EPA903-R-97-018
Integrating Build-Out Analysis and Water
Quality Modeling to Predict the Environmental
Impacts of Alternative Development Scenarios
A report prepared for the Chesapeake Bay Program
March, 1998
Chesapeake Bay Program
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ACKNOWLEDGMENTS
The Land, Growth and Stewardship Subcommittee of the Chesapeake Bay Program would like to
extend thanks to all of the following organizations that provided documentation on the various build-
out analyses reviewed in this report, offered comments on summaries of the build-out analyses
reviewed, and guided the development of this report through the willingness of key staff to share their
knowledge and experience in build-out analysis and/or watershed/water quality modeling:
The U.S. Environmental Protection Agency; Maryland Office of Planning; Buzzards Bay Project;
Thomas Jefferson Planning District Commission; National Oceanic and Atmospheric Administration;
Massachusetts Bays Program; Orange Water and Sewer Authority; State Highway Administration,
Maryland Department of Transportation; Johnson County Planning Office; and the College of
William and Mary.
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EXECUTIVE SUMMARY
This report provides background information on the use of build-out analysis and water
quality/environmental modeling as land planning and water quality predictive management tools. It
also provides information helpful in assessing the utility of certain versions of these tools for use by
the Chesapeake Bay Program in meeting the goals set forth in the Chesapeake Bay Agreement and
elsewhere.
This report originated from the land management and protection goals set forth in the 1987
Chesapeake Bay Agreement and its 1992 amendments, from the priorities set forth in the Chesapeake
Bay Program's 1996 report Priorities for Action for Land, Growth and Stewardship in the
Chesapeake Bay Region; and from the Chesapeake Executive Council's Adoption Statement on Land,
Growth and Stewardship.
This report provides background information helpful in determining if some form of build-out
analysis/water quality modeling methodology exists that could help meet the goals of the Chesapeake
Bay Program. It contains summaries of fourteen build-out analyses that have been conducted in
various regions of the United States, including the Chesapeake Bay watershed, to predict the character
of future landscapes of specific land areas such as watersheds and counties. A number of these
analyses also modeled impacts on water quality or other environmental attributes that might result
from the predicted changes in landscapes. In addition, the report provides general background
information on both build-out analysis and water quality and environmental modeling, including a
discussion of the purposes for these types of tools and models, brief descriptions of common versions
of each, and alternative ways they can be applied to meet typical objectives.
Five of the build-out analysis methodologies are summarized in-depth in the main body of the
document, while nine others are presented as two-page fact sheets. The five selected for in-depth
summary receive greater attention because they include both build-out analysis and water quality or
environmental modeling components in the same study and seem to have particular relevance to the
Chesapeake Bay. The nine fact sheets summarize studies that focused primarily on build-out analysis
methodologies, and not necessarily the application of water quality or environmental models.
The final chapter, "Evaluating Build-out Analysis and Water Quality Modeling Methodologies for
Potential Use by the Chesapeake Bay Program," presents suggested criteria that can be used to
evaluate the kinds of methodologies presented in this report. The criteria were developed by the
Chesapeake Bay Program, and are: 1) Accuracy in predicting environmental impact; 2) Cost; and 3)
Computer and staff resources required. These three general categories allow for evaluation based on
some of the most important criteria that should be considered when evaluating alternative
methodologies for further study or promotion.
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Finally, Appendix A includes a detailed discussion of the potential role of the Chesapeake Bay
Program's Hydrologic Simulation Program-Fortran (HSPF) Watershed Model in conducting build-
out analyses, concluding that certain aspects of the model and its output could be useful, but full-scale
model runs likely would not.
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TABLE OF CONTENTS
ACKNOWLEDGMENTS i
EXECUTIVE SUMMARY ii
I. INTRODUCTION 1
ORIGIN OF STUDY 1
PURPOSE OF STUDY 3
II. BUILD-OUT ANALYSIS AND WATER QUALITY MODELING AS A PLANNING
TOOL 4
BUILD-OUT ANALYSIS 4
Parcel-Level, Manual 5
Summed Area. Manual 5
Geographic Information System 6
WATER QUALITY MODELING 6
Simple Models 6
Mid-Range Models .. •. 7
Detailed Models 7
USE OF WATER QUALITY AND OTHER MODELS IN CONJUNCTION
WITH BUILD-OUT ANALYSES 8
HI. BUILD-OUT ANALYSIS/WATER QUALITY MODELING CASE STUDIES 10
RESEARCH METHODS 10
OVERVIEW OF PROJECT SUMMARIES PRESENTED IN THIS REPORT 11
IN-DEPTH CASE STUDIES 12
Growth Management for Watershed Protection in Maryland 14
Buzzards Bay Project 28
Biodiversity and Landscape Planning: Alternative Futures for the Region of Camp
Pendleton, California 39
Geographical Analysis of Bacterial Contamination 52
Cane Creek Reservoir Watershed Study 61
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IV. EVALUATING BUILD-OUT ANALYSIS AND WATER QUALITY MODELING
METHODOLOGIES FOR POTENTIAL USE BY THE CHESAPEAKE BAY
PROGRAM 67
EVALUATION CRITERIA 67
Accuracy in Predicting Environmental Impact 68
Scale 68
Recognition of Distinct Land Use Types 69
Input Data 69
Output Data 69
Cost/Resource Considerations 70
Ease of Meeting Computer and Staff Requirements 70
EVALUATION OF MODELS PRESENTED IN THIS REPORT 71
Basic Build-Out Analysis Methodologies 71
Parcel-Level, Manual 71
Summed Area, Manual 71
Geographic Information System 71
Basic Water Quality/Environmental Modeling Methodologies 72
Simple Models 72
Mid-Range Models 72
Detailed Models 72
COMPARISON OF BUILD-OUT ANALYSIS AND WATER
QUALITY/ENVIRONMENTAL MODELING METHODOLOGIES FOR
LARGE AND SMALL LAND AREAS 74
Additional Considerations When Selecting a Methodology 76
Determining Type and Number of Development Scenarios 76
Data Requirements 76
Manual Versus Computer-Aided Spatial Analysis 77
Scale 77
Required Resources 77
User Applicability 77
APPENDIX A: EVALUATION OF THE POTENTIAL APPLICATION OF THE
CHESAPEAKE BAY PROGRAM HSPF WATERSHED MODEL TO BUILD-OUT
ANALYSES A-l
APPENDIX B: BUILD-OUT ANALYSIS/WATER QUALITY MODELING
FACT SHEETS B-l
Virginia Eastern Shore Ground Water Supply Management B-l
Severn River Watershed Development Management Plan B-3
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US 301 Transportation Study B-5
Thomas Jefferson Planning District Commission B-7
Lancaster County Comprehensive Plan: Growth Management Plan B-9
Occoquan Watershed Water Quality Study B-l 1
Alternative Futures For Monroe County, Pennsylvania B-l3
Hillsdale Lake Watershed Population and Land Use Projections, 1990-2010 B-l5
Build-Out Analysis on a Geographic Information System (GIS) B-l7
APPENDIX C: RELEVANT LITERATURE C-l
FOR ADDITIONAL INFORMATION C-3
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I. INTRODUCTION
This report provides background information on the use of build-out analysis and water
quality/environmental modeling as land planning and water quality predictive management tools. It
also makes a number of recommendations on the potential utility of certain versions of these tools for
use by the Chesapeake Bay Program in meeting the goals set forth in the 1987 Chesapeake Bay
Agreement and elsewhere.
The report contains summaries of fourteen build-out
analyses that have been conducted to predict the character of What is a Build-°ut Analysis?
future landscapes of specific land areas, such as watersheds and A build-out analysis is a method
counties. A number of these analyses also modeled impacts on used to Predict me development
potential of future landscapes of
water quality that might result from the predicted changes in speciflc land areaS) such ^ watersheds
landscapes. Such analyses can be used to help predict whether or counties. It is commonly used to
- , , , .,.,„., , answer questions such as "What is the
future land use patterns may result in high pollution loads ^^ ^^ of development mat
delivered to impacted water bodies, and this information can be could occur here?", or "Will public
used to catalyze changes in zoning and land management where s™f be ade(?"ate * meet ^ needs
3 ° ° to of all future residents?
necessary to maintain pollution at or below acceptable levels. ^•^•••^^^^^^••^^^••i
In addition to summaries of projects that have been undertaken,
this report provides general background information on both build-out analysis and water quality
modeling, including a discussion of the purposes for these types of tools and models, brief
descriptions of common versions of each, and alternative ways they can be applied to meet typical
objectives.
ORIGIN OF STUDY
In 1983 Maryland, Virginia, Pennsylvania, the District of Columbia, the U.S. Environmental
Protection Agency, and the Chesapeake Bay Commission signed the Chesapeake Bay Agreement,
which was strengthened in 1987 and amended in 1992. The Agreement commits the signatories to,
among other things, implement strategies in each of the tributaries to the Chesapeake Bay that will
result in a reduction of nutrients necessary to support living resources in both the Bay and its
tributaries.
One of the formal Goals of the Chesapeake Bay Agreement is to "Plan for and manage the
adverse environmental effects of human population growth and land development in the Chesapeake
Bay watershed." One of the primary ways this Goal is being addressed is through the actions of the
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Introduction
Chesapeake Bay Program's Land, Growth and Stewardship Subcommittee (LOSS). As set forth in its
mission statement, the Subcommittee is responsible for:
Identifying growth and land use issues of a Bay-wide nature, addressing development topics, and
forging alliances with other organizations and interests to: 1) Promote sound land management
decisions; 2) provide growth projections and assess the impacts of existing growth on the Bay
and its tributaries; and 3) encourage public and private actions to reduce'the impacts of growth.
The CBP further refined these broad goals in its report Priorities for Action for Land, Growth and
Stewardship in the Chesapeake Bay Region, released on October 10,1996. Drawing from the
report's recommendations, the Chesapeake Executive Council's Adoption Statement on Land,
Growth, and Stewardship (October 10,1996), directed the Chesapeake Bay Program to:
Identify models, technologies and practices, that can be used to assess and minimize the impacts
of different development patterns and land use designs on nutrient loadings to the Bay. This
information will be useful to state and local jurisdictions as they work to achieve the nutrient
reduction and habitat restoration goals of the Program. The Chesapeake Bay Program will
communicate and distribute collected materials on these models, technologies and practices to
local governments, land use decision-makers, practitioners, realtors, homebuilders, and other
stakeholders.
The Chesapeake Bay Program has undertaken a number of projects pursuant to the objectives set
forth in the Chesapeake Bay Agreement, the Priorities for Action report, and the Executive Council
Directive. In July, 1996, CBP hosted a workshop at the Chesapeake Bay Program Office that brought
together land use and demographic experts from State and local government agencies and academic
institutions located throughout the Chesapeake Bay watershed. The workshop focused on alternative
methodologies for conducting projections of future land use/land cover, and for conducting
population projections. Also discussed in general terms was the use of build-out analysis as a tool to
forecast future land development in a given land area, such as a watershed or county.
Participants at the July workshop made a number of recommendations to the Chesapeake Bay
Program, among which was to promote further study of the potential of build-out analysis as a tool to
promote land management that resulted in less environmental degradation, particularly less nutrient
pollution to tributaries of the Chesapeake Bay. This report was prepared, in part, as a response to that
request.
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Introduction
PURPOSE OF STUDY
The purpose of this study is to provide background information necessary for determining if some
form of build-out analysis/water quality modeling methodology exists that would be useful in helping
to meet the goals of the Chesapeake Bay Program in promoting land development patterns that
protect water quality. In particular, this study was undertaken to accomplish the following:
• To examine the utility of build-out analysis and water quality modeling as tools for local and
regional land use and environmental planning
• To document as case studies relevant build-out analysis/water quality modeling projects that have
been conducted in the Chesapeake Bay region and elsewhere
• To determine the feasibility of the Chesapeake Bay Program's Watershed Model and other
watershed and water quality modeling tools that could be used in conjunction with build-out
analysis
• To recommend one or more methodologies that the Chesapeake Bay Program may be able to
promote or use for conducting build-out analysis/water quality modeling.
The remainder of this document is organized in three chapters and two appendices. Chapter n
discusses build-out analysis as a planning tool. Chapter m contains several in-depth build-out
analysis/water quality modeling case studies. Chapter IV consists of an evaluation of different kinds
of build-out analysis and water quality modeling techniques and practices, and presents a ranking
scheme to help determine which technique may be most appropriate for different needs. Appendix A
contains an evaluation of the potential role of the Chesapeake Bay Program's Watershed Model in
conjunction with build-out analyses. Appendix B contains nine summary fact sheets of build-out
analysis/water quality modeling projects that have been completed throughout the United States and
Canada.
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H. BUILD-OUT ANALYSIS AND WATER
QUALITY MODELING AS A PLANNING TOOL
Build-out analysis, traditionally a land planning tool, can be combined with water quality
modeling to predict the water quality impacts of alternative development scenarios. This chapter
describes build-out analysis techniques and their integration with water quality modeling and other
modeling approaches.
BUILD-OUT ANALYSIS
As noted in the Introduction, a build-out analysis is a tool typically used by land use planners to
predict future development patterns for a specific land area, such as a town, county, or watershed. A
land area is considered "built-out" if all development allowed by zoning regulations and local by-laws
and ordinances has occurred, and no further development is possible under existing regulations.
Typically, a build-out analysis is conducted by first inventorying current land development patterns
and characteristics, and then estimating the number and type of developments (e.g., single family
homes), that could be accommodated in all land areas zoned for, but currently absent of, development
(e.g., forested areas). Also common are "partial" build-out analyses, which analyze the number and
type of developments at a certain point in time, or at a certain population. For example, a partial
build-out analysis may be targeted to the year 2010, or to the addition of 100,000 residents.
