modeling dispersion for a large, complex region such as the San
Francisco Bay Area, it is useful to conduct simulations for different
geographic scale. This can be done on the basis of various dispersion-
transport scales and source categories, thus allowing for flexibility
in the choice of modeling techniques for the individual modules and
facilitating the separation of output concentrations into component
contributions. In constructing the Bay Area Planning Model, two
scales of dispersion-transport were considered: a "regional" scale
with a coarse resolution on the order of several hundred square
kilometers (county size) and a "local" scale with a much finer resolu-
tion on the order of one square kilometer. A different modeling
approach was used on each scale.
Regional Scale Sub-Model. In the regional case, it is assumed that
contaminants, after travel distances of tens of kilometers or more,
are quite thoroughly mixed vertically and horizontally, and their
concentrations appear as background to any strong local sources. On
the regional scale, therefore, where a large percentage of the area is
source-free open space, a box model with uniform volume mixing is a
resasonable model for estimating average county scale concentrations.
Regional transport conforms to a streamline pattern influenced by
prominent terrain features. A climatological set of such patterns was
developed for the San Francisco Bay Area by Clarence Smalley (1957)
and is ideal for the climatological modeling of regional transport.
In constructing the regional scale sub-model, resoultion is limited to
the individual counties comprising the BAAPCD because emissions inven-
tory data are currently prepared annually for each county with no
finer resolution available. A "box" is defined for each county by
extending a vertical plane, originating at the county political
boundary, between the sea level surface and the climatological average
of inversion base height as determied from Radiosonde ascents at
Oakland International Airport. The effect of hills or mountains is
accounted for by reducing the source area volume in each box by the
amount that is displaced by the irregular terrain. The dilution
C-2
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effect of wind flow through each box is accounted for in terms of
residence time computed'as the dimension along the principal stream-
line through the county, divided by the mean annual county wind speed.
Resultant values of adjusted source area (Ae), inversion base height
(H) and residence time (R) are given in Table C-l.
Transport from county to county through complex terrain is handled in
terms of Smalley patterns mentioned above (Figure C-l and Table C-3).
From each of the patterns, a subjective estimation is made for each
county box of the relative contribution of upwind boxes to the im-
ported background concentration. These relative contributions for
each Smalley pattern are then multiplied by the annual recurrence
frequencies of the patterns to obtain a set of annual average con-
tribution weighting factors as given in Table C-2.
Table C-l
COUNTY BOX MODEL PARAMETERS
ALAMEDA
CONTRA COSTA
MARIN
SAN FRANCISCO
SAN MATEO
SANTA CLARA
NAPA
SONOMA
SOLANO
DISTRICT
(meters2 x 109)
1.71
0.95
0.90
0.22
1.03
1.31
1.04
1.28
0.94
9.38
H
(meters)
457
457
457
457
457
457
457
457
457
457
R
(days)
0.25
0.18
0.20
0.04
0.12
0.33
0.14
0.35
0.14
0.50
In applying the regional model, a computation of contaminant concen-
tration is first made for each county box using the formula:
Where
C = ER
(1)
C = annual averaged box concentration
E = annual box emission rate
R = annual averaged residence time
Ae = adjusted source area
H = annual averaged inversion base height
C-3
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Table C-2
COUNTY WEIGHTS FOR TERRAIN ADJUSTED BOX MODEL ADVECTION
o
Alameda
Contra
Costa
San
Francisco
San
Mateo
Santa
Clara
Napa
Sonoma
Solano
Alameda
1.00
0.09
0.00
0.03
0.40
0.05
0.02
0.07
Contra
Costa
0.08
1.00
0.04
0.04
0.02
0.13
0.02
0.16
Mar in
0.06
0.24
0.03
0.02
0.02
0.46
0.36
0.35
San
Fran.
0.32
0.24
1.00
0.11
0.20
0.20
0.04
0.10
San
Mateo
0.19
0.03
0.09
1.00
0.37
0
0.03
0.02
Santa
Clara
0.15
0.05
0.09
0.12
1.00
0.04
0.02
0.06
Napa
0.01
0.04
0.00
0.00
0.01
1.00
0.02
0.35
Son-
oma
0.01
0.04
0.01
0.00
0.01
0.36
1.00
0.34
Solano
0.01
0.08
0.05
0.00
0.02
0.07
0.02
1.00
Total concen-
tration for a
county is
obtained by
multiplying
County Box
Model concen-
trations by
the weighting
factors 1n the
table and summing
across a receptor
row.
Weighting factors
were obtained by
analysis of Smalley
Flow Patterns to
arrive at an esti-
mate of advective
contribution from
out of County
sources.
Weighting factors represent the fraction of the time that a receptor in a county at the left would
receive a, pollutant contribution from sources in a county at the top.
-------
Figure C-l
a. Typical wind •Flow patterns in the San Francisco Bay Area
b. Surface streamline analysis for the afternoon of 15 August 1962
C-5
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Table C'-3
Percent monthly occurrence of typical wind flow patterns (1952-1955)
Pattern
type Jan Feb
A 1.2 1.4
B 6.4 5.6
C 3.6 9.0
D 8.1 3.4
E 2.4 3.1
F 0.2 0.5
G 13.2 4.3
H 5.9 3.6
I 5.3 1.6
J 0.4 0.5
K 0.1 0.2
L 0.6 1.8
M 0.2 0.7 .
N . 3.5 2.1
O 7.3 5.5
P 1.0 2.7
Q 3.4 8.3
R 1.8 5.0
S 1.2 3.6
T 0.2 0.9
"LV&UC 33.7 36.1
March
0.0
1.6
8.1
0.8
2.9
0.6
7.0
2.6
2.2
0.8
1.6
1.6
4.0
7.1
7.4
3.8
7.2
8.9
9.7
1.0
20.9
April
0.0
1.0
2.3
0.2
0.2
1.3
2.7
2.7
3.1
2.1
1.9
5.4
6.0
5.0
7.4
5.0
8.6
11.3
12.7
2.7
18.5
May
0.0
0.2
1.8
0.0
0.2
0.6
0.0
0.8
1.0
1.8
0.2
6.3
7.9
9.7
5.0
7.5
11.9
12.3
14.7
1.6
16.5
June
0.0
0.0
0.6
0.8
0.0
2.5
0.0
1.0
1.0
3.3
0.6
5.4
13.3
7.8
5.7
9.2
3.8
11.3
24.2
1.0
8.4
Month
July
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.0
0.0
3.6
1.0
19.7
14.9
5.8
2.2
4.8
1.4
13.5
23.1
1.4
8.5
Aug
0.0
0.2
0.0
0.0
0.0
1.2
0.6
0.4
0.8
2.1
1.0
17.6
16.0
9.0
4.9
3.7
1.7
15.3
18.3
1.7
5.4
Sept
0.0
0.2
0.4
0.2
0.0
1.2
0.2
0.6
1.7
6.2
0.6
9.8
10.4
6.2
3.5
7.5
2.9
9.6
14.1
0.0
22.9
Oct
0.8
1.2
4.8
0.2
0.4
2.0
0.2
1.0
3.0
2.9
1.2
4.9
8.9
3.4
2.4
7.5
7.7
7.5
4.3
2.0
33.9
Nov
1.2
2.9
3.7
2.8
0.7
0.2
8.1
1.5
2.1
0.2
0.0
1.0
1.6
2.9
2.4
1.4
7.6
1.5
1.9
0.9
55.3
Dec
3.2
7.2
3.4
8.6
4.0
0.2
17.6
5.0
1.8
0.0
0.0
0.4
0.8
2.2
3.2
0.2
8.1
2.2
2.4
0.4
28.9
Yearly
Avg.
0.7
2.3
3.1
2.2
1.1
0.9
4.6
2.1,
2.0
2.0
0.7
6.2
7.0
5.6
4.2
4.5
6.0
8.3
10.7
1.1
24.6
*LV - light and variable
UC = unclassified
-------
The resulting concentration may be construed as a "county background"
concentration due solely to sources within the county and does not
apply to locations within a kilometer or so of any strong local source.
By applying the weighting factors of Table C-2 to the individual county
box concentrations obtained through equation (1), contributions from
other counties may be added to produce an estimate of background from
all San Francisco Bay Area sources on a county by county basis. While
such estimates are crude, they are quite useful in indicating the
relative impact of various sections of the Bay Area upon local concen-
trations. Source categorization is relatively unimportant on the
regional scale because surface, elevated, point, line and area sources
are all quite thoroughly mixed over the long average travel distances
involved.
Local Scale Sub-Model. On the local scale, modeling detail becomes
much more important and the choice of modeling technique depends upon
the source category being modeled. For the most part, urbanized
locales consist of clusters of small stationary sources and networks
of line sources (streets and highways). In those locales where heavy
industry is located, the large stationary sources should be considered
as a separate category. In approaching the local area source problem,
the two mechanisms of dispersion and transport again come into play.
If emissions are assumed horizontally uniform within a local source
area, dispersion will take place almost exclusively in the vertical.
The extent to which locally produced pollutants are dispersed will be
determined by the wind speed, the balance between turbulent transport
and emission rates and the duration of the dispersal mechanism or
travel time within the local source area. Under a undirectional wind
regime, downwind concentrations will be higher than upwind concentra-
tions as the result of superposition. On an annual averaged basis,
several directions are involved and concentrations would be expected
to be distributed with much less directional bias. The local area
source problem is similar to the regional box model problem with one
additional level of sophistication: in the regional case, pollutants
are assumed to be distributed uniformly both horizontally and verti-
cally. In the local case, horizontal uniformity is still assumed
within the source area, but because of the smaller average distance
between source and receptor points within the source area, complete
mixing in the vertical cannot be assumed as an average condition. A
concentration profile must therefore be assumed in the vertical.
Two basic methods are traditionally employed in modeling the vertical
(and horizontal) distributions of contaminants. One is to solve the
diffusion equations employing diffusivity coefficients related to
terrain and meteorology on the basis of boundary layer similarity
theory. The other is to assume the steady state gaussian plume model
with normal plume concentration deviation parameters derived empirically
and related to meteorological factors alone. Both of these approaches
work best when applied on an infinite plane, with uniform meteorological
conditions and a uniform terrain. When applied to urban areas, partic-
ularly in complex terrain, both of these methods require the judicious
use of adjustment parameters. The gaussian method has the principal
advantage of requiring less extensive computational requirements that
C-7
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lend themselves readily to simplification. The steady state assump-
tion, characteristic of gaussian modeling, while considered a drawback
in episode modeling, is quite appropriate in climatological modeling
of the type required for the study. After considering the various
alternatives it was decided to employ the gaussian method in develop-
ing the local scale sub-model.
The local scale sub-model is run on a computational grid with a one-
kilometer mesh size. The grid size is variable but is no larger
than an area that can reasonably be assumed to be represented meteor-
ologically, on an annual averaged basis, by observations at a single
site. Choice of grid. location is such that terrain features will not
unduly interact with transport throughout the grid. Since most of the
densely developed areas throughout the Bay Area are areas of locally
level terrain, and are character ize'd locally by relatively uniform low
profile construction and vegetation, the local sub-model is applicable
to a large percentage of the urbanized Bay Area. In hilly or moun-
tainous areas, areas with rapid horizontal gradients of meteorological
parameters, or areas with large non-uniform structure profiles, such
as downtown San Francisco, the usefulness of the model is doubtful,
and special methods must be employed. The Sonoma study area, fortu-
nately, has reasonably level terrain.
Computation on the local grid proceeds in two distinct steps. First
of all, the average annual concentration is obtained for each in-
dividual 1-kilometer grid square considering only those sources
located within that grid square. In doing this, emissions from all
sources within the grid square are totalled, and an area source strength
is computed in units of mass per unit area per unit time. Average
contaminant concentration in the grid square is then computed by the
formula
1/2 I V a dXdX
.
Q Q o(X) (2)
where C is the average grid square concentration
Qa is the grid square source strength per unit area
L is the grid mesh size (1 kilometer)
U is the wind speed
and °z(x) is the plume standard deviation as a function of downwind
distance, X. The quantity (e) is an offset distance used to account
for initial mixing at volume sources. Formula (2) is simply the
double integration of the gaussian line source model over the length
of a grid square, once to obtain the concentration as a function of
downwind distance, X1, and once to average all downwind concentrations
over the grid square. The quantity 0Z(X) over a 1 kilometer distance
is closely approximated in the form:
az(X) = aXb (3)
C-8
-------
where a and b are constants whose values have been determined empiri-
cally for various meteorological conditions. In the Bay Area model,
the annual average dispersion is computed by using a weighted average
value of oz in the form:
az= 0.75 ad + 0.25 an (4)
where a. = 0.133 x 0.91 (daytime-evening)
and an 0.094 x 0.79 (early morning)
The second step in the grid computation involves the interaction
between grid squares as pollutants are transported by the wind. As a
pollutant cloud leaves a grid square and continues on its way, dis-
persion continues vertically, but horizontal dispersion takes on
greater importance as travel distance increases due to erosion at the
edges of the initially (assumed) uniform cloud. When considering the
contribution from an upwind grid square, on an annual average basis,
the horizontal and veritical dispersion as well as the directional
frequency of wind must be taken into account. This was done in the
Bay Area Model by considering upwind grid squares as point sources
located at the grid square centers. Emissions are then assumed to
diffuse downwind as a plume with gaussian distribution in the vertical,
and a uniform distribution crosswind within the angular confines of a
single wind rose sector. With this rationale, the annual average
contribution to the concentration in any downwind grid square, i, from
sources in any upwind grid square, j, may be computed as:
Ci = 2Q.jN (5)
J (2w) 3/2 oz UX
where
Q is the point source strength in terms of mass per unit time, N is
the number of wind rose sectors and X is the distance between centers
of the source and receptor grid squares. The total contribution, on
the annual average, from all upwind elements is obtained for each
receptor grid square by summing over all upwind elements and all wind
rose secdtors, weighting each sector by the annual frequency of occur-
rence of its direction. Finally, the concentration components in each
grid square, from its own sources and from upwind sources, are combined
with the regional scale background and any assumed global or natural
background to yield the total local scale annual average concentra-
tion. To avoid duplication, the county scale background is computed
after subtracting emissions associated with the local scale grid.