Build-out analyses can be conducted to serve a number of purposes. Most commonly, they are
undertaken by local or regional land use planning departments to determine whether the capacity of
public services such as public schools, fire departments, roads, road intersections, sewer networks,
and sewage treatment plants will be sufficient to serve the community if partial or full development
potential is reached. Such analyses are sometimes combined with population projections for the same
area, in order to predict development patterns at specific points in the future, such as 10 years from
the present. Exhibit 1 provides an example of an analysis of a partial build-out scenario.
Exhibit 1. A Simple Example of a Build-Out Analysis
A county planner may wish to determine where and how much development will occur by the year 2020, based on
U.S. Bureau of the Census projections that 100,000 additional people will live in the county by that time (a
population projection is used here, but is not necessary to conduct a build-out analysis). In a simplified method, this
100,000 figure could be divided by the county's average number of residents per household, producing an estimated
number of additional residential housing units. In this example, assume that the average household size is 4.
Dividing 100,000 by 4 yields an estimated 25,000 new residential housing units by the year 2020. This number is
then multiplied by the average number of acres that a typical housing unit currently occupies in that county, and the
result is subtracted from the total acres of undeveloped land in the county zoned for development. If the average lot
size for residential housing units in this county were one acre, the 25,000 new units would consume 25,000 acres of
currently undeveloped land. If there were currently 45,000 acres of undeveloped land zoned for residential
development in the county, this build-out analysis would indicate that over 55 percent of developable land would be
developed by the year 2020, and that only 45 percent of undeveloped land would remain.
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A Planning Tool
If full-build out will not be reached by the specified point in time (as was the case in the example
in Exhibit 1), the analysis is called a "partial" build-out analysis. An actual example of such an
analysis is the Maryland Office of Planning's study Developing Growth Management Options for
Maryland's Tributary Strategies, reviewed in this report, which based its analysis on potential
development patterns in the year 2010.
In general, it is possible to classify build-out analysis methodologies into three basic categories
for purposes of comparison. There are a large number of variations to methodologies that do not fit
neatly into any of these three categories, but the following descriptions provide basic working
definitions that should aid the reader in using this report.
Parcel-Level. Manual
This method involves forecasting potential development in a geographic area through a process of
manually drawing potential roads, structures, and other types of development onto paper maps until
all developable land areas are consumed. Individual development parcels are drawn onto
undeveloped areas on maps based on zoning requirements for minimum lot size, frontage, and other
constraints. Due to the time required to draw developments by hand, this method is only feasible for
relatively small areas, such as a town or small county. However, it is an inexpensive method that
requires little or no resources aside from paper maps and traditional drafting tools (such a manual
method is described in high detail in the handbook Manual of Build-out Analysis, cited at the end of
this report in "Relevant Literature.")
Summed Area, Manual
This method can be used as an alternative to the parcel-level analysis. Using this method,
development can be measured in a less precise, but much faster manner. Using a planimeter or other
device to measure areas zoned for development on paper maps, the researcher sums the total acreage
available for development in the study area, and then divides this number by an average that represents
typical housing unit lot size, plus a percentage representing required land that must be reserved for
frontage and infrastructure. The result is an estimate of the total number of new residential lots that
would be developed under build-out conditions. This method is less precise than the parcel-level
method because it does not account for different development patterns that result from the size and
shape of developable areas. For example, a long, narrow land area may comprise adequate acreage
for 20 residential housing unit parcels, but not reach that level of development because parcels might
not fit on either side of the road that currently runs down the middle due to frontage and road right-of-
way requirements. This method is particularly appropriate for land areas too large to feasibly
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A Planning Tool
examine using the parcel-level method, or when a rough average is appropriate to answer the
questions posed by the study.
Geographic Information System
This method is the fastest of the three ways to conduct a build-out analysis. The method is
essentially the same as the summed area method described above, but the calculation of total area is
conducted using a geographic information system (GIS), rather than a human being. This is
particularly useful when the land area is large and would require many hours of calculation by hand.
In addition, the GIS could be configured such that development is projected into undeveloped areas in
such a way as to maximize the number of units that could be accommodated. In other words, the GIS
could determine the most efficient spatial patterns required to fit the largest number of development
parcels in the developable areas, taking into account the size and shape of each area.
WATER QUALITY MODELING
In this report, the term "water quality modeling" is used to refer to a range of models that predict
the quality of runoff from land. Based on the number of processes they incorporate and level of detail
they provide, existing water quality models can be grouped into three categories:
1) Simple models
2) Mid-range models
3) Detailed models
Simple Models
Simple water quality models can provide a rapid estimate of pollutant loads with minimal effort
and required data input. However, they provide only a rough estimate of sediment and pollutant
loads, because they are not sophisticated enough to account for seasonal variations in meteorological
conditions such as temperature and rainfall. Typically, simple models consist of a list of land use
coefficients that translate an acre of land into a quantity of water pollution, based on the type of land
and quantity of water or time involved. For example, a simple water quality model may consist of a
computer spreadsheet containing estimates of the quantity of nitrogen produced per year per acre of
agricultural land, forest land, and urban land in various columns. Within the spreadsheet, in another
column, the actual acreage of each of these land use types in the overall land area under study can be
entered. Multiplying all coefficients by all total acreages yields estimates of nitrogen produced per
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A Planning Tool
land use type per year, and the sum of these sub-totals represents all modeled nitrogen produced in the
study land area per year. This procedure can be represented by the following equation:
(acres per land type)*(runoff coefficient per land type) = (load per land type)
Simple models can help determine the order of magnitude of pollution runoff from different land
areas. They are effective at producing rough estimates quickly, which can help target further research
priorities. Once that has been accomplished, it may be appropriate to engage a more sophisticated
model in order to improve the precision of the analysis.
Mid-Range Models
With slight modifications to a simple model, such as the addition of attenuation factors that
account for changes in topography and distance, the transport of nitrogen through different land areas
on route to water bodies can be more effectively modeled. These types of models can be classified as
"mid-range." Improved precision, especially in terms of accounting for differences based on the
location of the land areas being studied, is important because certain land types can serve as nitrogen
sources, and others sinks. In general, the more a model simulates actual processes that occur as rain
or other water travels on or through land, the more accurate are the resultant estimates of pollution in
reaching water bodies.
Detailed Models
The highest accuracy is found in detailed models, because they are designed to account for all
physical and biological processes that occur in a watershed, as well as the influence of management
practices such as application of best management practices (BMPs). Detailed models, often referred
to as watershed models, are tools that evaluate or estimate point and nonpoint source loads from
watersheds containing multiple pollutant sources and land uses. Typical model inputs include: time
history of rainfall, temperature and solar radiation, land surface characteristics such as land use/land
cover, and management practices such as nutrient management, and agricultural best management
practices BMPs. Watershed models are usually technically complex and require a team of computer
programmers and other technicians to calibrate and operate. If they are properly applied and
calibrated, detailed models can provide an accurate prediction of pollution runoff water quality at any
place in the study watershed. This additional precision, however, comes at the cost of much more
time and resources to operate.
A number of build-out analyses evaluated in this report incorporated models to predict water
quality resulting from different land uses. One, the Maryland Office of Planning's model, described
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A Planning Tool
in this report under the title Growth Management for Watershed Protection, incorporated a detailed
model (a watershed model). Others, such as the Buzzard's Bay Project's build-out analysis of
Buttermilk Bay, utilized a mid-range model. The choice of whether to use a detailed model or a more
simplified model is often determined by the size of the study area and resources of the organization
conducting the analysis. The larger the study area, the greater the need to account for processes
affecting the transportation of pollutants from points of origin to receiving water bodies, which favors
use of a detailed (watershed) model. For this reason, small organizations with limited financial and
computer resources are more likely to analyze smaller areas, using simple or mid-range, rather than
detailed, models.
This report contains a description of one highly sophisticated detailed (watershed) model
currently being used by the Chesapeake Bay Program. The Chesapeake Bay Program's HSPF
Watershed Model, discussed in Appendix A, is evaluated in this report for its potential use in
conjunction with build-out analyses to predict the water quality impacts of alternative development
scenarios. The Chesapeake Bay Program's Hydrologic Simulation Program-Fortran (HSPF)
Watershed Model is used to simulate and help quantify the amount of nitrogen and phosphorous
entering the Chesapeake Bay from its many tributaries. The Model is also used to help track progress
in reducing the concentrations of these nutrients in the Bay 40 percent from 1985 levels by the year
2000, as set forth in the 1987 Chesapeake Bay Agreement and its 1992 amendments.
USE OF WATER QUALITY AND OTHER MODELS IN CONJUNCTION WITH BUILD-
OUT ANALYSES
As noted above, water quality models can be used to simulate pollutant loads delivered to water
bodies from an inventory of current land use/land cover types. They can also simulate pollutant loads
from past or future inventories of land use. The key input for these models is the appropriate land use
input data; it makes no difference whether that data originated from a survey of current land use, or
from a build-out analysis of project land use twenty years hence. For this reason, build-out analyses
and water quality models can be applied in unison to predict the water quality impacts of alternative
land development scenarios, whether under full build-out or any number of partial build-out
conditions.
Four of the five in-depth build-out analysis summaries presented in the following section,
"Growth Management for Watershed Protection"; "Buzzards Bay Project"; "Geographic Analysis of
Bacterial Contamination"; and "Cane Creek Watershed Study," included some form of water quality
modeling in the evaluation of their study land areas under partial or full build-out conditions.
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The fifth study, "Biodiversity and Landscape Planning: Alternative Futures for the Region of
Camp Pendleton, California," presents possible impacts on biological diversity from alternative
development scenarios in the region of Camp Pendleton, CA. This study, although not focused on
water quality, was included in this report to highlight the fact that there are other forms of
environmental modeling in addition to watershed or water quality modeling that are appropriate for
use with build-out analyses. In addition to models of biological diversity, there are also models that
predict the air and water quality impacts of transportation-related forms of development, such as
roads, highways, and vehicle-emitted pollution.
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III. BUILD-OUT ANALYSIS/WATER
QUALITY MODELING CASE STUDIES
One of the primary purposes of this report is to provide information on build-out analysis and
water quality modeling projects that have been undertaken in the Chesapeake Bay watershed and
elsewhere. The intent is to provide members of the Chesapeake Bay Program (CBP) and particularly
the Land, Growth and Stewardship Subcommittee (LOSS) with sufficient background information on
these techniques to make informed decisions about whether to pursue application of build-out
analyses and water quality modeling as tools to meet CBP objectives, and if so, which of the tools to
investigate further.
In the following pages, five build-out analyses are summarized in-depth. A further nine build-out
analyses are summarized in Appendix B as two-page fact sheets. The first five summaries were
selected for in-depth review because they involved both build-out analysis and water quality or other
environmental impact modeling (e.g., impacts on biodiversity). The nine fact sheets in Appendix B
also provide useful background information about various build-out analysis methodologies, but they
do not have sufficient emphasis on water quality or environmental modeling to warrant inclusion as
in-depth summaries.
RESEARCH METHODS
The fourteen build-out analysis case studies presented in this report were compiled through a
combination of literature review, and telephone and personal interviews. Published reports and
supporting documents were reviewed as primary information sources, with follow-up interviews to
fill-in missing information and verify researchers' findings. In many cases, language contained in
published documents was copied directly for use in the summaries and fact sheets. In addition,
interviews often resulted in suggested wording from interviewees which was also incorporated
directly. All summaries and fact sheets contain citations indicating where the information and text in
the summary or fact sheet originated from.
Research for all summaries and fact sheets proceeded in an iterative fashion. Beginning with
initial contact information and documentation on-hand at the Chesapeake Bay Program Office, a first
set of projects was selected for research. During this initial research phase, additional projects and
contacts were identified through communications with individuals involved with the projects selected
for initial research. This process of identifying new projects and contacts ended when the
Chesapeake Bay Program determined that a sufficient range of projects and models had been
identified to meet the needs of this summary document.
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Case Studies
It should be noted that the level of detail presented in each of the case studies varies, particularly
in the "Methodology" sections. Many summaries present detail sufficient for the reader to follow and
understand each step of the project from start to finish, while others provide less detail. Attempts
were made to directly contact and/or exchange draft materials with the project principal investigators
or other contacts. Unfortunately, contact and exchange of materials was not possible in all cases. For
example, some principle investigators actually wrote materials that were included in the summaries
and/or fact sheets, while other researchers were unable or unwilling to participate. Nonetheless, the
case studies presented in this report provide a large amount of information, and indicate where further
information can be obtained by an interested individual through contact information, World Wide
Web and E-mail addresses, and relevant literature.
OVERVIEW OF PROJECT SUMMARIES PRESENTED IN THIS REPORT
Table 1 summarizes the project summaries and fact sheets included in this report, in the order that
they appear. The first five listed are in-depth summaries, while the remaining nine appear as two-
page fact sheets in Appendix B.
Table 1. Build-Out Analyses Reviewed in This Report
Title of Report,
Analysis, or Model
Developing Growth
Management Options for
Maryland's Tributary Strategies
Use of a Geographic
Information System to Estimate
Nitrogen Loading to Coastal
Watersheds
Biodiversity and Landscape
Planning: Alternative Futures
for the Region of Camp
Pendleton, California
Geographic Analysis of
Bacterial Contamination,
Ipswich, Beverly, and
Provincetown
Cane Creek Reservoir
Watershed Study - Draft Report
August 1996
Sponsoring Organization
Maryland Office of Planning,
Baltimore MD
Buzzards Bay Project, Marion
MA
Harvard Graduate School of
Design, Utah State University,
National Biological Service,
and USDA Forest Service,
Nature Conservancy, and the
Biodiversity Research
Consortium
Massachusetts Bays Program,
Executive Office of
Environmental Affairs, Boston
MA
Orange Water and Sewer
Authority
Geographical Location
of Study Area
Three MD watersheds: the
Patuxent, Lower Potomac, and
Lower Western Shore
Buttermilk Bay, embayment of
Buzzards Bay, south-eastern
coast of Massachusetts
Region of Camp Pendleton, CA
(located between Los Angeles
and San Diego)
Case study communities of
Ipswich, Beverly, and
Provincetown, MA
Carrboro, NC
Page Location
in this Report
14
28
39
52
61
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Case Studies
Title of Report,
Analysis, or Model
Ground Water Supply
Protection and Management
Plan for the Eastern Shore of
Virginia
Living With the River: A
Development Management Plan
for the Severn River Watershed
to the Year 2020
U.S. 301 Transportation Study
Technical Report: Land Use
and Growth Management
Build-out Analysis of the
Thomas Jefferson Planning
District - Second Draft
Lancaster County
Comprehensive Plan: Growth
Management Plan
U.S. EPA Clean Lakes Report
for the Occoquan Watershed
Alternative Futures for Monroe
County, Pennsylvania
Hillsdale Lake Watershed
Population and Land Use
Projections, 1990 - 2010, for
the Hillsdale Lake Nutrient
Study
Buildout Analysis on a GIS
Sponsoring Organization
Horsley Witten Hegemann,
Inc., for Eastern Shore of VA
Ground Water Study
Committee
The Severn River Commission
(prepared by Land Ethics and
Dodson Associates)
Maryland State Highway
Administration
Thomas Jefferson Planning
District Commission
Lancaster County Planning
Commission
Northern Virginia Planning
District Commission
Harvard Graduate School of
Design, funded by EPA Rffl
Johnson County Planning
Office
Edward Lyman (MA Thesis,
University of Vermont)
Geographical Location
of Study Area
Eastern Shore, VA
The Severn River watershed,
Anne Arundel County, MD
Route 301 corridor from the
Potomac River to Rt. 50
Charlottesville, VA
Lancaster County, PA
Parts of Loudon, Fairfax,
Prince William, and Fauquier
Counties
Monroe County, PA
Johnson, Douglas, Franklin,
and Miami Counties, KS
Four case study build-outs: two
in Woodstock, Ontario,
Canada; one in the Thomas
Jefferson Planning District VA
(reviewed here); and one in San
Diego
Page Location
in this Report
B-l
B-3
B-5
B-7
B-9
B-ll
B-13
B-15
B-17
IN-DEPTH CASE STUDIES
The following section contains in-depth summaries of five build-out analysis projects that
incorporate water quality and/or environmental modeling. As noted earlier, these projects are
summarized in-depth due to their particular relevance to the Chesapeake Bay Program (described in
each summary), and their focus on both build-out analysis and water quality/environmental modeling,
rather than on build-out analysis alone. Each case study begins with a summary box containing basic
March, 1998
12
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Case Studies
information about the project, including contact information for key individuals. Subsequent sections
of each summary describe the following:
• Introduction and Purpose of Study
• Relevance to the Chesapeake Bay Program
• Size and Geographic Boundaries of Study
• Description of Landscape
• Applicability of Method to Other Geographic Areas and Scales
• Alternative Development Scenarios Considered
• Methodology
• Study Results and Findings
• Types of Data Required for Model
• Data Acquisition and Level of Effort
• Required Computer and Other Resources
• Format of Final Product
• Lessons Learned and Alternative Approaches
• Additional Information, and
Sources of Information and Text in this Fact Sheet.
March, 1998 13
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GROWTH MANAGEMENT FOR WATERSHED PROTECTION IN MARYLAND
TITLE OF PROJECT/REPORT:
RESEARCH CONDUCTED BY:
SPONSORING ORGANIZATION^):
CONTACT INFORMATION:
MAILING ADDRESS:
WEB SITE:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION DATE:
PROJECT LOCATION:
Developing Growth Management Options for
Maryland's Tributary Strategies. Managing Maryland's
Growth, Growth and Watershed Planning Series. Draft,
March 1997.
Maryland Office of Planning; Anne Arundel, Calvert,
Charles, Harford, Howard, Montgomery, Prince
George's, and Saint Mary's counties; Patuxent River
Commission.
Maryland Office of Planning.
Mr. Joseph Tassone, Maryland Office of Planning.
301 West Preston Street, Room 1101; Baltimore, MD
21201-2365.
http://www.op.state.md.us/
Joe@mail.mop.md.gov
(410) 767-4500.
Publication expected January - February 1998.
The Patuxent River, Lower Potomac, and Lower
Western Shore watersheds, located in central & southern
Maryland.
INTRODUCTION AND PURPOSE OF STUDY
The State of Maryland, in cooperation with the Chesapeake Bay Program, has established 10
Tributary Strategies to reduce nutrient pollution in each of the State's major tributaries to the
Chesapeake Bay. The goal for each tributary of a 40 percent reduction from 1985 levels was set in
the 1987 Chesapeake Bay Agreement and its 1992 amendments, to which Maryland is a signatory.
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Growth Management for Watershed Protection in Maryland
In many areas in Maryland projected for large population increase and rapid development,
tributary-specific nutrient loading "caps," necessary to keep the total contribution of nutrients to the
Chesapeake Bay at or below 60 percent of 1985 levels, are projected to be exceeded by the year 2010
unless better planning and coordinated growth management and nonpoint source pollution controls
are implemented. In order to meet that goal, the Maryland Office of Planning is working with State
and local agencies responsible for managing growth and new development to examine the potential
effects of their management actions on land resources, nutrient pollution loads, and local water
resources.
This is being accomplished in large part through a Watershed Planning System that incorporates
both build-out analysis and water quality modeling. It is designed to coordinate planning and
management for growth and new development by watershed, and to predict future water quality-
related characteristics of the watershed under alternative development scenarios. The System is
intended to help local governments, State agencies, and Maryland's Tributary Strategy Teams more
effectively pursue management of land development to enhance watershed protection. The draft
report highlighted here provides guidelines for assessing the potential impacts of growth on local land
resources and streams, and on Maryland's Tributary Strategies and the Bay. It identifies growth
management activities that will contribute to the success of the Strategies while protecting local
watersheds; and it quantifies the effects of "watershed planning" and "resource protection"
management options defined in Maryland's Tributary Strategies.
The Patuxent River Demonstration Project is one of several pilot projects that have been
undertaken by the Maryland Office of Planning to help meet the goals of the Tributary Strategies, and
to maintain the nutrient "caps" after the year 2000. Several other pilot projects contributed to
development of the featured report, in addition to the Patuxent River Demonstration Project. These
include projects in the Winter's Run watershed (Harford County); Piney-Alloway Creeks watershed
(Carroll County); Lower Potomac watershed (Charles, Prince George's, and Saint Mary's counties);
and the Lower Western Shore watershed (Anne Arundel and Calvert counties).
RELEVANCE TO THE CHESAPEAKE BAY PROGRAM
The Maryland Office of Planning is an active participant in the Chesapeake Bay Program, and, as
noted above, has developed its Watershed Planning System in large part to help meet the nutrient
reduction goals set forth in the Chesapeake Bay Agreement for Maryland's tributaries. The Office's
work with the Watershed Planning System in the Patuxent River Demonstration and other pilot
projects is relevant for the following reasons:
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Growth Management for Watershed Protection in Maryland
• Several of the pilot projects were conducted in large watersheds which are major Bay tributaries:
the Patuxent, 560,000 acres; the Lower Potomac, 470,000 acres; and the Lower Western Shore,
171,000 acres. Analyses for each project took place at a "subcatchment" level, i.e.,
subwatersheds ranging in size from 1,100 to 20,000 acres. The Chesapeake Bay Program will
likely consider a wide range of scales for potential application of build-out analyses, including
analyses that may be conducted on large land areas within the Chesapeake Bay watershed.
• The Watershed Planning System has a high degree of flexibility in terms of data required for
input. The System can function with both highly detailed data (e.g., at the individual land parcel
level) and more generalized data (e.g., satellite images). This flexibility could prove useful for
analysis within the Chesapeake Bay watershed, because data managed by different States and
local jurisdictions on the land areas they manage is of widely differing levels of detail. For
example, a methodology identical to the one employed by the Maryland Office of Planning in its
analyses for the three tributary watersheds could not be used on the entire Chesapeake Bay
watershed, due to the lack of comparable land use data in all locations (Virginia, Pennsylvania,
and New York do not maintain land use data in as much detail as does Maryland). However, it
could be adapted to represent generalized scenarios commensurate with available data.
SIZE AND GEOGRAPHIC BOUNDARIES OF STUDY
The Patuxent River watershed is located in central Maryland. It is approximately 930 square
miles (577,000 acres) in size. The watershed includes parts of seven Maryland counties: Howard,
Montgomery, Anne Arundel, Prince George's, Calvert, Charles, and St. Mary's, with no county
located entirely within the watershed. The Lower Potomac watershed (470,000 acres) is comprised of
parts of Prince George's, Charles, and Saint Mary's counties; the Lower Western Shore (171,000
acres) is comprised of parts of Anne Arundel and Calvert counties.
DESCRIPTION OF LANDSCAPE
The Lower Western Shore is a small, relatively highly developed (33%) watershed with relatively
little agriculture (14%). Although it has the lowest projected rate of growth of the three tributaries (a
31% increase in households by 2010), the total amount of growth expected relative to watershed size
(.15 households per watershed acre) suggests that growth will be an important factor affecting future
pollution levels. Current programs in the watershed have the highest potential among the three
tributaries to accommodate growth in sewered areas at relatively high densities.
The Lower Potomac is a large rural watershed. It is expected to grow at the fastest rate (a 72%
increase in households), but the total amount of growth expected is smaller relative to tributary size
March, 1998 16
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Growth Management for Watershed Protection in Maryland
(.08 households per watershed acre) than in the other two tributaries. The potential to accommodate
growth in sewered areas is the lowest of the three tributaries, as is the potential to concentrate growth
at higher densities.
The Patuxent is a large heterogeneous watershed (24% developed, 45% forest, and 27%
agriculture). Compared to the other two tributaries, a moderate rate of growth is projected (54%
increase in households), but growth is likely to be a very important factor because the amount of
growth expected is large relative to tributary watershed size (.16 households per watershed acre).
Capacity for growth in sewered areas at higher densities is higher than in the Lower Potomac and
slightly lower than in the Lower Western Shore.
APPLICABILITY OF METHOD TO OTHER GEOGRAPHIC AREAS AND SCALES
The Maryland Office of Planning's Watershed Planning System can be applied to a variety of
geographic areas and scales. For smaller areas, a greater level of detail can be incorporated,
depending on data availability from the county(ies) included. For larger areas, a "coarser" analysis
based on more limited data is preferable due to likely constraints on resources and the type of data
analysis possible. Because of its flexibility, no land area is, a priori, too small or too large to be
analyzed with the Watershed Planning System. The dominant constraints are data availability and the
financial and staff resources of the entity conducting the analysis.
ALTERNATIVE DEVELOPMENT SCENARIOS CONSIDERED
The Maryland Office of Planning modeled land and water resource impacts in the three tributaries
based on three primary alternative development scenarios. Each scenario was modeled out to the year
2010 using population, housing, and employment projections:
1) 2010 Base Zoning. Base Zoning scenarios portray new development according to current zoning,
but without the influence of other existing county subdivision and environmental ordinances, and
without BMPs for nutrient pollution control. The effect of wetlands and forested riparian areas on
pollution loads is estimated for those areas that remain in 2010, in the absence of resource
protection programs to preserve them. Base Zoning provides a 2010 "worst case" scenario,
against which the performance of growth management and pollution control measures in the other
scenarios can be evaluated.
2) 2010 Current Programs. This scenario estimates the effects of existing programs for growth
management and pollution control. New development occurs according to current zoning,
subdivision, and associated environmental regulations and requirements. Implementation of
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Growth Management for Watershed Protection in Maryland
agricultural nonpoint source pollution control measures is projected to occur at approximately
current rates to the year 2010. Implementation of Stormwater Management practices represents
counties' current stormwater management programs, according to the guidelines provided by each
county. The effect of wetlands and riparian areas on pollution loads is estimated for those that
remain in 2010 under current protection programs and growth management options.
3) 2010 Directed Growth. "Directed Growth" scenarios include enhanced levels of growth
management, land conservation, and pollution control practices. They essentially represent the
Tributary Strategies, modified to account for growth to the year 2010, associated changes in land
use, and the effects of alternative growth management options. Growth management options
simulated under Directed Growth included a number of innovative planning, zoning, subdivision,
and resource protection techniques (see below). Agricultural pollution control measures modeled
were those specified in the Tributary Strategies. Stormwater management program requirements
are essentially the same as those represented under Current Programs. The effect of wetlands and
riparian areas on pollution loads is estimated for those areas that remain in 2010 as a result of the
growth management and resource protection techniques simulated.
Within the 2010 Directed Growth scenario, eight specific options for growth management and
resource protection were simulated:
• Forest Conservation;
• Stream Buffer Protection;
• Rural Clustering;
• Increased Development Potential in Growth Areas;
• Transfer of Development Rights (TDR) to Growth Areas;
• Extending Sewer Service in Designated Growth Areas;
• Protective Agricultural Zoning; and
• Purchase of Development Rights.
Specific details of each option are presented in the Office of Planning's report.
QUESTIONS AND VARIABLES INCLUDED IN STUDY
The following questions and variables were addressed in the build-out analyses:
Questions
• If current growth management and pollution control programs were practiced, and growth
occurred as projected to the year 2010, what would be the effects on local streams, land resources,
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Growth Management for Watershed Protection in Maryland
stream buffers, and nutrient loads? What if other management options for Directed Growth and
pollution control were practiced instead?