Because of the modular approach used in the model, it is easy to
output the individual component concentrations so that the relative
contributions of various segments of the local and regional source
area may be assessed.
The Statistical Model
This section discusses the application of a statistical model developed
by Dr. Ralph Larsen (1971) of EPA. The research by Larsen has established
C-9
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the lognormal distribution as a workable assumption for the distri-
bution of contaminant concentration data. Larsen has further demon-
strated that the dependence of the lognormal statistics on averaging
time is described in a simple analytic form. These results enable,
through a simple, semi-empirical technique, the combining of output
from the climatological model with statistics derived from our air
monitoring network to produce the necessary statistical information
most useful in land use planning applications.
Model Characteristics
In a lognormal distribution as assumed by Larsen, the logarithms of
observed pollutant concentrations have a normal or gaussian distri-
bution. We may therefore define a standardized variable or "Z-score"
in the form
(6)
where
X is the observed pollutant concentration and m and s are the mean and
standard deviation, respectively, of the concentration logarithms.
Expression (6) may then be solved for X in the form
X = (em) . (es)Z
(7)
where em is the geometric mean (MG) and e is the standard geometric
deviation (SGD) of the concentration distribution. Equation (7) is
an important one for our application since pollutant concentrations
and their probabilities of occurrence (a known function of Z) are
related if MG and SGD are known. The latter two parameters are
functions of the averaging times of the pollutant concentrations.
If their values are known for any averaging time, a, the correspond-
ing values for any other averaging time, b, are given according to
Larsen's model in terms of the relationships
(MG). = (MG) EXP [0.5(l-v)ln2 (SGD)l (8)
oa a
anc' y\r~ io\
(SGD)b = (SGD) V V <9'
where V = In (T/b) (10)
In (T/aj
T being the total averaging time of the data set, usually, 1 year.
The arithmetic mean (MA) may be used in place of MG because the two
are related in accordance with the formula
MA = MG.EXP (0.5 ln2SGD)
The arithmetic mean is invariant with averaging time.
C-10
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In applying the statistical model, the distribution of contaminant
concentrations as represented by equation (7) is assumed to represent
the influence of several component processes. We have found it reason-
able to consider these components in two categories: those that con-
tribute primarily to the pollutant concentration mean and those that
contribute to the concentration variance. The former are assumed
related primarily to the extent of human activities development
(sources) while the latter are assumed related primarily to climato-
logy.
With this rationale, the output of the dispersion model, previously
described, is treated as the arithmetic mean of the pollutant concen-
tration distribution. The standard geometric deviation is considered
as a climatological parameter, and is obtained by analysis of past
pollutant concentration data. If long enough records of data are
available, estimates of meteorologically based year to year vari-
ability may be obtained for both the mean and the variance. When the
mean and variance have been obtained, preferably with an estimate of
their variability, equations (7) through (10) may then be used to
obtain the recurrence frequency of any desired pollutant concentration
value.
The principal asset of the statistical model just described is its
role in minimizing the necessary sophistication of the dispersion
model without sacrificing the necessary detail of the concentration
variability. Normally, the concentrations resulting from extreme
meteorological conditions such as calm winds, recirculations, fumiga-
tions, etc. cannot be handled very accurately by currently available
dispersion modeling techniques. Moreover, any model that would be
considered even reasonably suited to this task would be extremely
sophisticated. Thus, episode modeling, in which concentrations are
related to emissions under specific sets of meteorological conditions,
has not met with a great deal of success in the extreme situations
that are of greatest interest from an air quality standpoint. When
modeling is done on a long-term averaged basis, over a season or a
year, however, as is the case in climatological modeling., fairly
simple models produce results of very useful accuracy. Moreover,
because the effects of nearly all possible meteorological regimes are
contained statistically in the variance of any historical data record,
the variability lost through the long-term averaging may be recovered
for statistical applications. Finally, if the variance in the data is
climatologically based, as has been assumed in this study, a prognostic
capability particularly suited to the needs of land use planning is
achieved.
OPERATIONAL CONSIDERATIONS
Input Requirements
In order to operate the model, certain types of data in specified
format are required as input information. These fall into four basic
categories as follows:
C-ll
-------
1) Regional scale emissions data: On the regional scale, the
model is currently configured to operate with county resolution.
On this scale there is a requirement for the total annual average
emission in tons per day for each county and for each contaminant
of concern. Subroutines for terrain adjustment and calculation
of Smalley pattern advection are included in the model code.
2) Local scale emissions data: On the local scale, the model is
configured to operate with a resolution of one square kilometer
on a grid of one kilometer by one kilometer squares. On this
scale there is a requirement in each grid square for the total
daily average vehicle-mileage, mean route speed and the total
population. Emissions corresponding to this information is
calculated using currently accepted emission factors.
3) Statistical data: To implement the statistical portion of the
model, estimates of the SGD for the local area and pollutants of
concern, and estimates of the climatological variability of both
mean and SGD must be supplied. The BAAPCD is engaged in an
ongoing program of research to provide this information on a
comprehensive and up-to-date basis.
4) Point source data: As mentioned earlier, emissions from large
stationary sources are not included among the emissions treated
by the model, but are considered separately. This usually in-
volves using standard gaussian plume dispersion techniques, and
superimposing the resultant ground level concentrations on thos
obtained from the regional model. In order that the effects of
large stationary sources may be properly included in the modeling
effort, detailed information is provided on the rate of emissions
in units of mass per unit time, along with data on flue gas exit
temperature and velocity, internal flue geometry and the geo-
graphic location and height above ground of each emission point.
C-12
-------
PART II - METEOROLOGY
LOCAL CLIMATOLOGICAL FEATURES
The Sonoma County study area, as indicated in Figures II-l and II-2,
lies in the northern portion of the nine-county San Francisco Bay
Area in a region of complex terrain features. The climate consists
generally of a warm dry summer season and a cool wet winter season
comprising a climatic type frequently referred to as "Mediterranean."
Juxtaposition of the study area to the nearby Pacific ocean coupled
with the presence on the west of a relatively low terrain profile
provide for a predominantly maritime influence, particularly in the
western portions, although pronounced continental conditions occur
with some frequency, particularly in the eastern portions. Four
sub-regions comprising the study area are the Santa Rosa plain,
which experiences the greatest maritime influence, the Petaluma
Valley to the south and the Sonoma Valley (Valley of the Moon) to
the east. The latter two valleys experience a climate more typically
continental.
o o
Summer maxima average from 29.4 C (85 F) on the Santa Rosa plain to
near 32°C (89.6F) in the valleys. Average summer minima are near
10°C (500pj. Sunshine is plentiful throughout the study are and
precipitation averages near 76cm (30 inches) per year.
Conditions of wind flow in the study area tend to exhibit a complexity
commensurate with the complexity of Bay Area and study area terrain
features. The location of the study area in the context of regional
Bay Area wind flow patterns is illustrated in Figure C-l. Statistics
accompanying this figure are given in Table C-3. From the regional
wind patterns it is evident that the study area is rarely subject to
pollutant transport from the principal regional source areas south of
the Golden Gate-Carquinez Straits axis. Terrain channeling of the
local wind flow regime, as illustrated in Figure C-l, suggests a
division of the study area into three sub-areas consisting of the
Santa Rosa-Healdsburg area, the Rohnert Park-Petaluma area and the
Sonoma Valley area.
Wind speeds in the study area tend to be quite light with typical
annual averages ranging from 2.5 meters per second in the north to
3.5 meters per second in the extreme south. Larger urban areas
experience lower than average wind speeds with typical values on
the order of 1.75-2.0 meters per second as an annual average. The
low annual averages are associated with a high frequency of near
calm wind events.
Meteorological Modeling Input
Meteorology enters the model on two scales, regional and local. On
the regional scale, transport to the study area from sources outside
of the study grid is treated by the model in terms of the occurrence
C-13
-------
statistics of regional wind patterns. Table C-2 provides the relative
weighting on an annual basis of the frequency of association of source
and receptor areas on a county scale. The weighting factors in Table
C-2 are used, as described in Part I, to determine the annual average
concentration due to regional non-grid sources. Annual average wind
speed is also included as part of the regional sub-model for each of
the counties in terms of a residence time for wind travel across the
county dimension.
On the local scale, consideration is given by the model to the annual
frequency of association of source and receptor grid squares in terms
of a directional wind rose and an annual average transport wind speed.
Wind rose and wind speed data available for use in the study area are
presented in Table C-4. Roses 2, 8,.and 10, from Table C-4, were
chosen as representative of the Santa Rosa-Healdsburg, Rohnert Park-
Petal uma and Sonoma Valley sub-areas respectively. An "intersquare
transport" wind speed of 3 meters per second was chosen as typical of
the study area with a small upward adjustment for increase of wind
speed with height above the ground to reflect averaging of transport
speed through a layer in the vertical.
Finally, modeling of source and receptor relationships within the same
grid square requires an annual average wind speed for each individual
grid square. Grid square wind speeds chosen for the study were of
three types: an open area type chosen as 2.5 meters per second
(slightly lower than the intersquare speed), a large urban center type
chosen as 1.75 meters per second to reflect lowered resultant wind
speeds due to urban roughness and finally a small urban center type
chosen as 2 meters per second to reflect a roughness effect inter-
mediate between the open areas and the large urban centers. The
distribution of annual averaged grid square by grid square speeds as
used in the model is given in Figures C-2 through C-4.
Current Air Quality in Sonoma County
Air quality in Sonoma County has been monitored somewhat sporadically
since May of 1969 by the California Air Resources Board and the Bay
Area Air Pollution Control District. A synopisis of monitoring in-
tervals, locations and contaminants monitored is presented in Table C-
5 and statistics of "full year" monitoring data are presented in Table
C-6.
On the basis of these statistics, a set of factors were chosen for base
year (1973) model calibration. Appropriate values for the standard
geometric deviation (SGD) characteristic of the study area were chosen
on the basis of Table C-6 and a set of area-wide patterns of SGD derived
from monitoring data (Figure C-5). Hydrocarbon analysis presented a
special problem. Monitoring data for base year were of total hydro-
carbons (THC) obtained by propane spanned flame ionization instrumen-
tation while the applicable air quality standard is for non-methane
hydrocarbons obtained by methane spanned instrumentation. Reconcilia-
C-14
-------
tion of modeling results and monitoring data for hydrocarbons was
obtained on the basis of the curve in Figure C-7 based on comparison
studies done in San Francisco.
Table C-7 is a presentation of the final set of statistics and cali-
bration factors chosen for the study area. The values in the table
were chosen to bring the modeling into reasonably close agreement with
the observed situation in base year. It should be born in mind,
however, that because the modeling is climatologically and spatially
averaged and the monitoring data are not, exact agreement is unreason-
able to expect. In future years, the modeling should be looked upon
as comparative with alternatives compared under a standard set of
atmospheric conditions.
C-15
-------
Table C-4
o
I
Wind observation
stations and
maintaining agencies
Santa Rosa
Army Air Field (NWS)
Sonoma County
Airport (FAA)
Jenner (NWS)
Santa Rosa (NWS)
Satita Rosa (BAAPCD)
Santa Rosa (CALTRANS)
Sonoma (CALTRANS)
Petaluma (CALTRANS)
Sears Point (CALTRANS)
Napa (BAAPCD)
Approximate
coordinates
(UTM)
4267 521
4263 516
4258 490
4252 522
4255 525
4254 527
4234 546
4232 533
4221 547
4241 562
Annual decimal frequency of wind direction by compass point
Calm N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW
.203 .060 .016 .024 .003 .016 .017 .133 .083 .142 .041 .079 .021 .044 .012 .078 .028
.379 .049 .012 .014 .002 .008 .010 .099 .073 .117 .035 .058 .018 .032 .009 .061 .024
.011 .010 .028 .038 .125 .088 .113 .034 .060 .042 .063' .057 .114 .070 .086 .041 .020
.044 .079 .004 .025 .003 .059 .004 .077 .014 .300 .020 .176 .010 .109 .009 .063 .004
.023 .023 .054 .079 .094 .152 .291 .125 .092
.001 .016 .027 .038 .042 .054 .033 .022 .034 .142 .195 .152 .088 .080 .044 .020 .012
.003 .050 .013 .008 .009 .039 .052 .064 .048 .053 .021 .076 .250 .224 .026 .023 .041
.002 .024 .009 .004 .010 .038 .068 .067 .023 .019 .020 .022 .064 .271 .151 .134 .074
.001 .016 .009 .009 .012 .040 .033 .023 .031 .214 .047 .022 .030 .117 .156 .191 .049
.014 .160 .038 .049 .153 .304 .138 .077 .067
Annual avg.
wind speed
(m/sec)
2.5 '
3.3
4.6
2.5
1.75
2.7
3.8
3.1
3.9
2.0
NWS - National Weather Service
FAA - Federal Aviation Agency .
CALTRANS - California Department of Transportation
BAAPCD - Bay Area Air Pollution Control District
-------
Figure C-2
Printout of BASIC datafile in array format indicating annual average wind speed (m/sec)
by grid square in modeling sub-section A (Santa Rosa). Areas of reduced wind speed are
outlined and UTM coordinates of the sub-section boundaries are indicated as a reference
DATARLE SPEEDSA IN UNITS OF MEIEHS PER SECOND
o
t
508
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4289 12\30 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
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2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 1 . /5 I.Jb 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.30 2.50 2.50 1./5 1.75 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 1.75 1 . /5 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 2". 50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
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2.30 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.30 2.50 2.50 2.50 2.50 2.50
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2.30 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.30 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50
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2-S°LA250
531
-------
Figure C-3
Printout of BASIC datafile in array format indicating annual average wind speed (tn/sec)
by grid square in modeling sub-section B (Rohnert Park-Cotati). Areas of reduced wind speed
are outlined and UTM coordinates of the sub-section boundaries are indicated as a reference.