• What effect will growth management have on overall pollution levels, compared to Best
Management Practices (BMPs) for pollution control?
• What changes can be expected in each tributary and subwatershed under each of the development
scenarios considered, in each of the following issue areas:
a. Loss or gain of forest cover, both riparian and upland;
b. Loss of agricultural land;
c. Percentage of the watershed covered by impervious surfaces;
d. Associated development impacts on local streams; and
e. Nutrient loads delivered to surface waterways and the estuary.
Variables
• Location and extent of soil types, wetlands, streams, stream buffer zones, and other
environmentally sensitive areas.
• Location of zoning, growth and land preservation boundaries, and sewer service boundaries.
• Location of watershed, subwatershed and county boundaries.
• Location and/or extent of land areas affected by each type of zoning, subdivision, environmental,
stormwater management, public health (septic system), and agricultural assistance programs and
regulations.
• Current and future population, household, and employment statistics, and number and location of
households on sewer and on-site sewage disposal systems, by county and subwatershed.
METHODOLOGY
MDOP collaborated with county and city planning and zoning offices, State and local resource
and environmental protection agencies, public works departments, and soil conservation districts to
obtain information about existing growth management plans and regulations and about stormwater
and agricultural management programs. It also compiled geographic information system (GIS) data
for land use, soil types, slope, location of streams and wetlands, location of septic systems, zoning,
sewer service, and current and projected population, households, and employment.
These data sources were used in the Office of Planning's Watershed Planning System (WPS) to
evaluate current and future conditions in the Patuxent, Lower Western Shore, and Lower Potomac
tributary watersheds. The WPS consists of three linked computer models that use data from these
GIS and a variety of other sources to model future development and associated impacts on land
resources, environmentally sensitive lands, nutrient pollution loads, and local water resources. The
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Growth Management for Watershed Protection in Maryland
three models are: 1) The Baseline Inventory model; 2) The Growth Management Simulation model;
and 3) The Nonpoint Source Management Scenario model. All of the models use data derived from
composite GIS overlays, as well as other data described below in this section and under the section
titled Types of Data Required for Model.
The specific steps taken to conduct the build-out analysis and project impacts on land and water
resources for the three tributary watersheds are described below. To accomplish similar things for the
Chesapeake Bay Watershed, each step in the analysis would be modified (in many cases greatly
simplified), commensurate with the data bases available and the specific objectives of the analysis.
Create GIS Data Layers
A Workstation Arclnfo geographic information system (GIS) was used to organize 1990 data
from each county in the watershed on land use/land cover, soils, streams, wetlands, and stream
buffers (physical features); zoning, sewer service, and subdivision, development, and environmental
regulations (land management data); current (1990) population, households, and employment
(demographics); animal production facilities, households on septic systems, and households on sewer
service (special source categories); and stormwater and agricultural management practices (NFS
management).
Develop Baseline Inventory of Land Features
These data were organized by sub watershed within each county. Within each subwatershed, 1990
conditions were inventoried for each of the following: land use/land cover, stream buffers,
households on sewer or on septic systems, nonpoint nutrient pollution sources, pollution management
practices for stormwater and agriculture (BMPs), wetlands, and the occurrence of riparian areas
within buffers of streams and other waterways.
Develop Baseline Inventory of 1990 Pollution Loads
Within each subwatershed, current (baseline) nutrient loads from forest, agricultural sources,
developed land cover, septic systems, and other miscellaneous sources were estimated using the
Baseline Inventory model of the Watershed Planning System. Data compiled from nonpoint source
research, monitoring, and modeling was applied to the Baseline Inventory of land features to estimate
nutrient loads delivered to streams by the following pathways: surface runoff, shallow subsurface
flow, and groundwater.
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Growth Management for Watershed Protection in Maryland
Loads delivered to streams were estimated first, assuming the absence of BMPs, wetlands, and
riparian buffers. To do this, distributions of in-stream loading rates for each source were compiled
from research, primarily from monitoring studies screened for a variety of conditions, but also from
the Chesapeake Bay Watershed (HSPF) Model. Values by source from appropriate Bay Model
segments (in-stream loading rates) were sorted by physiographic province and incorporated into
distributions of values compiled from other sources of information. The resulting range of values in a
distribution was used to characterize high, moderate, and low loading rates for each pollution source
type. These rates were then applied to sources within sub watersheds, using soil characteristics
(credibility, slope, hydrologic group, permeability, percolation, depth to groundwater, and presence of
impermeable subsurface layers) as indicators of high, moderate, or low nutrient pollution export
potential.
Delivered loads were partitioned by flow pathway using partitioning factors also derived from the
Bay Watershed Model. Those factors were used in conjunction with data from other sources needed
to partition loads from all of the source types represented in the Watershed Planning System, which
covers a finer breakdown of source categories than is represented in the Watershed Model.
Subsequently, the effects of BMPs, wetlands, and riparian buffers on loads from each source are
estimated by flow pathway. Removal efficiencies are based primarily on observations compiled from
monitoring research results, but findings from both HSPF and CREAMS modeling (Chemicals
Runoff and Erosion from Agricultural Management Systems) by the University of Maryland
Department of Agronomy were also employed. The resulting in-stream loads are then delivered to
the estuary using delivery ratios from the Chesapeake Bay and the Patuxent Watershed HSPF
models.1 Point source data (nutrient loads from waste water treatment plants) from the Patuxent,
Lower Western Shore, and Lower Potomac Tributary Strategies was also incorporated.
Estimate Demand and Capacities for New Development
Projected growth in population, households, and employment for the year 2010 represented the
demand for new development in each subwatershed. Round 5 Small Area Forecasts for
Transportation Analysis Zones were used. These are growth projections developed periodically by
regional planning agencies and local governments in Maryland, for a variety of planning purposes.
The forecasts were used to estimate growth in population, number of households, and employment in
each subwatershed comprising the three tributaries and seven counties.
1 The Patuxent Watershed HSPF model is distinct from the Chesapeake Bay Program's Watershed Model. The
former was developed by the Maryland Department of the Environment, and consists of 40 Model Segments for the
Patuxent River watershed; while the latter is less detailed, consisting of just 3 Model Segments.
March, 1998 21
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Growth Management for Watershed Protection in Maryland
Undeveloped land zoned for subdivision or other development represented the "supply" of
developable land. Zoning, subdivision, incentives, and other regulations and programs affecting
development were used to estimate the capacities of different types of developable land for new
development, i.e., how much development (e.g., number of new households) could be accommodated
on each type of land under existing or hypothetical programs. Capacities were determined for land
use types within zoning districts and sewer service boundaries.
Allocate Demand Under Different Growth Management Scenarios
The demand for new development was distributed to types of developable land based on capacity
and county-specific considerations. This was done first by assuming current zoning and
programs/regulations (the Current Programs scenario), and then for the two alternative scenarios
(Base Zoning and Directed Growth, see the section Alternative Development Scenarios Considered,
above). Each scenario assumed different zoning, regulations, and/or programs and procedures
governing new development, particularly the density and distribution of new subdivisions and
requirements/restrictions for site design and conservation of forested cover, stream buffers, and open
space.
Simulate Land Use Change and Project Implementation Levels of BMPs
Land use change to accommodate projected growth was estimated within each subwatershed for
each scenario. Based on the demand for new development relative to the supply available on each
type of developable land, the land was either:
• converted to a specific type of development to accommodate projected growth, based on zoning,
relevant regulations, and the number of new households or amount of new employment allocated
(in the preceding step);
• converted to forested cover to meet requirements of forest conservation programs;
• maintained in forested cover to satisfy requirements of stream buffer protection ordinances; or
• allowed to remain in its existing condition. This occurred when site design guidelines (e.g., rural
clustering) protected existing open space, or when there was not enough demand for new
development to warrant conversion to development.
Resulting conversions of land and "future" landscapes differed for each scenario. For each,
implementation levels for agricultural and storm water management practices were also estimated,
based on the implementation levels projected in the corresponding tributary strategies and counties'
future expectations of their programs. Implementation levels of pollution control practices were
adjusted to reflect estimated land use changes for the 2010 scenarios.
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Growth Management for Watershed Protection in Maryland
Inventory Conditions and Estimate Pollution Loads in Each Scenario
2010 conditions were inventoried by subwatershed. Content of the inventories (land features and
pollution loads) was the same as described for 1990 conditions: land use/land cover, stream buffers,
households on sewer or on septic systems, estimated nutrient pollution loads from nonpoint sources,
effects of management practices on loads, and effects of wetlands and riparian buffers on loads. Point
source data (nutrient loads from waste water treatment plants), derived from the three Tributary
Strategies, was also incorporated.
Compare Scenario Results
Conditions in each of the 2010 scenarios and for 1990 were compared. Differences in land
resources, pollution levels, and effects of management practices and riparian areas serve to quantify
the impacts of growth and the effects of management alternatives. The results of each scenario can be
compared to the nutrient pollution levels called for in the corresponding Tributary Strategy in order to
determine which growth management and resource protection options will maintain those levels and
which will not. The importance of these options can be compared to that of agricultural and
stormwater management practices, in terms of cumulative effects on pollution loads. Results are also
used to provide information and guidelines to local resource protection and planning agencies, to
assist them in protecting local land resources and watersheds.
STUDY RESULTS AND FINDINGS
»
• Implementation of both growth management and pollution control options are essential if
Maryland is to maintain the nutrient loading caps called for in the Patuxent Tributary Strategy
beyond the year 2000.
• In the year 2010, pollution levels will be much lower if growth and new development is well
directed. In conjunction with other management tools like Best Management Practices (BMPs),
growth management will be one of the most important factors determining future pollution levels.
For example, the MDOP estimates that in the year 2010, nitrogen pollution loads in the Patuxent
River watershed could be about 1,141,000 pounds lower if certain "Directed Growth" and
"Resource Protection" options (defined in the report highlighted in this study) were used to
manage growth as part of the Patuxent Tributary Strategy, in addition to BMPs. Similar findings
for the Lower Western Shore and Lower Potomac tributaries and for phosphorus are also reported.
• By the year 2010, stream quality would degrade in nearly half the Patuxent watershed under
Current Programs. Growth management, per the Directed Growth scenario, would limit
degradation to about one quarter of the watershed. For an example at the county scale, significant
degradation could occur in about 62% of one county's streams under Current Programs, but
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Growth Management for Watershed Protection in Maryland
would be limited to about 22% under Directed Growth. As expected, results vary by county, but
follow a similar pattern.
• Results, findings, and guidelines are specific to individual county programs and subwatersheds, as
appropriate for the objectives of these pilot projects. Findings and guidelines can be generalized
for areas with similar conditions, projected amounts of growth, and existing management
measures in place. Alternatively, the analysis itself can be generalized to compare more general
scenarios for multiple jurisdictions over larger- areas.
TYPES OF DATA REQUIRED FOR MODEL
The following types of data were used in Maryland Office of Planning's analysis of the Patuxent
River watershed:
Maps:
Management Programs:
The U.S. Census:
County Forecasts:
Small Area Forecasts:
Literature, Research,
and Modeling:
Land use; soils; watershed and county boundaries; wetlands; streams;
buffer zones; other environmentally sensitive areas; zoning, growth and
land preservation boundaries; and sewer service boundaries. MDOP
used a data base included in its proprietary computer program
Maryland Property View. This data base includes parcel data that was
obtained through 1:40,000 scale aerial photographs. Other data
originated from satellite images.
Zoning, subdivision, and environmental and stormwater management
regulations; public health (septic systems), and agricultural assistance
programs.
Population; households; households on sewer and on-site sewage
disposal; all for 1990 and (projected) 2010.
Population and household projections by County.
Population, household, and Round 5 Small Area Forecasts by
Transportation Analysis Zone.
Nonpoint source monitoring studies; research on the effects of land use,
land use patterns, and sensitive areas; BMPs; and BMP systems on
nonpoint source pollution; results from the Chesapeake Bay Watershed
and Patuxent Watershed HSPF models; CREAMS applications; and
Maryland's tributary strategies for the Chesapeake Bay.
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Growth Management for Watershed Protection in Maryland
DATA ACQUISITION AND LEVEL OF EFFORT
The costs of obtaining and preparing data for these projects, interacting with local jurisdictions,
and modeling and analyzing results at the level of detail used in the pilot projects is estimated at
about $80,000 to $100,000 for each of the seven counties included. A typical single county project
requires about 6 months. More generalized analyses, comparing generic alternatives across all
jurisdictions, could be done for a small fraction of this cost and time.
REQUIRED COMPUTER AND OTHER RESOURCES
• Workstation Arclnfo GIS, which can be run on a Unix, Windows NT, or VMS platform.
• The Office of Planning used Paradox Applications Language for the analysis. However, for larger
areas and faster completion of projects, a more robust relational database management system
(RDBMS), such as Oracle, would be preferable. Such a system can be run on a variety of
operating platforms, such as Unix, Windows NT, or VMS.
FORMAT OF FINAL PRODUCT
A paper report is nearing completion. The report is intended for local and State agencies
responsible for growth management and related watershed protection activities; local officials;
Maryland's ten tributary teams; Maryland citizens and businesses involved in the implementation of
Maryland's Economic Growth, Resource Protection, and Planning Act of 1992 and of the Tributary
Strategies; and interested Chesapeake Bay Program participants. Other products generated in this
project include numerous GIS data layers and data sets containing zoning and other county-specific
land use information.
LESSONS LEARNED AND ALTERNATIVE APPROACHES
• Reconciling boundaries or other aspects of geographic information system data from different
sources can be time consuming and difficult. Allow sufficient time for this important aspect of
the project.
• Communicate early and often with the local jurisdictions involved in the study to ensure that they
are aware, and supportive, of the assistance and collaboration that will be asked of their agencies.
• Clearly determine up-front the intended uses and users of the project: what questions must be
answered and at what level of detail, to support what kinds of management decisions.
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Growth Management for Watershed Protection in Maryland
ADDITIONAL INFORMATION
The Maryland Office of Planning will work indefinitely with the seven counties comprising the
Patuxent River watershed, as well as other counties participating in the Watershed Planning process,
to implement watershed protection strategies designed to reduce projected inputs of nutrients to
Maryland's Chesapeake Bay tributaries. Based on the individual and cumulative effects of
management options, alternatives have been identified that are feasible and that will conserve land
and protect water resources. The estimated performance of these management actions is being used
as a tool to help support their adoption through programs, procedures, or law, and to estimate their
value in contributing to cumulative impacts or benefits at the watershed scale.
Additional information can be obtained from the Maryland Office of Planning using the contact
information presented on the first page of this summary. Additional information sources are listed
below under Relevant Literature. A particularly useful set of publications is the Office of Planning's
"Models and Guidelines" series, which provides detailed information on growth management
techniques used to concentrate growth. Specific Models and Guidelines reports that discuss such
techniques include:
• Regulatory Streamlining;
• Transferable Development Rights;
• Overlay Zones;
• Achieving Environmentally Sensitive Design in Growth Areas through Flexible and Innovative
Regulations; and
• Urban Growth Boundaries.
SOURCES OF INFORMATION AND TEXT IN THIS FACT SHEET
Information and text for this fact sheet were compiled from the following sources:
Maryland Office of Planning. 1997. Developing Growth Management Options for Maryland's
Tributary Strategies. Growth and Watershed Planning Series. (March 28 draft). Baltimore.
Maryland Office of Planning. 1995. Growth, Resource Lands and Watersheds: The Need for
Integrated Planning and Management. Baltimore. Fact sheet.
Maryland Office of Planning. 1995. An Integrated Watershed Planning Tool for Land Use
Management and Nonpoint Source Pollution Control. Baltimore. Fact sheet.
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Growth Management for Watershed Protection in Maryland
Tassone, J.F., R. E. Hall, N.S. Edwards, and D.M.G. Weller. 1996. Integrated Watershed Planning
and Management: Growth, Land Resources and Nonpoint Source Pollution. Published in the
Proceedings of the Watershed '96 Conference, Baltimore, MD.
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BUZZARDS BAY PROJECT
TITLE OF PROJECT/REPORT:
RESEARCH CONDUCTED BY:
SPONSORING ORGANIZATIONS):
CONTACT INFORMATION:
MAILING ADDRESS:
WEB SITE:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION DATE:
PROJECT LOCATION:
Use of a Geographic Information System to Estimate
Nitrogen Loading to Coastal Watersheds. 1994.
Buzzards Bay Project.
Buzzards Bay Project and U.S. Environmental
Protection Agency (through the National Estuary
Program).
Dr. Joseph E. Costa, Executive Director, Buzzards Bay
Project.
Two Spring Street; Marion, MA 02738.
http://www.epa.gov/nep/nepbroc.html
Joe.Costa® state.ma.us
(508) 748-3600.
1991.
Buttermilk Bay, an embayment of Buzzards Bay, a large
estuary located on the south-east coast of Massachusetts.
INTRODUCTION AND PURPOSE OF STUDY
The Buzzards Bay Project, a participant in the U.S. Environmental Protection Agency's National
Estuary Program, has developed a management strategy to protect and restore water quality and living
resources in embayments of Buzzards Bay, Massachusetts, from excessive inputs of nitrogen from
human activities. The implementation of this strategy requires an evaluation of existing and potential
future inputs of anthropogenic nitrogen from sources within each embayment's drainage basin to
determine if existing or future inputs will exceed recommended nitrogen loading limits. Such an
approach requires an evaluation of each parcel of land within each drainage basin to determine the
number of existing housing units and future development potential based on local zoning regulations
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Buzzards Bay Project
(build-out analysis). In this way, existing and potential future non-point sources of nitrogen can be
determined, and land development curtailed where necessary to limit nitrogen loading to the estuary.
The first build-out analysis conducted by the Buzzards Bay Project was carried out in the Buttermilk
Bay embayment of Buzzards Bay, and this analysis serves as the focus of this report.
RELEVANCE TO THE CHESAPEAKE BAY PROGRAM
There are two primary reasons why the Buzzards Bay Project's build-out analysis of Buttermilk
Bay is highlighted in this report:
1) The build-out analysis was conducted on a watershed in order to predict future land use in a
quantitative manner (i.e., total number of residences and other land uses) at full development.
2) This build-out analysis was combined with nitrogen loading rates for every type of land use in
the watershed studied in order to predict the total nitrogen loading rate for the entire watershed at
full development potential.
As such, the method employed by the Buzzards Bay Project could be adapted to perform several types
of analyses that could be useful to the Chesapeake Bay Program. Although this type of parcel level
analysis would be infeasible for a large watershed such as that of the entire Chesapeake Bay, it could
be effectively used in small watersheds, counties, or municipalities within the Chesapeake Bay
Watershed. In addition, the Buzzards Bay Project has developed loading methodologies based on
GIS coverages (described below) to estimate existing and future nitrogen loads that could also be
applied for larger watersheds.
SIZE AND GEOGRAPHIC BOUNDARIES OF STUDY
Buzzards Bay is a large estuary with a 430 square mile drainage basin and over 30 major coastal
embayments. It is located on the south-eastern coast of Massachusetts, surrounded by 17
municipalities. The build-out analysis discussed in this report was conducted on Buttermilk Bay, one
of the embayments of Buzzards Bay.
DESCRIPTION OF LANDSCAPE
Buzzards Bay encompasses more than 280 miles of jagged Massachusetts coastline, salt marshes,
tidal streams and flats, barrier beaches, rocky shores, and eelgrass beds. It provides a livelihood for
many shell fishers, and offers recreational opportunities for both residents and tourists. Buttermilk
Bay, the embayment highlighted in this report, has been characterized as typical of most embayments
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Buzzards Bay Project
in the Buzzards Bay estuary. Like most other Buzzards Bay embayments, the soils of the Buttermilk
Bay watershed are sandy and highly-permeable, dominated by ground water inflow rather than surface
runoff.
APPLICABILITY OF METHOD TO OTHER GEOGRAPHIC AREAS AND SCALES
The build-out and nitrogen loading estimation methods used by the Buzzards Bay Project are
applicable at scales as small as one residential housing parcel. There is no upper size limit to these
methods, although time and cost will become constraints at a scale that depends on the resources of
the organization conducting the analysis. For larger watersheds and for establishing regional
priorities, the Buzzards Bay Program's GIS methodology would be more appropriate.
ALTERNATIVE DEVELOPMENT SCENARIOS CONSIDERED
The Buzzards Bay program estimated nitrogen loading from the Buttermilk Bay watershed at full
development potential, or completely "built-out." It was assumed in this model that all developable
land was developed to the fullest capacity allowable under current zoning regulations. The future
date at which full build-out potential would be reached was not estimated.
VARIABLES AND QUESTIONS INCLUDED IN STUDY
Two primary questions were posed in this study:
1) How many acres of land in the Buttermilk Bay watershed would be developed at full
development potential, and how many acres of each type of development would exist?
2) What are the nitrogen loading rates for each land use type in the watershed? At full
development potential, how many pounds of nitrogen would enter Buttermilk Bay from the
entire watershed?
There were two types of variables included in the build-out analysis of Buttermilk Bay:
Demographic/land use-related variables, and nitrogen loading-related variables. The variables
included were as follows:
Demographic and Land Use-Related Variables
• Number of families and residents per dwelling unit.
• Local zoning requirements for minimum lot size.
• Ownership characteristics and location of each dwelling unit parcel.
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Buzzards Bay Project
• Percentage of forest land consisting of wetlands.
• Percentage of forest land available for development.
• Percentage of undeveloped land that would be required for roads and other infrastructure (and
therefore not available for location of dwelling units).
Nitrogen Loading-Related Variables
• Pounds of nitrogen produced per septic system, per person.
• Pounds of nitrogen produced per farm livestock per year.
• Point source discharges of nitrogen.
• Pounds of nitrogen produced per unit area of lawn, roof, parking lot, road and other impervious
surface area.
• Pounds of nitrogen produced per unit area of agricultural land (primarily cranberry bogs).
METHODOLOGY
This section is divided into two parts. The first part consists of a description of the methodology
used to estimate the current extent and character of land use in the Buttermilk Bay watershed, and
resulting nitrogen loading to the Buzzards Bay estuary. The second part consists of a description of
the methodology used to conduct the build-out analysis, which predicted nitrogen loading from the
watershed in the future at full development potential. The first part describes two separate methods
that were used to estimate current land use patterns in the watershed, one involving a Geographic
Information System (GIS) and one involving parcel-level data from town assessors offices. Both
methods result in the same type of land use data, but the parcel-level analysis produces a much more
accurate assessment than the coarser, GIS-based analysis.
Methodology Used to Determine Current Land Use and Nitrogen Loading
Method One: A GIS-Based Analysis
The following methodology was employed at the outset of the Buzzards Bay Project's effort to
determine land use patterns in the Buzzards Bay watershed, which includes the Buttermilk Bay
subwatershed. This method, which relied upon data layers from a Geographic Information System,
was used to target subwatersheds with extensive development. A second, more detailed approach,
was used to determine land use patterns in the Buttermilk Bay watershed. The second approach is
described later in this section.
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1) Land use types within the 30 Buzzards Bay sub-drainage basins were derived from the
Commonwealth of Massachusetts MassGIS project, which employs Arclnfo software. The land use
data was compiled by interpreting 1:25,000 scale infra-red aerial photographs taken in 1984. Features
as small as 1 acre were interpreted and classified as one of 21 possible land use categories. Among
these land use classifications were three agricultural land use categories and four residential
categories.
2) For most of these categories, applicable nitrogen loading rates were compiled from published data
and other assumptions described in the technical report cited at the beginning of this summary. Most
of the effort involved estimating dwelling unit and population density within the four residential land
use categories. It was assumed that residential land use accounts for the majority of nitrogen inputs to
most Buzzards Bay embayments. Once housing unit densities were calculated, assumed loading rates
were applied for septic systems, lawns, and impervious surfaces that were adopted by the Buzzards
Bay Project.
3) To estimate housing unit density for the four residential land use categories, residential structures
were counted within randomly selected polygons for each of the four residential land use categories
on the GIS system. Residential structures were counted on either USGS 1:25,000 scale quad sheets,
color photographs, or black and white orthophotographs. Different media were used due to a lack of
an adequate range of years for any single medium. Counts from photographs from different years
were sometimes interpolated, and each house counted was assumed to be a single family unit.
4) After estimating the number of units in the subbasin using the MassGIS land use data, this number
was multiplied by the occupancy rate for that subbasin as estimated from US Census data to obtain
the existing subbasin population. Both US Census population "block" and housing unit "block
group" aggregate polygons have been digitized and registered with the land use data. For those
blocks that crossed subbasin boundaries, an algorithm to divide populations within the block
proportionally to the area of the polygon within the subbasin was developed.
5) The relatively large size of the "block group" polygons meant that they often crossed subbasin
boundaries. To avoid potential error associated with assuming that housing densities were uniform
over the block group aggregates, the ratio of population of the block group in the subbasin versus the
total for the entire block group was estimated. This ratio was then multiplied by the total number of
units in the block group to obtain the units of that block group in the subbasin.
6) The number of housing units in the subbasin was next multiplied by a per-unit nitrogen loading
factor. This factor included assumptions about the contributions of nitrogen from septic systems,
lawns, and impervious surfaces. Application of these assumptions required estimation of the average
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lot size and associated impervious surface area for a "typical" housing unit, as well as the amount of
nitrogen created by an average septic system. Although actual lot size varied widely in the four
residential GIS land use categories, in practice lots were typically found to conform to lot sizes
defined in zoning regulations. The density of housing units (units/acre) were determined through
analysis of aerial photographs and other sources. Nitrogen loads from housing units were then added
to the total of all estimated loads from all other land use types and point source loads.
7) The above steps were used to estimate existing loads. Nitrogen loading at build-out was estimated
by taking undeveloped land in the watershed (primarily forest category) and projecting new housing
units based on existing zoning and after subtracting land out for unbuildable wetlands, infrastructure,
and open space.
Method Two: A Parcel-Level Analysis
While appropriate for large land areas and to obtain a quick, "rough" sense of current
development in a land area, the methodology described above involves numerous assumptions and
estimates that are necessary when data is obtained from data layers derived from aerial photographs or
other remotely-sensed data. In the case of Buttermilk Bay, the Buzzards Bay Program chose to obtain
a higher level of detail in its assessment of current land use patterns, because the analysis was to be
the basis of local regulation and land use decision making. The methodology employed was as
follows:
• Data on all land parcels in the Buttermilk Bay watershed, as well as the characteristics of each
land parcel (e.g., ownership, size, location), were obtained from the town assessor's office in each
of the three towns that comprise the watershed (Wareham, Plymouth, and Bourne).
• As in the methodology described above, nitrogen loading rates for each type of land parcel or use
were compiled from published literature and other assumptions made by the Buzzards Bay
Project.
• The total number and type of dwelling units were multiplied by the nitrogen loading rates per
dwelling unit. The resulting totals were added to the nitrogen contributions from point and non-
point sources in the watershed.