DATAFILE SPEEDSB IN UNITS OF METERS PER SECOND
o
i
»-
00
4251
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i
3
4221
508
12.50
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50 2.50 2.50 .
50 2.50 2.50
50 2.50 2.50
50 2.50 2.50
50 2.50 2.50
50 2.50 2.50
50 2.50 2.50
50 2.50 2.5014221
1 -
531
-------
Flqure C-4
Printout of BASIC datafile In array format indicating annual average wind speed (tn/sec)
by grid square in modeling sub-section C (Sonoma). Areas of reduced wind speed are
outlined and UTM coordinates of the sub-section boundaries are indicated as a reference.
DATAF1LE SPEEDSC IN UNITS OF METERS PER SECOND
4259,"
vo
1.7512.50
1.7512.50
T.7512.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.bO 2.50
2.bO 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.bO
2.5O- 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50 2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.bO
2.50
2.50
2.bO
2.50
2.50
2.50
50
50
50
50
50
50
2.50
2.50
2.50
2.50
2.50
50
50
bO
50
50
50
50
50
50
50
50
50
50
50
,50
,50
50
,50
,50
,50
,50
,50
,50
,50
2.50
2.50
2.bO
2.bO
2.50
.bO
4229
r./5
1.75
l./b
1.75
1.75
1 .75
1 ,/b
1.75
1.75
I./5
1.75
1.75
1.75
1.75
1.75
.30 2.50 2.50 2.50 2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.bO
2.50
2.bO
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.bO
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
50
2.50
• ! . (5
1.75
,1.75
11.75
1 . /b
1.75
1.75
1.75
2.50
2.50
2.50
2.50
2.50
2.50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
2.50
2.50
50
50
50
50
50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.bO
2.bO
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
2.50
50
50
50
50
50
bO
bO
50
bO
bO
bO
bO
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
553
2.50
2.50
2.5Q
2.50
2.50
2.5O
2.50
2.50
2.50
2.50
2.5O
50
50
50
50
2.50
50
50
50
50
50
50
50
50
50
2.50
50
50
50
2.50 2.501
4259
4229
530
553
-------
Table C-5
A HISTORY OF AIR MONITORING ACTIVITY IN SONOMA COUNTY
Year
1969
1970
1971
1972
1973
1974
Santa Rosa
Santa Rosa
Petal uma
Petal uma
Monitoring site
Santa Rosa (1)
Santa Rosa (1)
Santa Rosa (1)
Petal uma (1)
Santa Rosa 2)
Petal uma 1)
Petal uma 2)
Santa Rosa (2)
Petal uma (2)
Santa Rosa (2)
Petal uma (2)
(1) 37 Old Court
(2) 437 Humboldt
Interval
May - Dec
Jan - Dec
Jan - Apr
May - Dec
Aug - Dec
Jan - Jul
Jul - Dec
Jan - Dec
Jan - Dec
Jan - Dec
Jan - Dec
House Square
Street
Agency
ARB
.ARB
ARB
ARB
BAAPCD
ARB
BAAPCD
BAAPCD
BAAPCD
BAAPCD
BAAPCD
(1) 12 North Petal uma Boulevard
(2) 301 Payran Street
C-20
-------
Table C-6
Available data on annual averages (Ma) and standard geometric deviations (SGD) for
various pollutants in Sonoma County
Year
1970
o 1971**
PO
1— «
1972
1973
1974
Monitoring Carbon Total
Site Monoxide Hydrocarbons
(ppm) (ppm)
M. SGD M SGD
« a
Santa Rosa 1.9 1.8 2.5 2.5
(Petaluma) ( - ) ( - ) ( - ) ( - )
Santa Rosa - -
(Petaluma) (1.8) (1.9) (3.0) (1.6)
Santa Rosa - -
(Petaluma) (-) (-) (-) (-)
Santa Rosa * * 2.2 1.3
(Petaluma) (-) (-) (-) (-)
Santa Rosa * * 2.1 1.8
(Petaluma) ( - ) ( - ) ( - ) ( - )
Suspended Oxidant
Parti cul ate
(yg/m3) (pphm)
Ma SGD Ma
a a
1.9
(67+) ( - ) (iTe)
< = ) (") (-")
40+ - 2.1
( - ) ( - ) (2.2)
43+ - 2.1
( - ) ( - ) (2.2)
SGD
2.0
U~7)
<:>
1.6
(1.6)
1.5
(1.5)
** May 1971 - April 1972
* Bad data
- Partial data or no data
+ Annual geometric mean
Note: Standard geometric deviation (SGD) is computed using only the 70th and 99th
percent!le values of the observed data with the assumption of a lognormal
distribution.
-------
CARBON MONOXIDE AND HYDROCARBONS
SUSPENDED PARTICULATE
"O
OXIDANT
NITROGEN DIOXIDE
Geographic distribution of annual standard geometric deviation for pollutant
concentration in the San Francisco Bay Area based on four years of observation.
— *
-------
F1gure..C-6_
-------
Table C-7
DATA FOR MODELING CALIBRATION AND STATISTICAL ANALYSIS
Pollutant
species
Carbon
monoxide
Non-methane
hydrocarbons
Sulfur
dioxide
Suspended
particulate
Raw
Value
1.69
0.56
0.004
35
Cal ibrated
value
2.02
0.22
0.004
47
Calibrated
factor
x 1.20
x 0.38
x 0.00
+ 12
Assumed standard
geom. deviation
1.9
1.9
2.0
1.8
Notes: -? ,
Values for gases are. in,units of parts perrmil lion by volume.
Values for particulates are in units of micrograms per cubic
meter.
Raw and calibrated values apply to the downtown Santa Rosa grid
square (UTM 525E 4254N, south west corner) and to base year.
Calibration factors and standard geometric deviations are
assumed valid for all grid squares and all future years.
C-24
-------
APPENDIX D
Technical Description of Oxldant Modeling
-------
METHODS FOR OXIDANT ANALYSIS
The oxidant analysis applied a modified proportional rollback technique
to determine the effect of future changes in pollutant emissions on
oxidant concentrations. Although there are shortcomings in using pro-
portional rollback techniques, it was the only method judged feasible
for this study. The modifications made to the usual rollback analysis
have made its application to this study reasonable and useful.
A basic problem in applying the rollback approach to a specific area,
such as Sonoma County, is that oxidant concentrations are not only a
function of emissions in Sonoma County but of emssions in other sec-
tions of the Bay Area. Furthermore, different areas in Sonoma County
are affected differently by transported emissions. On one extreme,
oxidant concentrations in various areas of Sonoma County can be assumed
to be proportional to County emissions only. On the other extreme,
oxidant concentrations in Sonoma County can be assumed to be propor-
tional to emissions of the entire San Francisco Bay Area Basin. This
analysis uses an approach between these two extremes, as described
below.
The first step was to determine the weighting factors for estimating
transport from county to county in the entire basin. The method for
determining these factors is explained in Appendix C. The only alter-
ations to that method used in the oxidant analysis are:
1) separating Sonoma County into three "boxes", based on the
location of the three county oxidant monitoring station and
2) using the April-October frequencies of wind types because
oxidant is a seasonal phenomenon that depends on solar
radiation.
Once the weighting factors are determined, they are multiplied by the
county concentrations to determine the concentration that is trans-
ported to the receptor box. These weighting factors are presented in
Table C-l. The rows are the receptor boxes ~ Santa Rosa, Petaluma
and Sonoma -- while the columns are the source boxes. The source box
concentration is multiplied by the appropriate weighting factor to
determine its affect on any one of the receptor boxes.
This, then, defines the total non-methane hydrocarbon burden in the
three areas of Sonoma County, and also estimates the relative impor-
tance of transport and local sources. The analysis so far has assumed
a direct proportionality between non-methane hydrocarbons and oxidants.
This assumption does present a basic problem of the proportional
technique because oxidants are actually a complex funtion of non-
methane hydrocarbons and nitrogen oxides. The remainder of the
analysis will continue to assume a direct proportionality because it
has been found to give a reasonably good approximation in the range of
oxidant concentrations under consideration.
The total non-methane hydrocarbon burden for each area of Sonoma County,
then, is assumed to be directly proportional to the annual mean oxidant
concentration for each area. A lognormal statistical frequency distri-
D-l
-------
bution used to represent base-year oxidant monitoring data for purposes
of this analysis are recommended by R. I. Larsen (EPA, 1971). The
magnitude of oxidant concentrations in this type of analysis is assumed
to be proportional to the magnitude of pollutant sources (in this
case, non-methane hydrocarbon box-model concentrations) and is repre-
sented by the mean concentration of the statistical distribution of
hourly oxidant values. The variance of oxidant concentrations is
proportional to meteorological factors and is defined by the standard
geometric deviation of the statistical distribution. The latter is
assumed to be invariant from base-year to any future year, which is a
reasonable assumption if a representative base-year is selected.
The base-year oxidant concentration distributions for this analysis
are actually an average of two years, 1973 and 1974, for Santa Rosa
and Petaluma, and a one-year period, September 1974 - August 1975, for
Sonoma. These data amounted to the only complete records available at
the time of the study. The relevant parameters needed to define the
statistical distribution were determined from the data and are as
follows:
Table D-l
BASE-YEAR OXIDANT DISTRIBUTION PARAMETERS
GEOMETRIC STANDARD GEOMETRIC
MEAN DEVIATION
Santa Rosa 0.023 1.55
Petaluma 0.026 1.55
Sonoma 0.033 1.55
Because the geometric mean is proportional to emission sources, any
change in non-methane hydrocarbon emission rates in any sub-area of
Sonoma County or other county can be evaluated for their effect on
mean oxidant concentrations in a particular sub-area of Sonoma County
by use of the following formula:
Cp. = Cf
X1Y1 + X2Y2 — + Vn X1Z1 + X2Z2--- + Vr
where Cp = present geometric mean oxidant concentration
Cf = future geometric mean oxidant concentration
Xj - weighting factors for a given county or area
of Sonoma County
D-2
-------
z, =
present box-model non-methane HC concentration
of a given county or area of Sonoma County
future box-model non-methane HC concentration
of a given county or area of Sonoma County
Once the future mean oxidant concentration has been determined, the
lognormal frequency distribution can also be determined allowing
calculation of maximum annual oxidant concentrations and number of
times standard are exceeded. This can be accomplished graphically or
by use of the following formulas that are defined by the lognormal
distribution:
Cmax = (MG) (S6D) 1
r
'(.09) = In. 09 _ ln(MG)
In(SGD) In(SGD)
where max = annual hourly oxidant concentration
SGD = standard geometric deviation
MG = geometric mean oxidant concentration
Z. = 3.81 - number of standard deviations from
the annual hourly maximum oxidant concen-
tration
(0.9) - number of standard deviations from the
mean of the percentage frequency that the National
Ambient Air Quality Standard for oxidants is
exceeded.
Once the value of (.09) has been determined, one must use a statistical
table to find the percent frequency that it represents, such as Table 11 on
page 30 of EPA publication AP-89, "A Mathematical Model for Relating Air
Quality Measurements to Air Quality Standards," by R. I. Larsen. This
percent frequency can then be used to multiply the total hours in a year
t
-------
APPENDIX E
Technical Description of Traffic Estimation Procedures
-------
APPENDIX E - TECHNICAL DESCRIPTION OF TRAFFIC ESTIMATION PROCEDURES
OVERVIEW
One of the tasks in the study was the projection of air pollution emissions
for each of the alternative development patterns. This appendix describes
the procedure used to predict vehicular emissions for these alternatives
and presents a brief discussion of the advantages and disadvantages of the
selected approach.
The land use alternatives were represented by population, employment and
land use information at 1-km2 gridded detail. The subsequent tasks involved
developing air pollution emissions at the 1-knr grid cell level from land
use information for input to air quality models. The pollutants considered
in the study were carbon monoxide, particulate matter, non-methane hydro-
carbons, oxides of nitrogen and sulfur oxides. The hydrocarbon inventories
were totaled for the Santa Rosa, Petaluma and Sonoma subbasins in the study
area to facilitate the oxidant analysis.
ANALYSIS PROCEDURES
A multiple regression formulation was used to determine the relationship
between different study variables and vehicular emissions. Coefficients
were determined by analyzing two cases where emissions were known; these
coefficients, in turn, were used to predict emissions for the other land
use alternatives.
The two alternatives that provided the input data were Base Year (1973) and
Continuing Trends 478. Gridded emissions data were available for these
conditions from previous work. The Base Year traffic data were compiled by
the county from observations and traffic counts. The Continuing Trends 478
data were developed through modeling techniques by JHK and Associates at a
detailed traffic zone level, with adjustments made by the County Engineer.
These link loadings, consisting of average daily traffic and average speed,
were then manually allocated to the appropriate grid cells and the infor-
mation punched onto computer cards. The result was a 4000-card deck of all
the traffic links by grid cell.
The gridded vehicle kilometer traveled data was translated to gridded
emissions using speed dependent emission factors from the Bay Area Air
Pollution Control District.
The steps in the regression analysis procedure were as follows:
I. For Continuing Trends 478
1. Perform regression analysis on Continuing Trends 478 data to
determine regression coefficients.
2. Use regression coefficients (Step 1) to predict emissions in
each grid cell.
E-l
-------
3. Compute residual emission by subtracting predicted emissions
(Step 2) from the emissions developed from JHK traffic model
and BAAPCD emissions factors.