The resulting land use and nitrogen loading data was similar to that generated by the GIS-based
methodology described above, but at a more accurate, finer level of detail. This methodology was
made possible due to the availability of computerized parcel-level land use data sets from each of the
three municipalities that comprise the watershed. This same methodology would have been far more
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difficult, if not impossible, to implement at the much larger scale of the entire Buzzards Bay
watershed, of which the Buttermilk Bay watershed is but one of 30 subwatersheds. In other words,
both methodologies are useful depending on the type of analysis required.
Determining Potential Future Development
Once current housing unit density and nitrogen loading rates had been established, the Buzzards
Bay Project used the following methodology to estimate the extent and character of land use in the
Buttermilk Bay watershed at full development potential, as well as the resulting nitrogen loadings:
1) Data on all land parcels in the Buttermilk Bay watershed, as well as the characteristics of each land
parcel (e.g., ownership, size, location) were obtained from the town assessor's office in each of the
three towns that comprise the watershed (Wareham, Plymouth, and Bourne).
2) It was assumed that 50 percent of the area defined as "forested land" was unbuildable because of
wetlands or need for infrastructure, open space, protection of drinking water supplies, etc. The
remainder of the forest land was presumed to be available for development in the residential and
commercial/industrial land use classes.
3) The existing ratio between the area used for residential purposes and the commercial/industrial
categories was assumed to remain constant into the future.
4) For the residential categories, it was assumed that new residential development would be
proportional to existing land-use categories. The smallest land class (lots less than 1/4 acre) were
excluded from the study because very few of such small lot sizes were expected to be approved for
future development, because of current zoning regulations.
5) Agricultural land conversion to residential or commercial industrial land uses were considered in
these build-out projections using the same assumptions as forested land. Cranberry bogs were
excluded, because this agricultural land use has been expanding.
6) The total number of acres of remaining land was calculated. This land was classified as
developable.
7) Massachusetts subdivision regulations and each town's zoning ordinances were examined to
determine the allowable development density in each town.
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Buzzards Bay Project
8) The data from steps 6 and 7 were combined, yielding an estimate of the total potential future
number and type of dwelling units per town and for the entire watershed.
9) The total number and type of dwelling units were multiplied by the nitrogen loading rates per
dwelling unit, plus the nitrogen contributions from point and non-point sources in the watershed.
STUDY RESULTS AND FINDINGS
For embayments like Buttermilk Bay, the Buzzards Bay project established nitrogen loading
limits of 200 milligrams per cubic meter per flushing time. This translates to an acceptable yearly
load of 115,617 pounds of nitrogen.
The parcel-level methodology described above was applied to the Buttermilk Bay embayment.
The results of the modeling showed that impacts from the "build-out" population (that which is
allowable under current zoning) would exceed critical loading rates for the embayment. To address
this problem, amendments to the zoning of the three towns surrounding the embayment were drafted
and ultimately adopted and implemented by each town.
The largest expected changes in land use will be the result of an increase in rural residential uses.
This occurs because of the large lot size of those types of units, which range from one unit per one
acre in one of the towns, to one unit per 17 acres in parts of another.
It was also recommended that, as a land use policy, the rural outlying areas not be developed at
densities requiring waste water treatment facilities. Instead, each unit will be required to use a septic
system.
TYPES OF DATA REQUIRED FOR MODEL
Land Use Data
• USGS 1:25,000 scale quad sheets, color photographs, or black and white orthophotographs.
• Parcel-level housing data in delimited format from the town assessor's office in each town
included in the study. (Note: this level of detail not necessary for a simplified analysis, which
requires only GIS land use coverages.)
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Buzzards Bay Project
Demographic Data
• U.S. Census data stored in a Geographic Information System. Can be provided in delimited
format for use in a spreadsheet (use of a GIS is optional).
DATA ACQUISITION AND LEVEL OF EFFORT
Acquiring the data necessary for the type of methodologies described above does not have to be
expensive or particularly time-consuming. Depending on availability, GIS data layers containing land
use or Census data can be obtained at little or no charge, depending on the type of organization
conducting the analyses. However, it is necessary to have staff members skilled in GIS manipulate
the data layers to produce meaningful results. If such staff are not on-site, it may be necessary to hire
an outside contractor, which has the potential to be expensive.
Parcel-level land ownership data can usually be obtained from town assessor's offices at little or
no cost, if available. If these data are available computerized on disk, entering them into a
spreadsheet can be done quickly and cheaply. If they are not computerized, the process of entering
them into a spreadsheet (which is necessary for determining nitrogen loadings) can be time-
consuming, particularly if the watershed to be analyzed is large and contains many separate land
parcels. If the land area is very large, and parcel-level data are not available in a computerized
format, it may be more time and cost effective to utilize a Geographic Information System such as
that described above under "Method One: A GIS-Based Analysis."
REQUIRED COMPUTER AND OTHER RESOURCES
Analytical Tools
• None required. The Buzzards Bay Program created a methodology that did not require previously
created analytical tools, and utilized instead standard spreadsheet software. However, use of a
Geographic Information System such as Arclnfo is optional and can be used to conduct an
analysis similar to the one conducted on the Buttermilk Bay watershed. The result would be
similar, but at a coarser scale.
Computer Resources
• IBM-compatible computer, 386 or greater.
• Town assessor's data on computer disk, in ASCII or other delimited format readable by a
spreadsheet program.
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Buzzards Bay Project
• Land use maps containing parcel ownership data on a computer disk in ASCII or other delimited
format readable by a spreadsheet program. Optionally, Arclnfo software can be used if town
assessors data is available for all land areas to be included in the analysis.
• A commercial spreadsheet program.
FORMAT OF FINAL PRODUCT
The Buzzards Bay Project has released several reports outlining both the methods used in, and the
results of, its build-out analysis. These reports are listed at the end of this summary.
LESSONS LEARNED AND ALTERNATIVE APPROACHES
• Build-out analyses can be conducted at low cost if in-house staff are skilled in this type of
analysis. Otherwise, outside contractors may need to be hired, at potentially high cost.
• For time-consuming tasks that do not require a high level of skill (e.g., entering hundreds or
thousands of lines of land parcel data into a spreadsheet, or measuring road frontage of parcels),
utilizing volunteers or interns can result in significant cost savings.
• If the build-out analysis will include recommended changes in zoning regulations, be sure to work
closely with local planners and citizens' groups to ensure a sense of buy-in and to avoid errors in
the interpretation information about specific land parcels.
ADDITIONAL INFORMATION
To protect Buzzards Bay, the Commonwealth of Massachusetts and the US Environmental
Protection Agency (EPA) formed a partnership in 1985 to create the Buzzards Bay Project. Three
years later, the Project joined the EPA's National Estuary Program to develop a comprehensive plan
to restore and preserve the Bay's water quality and natural resources. Today that plan, the Buzzards
Bay Comprehensive Conservation and Management Plan (CCMP), is considered by some as a
blueprint for estuary protection, and the Buzzards Bay Project is working to implement this plan in all
30 embayments of the Buzzards Bay estuary. With this in mind, build-out analyses are currently
underway for the Westport River, Aliens Pond (in Dartmouth), Little Bay (in Fair Haven), Onset Bay
(in Wareham), and West Falmouth Harbor (in West Falmouth). Ultimately, the Buzzards Bay Project
hopes to conduct build-out analyses on all 30 embayments in the Buzzards Bay basin.
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SOURCES OF INFORMATION AND TEXT IN THIS FACT SHEET
Information and text for this fact sheet were compiled from the following sources:
Costa, J.E., D. Janik, N. MacGaffey, and D. Martin. 1994 (draft). Use of a Geographic Information
System to Estimate Nitrogen Loading to Coastal Watersheds. Technical Report. Buzzards Bay
Project. Marion, MA.
Costa, J.E., B.L. Howes, A.E. Giblin, and I. Valiela. 1992. Monitoring Nitrogen and Indicators of
Nitrogen to Support Management Action in Buzzards Bay. In Ecological Indicators. D.H.
KcKenzie, D.E. Hylact, and V. Janet McDonald (eds.), Vol. 1. Elsevier Press, London. Pp 499-
531.
Buzzards Bay Project. 1991 Buttermilk Bay Nitrogen Management Strategy. Fact Sheet. Marion,
MA.
Buzzards Bay Project. 1992. Managing Nitrogen to Sensitive Embayments. Fact Sheet. Marion,
MA.
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BIODIVERSITY AND LANDSCAPE PLANNING: ALTERNATIVE FUTURES FOR
THE REGION OF CAMP PENDLETON, CALIFORNIA
TITLE OF PROJECT/REPORT:
RESEARCH CONDUCTED BY:
SPONSORING ORGANIZATION(S):
CONTACT INFORMATION:
MAILING ADDRESS:
WEB SITE:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION DATE:
PROJECT LOCATION:
Biodiversity and Landscape Planning: Alternative
Futures for the Region of Camp Pendleton, California.
1996.
A team of investigators from the Harvard University
Graduate School of Design, Utah State University, the
National Biological Service, the USDA Forest Service,
The Nature Conservancy and the Biodiversity Research
Consortium.
The Strategic Environmental Research and Development
Program (SERDP), a joint program of: U.S. Department
of Defense, U.S. Department of Energy, and the U.S.
Environmental Protection Agency.
David Mouat, SERDP Principal Investigator, U.S.
Environmental Protection Agency, Environmental
Research Laboratory. Bob Snieckus, U.S. Department
of Agriculture, Natural Resources Conservation Service.
For David Mouat at EPA: 200 S.W. 35th Street,
Corvallis, OR 97333. For Bob Snieckus at USDA:
2121-C Second Street, Davis, CA 95616.
Harvard Web Site for the Project:
http ://www .gsd.harvard.edu/brc/brc .html
Bob Snieckus at USDA: rsnieckus@ca.nrcs.usda.gov
David Mouat: (541) 754-4330.
Bob Snieckus: (916) 757-8221.
1996.
Greater region of Camp Pendleton, California, located in
southern California between Los Angeles and San
Diego.
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Camp Pendleton
INTRODUCTION AND PURPOSE OF STUDY
Biodiversity and Landscape Planning: Alternative Future for the Region of Camp Pendleton,
California was a two year research program aimed at exploring how urban growth and change in the
rapidly developing area located between San Diego and Los Angeles might influence native habitats
and the biodiversity of the region. The research strategy, which examined the impact of various
development scenarios on the region, was based on the hypothesis that the major stressors causing
biodiversity change are related to urbanization. As population in an area increases, habitat is typically
lost due to grading, paving, ornamental landscaping, and other human activities related to
development. There are also indirect, secondary, and cumulative effects on vegetation through
hydrologic and fire influences resulting from development.
The purpose of the study was to provide information regarding issues, strategic planning options,
and possible consequences related to biodiversity to the many stakeholders and jurisdictions whose
actions will influence the region's future biodiversity. The team of researchers developed a
computer-based geographic information system (GIS) to describe the region and for use in analyzing
the possible future changes in land use patterns. The team studied future land use change at different
scales (i.e., several restoration projects, a subdivision, a third order watershed, and the region as a
whole) and simulated five regional-based alternative development scenarios. Each development
scenario was evaluated using a set of process models that define the natural conditions of the region
(e.g., soils, hydrology, fire, biodiversity and visual preference characteristics). The research team did
not make specific recommendations on which alternatives to pursue; their purpose was to educate
stakeholders of the risks and benefits of a range of alternatives for the Camp Pendleton region and to
provide tools and techniques which may be helpful in guiding the future of urbanization and
landscape changes in the region.
RELEVANCE TO THE CHESAPEAKE BAY PROGRAM
The Camp Pendleton region biodiversity and landscape planning study is highlighted in this report
for three primary reasons:
1) The build-out analysis was conducted at a scale large enough to include five major river drainage
basins of a coastal region. The purpose of the build-out and development of alternative future
scenarios for the region was to evaluate the impacts associated with increased urbanization on the
natural resources of the region, in particular the impacts of urbanization on native habitats and
biodiversity. While this study was not conducted at a scale large enough to encompass the entire
Chesapeake Bay watershed, it does provide a context in which several different subwatersheds
may be evaluated. In addition, some of the impacts associated with urbanization in the region of
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Camp Pendleton
Camp Pendleton may have similar characteristics and consequences that can be evaluated within
the context of the Chesapeake Bay.
2) The Camp Pendleton study provides several alternative development scenarios and options that
may be considered for managing urbanization in the Chesapeake Bay. Although the study
focused on biodiversity management, it does provide a general context for developing alternative
futures that minimize impacts to the natural environment. In addition, the Camp Pendleton study
examines alternatives at four different geographic scales. Depending on the geographic scale of a
build-out analysis in the Chesapeake Bay, this report may be a useful reference for such efforts.
3) The study draws upon a complex array of data sources to fully describe the natural environment of
the Camp Pendleton region (e.g., soils, hydrology, biological species). It applies those types of
data within the context of the region's demographic qualities and potential (e.g., population
projections) to produce a thorough and well-defined description of the existing environment as
well as a vision of the region at full build-out. Because performing build-out analyses in the
Chesapeake Bay would require similar types of data, it would be useful to understand how the
research team in the Camp Pendleton region acquired and applied the data using a geographic
information system (GIS).
SIZE AND GEOGRAPHIC BOUNDARIES OF STUDY
The Camp Pendleton region is located in southern California between Los Angeles and San
Diego. The study region is a 50 by 84 mile rectangle that encompasses the five major river drainage
basins directly influencing Camp Pendleton: San Juan, San Mateo, San Onofre, Santa Margarita, and
San Luis Rey. The study area reaches east through portions of Orange, Riverside and San Diego
Counties.
DESCRIPTION OF LANDSCAPE
The landscape of the study area is unique in that it includes several different physiographic
provinces: coastal plains, foothills, the Temecula Valley, mountains and at the eastern edge, desert.
The study area is one of the most biologically diverse environments in the continental United States.
It supports a variety of habitat types including coastal lagoons and estuaries, coastal scrub areas,
maritime-influence chaparral and scrub communities, oak woodlands, coniferous mountain areas, and
dry , hot, sparsely vegetated deserts. Each of these supports a unique range of animal species,
including more than 200 plant and animal species listed by Federal or State agencies as endangered,
threatened or rare.
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Camp Pendleton
The Marine Corps Base (MCB) Camp Pendleton is the largest unbuilt portion of land on the
southern California coastline (49,857 ha) and thus central to maintaining the long term biodiversity of
the region. In the surrounding Counties, population continues to increase and is expected to reach 1.6
million by 2010 (1990 population: 1.1 million).
APPLICABILITY OF METHOD TO OTHER GEOGRAPHIC AREAS AND SCALES
The methodology used in the study encompassed four different geographic scales: the region of
Camp Pendleton was examined through several alternative planning scenarios (the focus of this
section); a sub-watershed of the Santa Margarita River was examined by comparing several different
planning and development guidelines; a residential subdivision on the biologically sensitive Santa
Rosa Plateau was examined for the creation of wildlife corridors within a rural residential area; and
site-specific habitat improvements were proposed. These habitats consisted of a wildlife crossing on
an interstate highway, and three zones of rare and endangered species habitat within Camp Pendleton.
Although many of the specifics of the study cannot be applied directly to the Chesapeake Bay due
to differences in ecosystems and other characteristics, the methodology may provide useful insight
into how the research team in the Camp Pendleton region approached biodiversity and landscape
planning at four different geographic scales. Constraints on data availability and the financial and
staff resources of the organization conducting such a study in a particular portion of the Chesapeake
Bay will determine the applicability of the methods used in the Camp Pendleton region study.
ALTERNATIVE DEVELOPMENT SCENARIOS CONSIDERED
Six alternative development scenarios were considered for the region of Camp Pendleton. All of
the scenarios are based upon a base map showing "constrained land" — land that is either already
developed or that is assumed to be protected from urban development, including Camp Pendleton's
Military Impact Areas. The following discussion focuses on the six regional scenarios that include:
1) Plans Build-Out. This scenario assumes the continued demands of population growth, continued
water supply, adherence to existing plans and the absence of compelling and intervening
alternatives. This alternative scenario represents the single most likely long-term future for the
study area and it is the scenario against which all other alternatives are compared. The scenario is
based on the premise that if land is "unprotected" and developable, it will be altered (eventually)
to its planned land use.
2) Alternative #1. Spread. This scenario assumes the continuation of the predominant regional
trend of the spread of low density rural residential and clustered single family residential
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Camp Pendleton
development. It also assumes the weakening of some development constraints and the absence of
any new conservation-oriented land acquisitions.
3) Alternative #2. Spread with Conservation 2010. This scenario follows the spread pattern, but
implements a conservation strategy beginning in 2010. The conservation strategy assumes that all
remaining areas of high conservation priority and all areas of riparian vegetation, coastal sage
scrub and chaparral, will be conserved beginning in 2010 by purchase or other means. All land
outside protected zones and not developed as of 2010 is assumed to be developed as zoned, to
build-out.
4) Alternative #3. Private Conservation. This scenario follows a low-density pattern but proposes
private conservation through large-lot ownership and management of land adjacent to and within
important habitat areas as a means of conserving biodiversity.
5) Alternative #4. Multi-Centers. This scenario focuses on cluster development and new
communities within the region as a means to focus urban growth and have the least possible
impact on the ecological regimes. The scenario identifies a number (11) of development
"centers" that will have a density of people and commerce sufficient to create a critical mass of
activity including pedestrian and public spaces. The centers were located to avoid impacts to
biodiversity, near intersections of major roads and on developable land that was neither steep nor
wet.
6) Alternative #5. New City. This scenario focuses on accommodating most growth in the region
in one new city. To encourage development within areas appropriate for urban development and
away from areas critical for biodiversity, a new single center was located that would incorporate
existing urban areas as satellite communities. To identify the appropriate location, consideration
was given to the presence of transportation, sewer and water infrastructure and avoidance of steep
and flood prone areas.
QUESTIONS AND VARIABLES INCLUDED IN STUDY
The following questions were included in Biodiversity and Landscape Planning: Alternative
Futures for the Region of Camp Pendleton, California to define the context of the landscape planning
study. These questions were asked three times during the course of the study: the first time to define
the context and scope of the research, the second time to specify the methods of study, and the third
time to carry the project forward to a set of conclusions.
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• How should the state of the landscape be described in content, space and time?
• How does the landscape operate? What are the functional and structural relationships among its
elements?
• Is the current landscape working well?
• How might the landscape be altered — by what actions, where and when?
• What predictable differences might the changes cause?
• How should the landscape be changed?
Additional questions developed by specific Federal and State agencies, regional planning agencies
and local constituents were asked of the research team, but are not included here.
The variables that influence the impact of the various alternative scenarios on the landscape,
including biodiversity, are as follows:
• Developable terrain (e.g., slope percentage and influence in constraining development)
• Soil composition, management requirements and productivity (e.g., agriculture, biodiversity
management, development)
• Hydrological regime (i.e., the quantity, timing, location and quality of available surface water, soil
water and groundwater)
• Fire regime (e.g., fire needs of biological species, fire needs in developed areas)
• Vegetation (e.g., climate, soil type, soil moisture, elevation and solar requirements of regional
vegetation; relationship between vegetation types and species habitats; changes in vegetation
resulting from development)
• Landscape ecological pattern (i.e., spatial relationships between structural and functional elements
of the land needed to protect biodiversity)
• Single species potential habitat (i.e., emphasis on the quantitative relationships between
environmental variables and habitat suitability for threatened and/or endangered species)
• Species Richness
• Visual Preference (i.e., what humans want to see in their surrounding environment)
Other variables that will influence the outcome of each alternative scenario include:
• Percentage of land that is currently protected or managed for biodiversity.
• Percentage of land that is currently protected or managed for biodiversity and will not likely be
converted to another use in the future.
• Percentage of land that is currently protected or managed for biodiversity, but that may be
converted to another use in the future.
• Percentage of land that cannot be developed due to physical constraints (e.g., slope, wetness).
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METHODOLOGY
The methodology used in the Camp Pendleton region study was conducted in four separate, yet
integrated parts: development of a map describing the existing land cover and land use; development
of a map showing the region at full build-out; development of five alternative development scenarios
based on the build-out analyses; and development of specific models to evaluate the impacts of each
alternative on the natural environment, in particular the impacts to biodiversity and species habitat. A
GIS was designed to manage, integrate and analyze all of the data used in the study.
Existing Land Cover and Land Use
To develop the base map of existing land cover and land uses in the Camp Pendleton region,
researchers acquired data from several sources, with variations in spatial resolution and accuracy.
Sources ranged from detailed observations made by wildlife biologists in the field to descriptions of
roads and stream networks from national data bases of the U.S. Geological Survey and the Census
Bureau. Additional data were provided by regional agencies and organizations, universities and
others. While most source data were acquired in digital form, some data, such as the county level
soils surveys, were digitized from printed originals. All data were assembled, standardized to a
common set of descriptive terms and combined to produce the study's representation of the
landscape.
The following categories of data were input to the GIS: water, riparian vegetation, oak-woodland,
mixed forest, orchards, sage, chaparral, grassland, "altered land " (extensive agriculture), rural
residential (1 house per 2 ha), single family residential (1 house per 1/10 ha), multi-family residential
(1 house per 1/20 ha), military maneuver, military impact, commercial/industrial, and transportation.
An additional eleven categories showing lands that are or could be protected or managed for
biodiversity were included: Biological reserves (the most protected), National Forests; Bureau of
Land Management Lands; State, County and local parks; steep or wet land; military impact areas,
military maneuver areas, Indian reservations; agricultural land; private holdings; and urban areas (the
least protected).
In the GIS used for the study, separate digital "layers" or maps, were used to represent the
important aspects of the study area: topography, soils, vegetation, hydrology, roads, existing and
planned land use, county and municipal boundaries, etc. Each separate layer is stored in "raster"
form, which is a two dimensional array of "grid-cells" or "pixels." In addition, a number of linear
features, such as roads, streams, county, municipal and other legal boundaries are maintained as a
linear or "vector" data base.
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Camp Pendleton
Build-Out Analysis
To perform the build-out analysis, researchers used the GIS to integrate information about the
future plans for land use in the region, including the anticipated needs for housing, recreation,
transportation commerce and industry. The build-out was completed using information derived from
generalized community land use plans, which are coordinated at the county and regional level by San
Diego Association of Governments (S ANDAG) and Southern California Association of Governments
(SCAG), from Marine Corps Base Camp Pendleton, and from information on other Federally
managed lands. This data was collated and re-classified into land cover categories using the
IMAGINE software developed by ERDAS.
The build-out analysis assumed that all existing urban land uses such as residential, commercial,
industrial and transportation would remain as they are and that existing protection and management
policies would be continued. All lands in higher levels of protection, including bioreserves, National
Forests, BLM lands, special districts, and state and county owned lands were considered
undevelopable. Military impact areas were also considered undevelopable. In the special case of
Indian Reservations, which are not included in local and regional plans, it was assumed that they were
developable at an overall rural residential density, while remaining subject to the full range of
development and conservation alternatives.
Alternative Development Scenarios
Six alternative development scenarios (including the build-out scenario) are compared in this
study. They are listed and discussed in a preceding section of this chapter, "Alternative Development
Scenarios Considered." All of the alternatives are based upon the same assumptions reflected in the
build-out analysis (e.g., continuance of existing land uses, developable land, constraints to
development because of protected or managed lands, etc). Each alternative is represented in two
stages: its projected state by the year 2010 which accommodates the forecasted population increase of
about 500,000 additional persons, and its projected state at build-out.
The final research report provides detailed information about how each of the alternatives were
developed: what assumptions were made, what factors guide implementation of the alternative, and
how the alternative scenario changes the existing landscape.
Evaluation of Scenarios Using Specific Models
Models for soils, hydrology, fire, landscape ecological pattern, single species potential habitat,
species richness, and visual preference were developed to evaluate the environmental impact of each
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alternative development scenario. Each model combines selected layers of the base data stored in the
GIS to analyze or predict some aspect of the structure or function of the regional landscape. Some
models require as an input the results of other models. Researchers presented the results of the
evaluation in a graphic and detailed discussion. The graphic exhibits each of the alternative
development scenarios along the x axis and the models along the y axis. Using color codes, each
alternative is ranked from worst to best, depending on its impact on the particular aspect (e.g., soils,
hydrology) represented in the model.
The results of most models are represented by one or more thematic maps. A thematic map might
represent a conditional state, such as land cover in 1990+, an evaluation of species richness, or an
impact such as loss of productive agricultural soil. Colors are used to identify different categories of
that theme, or relative degrees of a characteristic such as density of development or soil moisture. In
almost all cases, maps are rendered on shaded relief to clarify the relationships between the map
theme, the physiographic terrain, and the hydrologic pattern of the study region.
STUDY RESULTS AND FINDINGS
A comparison of the alternative futures was assessed by a series of specific models for the impacts of
changes between 1990+ and 2010 and between 1990+ and Build-Out. The models used to evaluate
the impacts of each alternative scenario include: Soils, hydrology, fire, landscape ecological pattern,
single species potential habitat, species richness, and visual preference.
• In general, the Build-Out and Spread alternative scenarios would have the most severe impact on
each of the elements modeled. For example, the Build-Out and spread scenarios would have the
most severe impact on the hydrological regime of the region due to increased amounts of
imperviousness that accompany development.
• In general, the Private Conservation alternative scenario would have the least severe impact on the
effective management of the natural environment. For example, while fire management would be
most difficult after implementation of the Build-Out, Spread and New City alternatives, Private
Conservation would permit an adequate spatial distribution of development suitable for fire
management within developed areas.
• From the perspective of landscape planning for biodiversity, the Build-Out and the Spread
alternatives which do not have the management of biodiversity as a primary objective, perform
poorly as alternative futures. The Multi-Centers and New City strategies seek to conserve
biodiversity by attracting more concentrated development into appropriate areas while minimizing
public cost for conservation and infrastructure. The alternative which seeks to protect the most
significant habitat areas through Private Conservation succeeds, but at the risk of impacts
associated with very low density and clustered development in some of the region's most
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sensitive environments. The Multi-Centers and New City alternatives may present the best, most
feasible options for future development even though they are less effective in protecting
biodiversity.
TYPES OF DATA REQUIRED FOR MODEL
The types of data required to develop a complete description of the study area landscape included:
Maps: Topography, soils, vegetation, hydrology (e.g., presence of
wetlands, streams, etc.), roads, existing and planned land use,
county and municipal boundaries, habitat of endangered,
threatened or rare biological species, agricultural land, existing
management areas (e.g., Federally managed lands (especially
MCB Camp Pendleton), Indian reservations, State and local
parks), and private land holdings.
U.S. Census Data: Population for 1990+ and projections for 2010.
Summary of Developable Lands: Generalized community land use plans generated at the county
and regional level by the SANDAG, the SCAG and MCB Camp
Pendleton, and from information on other federally owned lands
and several large special projects.
For each of the models used in the analyses (i.e., soils, hydrology, fire, landscape ecological
pattern, single species potential habitat, species richness, and visual preference), arrays of the above
mentioned data types were combined with additional data relating to each specific model. This
combination of data was used to complete a thorough representation of the landscape characteristics
and potential impacts from changes in land use for each model. For example, additional data on the
annual precipitation rates and runoff calculations were used in the development of the hydrology
model. The report provides detailed information on specific data requirements for each of the
models.