II. For each Land Use Alternative
4. Use regression coefficients to predict emissions for each
cell for each alternative.
5. Compute residual correction factor.
6. Add corrected residuals (Step 3 times Step 5) to each cell
emission value (Step 4) to produce corrected emission value.
f
The remainder of this appendix details this procedure.
Regression Analysis
Considerable effort was devoted to investigation of the most significant
variables to be included in the regressions. The variables that were most
useful were total population per grid, total employment per grid, amount of
land in commercial and medium density residential land uses per grid and the
ratio of average daily traffic on major arteries to the distance of the
cell from the major arteries.
The final form of the prediction equation used for CO was:
C0cell(kg/day) - -012 x popcel]
+.16 x f£
+.069 x empcell
+1.91 x Commercial Suburban Acreage
+1.70 x Medium Density Residential Acreage
+1.61 x Commercial CBD Acreage
+1.06 x Freeway Dummy Variable
-11.6
Table E-l presents the coefficients for the other pollutants. The technique
explains 68% of the variance for CO.
The primary reason the population, employment and land use variables were
useful in the regression analysis was because they, or their equivalents,
were key variables in the JHK traffic models. For example, the traffic
model generates a high proportion of trips from commercial employment
categories that the study had allocated to commercial land uses. There-
fore, commercial land uses became a key variable in the regression
analysis.
E-2
-------
TABLE E-l
REGRESSION COEFFICIENTS
CO
Commercial Suburban
Acreagece-j i 1.91
Medium Density Resi-
dential Acreagecel-j 1.70
Commercial City
Centered Acre-
a9ecell
1.61
Freeway dummy vari-
able 1.06
f£cell
(Constant)
.16
-11.66
Particulate Non-methane
Matter Hydrocarbons Nov SO
A x
Employmentcell
Populationce-|-|
.069
.012
.00185
.00022
.0116
.00285
.0223 .00181
.00429 .00038
.0475
.051
.0342
.0358
.0042
-.147
.294 .489 .0427
.236 .516 .0400
.197 .270 .0248
.214 .501 .0380
1.84 6.00 .407
Another variable that proved successful was the relationship of traffic
volume on the major traffic links to the distance from the grid cell to
those links. This relationship was explained by:
fn~ j= all major (loading on a traffic link)..
links (distance of grid to link)j
Specifically, fjiis the summation of the ratios of the average daily traffic
(ADT) of each major traffic link (roadways having greater than 10,000 ADT
in 1973) to the distance between the grid cells to the link. The ADT on
the major links was projected for the alternative development patterns by a
proportionality to population and employment in nearby cities, using
regression analysis supplemented by professional judgment.
Finally the use of dummy variables proved fruitful. Grids which contained
major traffic links were assigned a value equivalent to their ADT; those
not containing major links were given a 0.
E-3
-------
Variables that were tested but which did not prove fruitful included the
other land uses and the distance of the grid cell from all cities. On the
assumption that one set of coefficients was not sufficient to explain the
variance for the entire county, the data were separated, or "stratified",
by certain charactersitics, e.g. urban/rural, low/high emissions, proximity
to freeways or city centers. Also an analysis was made of the logrithms of
the variables, to demonstrate any multiplicative correlations, and of the
differences between 1973 and 2000 variables. None of the above investiga-
tions produced any significant improvements in the variance explained.
Addition of Residuals
The existing pattern of emissions in the county shows large values in cells
containing freeway links or within cities and often very low emissions in
adjacent rural cells. The formula as set up, however, produces an emissions
pattern that tends to smooth these features and does not account for the
sharp differences between cells. A procedure of adding residuals was
employed to adjust for the smoothing problem. Using Continuing Trends 478
with its "known" gridded emissions, the residual for each cell was deter-
mined by subtracting the predicted value from the actual value. This
residual, multiplied by a correction factor, was then added to the cell's
predicted value for each alternative.
Thus, when a cell contained especially large or small emissions, which were
not represented by the regression formula (e.g. intersection of several
arteries), the correction factor raised or lowered the emission value
proportional to the difference between the actual Continuing Trends 478
values and the regression-predicted values. In this manner the underlying
traffic structure was constrained to resemble the Continuing Trends 478
distribution of traffic, while the land use differences between the various
alternatives were represented through the regression equation. This procedure
was used to predict the Continuing Trends 478 values from the 1973 data and
the comparison with the results of the traffic model for Continuing Trends
478 emissions was very good.
It was necessary that the above correction factor indicated activity
differences between Continuing Trend 478 and the other alternatives and
emphasized accuracy in the prediction of hot spots. The sum of the ADT's on
the four largest traffic arteries was chosen as a correction factor to
satisfy these criteria. The equation demonstrating the use of this factor
is:
E, = E. + (R- x CF)
1 'regression
Where E^ is the concentration in the ^th_ cell
E. is the regression predicted concentration in the
degression
is the CT478 residual
= E. E \
1CT478 *CT478 I
"actual" regression )
and CF is the correction factor.
E-4
-------
This technique, however, iresults in patterns that were forced to superficially
resemble the Continuing Trends 478 pattern by the addition of the Continuing
Trends 478 residuals. This was not considered too significant a restriction
in certain particular cases (e.g., Santa Rosa Centered, Urban Centered)
since these alternatives were basically similar (i.e., city centered); but
other alternatives (e.g. Rural Disperesed, Suburban Dispersed) represented a
more dispersed pattern of growth and were expected to be less accurately
represented with this technique.
CONCLUSIONS
There were two main drawbacks to the use of the regression technique.
First, it was unable to precisely predict emissions in grids between trip
origins and destinations. Therefore, the technique would tend to under
estimate total.emissions associated with dispersed land use patterns
relative to Compact ones because the former would generate longer trips.
A second drawback of the regression technique was its inability to
represent the effects of,possible traffic control measures. The regression
analysis was constrained by the traffic modeling assumptions made under the
Continuing Trends 478 alternative. Therefore, similar assumptions had to
be used for all alternatives thereby precluding new assumptions based, for
example, on higher transit use or restricted car use.
In conclusion, the regression technique provided a good representation of
the emissions patterns associated with most of the land use patterns devel-
oped in the study. However, it was somewhat less accurate with the dis-
persed patterns and did not provide an adequate means to test traffic
control measures.
E-5
-------
APPENDIX F
Technical Description of the Water Quality Modeling
-------
APPENDIX F - TECHNICAL DESCRIPTION OF THE WATER QUALITY MODELING
RUNOFF-QUALITY MODEL
An urban storm drainage model developed by WRE and used most recently
in Seattle and an agricultural runoff model developed by WRE for EPA
were meshed to create the ABA6 Runoff-Quality Model. Following is a
brief description of each model and references to reports providing
a detailed discussion of those models.
Urban Storm Drainage Model
In October of 1971, under the sponsorship of the Environmental
Protection Agency, a consortium of private contracts — Metcalf and
Eddy, Inc., the University of Florida, and Water Resources Engineers,
Inc. — presented a comprehensive mathematical model capable of re-
presenting urban stormwater runoff and combined sewer phenomena. The
model was comprised of a series of individual sections or blocks which
could be used either separately or in combination. The principal
elements of the model are the runoff, transport, storage and receiving
water blocks.
Subsequent to initial development, the various blocks of the model
have been extensively developed and modified in further applications.
In a major study of stormwater drainage for the City of San Francisco,
the runoff block was updated to include revised concepts of gutter
flow and the transport model was rewritten to develop a model capable
of handling looped networks typical of sewers, plus irregular piping
systems and surcharge.
The model developed for the City of San Francisco was used in the
Seattle Metropolitan area. The Seattle version of the urban storm
drainage model is the one WRE adapted to Sonoma County. The reader is
referred to the program documentation and users guide for a detailed
description of the model (1).
The model consists of four primary sections or blocks which are used
to simulate the quality and quantity of flow from a wtershed, through
a drainage system, and then to display the results.
Specifically, the blocks are:
1. Display Block - A graphical output routine for producing
plots on the line printer.
2. Runoff Block - A set of computer routines which simulates
quality and quantity of surface flow from watersheds plus
routing tributary drainage channels and/or pipes.
3. Transport Block - A set of computer routines which dynamically
routes flow through drainage systems.
F-l
-------
4. Transport Quality Block - A computer routine which uses the
flow simulation of the Transport Block to route quality
constituents in drainage systems.
The Runoff Block is of primary interest in the ABAG study. Flow
routing through combined sewer systems was not a part of the ABAG
study.
The Runoff Block consists of a set of computer routines and appropriate
data which will simulate the rainfall-runoff characteristics of an •
urban area. In the model flow is traced from the onset of rainfall to
the watershed, through overland flow, and then to flow in the tributary
channels. Water quality mass emissions are generated as they occur on
the watershed surface.
Hydraulic flow is represented by the kinematic wave solution for flow
across a plane surface. This rather simple approach is applied to a
geometric representation of an urban area which includes the major
hydrologic subunits of surface drainage. In the model each of the
watershed subunits is treated as if it were completely independent of
all others in the systme. This idealization is basic to the structure
of the Runoff Model; when it is found that this is not a good approxi-
mation corrections must be made by changing watershed boundaries or
creating new unit watersheds.
Rain falls directly on the pervious and impervious areas. On the
former, some is lost by infiltration to the groundwater. After
deducting losses, flow moves from the watersheds to the tributaries.
The model assumes that the pervious and the impervious areas are
separate within the watersheds, each of which drains into the adjacent
tributary.
The quality of the surface runoff is important in the analysis of
urban systems, and more than 20 water quality constitutents have been
included in the Runoff Model. The contribution from each subarea for
each constituent is determined by combination of land use and equivalent
street-gutter length. These values must be specified for all subareas
in the watershed.
The constitutive relationships for all quality parameters in the
Runoff Model have been determined from observations of actual runoff
quality in the Seattle Metropolitan area. These relationships were
used in the ABAG study.
Agricultural Runoff Model
The model used to simulate runoff and washoff from nonurban areas in
Sonoma County was developed by WRE in a project for the EPA. This
model evolved from a series of modifications to urban storm runoff
models. These modifications concerned the manner in which pollution
loads were washed off and the addition of the capability to route
pollutants through tributary channels. For details, the reader may
find them in WRE's report (2) to EPA.
F-2
-------
As presently structured, the Agricultural Runoff Model (subsequently
called AGRUN) has the capability to simulate storm runoff hydrographs
and pollutographs for up to 22 water quality parameters from agri-
cultural watersheds. The watershed may be subdivided into as many as
200 subareas. For each subarea, the surface area, width and slope
must be specified, plus the crop cover. The Manning n, surface
depression storage, and Norton infiltration coefficients are entered
as input data for each land use type.
The tributary drainage system may be subdivided into as many as 200
channels. The system must be dendritic in form. For each channel the
length, invert slope, and Manning n are specified, plus appropriate
cross section data. Cross sections may be triangular, trapezoidal or
rectangular.
The user has the option of representing infiltration by the Morton
equation alone, in which case interflow computations are neglected; or
he may specify the additional data which will be used to compute the
contribution of interflow to storm runoff. If the latter computation
is desired, the following data are require for each subarea:
1. Number of soil layers above groundwater table.
2. Soils data for each layer, i.e.
a. depth of layer,
b. permeability coefficient,
c. field capacity,
d. saturation level, and
e. present field capacity available at the beginning of
the storm.
3. Constant baseflow (if any) from the watershed.
Computations of quality can be made for up to 22 constituents. The
number desired is specified by the user. Constituents include:
1. Total suspended solids 12. Organic N
2 Suspended solids 13. Nitrite and nitrate
(Non-settleable) 14. Phosphate
3. JDS 15. Orthophosphate
4.' BOD 16. Mercury
5. COD 17. Copper
6. Chlorides 18. Zinc
7. S04 19- Lead
Q'. Grease 20. Chromium
9. Total coliforms 21. Cadmium
10. Fecal coliforms 22. Arsenic
11. Ammonia
F-3
-------
STREAM QUALITY MODEL - QUAL-II
In 1971 Water Resources Engineers, Inc. added a great deal of
simulation capability to an existing model known as QUAL-I, which
simulated dissolved oxygen and a conservative constituent in streams.
QUAL-I was developed in Texas by the Texas Water Development Board and
a consultant, Frank D. Masch and Associates. QUAL-II was developed by
WRE for the Environmental Protection Agency. QUAL-II has now been
used by many people for simulating stream quality in rivers throughout
the United States.
QUAL-II, in its most basic version, is a steady-state model of stream
quality. It works best in moderately sized streams having flows that
are a foot or more deep and that are contained within a well defined
channel. It also simulates only aerobic conditions, so pollutional
loads of BOD and/or ammonia must be small enough so that dissolved
oxygen levels remain greater than zero. The model currently will
continue to remove oxygen in response to BOD or nitrogenous loads even
to the point of indicating negative concentrations of dissolved oxygen,
which obviously could never occur. But the model remains useful in
this regard, because it indicates rather dramatically where in a
stream network such serious conditions might arise that dissolved
oxygen would be completely depleted.
In addition to BOD and dissolved oxygen, QUAL-II simulates ammonia,
nitrite, nitrate, chlorophyll a_ (algae), orthophosphate (PO*), coliform
organisms and several conservative constituents which the user may
specify. In this study, COD and suspended solids were modeled as
conservative constituents, which obviously they are not; but the model
cannot deal with these particular constituents otherwise.
The hydraulics of a stream are represented in the model with logarithmic
relations between flow and depth and between flow and velocity, as
follows:
H = a Qb, and V = c Qd
where H is depth, Q is flow and V is velocity. The coefficients, a
and c, and the exponents, b and d, must be determined for each reach
of the stream, either from field data of flow, depth, and velocity, or
from cross-sectional area information and solution of Manning's equation
or the equivalent. The latter procedure was used.
The quality simulation operates as follows:
BOD is consumed by a first-order decay expression
BOD =
where BOD is the amount of biochemical oxygen demand remaining after a
travel time, t; BOD0 is the amount at the beginning of the time period;
and k, is the stream decay rate for BOD. At steady-state, there will
always be BOD entering each stream section and BOD will be left at the
end, after the travel time has expired.
F-4
-------
In the nitrogen system, ammonia is similarly decayed to nitrite, and
very quickly nitrite is decayed to nitrate. In actuality these re-
actions are biological, not chemical; but as with BOD, the trick is
merely to find the proper values for the coefficients. During the
simulation ammonia is decreased and nitrite is increased according to
the first-order reaction; then nitrite is increased according to a
second reaction.
Nitrate (only) and phosphorus are used by algae then, along with
light, to "grow" more algae. The algae in turn produce oxygen and use
a little of it to keep themselves alive.
The conservative constituents such as salts, and in this case COD and
suspended solids, are not changed in concentration by any reactions.
They are increased or decreased only by additions to the stream or by
dilution.
In essence, then, the stream is viewed as though it were timeless,
with constant inflows at the headwaters and at waste discharge points
and with constant inflows at the headwaters and at waste discharge
points and with constant concentrations in these input quantities. So
logically all the outflows will be the same and the concentrations
will change downstream to a new constant value by decay or by dilution.
Hence one could conceive the stream to be a solid string, of cheese
which can then be sliced into small pieces, each of which can be
analyzed for its contents. This is pretty close to what the model
does. The slices are called stream "elements", and the elements are
grouped into similar packages called "reaches" wherein many physical,
chemical and biological properties can be assumed to be constant. In
the Laguna de Santa Rosa Basin 20 reaches and 176 elements were used.
For a complete description of QUAL-II, the reader is referred to the
program documentation manual (3).
The Petaluma River, like most estuaries, has a tidally affected
downstream portion which is predominated in dry weather by the behavior
of the downstream tide condition and affected only insignificantly by
the upstream inflows of freshwater. To deal with this situation, the
steady-state stream model, QUAL-II had to be altered somewhat. Three
significant changes were made.
First, a tidally averaged depth for the estuarine reaches was added to
the depth calculated on the basis of freashwater inflows alone. In
the Petaluma River this ranged from 0 meters at the upstream end of
reach 3 to about 4 meters at the mouth. The program reads data for
the tidally averaged depth at the end of each estuarine reach and
interpolates to find the depth to be added in each computational
element.
Secondly, the expression in the program for the dispersion coefficient
was altered for the tidally affected reaches to account for 1) tidally
induced mixing and 2) salinity induced mixing. The new relationship
is:
F-5
-------
D1 = Cr (vj + avr) (hj + ahr) + (T 5F)r W>r
Where
2
D. = mixing coefficient for element, i, L/T
C = a coefficient for reach, r, dimension! ess
r
v-j = average velocity in element, i, L/T
a = standard deviation of velocity in reach, r, L/T
vr
h. = depth in element, i, L
a. = standard deviation of the depth in reach, r, L
ni
(T Lo/So) = a coefficient over the reference concentration gradient,
3
(dS/dX)r = salt concentration gradient in reach, r, M/L /L
Previous WRE work on San Francisco Bay and the Sacramento-San Joaquin
Delta suggests that the values of Cr can range from 3.0 to 16.0, and T
Lo/So can range from 750 to 50,000. The value of Cr used for the
Petal uma River was 3.0. The values of T Lo/So ranged from 10,000 to
50,000. The values of dS/dX ranged from 1000 near the mouth to 5000
at the upstream end of the estuarine portion. This expression was
calibrated with data for salinity obtained from the San Francisco Bay
Regional Water Quality Control Board.
The third change in QUAL-II was the addition of a capability to read
and then use the downstream, tail water quality concentrations of all
the constituents being simulated. This was necessary so the altered
model could disperse or mix properly upstream in response to the
salinity gradient. The modeled results for concentrations approach
the values given for San Francisco Bay, which were determined from
prior WRE simulation results.
MODEL ADAPTATION
A great deal of basic data was required in order to adapt the Runoff-
Quality and QUAL-II Models to Sonoma County. Watersheds, channels and
precipitation patterns unique to the Laguna and Petal uma Basins were
defined for the Runoff-Quality Model. In addition to the length,
width, and slope of each watershed, the infiltration characteristics
and percentage of impervious area must be specified for the Runoff-
Quality Model. QUAL-II requires a definition of the channels it
simulates, the headwater inflows and qualities, and the flow rates and
qualities of discharges to the channels represented by the QUAL-II
Model .
F-6
-------
Watershed and Channel Characteristics
One of the first tasks in the investigation was to define the hydrologic
areas to be modeled within the Laguna de Santa Rosa and Petaluma River
drainage areas. Three levels of detail were established for drainage
areas. In descending order areawise, they are:
Basin
Waterhsed
Subarea
Figures VI-16 and VI-28 show the subareas and channels for the Laguna and
Petaluma Basins, respectively. After the hydrologic subareas were
identified, the ABAG one kilometer grid system for Sonoma County was
overlaid on the subarea map and the boundary of each subarea was
modified to follow the grid system. This procedure was adopted so
that land use data prepared by ABAG on one kilometer squares could be
aggregated directly for the Runoff-Quality Model. Some degree of
accuracy in terms of the area of subareas is sacrificed by using this
procedure; however, this loss of accuracy is offset by being able to
use the land use data directly.
The Runoff-Quality Model requires the length, width and slope of each
subarea. Thts information was taken off the U.S.G.S. 7-1/2 minute
quad sheets. Tables F-l and F-2 show these watershed characteristics for
the Laguna and Petaluma Basins, respectively.
The surface infiltration rates of the soils within Sonoma County were
measured by the USDA Soil Conservation Service in 1964 and are appro-
priate for use in the Runoff-Quality Model. There were seven permea-
bility (infiltration) groups. Maps were then made by ABAG, using the
SCS data, indicating one of the three infiltration rate groups (high,
medium, or low) for each soil type.
As land use becomes more intese infiltration rates are reduced from
the natural rates (i.e. those indicated for Parks/Dedicated Open
Space, Agriculture, Unused Land). This reduction in rates is due to a
greater compaction of the surface soils as a result of clearing and
grading operations associated with the construction of homes, build-
ings, industrial facilities, etc. Infiltration rates and the maximum
allowable infiltration are shown in Table F-3.
Both the initial (maximum) infiltration rates and base (minimum)
infiltration rates are used in the Runoff-Quality Model. The rate of
decay is 4.14/hr for all soil types. Infiltration of rainfall on
impervious areas is to be considered negligible.
The ABAG staff made several checks on the percentage of impervious
area in Rohnert Park, Cotati, Sebastopol, Santa Rosa, Petaluma and
.other communities in Sonoma County. Aerial photographs of the above
areas were used to estimate impervious areas associated with resi-
dential, commercial and industrial land uses. These checks together
with the results of the other investigations were then used to
finalize values for use in the Runoff-Quality Model. The values used
are presented in Table F-4.
F-7
-------
TABLE F-l
WATERSHED DATA—LAGUNA BASIN
HATERSHED DATA FOR SA3IN HO. I, LAND USE PLAN - SRC478
I
00
INT
HUM
1
2
3
a
5
6
7
e
9
10
II
12
13
la
15
16
17
18
19
20
21
2?
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
30
39
40
SUBAREA
NI/MHE*.
1001
1002
1003
1004
1005
1006
2001
200?
2003
2004
2005
2006
2007
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
4001
1002
0003
4000
4005
0006
4007
4008
4009
aoin
1012
4013
aoia
4015
CHANNEL
NU«RER
1001
1005
1006
1003
1007
1002
200?
2001
2003
2ooa
2005
2004
2007
3001
3005
3004
3002
3008
3011
3010
3007
3006
3015
3914
3013
4001
4001
4002
4003
4003
4004
4004
4005
4006
4007
4008
4012
4009
4011
4013
M10TH
(M)
69*0.
6968.
12006.
9206.
10461 .
54?4.
11973.
5987.
10445.
13551.
7226.
1585?.
16335.
6695.
59R7.
8868.
15PU1.
9399.
6fl?4.
769J.
15241.
12408.
7210.
89f<0.
149H3.
6679.
3090.
3621.
4I?0.
4281.
9302.
«"!?.
11 56?.
56"1.
4619.
7242.
13438.
8256.
12408.
14484.
AREA
(KM?)
9.
9.
1".
1 J.
14.
7.
12.
11.
15.
19.
22.
24.
?9.
18.
11.
14.
15.
10.
11.
16.
14.
. 20.
22.
21.
35.
7.
7.
|4.
8.
20.
18.
26.
22.
13.
17.
7.
44.
35.
12.
10.
SLOPE
(M/M)
.006
.027
.010
.006
.005
.006
.006
.006
.200
.200
,?40
.230
.140
.002
,014
,036
.00?
.fl?6
.080
.130
.110
.110
.100
.170
.160
.100
.0?7
.005
.028
.005
.023
.004
.059
.014
.002
.00?
.009
.004
.100
.080
PRCNT
IMP
8.7
10. 1
8.5
8.8
6.0
30.9
30.0
10.4
7.7
6.0
6.0
6.0
6.0
14.8
58.2
28.8
50.7
26.8
19.?
10.3
2?. 7
14.1
6.7
10.5
6.0
8.7
9.2
6.8
8.0
1?.2
17.3
23,0
8.0
8.2
24.5
7.4
19.5
14.9
6.8
6.0
PANNING N DEP STOR (MM)
IMP
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.on
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
PFRV '
.200
.200
.200
.200
.200
,?00
.200
.200
.200
.200
.200
.200
.200
.?00
.200
• 2ftO
.188
.?00
.200
.200
,?00
.200
.?00
.200
,?00
.200
.?00
,?00
,?00
.?10
,?00
,?00
.200
,?00
.?00
,?00
.200
.200
.200
.200
•
•
•
•
•
•
•
»
*
•
•
•
•
*
•
,
•
*
•
*
*
•
,
.
,
.
•
»
•
*
*
•
•
•
•
' •
*
»
•
IMP
588
587
588
588
588'
588
588
588
588
588
588
588
588
588
588
587
587
588
583
588
588
588
588
5"P
589
5^8
588
588
588
588
588
588
5H8
588
5*8
588
588
588
588
588
PEHtf
.350
.350
.350
.350
.350
.350
.350
.350
.350
6.350
6.350
6.350
6.350
6.3SO
6.350
6.350
5.97?
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.350
6.. 350,
6.350
6.350
6.350
6.350
6.350
INFL RT (HM/HR)
MAX MIN INF(.(MM)
190.56
206.13
217.27
205.43
217.71
200.41
220.61
217.69
226.02
254.00
244.76
239.18
246.99
20?.52
197.66
19?.63
170.60
225.?!
209.76
213.64
240.43
223,34
21?.92
2*5.19
2US.74
239.03
194.10
20?.9?
196.21
1*4.17
173.05
190.30
205.51
219.78
183.13
166.39
176.72
187.14
246.09
233.66
41.93
44.84
46.49
44.65
43.54
U'l.«8
45.18
47.14
45. ?4
50.80
49.88
49.52
50.10
45.02
00.51
40.78
36.00
46.48
«2. 27
44.118
«8.33
«4.72
43.51
U9.-J8
50.07
49.30
«2.99
44.90
43.62
40.01
36.67
41.85
42.9?
44.85
$9.70
34.68
35.68
38.05
49.23
46:74
2.29
2.99
3.34
2.*S
3.81
2.48
3.75
3.27
4.10
5.08
4.6?
4.34
4.73
2.60
2.96
2.59
2.11
3.86
3.48
3.40
4.57
a. oo
3.50.
«.t?
a. 7?
4.33
?.3»
2.64
2.40
2.16
1 ,9tt
2.28
3.11
3.75
2.14
1.80
2.32
2.65
4.80
1.37
MYET
NO
2
3
3
3
a
2
2
2
3
4
a
5
5
1
2
2
1
2
3
3
2
2
3
3
5
2
2
2
2
2
2
1
2
2
I
1
1
2
2
4
LNO
USE. PRCNT
RES C0«* I NO OPEN
2
2
0
5
0
t
1
5
t
0
0
0
0
7
15
aa
46
«i
02
13
20
15
1
8
0
0
7
0
1
13
21
19
4
6
36
5
t7
15
1
0
0
0
1
0
0
a
0
i
1
0
0
0
e
0
8
7
17
3
3
1
3
?
0
1
0
0
0
0
0
0
3
2
0
0
2
0
5
2
0
0
t
3
1
1
0
22
25
1
0
0
0
0
0
7
12
0
11
2
0
0
2
0
0
1
0
1
1
0
1
2
2
10
0
0
8
0
3
I
0
0
95
93
96
92
99
71
72
91
97
99
99
99
99
84
33
«6
21
51
50
85
72
82
98
88
99
98
90
98
96
63
72
67
9a
93
52
94
73
78
97
100
TOTAL NUMBER OF SIJBCATCHMeNTS, "0
TOTAL TRIBUTARY AREA (KM?), 667.22
-------
TABLE F-2
VIATERSHED DATA—PETALUMA BASIN
MATCRSMED OAT* FOR BASIN NO. I, LAND USE PLAN « 3RC47B
I
2
3
a
5
6
7
e
9
10
It
12
13
Id
1401
100?
1003
1000
1005
1006
1007
1008
1009
1010
1011
101?
1011
iota
lots
• NNEL
U"9ER
toon
100?
1005
1007
1009
1003
1009
1011
1006
1010
1018
101T
1015
1014
1016
WIDTH
(M)
396?.
579i.
115??.
«?67.
457?.
10973.
10971.
4?67.
MOt.
I5?40.
h096.
1066*.
1159?.
9534.
10973.
AREA
(KM?)
T.
7.
7,
8.
1«.
?l.
7.
14.
1?.
H.
«7.
25.
15.
13.
9.
SLOPE
(M/M)
.035
.018
.010
.005
.010
.020
.010
.014
.150
.100
.010
.020
.015
.013
,025
P9CMT
IMP
10.7
6.1
16.5
35.9
21. A
6.0
??.S
17.9
6.0
6.0
10.0
10.?
9.6
6.7
7.8
MANNING N PEP STOR (MM)
IMP
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
.013
PFRV 'IMP PERV
.200
.200
.200
.200
.?00
.?00
.?00
.?00
,?00
.?00
.200
.?00
.200
.200
.200
.5*8
.5*8
,5ft9
.588
.5P8
,5C8
.5P8-
.588
.SflR
.5AH
.58A
.5R8
.588
.588
.588
.350
.350
.350
.350
.ISO
.ISO
.350
.350
.150
.350
.350
.150
.350
.350
.350
INFL RT (MM/MR) MAXIMUM MYCT
MAX MIN 1NFL("M) NQ
LNO USE, "PCNT
RES COX 1*9 OPE*
TOTAL «y«n»E<» OF SOeCATCHMENtS. 15
TOTAL TRIBUTARY AREA (KM?), 188.78
33.34
10.08
30.U8
10.48
«M.9«
36.?9
10.»8
IS.31
85.7?
36.7)
49.AQ
49.14
Hi. 53
35.20
•32.78
2.01
1.5?
1.5?
1.5?
3.17
2.54
1.5?
2.16
0.19
2.62
1.59
«.52
3.60
?.35
1.93
166.05
15?.40
152.00
152.DO
?04.?0
181.43
152.40
176.38
228.60
183.66
200.lt
2AI.55
212.15
176.02
161.91
5
5
3
3
3
t
o
?l
38
3«
0
«0
9
0
0
9
0
3
0
1
3 9]
0 99
72
I
0
0 5
7 13 40
5 0 60
0 99
I
53
4 80
0 99
0 99
68
94
93
I
3
I
0 99
0 9T
-------
Table F-3
INFILTRATION RATES AND MAXIMUM POSSIBLE INFILTRATION
Infiltration Rate Infiltration
Land Use Soil Group Maximum
Residential Light
Residential Medium
Residential Heavy
Commercial Centered
Commercial Suburban
Industrial
Grazing/Open
Agricultural -- Field/
Truck Crops
Agricultural — Vineyards/
Orchards
High
Medium
Low
High
Medium
Low
High
Medium
Low
45.7
30.5
30.5
30.5
30.5
30.5
50.8
45.7
30.5
Rates, mm/hr
Minimum
2.5
1.5
1.5
1.5
1.5
1.5
5.1
2.5
1.5
Maximum Possible
Infiltration, mm
203.2
152.4
152.4 '
152.4
152.4
152.4
254.0
203.2
152.4
-------
Table F-4
PERCENT IMPERVIOUS AREAS
Land Use Category Percentage of Impervious Area
Residential Light r 30
Residential Medium 65
Residential Heavy 80
Commercial Centered . . , 95
Commercial Suburban , 90
Industrial 98
Grazing/Open , 6
Agricultural Field 6
Agricultural Vineyard 6
In order to obtain channel geometry for representation in both the
Runoff-Quality Model and QUAL-II, it was necessary to make field
measurements in both the Laguna and Petaluma River Basins. Sixty
stations were visited in the Laguna Basin and 20 stations were
visited in the Petaluma Basin by the ABAG staff. At each station,
the cross-sectional area of the channel was recorded along with
the field party's estimate of channel roughness conditions.
Length and slopes of channels were taken off the U.S.G.S. 7-1/2
minute quad sheets. Tables F-5 and F-6 show the channel characteristics
for the Laguna and Petaluma Basins, respectively.
Precipitation
The Environmental Data Service of the National Oceanic and Atmospheric
Administration publishes hourly precipitation data each month for two
continuous recording rain gages in the study area. They are Sebastopol
and Petaluma Fire Station. The Sonoma County Water Agency has a con-
tinuous recording gage at the County Administration Building in Santa
Rosa. There are several other rain gages in the Laguna and Petaluma
Basins but none are continuous recording units.
Historical precipitation in Santa Rosa was reviewed and on the basis
of precipitation in 1966, a "typical" year insofar as total annual
rainfall and monthly distribution, a typical winter storm was developed
and used in the wet weather simulations. Figure F-l shows rainfall for
1966 at Santa Rosa. The typical winter storm produced 2.45 cm of pre-
cipitation over a 4-hour period. The assumption was made that the
typical winter storm would produce total rainfall over the four hour
period in proportion to the mean annual rainfall. Consequently, the
2.45 cm of rainfall produced by the typical storm at Santa Rosa corre-
lates to Santa Rosa's mean annual rainfall of about 76.2 cm (30 in).
For subareas having annual totals greater (or less) than 76.2 cm the
F-ll
-------
I
I—»
ro
TABLE F-5
CHANNEL DATA-LACUNA BASIN
DRAINAGE CHANNEL INPUT DATA FQft BASIN NO. J
INT
NU*
I
2
3
*
5
b
7
8
9
10
11
12
13
14
15
16
17
1 B
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
39
40
42
«3
49
45
CHAN
NJW
loot
1002
1003
1004
1005
1006
1007
2001
2002
2«03
2004
2005
2006
2037
2008
3001
3P02
3003
3004
3005
3006
3097
3008
Jft09
3010
3011
3012
3013
3014
3015
3016
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013"
4014
CHAN
CONV
4014
1001
1001
toot
1004
1004
1003
2008
2006
2002
2003
2004
?004
2POS
4001
4002
3001
3001
3003
300$
3002
3002
3016
3016
3009
3009 '
3008
3012
3006
3006
300? '
4014
4001
4002
4003
4004
4004
u004
4006
4008
4009
4010
4006
40(2
9099
KIOTM
f W) .
10.67
4.57
9.14
13.7?
4.57
7.62
5. IB
4.57
76.20
27.43
16.76
3.05
16,29
15.24
91 .44
13.72
13.72
6.10
6.10
9.14
4.57
3.05
4.66
9.14
7.62
4. 57
3.66
' ' 4.57
15.24
5.49
7.62
121.92
121.02
21.34
13.72
15.24
9.14
9.14
60.96
24.38
IB. 29
6.10
9.14
6.10
162.66
LFN6TH
(**)
35)6.
1951.
67-06.
1219.
2926.
5466.
2134.
4877.
5364.
546*.
7315.
4«77.
6230.
6096.
2256.
5334.
6401.
2438.
6553.
4«77.
10056.
9144.
44?0.
1524.
,3658.'
2743.
1629.
5791.
,-4572.
3658.
3962.
3 0 H 6 ,
2743.
4572.
79?}.
3536.
5791.
3J53.
3353.
3200.
1524.
1372.
6230.
2743.
4877.
SLOPE
(W/M)
.00300
,00300
.00400
.00100
.00400
' .00400
.0250(1
.00300
.00300
.00500
.01200
.OP'lOO
.00700
.02000
.00300
.00300
.00300
.00400
.01000
.00400
.OOROO
.03000
.00500
.00500
.00900
.02000
, .01200
.02000
.00600
, .01000
.00500
.00030
.00030
.OOOJO
.00060
.00200 .
• .00050
.00100
.00040
-.00100
.02000
.16000
.00400
.03000
.00040
SIDE
LEFT
.2
.0
.2
.0
.3
.3
.0
.3
.3
.2
.3
.3
.5
.3
.3
2.5
2.5
1.0
1.0
.5
.3
.3
.5
1.0
.0
t.o
1.0
.3
.5
1.0 , ,
.5: *
2.0
2.0
.0
.5
1.0' -••>'<
2.0
.0
1.0
1.0
1,0
1.0
.0
.3
2.0
SLOPES
RIGHT
.2
.0
.2
.0
'.3
.3
.0
.3
.3
, j
.3
.3
.5
.3
.3
2.5
2.5
1.0
.3
.5
.3
.3
.5
1.0
.5
1.0
i.O
.3
.5
, 1.0
• 5,- •«
.3
.3
.0
.5
1.0
2.0
.0
1.0
1.0
1.0
1.0
.0
.3
' 2.0
MANNING
N
.050
.060
.040
.040
.050
.050
.040
,040
,040
.040
.040
,0
2.06
1.02
1.76
U35
1.23
3.65
1.22
1.77
3.10
4.56
4.32
3.3?
3.70
1.79
2.64
2.64
2.42
?.h5
1.35
1.99
1.97
2.69
2.01
2.29
2.91
3.65
4.73
1.99
2.39
' 2.98
.68
.89
.77
1.41
.89
.90
.94
,43
1.09
3.15
11.11
2.36
3.65
' 1.02
0 FULL
(CMS)
109.065
11.365
25.361
13.531
12.418
12.042
30.372
7.245
207.166
236.109
221.176
44.226
156.150
70.591
249.109
246.720
246.720
67.465
26.511
11.611
11.830
10.637
66.023
32.611
22.102
27.060
7P.630
80.4P7
2". 361
13.975
' 10?.<»f>9
336.540
336.268
50.074
65.375
2?. 765
41.769
15.801
40.838
52.325
55.327
132.539
65.913
36.694
569.957
TOTAL NUMBER OF CHANNELS* 45
-------
I
•-•
CO
TABLE F-6
CHANNEL DATA-PETALUMA BASIN
CHANNEL IWUT DATA FQ« MSI* MO. 2
«T
u«
t
2
S
4
S
6
7
e
9
to
II
12
IS
|4
IS
16
17
16
CHA<|
•JO*
loot
1002
IOOS
1004
IOOS
1006
1007
too*
1009
1010
1011
101?
1013
1014
1015
1016
1017
1016
CHAN
CP^V
1099
toot
1002
1001
1004
IOOS
1004
1007
1008
1009
loos
toil
101?
1013
101?
1015
1011
toil
NtflTH
t")
lo. an
7.6?
3. OS
27.4)
10.67
6.10
24.39
2?. 86
10. 67
6.10
15.24
6.10
«.57
4.57
9.14
4.57
7.62
7.62
LCN6TM
(")
1219.
3962.
2296.
1372.
4267.
4267.
1829.
2743.
4877.
4?67.
54B6.
1629.
1067.
41 IS.
4877.
3993.
4328.
4267.
SLOPE
.00100
.00300
.00400
.00100
.01000
.04000
.ootpo
.00100
.01000
'.04000
.00200
.00200
.00400
.02000
.00400
.02000
.00300
.00300
SIDE SLOPES
BIGHT
1.0
.5
.3
1.0
•.s
.)
.3
1.0
.3
1.
I.
•
1.
.7
.3
.3
MANNING
N
.040
.040
.040
.040
.040
• .050
.040
.040
.050
.050
.050
.040
.040
.040
.040
.050
.050
.050
IPTN
(M)
.05
.5?
.05
.05
.52
.52
.05
.05
.52
.52
.05
.05
.52
.52
.52
.52
.52
.52
¥ FULL
(MP5)
1.50
1.51
1.63
1.49
2.65
4.21
1.46
1.46
2.2ft
4.30
1.55
1.65
1.63
J.OB
1.79
2.69
1.19
1.20
0 FULL
(CMS)
IS J. SIT
19.29*
21.247
ISA. 070
46.054
42.370
111.609
115.273
36.444
49.9»4
76.674
38.414
15.136
26.309
29.168
24.662
14.520
14.714
TOTAL SU«flEU OF CHANNELS, 18
-------
4.0-
-
S" 3.0-
1
O
f^_
2
o
Ul
£ 2-°-
-
1.0-
-
0-
9.
h
34
1
1 fl
ITT i n n
9 19 29 9 19
J F
I.
1* n
29 9
... 1 , .
ill I i i I I I r I i i i i i i i i i i i i i n it i i i i i i .1 i i i r
19 29 9 19 29 S 19 29 9 19 29 9 19 29 9 19 29 9 19 29 S 19 29 9
MAMJJASO
TIME
J
ul
ii i
19 25
N
L
5 IS 24
0
-120
•»
-100
-80
E
E
1
O
2
a
0
UJ
tc
a.
-40
*
-20
-O
Figure F-l
HISTORICAL PRECIPITATION FOR 1966 AT SANTA ROSA
-------
Santa Rosa rainfall was increased (or decreased) in direct relation-
ship to the annual rainfall. For example, a subarea having an annual
rainfall of 114.3 cm would receive 50 percent more rainfall during a
storm than would a subarea with an average annual rainfall of 76.2 cm.
This annual rainfall relationship is used by the Sonoma County Water
Agency.
Five hyetographs were prepared based on mean annual rainfall and the
appropriate hyetograph was assigned to each subarea. These assign-
ments are given in Table F-l and F-2. The intensity of rainfall at 30
minute intervals is given for each of the five hyetographs used in the
Laguna and Petaluma Basins in Table F-7.
Headwater Flows and Point Source Discharges
Figures VI-3 and VI-9 show the QUAL-II stream network setup for the Laguna
and Petaluma Basins. Flows and their qualities are required for the
headwaters of the networks and the point source (STP) discharges. In
dry weather there is almost no flow in the headwaters of the Laguna de
Santa Rosa and its main tributaries, Windsor, Mark West and Santa Rosa
Creeks. There is no flow in the upper reaches of the Petaluma River.
Consequently, it was necessary to assume a small flow (0.1 m3/sec) at
the headwaters in order to have some water flowing in the upper elements.
It was also necessary to make assumptions as to the quality of the
headwater flows. Obviously, these assumptions complicate the task of
calibrating the model. A trial and error procedure was required to
set headwater flows and qualities so that the model could come close
to simulating the observed quality downstream. This is discussed
later in this appendix.
The point source discharges did not present much of a problem insofar
as obtaining flow rates and effluent qualities. The Regional Water
Quality Control Boards have records of sewage treatment plant flows
and qualities and these records were used in calibrating the model.
Under future levels of development, the recently completed Basin Plans
were used to determine the location of sewage treatment plants. Flow
rates were estimated by multiplying population by the historical per
capita wastewater flows for the area and effluent qualities were based
on actual discharge permit conditions or theoretical effluent qualities
associated with various treatment levels.
KEY MODEL VARIABLES
The Runoff-Quality Model estimates the washoff loads from urban areas
and rural areas for a single storm event. These washoff loads are
then transported through the model channel system. The manner in
which the pollution load available for washoff is estimated is de-
scribed in the following pages.
F-15
-------
Table F-7
DISTRIBUTION OF RAINFALL USED IN WET WEATHER SIMULATIONS
Hyetograph k hr.
1 hr.
Intensity at 30 minute intervals, mm/hr.
Us hrs. 2 hrs. 2h hrs. 3 hrs. 3% hrs. 4 hrs.
Laquna Basin
No.
No.
No.
No.
No.
1
2
3
4
5
Petal urna
No.
No.
No.
No.
No.
1
2
3
4
5
2
3
3
4
4
Basin
2
2
3
3
4
.79
.30
.81
.32
.57
.29
.79
.30
.81
.32
3.56
4.06
4.83
5.33
5.84
3.05
3.56
4.06
4.83
5.33
4.57
5.33
6.10
6.86
7.62
3.81
4.57
5.33
6.10
6.86
18.29
21.34
24.38
27.43
30.48
15.20
18.29
21.34
24.38
27.43
7.11
8.38
9.40
10.67
11.94
5.84
7.11
8.38
9.40
10.67
5.08
5.84
6.86
7.62
8.38
4.32
5.08
5.84
6.86
7.62
4.06
4.83
5.33
6.10
6.86
3.30
4.06
4.83
5.33
6.10
3
3
4
5
5
2
3
3
4
5
.30
.81
.32
.08
.59
.79
.30
.81
.32
.08
-------
Urban Areas
Pollutants in developed areas accumulate on impervious surfaces and
are washed off with the next storm. The key variable in the Runoff-
Quality Model accounting for the pollution load in urban areas avail-
able for washoff is the accumulation of dust and dirt. The daily rate
of the buildup of dust and dirt per unit length of curb and gutter
variable by land use is given in Table F-8.
Table F-8
BUILDUP OF DUST AND DIRT
Curb and Gutter, Rate, kilograms/ Accumulation
meters/hectare meter/day kilograms/hectare/
Land Use day
Residential Light
Residential Medium
Residential Heavy
Commercial Centered
Commercial Suburban
Industrial
150.57
225.86
301.14
301.14
301.14
225.86
0.006
0.009
0.016
0.024
0.024
0.33
0.90
2.03
4.82
7.23
7.23
7.45
All water quality parameters are expressed as a function of the
accumulation of dust and dirt variable by land use. Table F-9 shows the
relationship of the eight parameters modeled to dust and dirt.
The total accumulation of pollutants in urban areas available for
washoff is dependent on the number of dry days proceeding the storm.
Referring back to Figure F-l, the average interval between storms during
1966 in the Santa Rosa area was about 20 days. All wet weather simu-
lations which are made to compare the effects of the various land use
alternatives on wet weather quality were made with 20 days of buildup in
urban areas.
NONURBAN AREAS
The Universal Soil Loss Equation is used to predict total erosion from
a nonurban land area. The universal soil loss equation states that
(5):
A = (R)*(K)*(L)*(C)*(P)
F-17
-------
Where A Is the soil loss per unit area in tons/acre/time step,
R represents the rainfall factor,
K is the soil erodibility factor,
L represents the slope length gradient ratio
C is the cropping management factor, and
P is the erosion control practice factor.
R, in turn, is given by
R = El = 1^(9.16 + 3.31 log X^D-DI
Where E represents the rainfall energy in hundreds of foot-tons/
3CY*G
i is the rainfall hyetograph interval,
The value of L is given by
L = X1/2(0.0076 + .0053S + .00076S )
Where x is the length in feet from the point of origin of flow
to the point at which sedimentation occurs or at'which
flow enters some defined channel, and
S is the average percent slope over the runoff length.
Table F-9
RELATIONSHIP OF WATER QUALITY PARAMETERS TO DUST AND DIRT
Parameter/Dust and Dirt, mg/g
Parameter RL RW RH CC CS
Total
Suspended Solids 340
Nonsettleable So i Ids
BOD
Oil and Grease
Fecal
Total
Total
Total
Coli forms*
Nitrogen
Phosphorus
Heavy Metals
180
35.7
45.1
82xl03
7.51
1.06
2.16
340
180
35.7
45.1,
82xlOJ
7.51
1.06
, 2.16
250
280
53.1
78.6 ,
190xlOJ
5.12
1.08
2.28
445
240
35.9
30.2 3
0.82x10
6.32
0.65
2.26
445
240
35
30
0.
6.
0.
2.
.9
•2 3
82x10
32
65
26
249
176
14
35
7.
4.
0.
1.
.0
.4
7x10
52
69
90
*0rganisms/g - The number of fecal organisms/gram of dust and dirt was
determined by dividing the number of organisms in the runoff samples
by the weight of total solids (dust and dirt) in the samples.
F-18
-------
The remaining variables (K, C, and P) are empirical in nature and are
generally obtained from a table or monograph. For K, the Sonoma
County Soil Survey (4) provided the basic information on the five soil
parameters that constitute this term. The parameters are:
1. % silt + very fine sand
2. % sand > 0.10 mm
3. Organic matter content
4. Soil structure
5. Permeability
Six soil types may be used to approximate the soils in Sonoma County
and an average value for each parameter was calculated and then used
in a monograph to determine a K value of 0.20 for Sonoma County. The
crop management factor "C" used was as follows:
Grazing and Open 0.0002
Agricultural - Orchards/Vineyards 0.0020
Agricultural - Truck/Field Crops 0.0016
The Runoff-Quality Model solves the Universal Soil Loss Equation
giving total suspended solids washed off each subarea within each
watershed. All other constituents are computed as a constant fraction
of total suspended solids. The fractions are variable by constituent
and constant by land use type.
The surface loading rates for constituents other than suspended solids
are based on the mass emissions of nonpoint source pollutants provided
in the San Francisco Bay Basin Plan (6). The ratios of several con-
stituents to suspended solids for Sonoma County are:
(1) BOD = 3.2
TSS"
(2) Nitrogen = 2.6
TSS
(3) Phosphorus - 0.2
TSS
(4) Oil & Grease- 2.2
TSS
(5) Total Heavy Metals = 0.3
TSS
Two other constituents, including settleable solids and fecal coliform,
are of interest in the ABAG investigation and the loading rates for
these were adopted from work WRE did in Iowa where the nonurban portion
of the runoff was calibrated and verified. The proceeding ratios
developed from the Bay Basin work are in good agreement with the same
ratios used in Iowa. Table F-10 shows the surface loading rates used in
the ABAG investigation for the three classes of nonurban land use
provided for each alternative.
F-19
-------
Table F-10
NONURBAN LAND USE SURFACE LOADING RATES,
CONSTITUENT/TSS, mg/g
Constitutent
Settleable Solids
BOD5
Suspended Solids
Fecal Coli forms**
Oil and Grease
Total Nitrogen
Phosphorus
Total Heavy Metals
Grazing and
Open
(600)*
3.2
1,000
(28,000)
2.2
2.6
0.2
0.3
Land Use
Ag-Orchard/
Vineyard
(600)
3.2
1,000
(11,000)
2.2
2.6
0.2
0.3
Ag-Truck/
Field/Crops
(600)
3.2
1,000
(11,000)
2.2
2.6
0.2
0.3
* ( ) Ratio adopted from WRE's Iowa work.
** Fecal coliforms per gram SS.
MODEL CALIBRATION
Very little data was available for calibrating either the Runoff-
Quality Model or QUAL-II. A few streamflow measurements in the Laguna
and Petaluma Basins were used to calibrate the Runoff portion of the
Runoff-Quality Model. There is no historical wet weather quality data
against which to compare the quality simulations. Consequently, wet
weather quality results are based on coefficients that were developed
for three different areas. Urban surface loading rates come from the
storm drainage work performed by WRE in Seattle, certain of the rural
loading coefficients and other coefficients were developed from data
presented in the Basin Plan for Sonoma County. Dry weather data for
calibration consisted of several grab samples taken during the summer
of 1973 at several stations along the Laguna de Santa Rosa and a few
samples taken in the vicinity of the old Petaluma STP on the Petaluma
River.
Calibration of Runoff-Quality Model
The only streamflow records appropriate for calibration purposes are
those published by the U.S. Geological Survey in the annual "Water
Resources Data for California, Surface Water Records." These are:
F-20
-------
Drainage Area
Stream (sq. kilometers) Period of Record
Petaluma River at Petaluma 80.3 1948-1963
Mark West Creek at Windsor 111.4 1940-1941
Santa Rosa Creek near Santa Rosa 33.7 1959-1970
The U.S. Geological Survey has a gage on Laguna de Santa Rosa near
Graten, but is of no value in calibration because only water levels
are measured and these levels are directly affected by flow conditions
in the Russian River.
•
The calibration process was confined entirely to quantity of runoff,
as there is no available water quality data for individual storm
events.
Results from applications of the model in other locations have shown
that the percent impervious and the maximum and minimum infiltration
rates are the only parameters to be determined in the runoff quantity
calibration process. All other parameters have been found to be
relatively standard for several locations in the United States.
The standard values for Manning's coefficient of roughness are 0.013
for impervious surfaces and 0.250 for pervious surfaces. The surface
storage detention depth is 1.6 mm (1/16-inch) for impervious surfaces
and 4.8 mm (3/16-inch) for pervious surfaces.
In calibrating the model, it is necessary to have a specific rainfall
hyetograph and the resulting streamflow hydrograph. After reviewing
the available data it was found that there were rainfall and runoff
measurements for only a few medium to heavy storms. Low intensity
storms are inappropriate for calibration because anticedent moisture,
high base flows, and other conditions can greatly modify the runoff
process. Therefore, the calibration work had to be confined to these
few medium to heavy storms.
The first step was to select a specific storm event, use the rainfall
hyetograph for that storm to drive the model, and then compare the
simulated streamflow hydrograph with the gaged hydrograph. This was
done for the Petaluma Basin and the initial simulation results were
lower than the gaged flows. The impervious percentages in uplands and
hill areas were then increased to reflect the rock outcrops and shallow
soil depth over bedrock as reported in the 1972 Soil Survey of the
U.S. Department of Agriculture (4). In addition, the infiltration
rates were decreased from those reported by the USDA Soil Survey for
agricultural lands to lower values used by the Crops of Engineers in
their "Survey Report for Flood Control and Allied Purposes, Petaluma
River Basin", of 1972 (7).
With these above described changes, subsequent simulations were made
which result in increased runoff. Figures F-2 and F-3 show the simulated
and gaged hyrdographs for two storms in December 1955, both of which
represent flows resulting from rain storms having approximately 10 to
20 year recurrence intervals.
F-21
-------
2400
2000
1600
FLOW
/CUBIC FEET^
\KR SECOND/
(CUBIC METERS\
PER SECOND I
12 HOUR
I 12 /IB \ 12/19
12 / 20
1 12 / 21 I DAY
1955
TIME
.Figure F-2
MEASURED FLOWS VERSUS MODEL SIMULATIONS
December 1&-21, 1955
F-22
-------
2400
2000
1600
I20°
VPER SECOND/
800
400
12/25
-60
- SO
-40
(CUBIC METERSN
\ PER SECOND )
- 20
- 10
12
12
12
12
12 HOUR
12/26
12 /27
~\ DAY
1955
TIME
Figure F-3
MEASURED FLOW VERSUS MODEL SIMULATION
December 25-27, 1955
F-23
-------
These simulations are based on rain storms applied uniformly over the
entire Petaluma Basin when, in fact, there are variations in time and
in rainfall amounts as the storm moves across the Basin. Therefore,
more refined calibration cannot be made without additional rainfall
data.
The adjusted parameters from the Petaluma Basin were then applied to
the Laguna Basin. A specific storm was selected and applied to the
Laguna Basin.
The results of this initial Laguna Basin simulation, and a second
simulation, yielded good results. However, only peak flow rates were
compared to gaged values as hydrographs were not available for Santa
Rosa Creek. The results are as follows:
Date of Storm Gaged Peak Flow Simulated Peak Flow
December 22, 19764 52.4 nu/sec 50.4 m /sec
January 21, 1970 60.2 md/sec 64.4 nT/sec
In addition, a rough comparison of peak flows was made for Mark West
Creek near Windsor. Based upon limited U.S.G.S. gaging records, and ,
Sonoma County Water Agency estimates, the peak flow from a storm event
having a five-year recurrence interval should be roughly 224 to 252
nr/sec. The peak flow simulated by the model for a five-year storm
was 207 m3/sec.
The Runoff-Quality Model calibration process was adequately completed
for use in this study, but it was not an extensive techical research
effort. The results indicate adequate to good representation of both
the Petaluma and Laguna Basins, and the user can be confident that the
calibrated model reasonably represents the runoff process.
Calibration of the QUAL-II Model
Laguna de Santa Rosa - Comparisons of computed quality results with
field data measured during the summer of 1973 are shown in Figures F-4
and 9, The differences exhibited reflect a number of things about the
model, the Laguna itself, and the measured data.
First, an overview of all the results indicates that algal activity
was phenomenal in the Laguna near Occidental Road, just downstream of
the Sebastopol waste treatment plant and upstream of Santa Rosa Creek.
The algal numbers were very high (5900/ml maximum); the nutrients, N03
and ?QA> were being depleted by the growing algae; NH3 was being
converted to nitrate or used directly by algae; and the photosynthetic
process was producing dissolved oxygen at a rate that resulted in
concentrations as high as 24 mg/1, a significant degree of super-
saturation.
F-24
-------
I
•
MuO
ZOO
200
DO
(SI MODEL ELEMENT NUMBERS
' •• COMPUTED V4LUES
O MEDIANS OF MEASURED VALUES
I RANGE OF MEASURED VALUES
NH.-N
aoo
OX)
NO.-N
I I l"l I M I I I I I I I I I I I I I I I
Figure F-4
MEASURED AND MODELED QUALITY PROFILES
FOR THE LACUNA DE SANTA ROSA
F-25
-------
•00
woo
-4.
£ MOO
? BO.O
2
w
woo
80.0
60.0
4ao
20.0
OJO
1
I
P04-P
.6000
SOOO
I
^4000
£ 3000
tu
J 2000
I
1000
(5) MODEL ELEMENT NUMBERS
—^— COMPUTED VALUES
O MEDIANS OF MEASURED VALUES
RANGE OF MEASURED VALUES
1
ALGAE
I I I I I I I I I I I I I 1 I I I I I I I I
Figure F-5
MEASURED AND MODELED QUALITY PROFILES
FOR THE LAGUNA DE SANTA ROSA
F-26
-------
Several differences between the measured and modeled profiles are
worth noting. First the measured nitrate nitrogen and phosphate
phosphorus concentration were quite different from the modeled con-
centrations. The measured nitrate values were much lower and the
phosphate values were much higher than those modeled. The concen-
trations of nitrate assumed for the headwaters and waste treatment
plants were actually not unreasonable (1-20 mg/1). The measured
values of phosphate at 50 to 150 mg/1 are inextricably high. One has
to wonder if these measurements were not made from unfiltered samples
containing insoluble phosphate, particularly since the reported PO -P
values were sometimes higher than total dissolved solids concentra=
tions measured at the same time. In one respect it is not terribly
significant that the reported values and the modeled values for the
two nutrients were always higher thanlFTe "half saturation constants"
for N03 (0.3 mg/1) and P04 (0.03 mg/1), which means that neither
nutrient was limiting to the algal growth that occurred, either in the
model or in the Laguna.
An interesting feature of the model's results is the continuity of the
profiles produced; which by contrast with the measurements taken at
sparse and discrete points in the field, gives a truer, more infor-
mative picture of how each plant discharge and tributary inflow affects
the concentrations downstream. An especially notable example is ti:e
impression given by the algae data that a peak bloom occurred near
Occidental Road and somehow disappeared by the time the water reached
Guerneville Road downstream. The model probably more accurately
reflects that the algae continued to grow downstream of Occidental
Road, but they were then drastically diluted by the inflow of water
from Santa Rosa Creek which occurs just slightly upstream of where the
next measurement was made, at Guerneville Road. In other words, the
model and the data measured in the field are best utilized when they
are used together to ascertain both the form and the degree of behavior.
Finally it should be made clear that WRE did not model algal numbers
but indeed algal mass. Algal mass was in turn reflected as mass of
chlorophyll-A which was assumed to be one-twentieth of the algal
cell's mass. The conversion to algal numbers per ml was made merely
to compare the modeled results with what was measured in the field.
The relevant data for the conversion were a 0.025 mm diameter of a
spherical algal cell, a specific gravity of the algae of 1.05, and 1
mg of algae per 50 pg of Chi-A.
The results for algae and dissolved oxygen which are the constituents
most reflective of the final effect of what occurs, indicate that the
model was reasonably well calibrated, if not a perfect representation
of prototype behavior. The data are fraught with inaccuracies as
well, of course; but again the two together give an explainable picture
of how the Laguna behaves during dry weather. This was the point of
the exercise.
F-27
-------
Petaluma River - Quality data available for calibration of BOD, DO,
and other model parameters were measured by the City near the old
Petaluma waste treatment plant. The results from the model compared
favorably with the measured data at this one point, but the measure-
ments were not areally extensive enough to permit comparisons of
profiles.
As described in Chapter III, the model was calibrated with total
dissolved solids concentrations measurecTBy the Regional Board.
F-28
-------
REFERENCES
1. U. S. Army Corps of Engineers, Seattle District, "Appendix B,
Urban Storm Drainage Simulation Models", Environmental Manage-
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Washington, December 1974.
2. Water Resources Engineers, Inc., Agricultural Watershed Runoff
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7. Corps of Engineers, "Survey Report for Flood Control and Allied
Purposes, Petaluma River Basin", 1972.
F-29
-------
BIBLIOGRAPHY
-------
BIBLIOGRAPHY
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-------
Books (cont'd)
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r,
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-------
Articles (cont'd)
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-------
Reports (cont'd)
Argonne National Laboratory, Energy and Environmental Studies Division,
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-------
Reports (cont'd)
California Air Resources Board, Summary Report on Current Methodologies for
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-------
Reports (cont'd)
Engineering Science, Inc. and Howard, Needles, Tammen and Bergdorf,
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-------
Reports (cont'd)
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May, 1973^ ~~"— * * a
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-------
Reports (cont'd)
Metcalf and Eddy, Inc., University of Florida and Water Resources Engineers,
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Metropolitan Transportation Commission, Regional Transportation Plan for the
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Northeastern Illinois Planning Commission, Managing the Air Resource in
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PEDCo Environmental Specialists and Vogt, Sage, and Pflum, Air Pollution
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Roddin, Marc, et. al., An Analysis of the Proposed Parking Management
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Rivkin/Carson, Inc., The Sewer Moratorium as A Technique of Growth Control
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San Bernardino Environmental Improvement Agency, The Air Quality Plan of
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San Diego Comprehensive Planning Organization, Water. Wastewater and Flood
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Sartor, James D. and Gail B. Boyd, Water Pollution Aspects of Street Surface
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Office of Research and Monitoring, November, 1972.
-------
Reports (cont'd)
Sedway/Cooke Urban and Environmental Planners and Designers, "Guide to
Implementation Techniques for Air and Water Quality Management
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Shaheen, Donald G., Contributions of Urban Roadway Usage to Mater Pollution.
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Stone, Ralph and Herbert Smallwood, Intermedia Aspects of Air and Water
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Strong, Ann L. and John C. Keene, Environmental Protection Through Public
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Texas Water Development Board, QUAL - I - Simulation of Water Quality in
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Thuillier, Richard H., A Regional Air Pollution Modeling System for
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Thuillier, Richard H., Air Quality Statistics in Land Use Planning
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Thurow, Charles, William Toner and Duncan Erley, Performance Controls
for Sensitive Lands: A Practical Guide for Local Administrators,
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Tourbier, Joachim, Water Resources as A Basis for Comprehensive
Planning and Development of the Christina River Basin, Newark,
Delaware:Water Resources Center, University of Delaware, 1973.
Tourbier, Joachim and Richard Westmacott, Water Resources Protection
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TRW Inc., Air Quality Management Plan and Program Recommendations
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TRW Inc., Development of A Sample Air Quality Maintenance Plan for
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Protection Agency, September, 1974.
-------
Reports (cont'd)
TRW, Inc., Prediction of the Effects of Transportation Controls on
Air Quality In Major Metropolitan Areas, Prepared for U.S. Environ-
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TRW Systems Group, Air Quality Display Mode]. Washington, D.C.: National
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TRW, Inc., Transportation and Environmental Operations, Air Quality
Implementation Plan Development for Critical California Regions:
San Francisco Bay Intrastate Air Quality Control Region, August, 1973.
University of Delaware, Water Resources Center, The Christina Basin: The
Protection of Water Resources as A Basis for Planning in Developing
Areas, Newark, Delaware: Delaware University, 1972. "'
Urban Systems Research and Engineering, Inc., Interceptor Sewers and
Suburban Sprawl: The Impacts of Construction Grants on Residential
Land Use, Cambridge, Mass.:1974.
URS Research Company, Water Quality Management Planning for Urban Runoff,
San Mateo, Calif.": December, 1974. '
U.S. Corps of Engineers, Hydrologic Engineering Center, "Urban Storm
Water Runoff: STORM," Computer Program 723-S8-L2520, January, 1975.
U. S. Department of the Interior, Federal Water Quality Control
Administration, Storm Water Pollution from Urban Land Activity,
Washington, D.C.: U.S. Department of the Interior, FWQC Admin-
istration, July, 1970.
U. S. Environmental Protection Agency, Guidelines for Air Quality
Maintenance Planning and Analysis - Volume 3: Control Strategies,
Research Triangle Park, N.C.: July, 1974.
U. S. Environmental Protection Agency, Guidelines for Air Quality
Maintenance Planning and Analysis. Vol. 13: Allocating Projected
Emissions to Subcounty Areas. Washington. D.C. November. 1974.
U. S. Environmental Protection Agency, Water Quality Management Planning
for Urban Runoff. Washington, D.C., 1974.
U. S. Environmental Protection Agency, Office of Air and Water Programs,
Methods for Identifying and Evaluating the Nature and Extent of
Nonpoint Sources of Pollution. Washington:U.S. Govt. Printing
Office, 1973.
U. S. Environmental Protection Agency, Office of Air and Water Programs,
Processes. Procedures, and Methods to Control Pollution Resulting
from All Construction Activity. Washington. D.C.. October. 1973.
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Reports (cont'd)
U. S. Environmental Protection Agency, Office of Water Planning and
Standards, Water Quality Management Planning for Urban Runoff,
Washington, D.C., 1974.
U. S. Environmental Protection Agency, Water Planning Division,
Urban Stormwater Management Research and Planning Projects for
FY 1975 and FY 1976, Information package. Washington. D.C..
March, 1975.
U. S. Environmental Protection Agency, Water Planning Division, Areawide
Management Branch, "Annotated Bibliography for Areawide Water
Quality Management," Washington, D.C., 1975.
U. S. Water Resources Council, Water and Related Land Resources;
Establishment of Principles and Standards for Planning. Washington,
DTcT:National Archives, 1973.
U. S. Water Resources Scientific Information Center, Urbanization and
Sedimentation; A Bibliography. Washington, D.C.: The Center, 1971.
Alan M. Voorhees and Associates, Inc., Baltimore Regional Environmental
Impact Study (BREIS), March, 1974.
Alan M. Voorhees and Associates, Guidelines for Air Quality Maintenance
and Analysis; Volume 4: Land Use and Transportation Consideration's,
Research Triangle Park, N.C.:U. S. Environmental Protection Agency
August, 1974.
Alan M. Voorhees and Associates, Guidelines to Reduce Energy Consumption
Through Transportation Actions, Washington, D.C.:Urban Mass Transi
Administration, May, 1974.
Alan M. Voorhees and Associates, In Association witK Herman D. Ruth and
Associates, An Assessment of Secondary Air Quality Impacts and
Potential Mitigation Measures for A Wastewater Treatment Facility
in Central Contra Costa County - Interim Progress Report, June 4, 1975.
Alan M. Voorhees and Associates; Ryckman, Edgerly and Tomlinson and
Associates, A Guide for Reducing Air Pollution Through Urban Planning,
Research Triangle Park, N.C.:U. S. Environmental Protection Agency,
December, 1971.
Alan M. Voorhees and Associates, Water Resources Engineers, Inc., and
Environments for Tomorrow, Inter-Relationships of Land Use Planning
and Control to Water Quality Management Planning, Washington. D.C.:
U. S. Environmental Protection Agency, April, 1973.
i1''1- "* i
Water Resources Engineers, Application of the EPA Stormwater Management
Model to Agricultural Watersheds for the Iowa - Cedar River Basins,
Washington, D.C.:U. S. Environmental Protection Agency, Systems
Development Branch, 1973.
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Reports (cont'd)
Water Resources Engineers, Computer Program Documentation for the
Stream Quality Model QUAL II, Washington. D.C.:U. S. Environmental
Protection Agency, October, 1973.
Wei son, John R. and Benjamin H. Stevens, Air Quality and Its Relationship
to Economic, Meteorological, and Other Structural Characteristics of
Urban Areas in the United States, RSRI Discussion Series Paper,
Series No. 42, Philadelphia, Pa.: Regional Science Research Institute,
1970.
Williams, J. D., et. al., Air Pollutant Emissions Related to Land Area -
A Basis for A Preventatiye Air Pollution Control Program, Durham, N. C.:
U. S. Public Health Service, 1968.
Willis, Byron H., The Hackensack Meadowlands Air Pollution Study, Summary
Report, Research Triangle Park, N.C.:U.S. Environmental Protection
Agency, July, 1973.
Willis, Byron H., The Hackensack Meadowlands Air Pollution Study; Task 3
Report: The Evaluation and Ranking of Land Use Plans, Research Triangle
Park, N.C.:U.S. Environmental Protection Agency, November, 1973.
Willis, B. H., J. R. Mahoney and J. C. Goodrich, The Hackensack Meadowlands
Air Pollution Study; Task 4 Report; Air Quality Impact of Land Us"?
Planning, Research Triangle Park. N.C.:U.S. Environmental Protection
Agency, July, 1973.
Willis, Byron N., John C. Goodrich and E. C. Reifenstein, "Incorporating
Air Pollution Considerations in the Planning Process," Paper Presented
at the Annual Meeting of The American Institute of Planners, San
Francisco, Ca.: October 24-28, 1971.
Yocom, J. E., D. A. Chisholm, G. F. Collins, J. A. Farrow, R. A, Gagosz
and J. C. Magyar, Summary Report: Air Pollution Study of the Capitol
Region, Hartford, Conn: TRC Service Corp., 19157.
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