DATA ACQUISITION AND LEVEL OF EFFORT
The data acquired for this study and for the development of research models are based on existing
and publicly available data. No other information regarding the actual effort to gather this
information was discussed in the report. However, more than 100 people representing numerous
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Federal and State agencies, a non-profit organization, regional planning agencies, universities and
technical consulting firms, contributed to the study.
A complex GIS was designed to contain digital data about the region, perform the analyses and
produce maps, charts and other graphic and tabular results. The cost and level of effort required for
this task is not known. However, given the quantity and different types of data entered into the
system, is it assumed that substantial resources went into the development of the GIS and data
collection effort.
REQUIRED COMPUTER AND OTHER RESOURCES
Computer Resources
• A computer system capable of performing the functions associated with the use of a GIS.
• The analytical models that use the base data were implemented as computer program modules
using the Arc/Info GRID analysis package developed by Environmental Systems Research
Institute, Redlands, California.
• Additional data re-classification and satellite data interpretation was performed in IMAGINE
software developed by ERDAS, Atlanta, Georgia.
• Alternative development scenarios were developed with MapFactory GIS software produced by
Think Space, Ontario, Canada.
Other Resources
• Field observations made by wildlife biologists
• National data bases of the U.S. Geological Survey and the Census Bureau
• Various land use maps provided by SANDAG, SCAG and MCB Camp Pendleton
• Soil surveys of the Natural Resources Conservation Service.
FORMAT OF FINAL PRODUCT
Biodiversity and Landscape Planning: Alternative Futures for the Region of Camp Pendleton,
California is presented as a full color written report, including a series of maps that represent all
examined aspects of the study area. A map of the study region, the existing land cover, managed
areas, and maps for each alternative development scenario as well as many others are included in the
report, in full color. The report also provides an extensive bibliography and a list of the associated
members of the research team and other participants in the study, including their representation of the
respective agency or organization.
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LESSONS LEARNED AND ALTERNATIVE APPROACHES
• The cooperation of all regional stakeholders including private, State, non-profit, and Federal
interests, is essential to the long-term protection of biodiversity in the region of Camp Pendleton,
CA.
• A collaborative and well-funded process for gathering and analyzing data will yield more
thorough results in a regional biodiversity and landscape planning study and will contribute to the
positive buy-in of Federal, State, regional, and local decision makers.
• Use of a GIS was a critical component of the Camp Pendleton region study.
ADDITIONAL INFORMATION
There are several reasons that the research team selected the region of Camp Pendleton for study.
First, it has one of the highest levels of biodiversity in the United States. Second, it is experiencing
dramatic growth and will have to manage increasing development pressures. Third, a considerable
amount of information about the area has been compiled, but had not yet been synthesized across
county boundaries for the regional management of biodiversity in this part of California. Fourth, the
research team, among many others, believe that there is still time to make a difference.
Effective management of biodiversity through landscape planning can only be addressed through
the cooperation of interested parties, since species and their habitats cannot be confined to imposed
boundaries such as political jurisdictions. To address this need for cooperation in the region of Camp
Pendleton, the Biodiversity Research Consortium (BRC) was formed to develop analytical methods
for assessing and managing risks to biodiversity. Current membership in the consortium includes the
U.S. Environmental Protection Agency, U.S. Department of Interior through the National Biological
Service, the U.S. Geological Survey, the U.S. Bureau of Land Management, U.S. Department of
Agriculture Forest Service, U.S. Department of Defense, the Smithsonian Institution, and The Nature
Conservancy. In addition, a number of academic institutions participate as research collaborators,
including Harvard and Utah State Universities. In addition to the study of the Camp Pendleton
region, other BRC studies include state-scale analyses of Oregon and Pennsylvania and a national-
scale analysis of bird species diversity.
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SOURCES OF INFORMATION AND TEXT IN THIS FACT SHEET
Information and text for this fact sheet were compiled from the following sources:
The Strategic Environmental Research and Development Program. 1996. Biodiversity and
Landscape Planning: Alternative Futures for the Region of Camp Pendleton, California.
SERDP, a joint program of: U.S. Department of Defense, U.S. Department of Energy, and the
U.S. Environmental Protection Agency.
Schiffman, Irving. Alternative Techniques for Managing Growth. Berkeley, California: Institute of
Government Studies, University of California at Berkeley, 1990, c!989.
Southern California Association of Governments. Open Space and Conservation. In DRAFT
Regional Comprehensive Plan. Los Angeles: California, December 1993.
Steinitz, Carl. A Framework for Theory and Practice in Landscape Planning. GIS Europe (July
1993).
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GEOGRAPHICAL ANALYSIS OF BACTERIAL CONTAMINATION
TITLE OF PROJECT/REPORT:
RESEARCH CONDUCTED BY:
SPONSORING ORGANIZATION(S):
CONTACT INFORMATION:
MAILING ADDRESS:
WEB SITE:
PHONE NUMBER:
STUDY COMPLETION DATE:
PROJECT LOCATION:
Geographic Analysis of Bacterial Contamination,
Ipswich, Beverly, and Provincetown. 1996.
Horsley & Witten, Inc., Environmental Services;
Applied Geographies, Inc.; and the Massachusetts Bays
Program.
The Massachusetts Bays Program, Executive Office of
Environmental Affairs (Boston); Massachusetts Coastal
Zone Management Office; and U.S. Environmental
Protection Agency.
Ms. Ruth Kuykendall, Massachusetts Bays Program;
Office of Coastal Zone Management; Executive Office
of Environmental Affairs.
100 Cambridge Street, Room 2006; Boston, MA 02202.
http://www.epa.gov/nep/nepbroc.html
(617) 727-9530, extension 402.
October, 1996.
The towns of Ipswich and Beverly (north of Boston),
and Provincetown (outermost extreme of Cape Cod).
INTRODUCTION AND PURPOSE OF STUDY
Many coastal communities in the Commonwealth of Massachusetts have experienced frequent
shellfish area closures due to fecal coliform counts in excess of Commonwealth environmental limits.
This problem was most severe in the late 1980s and early 1990s, but closures continue to be issued.
In an attempt to resolve this problem, a Clean Water Act enforcement suit was brought by the
Environmental Protection Agency against the Commonwealth of Massachusetts in 1988 to force the
Commonwealth to take measures to better manage sewage discharged into Boston Harbor and
elsewhere off of the Massachusetts coast. As part of the settlement, the Massachusetts Environmental
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Trust was established, which is an environmental philanthropic organization dedicated to improving
the Commonwealth's coastal and marine resources. The Trust, in turn, established the Massachusetts
Bays Program (MBP), which is a collaborative effort of public officials, civic organizations, business
leaders, and environmental groups to work towards improved coastal water quality. In 1990, the
MBP became part of the EPA's National Estuary Program. This resulted in significantly increased
funding available for research.
One of the primary research goals of the MBP is to study the sources, fate, transport, and effects
of contaminants in the Massachusetts and Cape Cod Bays ecosystems. This research is intended to
support the development of a comprehensive conservation and management plan for the coastal and
marine resources of Massachusetts and Cape Cod Bays. This report presents a summary of one of the
research projects that was carried out on behalf of the MBP.
The project created a water quality modeling tool, called FecaLOAD, which is used to estimate
fecal coliform loading to selected embayments from stormwater runoff. The model was developed as
a management tool for application in areas of shellfish beds and swimming beaches. The intended use
of FecaLOAD is to calculate fecal coliform loading from the various land uses within a watershed
under stormwater runoff conditions of various magnitudes. Environmental managers, land use
planners and local officials can use FecaLOAD to evaluate water quality impacts from existing
conditions as well as to provide predictions of impacts under differing future development scenarios.
RELEVANCE TO THE CHESAPEAKE BAY PROGRAM
This study is relevant to the Chesapeake Bay Program for the following reasons:
• The study focuses on modeling of estuarine water quality contaminants that can result in shellfish
bed closures, which has the potential to be a problem in the Chesapeake Bay depending on the
density of residential developments in the Bay's watershed and their dependence on septic
systems.
• The study resulted in the compilation of fecal coliform loading rates for a variety of land uses, and
these loading rates could be applied to the evaluation of loadings from land areas in the
Chesapeake Bay watershed.
• The geographic information system (GlS)-based build-out analysis methodology used is
appropriate for any land area, including subwatersheds within the Chesapeake Bay watershed. It
utilizes land use/cover data sets comparable to data sets available for large portions of the
Chesapeake Bay watershed, including the entire State of Maryland.
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SIZE AND GEOGRAPHIC BOUNDARIES OF STUDY
Three Massachusetts towns were included in the study, Ipswich, Beverly, and Provincetown.
Ipswich and Beverly are located North of Boston, and Provincetown is located on the outer extreme
of Cape Cod. Specifically, the watersheds of the Lower Ipswich River, the Bass River (in Beverly),
and Provincetown Harbor, and their 21 subwatersheds, were evaluated with the FecaLOAD model.
The size of the watersheds evaluated are as follows: Lower Ipswich River watershed: 2,846 acres;
Bass River watershed: 2,347 acres; and Provincetown Harbor: 288 acres.
DESCRIPTION OF LANDSCAPE
The three study areas included in the Massachusetts Bays analysis represent a variety of
hydrogeologic, climatic, and land use conditions including low, medium and high density
development, impervious surfaces, storm sewers and drainage swales, septic systems and sewered
areas, and wetlands (fresh and salt water). Surface geology in Beverly and Ipswich is predominantly
till-covered bedrock having a generally low permeability. Provincetown is situated on high-
permeability sand which has been strengthened with added fill to support development.
APPLICABILITY OF METHOD TO OTHER GEOGRAPHIC AREAS AND SCALES
The FecaLOAD model can be used to quantify fecal coliform bacteria loading from land uses in
coastal watersheds. Provided necessary input data are available, FecaLOAD could conceivably be
used to evaluate any coastal watershed of any size. However, one necessary model input is detailed
soils information for all areas within the study watershed. In the watersheds evaluated in the study
summarized in this report, soils information was digitized into a GIS from Natural Resources
Conservation Service County Soil Surveys. This can be a time-consuming process if the land area is
large. The largest watershed included in the Massachusetts Bays study was only 8,486 acres. This
represents, for example, only .0002 (two hundredths of a percent) of the Chesapeake Bay watershed.
It is possible to substitute estimated soils data based on averages rather than using more accurate
sources such as Soil Surveys, but the resulting reduction in the accuracy of modeled fecal coliform
loadings may be unacceptably high.
The FecaLOAD model has also been successfully applied in Casco Bay, Maine, in an evaluation
of three subwatersheds of Maquoit Bay. In general, there is no reason to assume that FecaLOAD
model could not be applied in any other coastal watershed of sufficiently small size provided the
necessary data for input into GIS data layers were available.
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ALTERNATIVE DEVELOPMENT SCENARIOS CONSIDERED
The FecaLOAD model evaluated the three study watersheds under two conditions:
1) Current Development. This scenario was based on GIS data layers from aerial photography and
land parcel maps from town assessors, and
2) Full-Development (Build-Out). In this scenario, no attempt was made to estimate the future
date at which build-out conditions would be reached.
QUESTIONS AND VARIABLES INCLUDED IN STUDY
The questions and variables included in each study watershed were as follows:
Questions
• What average fecal coliform loadings would result in runoff from 0.5 and 3.0 inch rainfall events
in each of the three study watersheds under both current and build-out conditions?
• How many residential units are there in the three study watersheds both on and off septic
systems? How many will be in each of these categories under build-out conditions?
• What kind of buffering efficiency do different soil types exhibit?
Variables
Soil permeability and fecal coliform buffer capacity per soil type
Number of households on and off septic systems under current and build-out conditions
Number of fecal coliform bacteria released per day from humans, domesticated and
undomesticated animals, and type of land use
Amount of flow from each study watershed to each watershed's discharge point from 0.5 inch and
3.0 inch rainfall events
Location of point sources of fecal coliform bacteria, and magnitude and frequency of discharge
Extent and location of land areas under different zoning ordinances in each subwatershed
Rainfall (inches)
Time since last rain (days)
Amount of precipitation in previous five days (inches)
Season (summer, fall, winter, or spring)
Days since manure was applied (to croplands, or agricultural land)
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METHODOLOGY
1) Subwatershed boundaries were delineated on USGS topographic quad maps and then digitized into
an Arclnfo GIS, as were local soil characteristics, which were digitized directly from Natural
Resource Conservation Service County Soil Survey maps.
2) These digitized data were combined with digital GIS maps of all land use/cover types in 1985 (for
Ipswich and Beverly) and 1990 (for Provincetown), which were obtained from MassGIS
(MacConnell Land Use data), and, in the case of sewerage, from the Metropolitan Area Planning
Council. The 21 land use classifications in these data layers were converted into 8 categories used by
the FecaLOAD model. Each land use type is associated with a unique set of fecal coliform generation
or buffer coefficients. These data layers were used to determine aerial extent of different land uses
and soil types as well as the proximity of those land uses to downgradient surface waters.
3) These data layers were entered into FecaLOAD, a spreadsheet model designed by Horsley and
Witten. FecaLOAD automatically calculated the number of residential dwellings in the residential
land use categories based on corresponding MacConnell Land Use Housing Density factors, which
ranged from 1 dwelling per acre for low density land use areas to 5 dwellings per acre for multi-
family land use areas. The model estimated fecal coliform loadings from different land uses within
the study subwatersheds associated with runoff from two hypothetical events, one of 0.5 inches and
one of 3.0 inches. Also calculated were the amount of watershed runoff and concentration of fecal
coliform within that runoff. Fecal coliform concentrations were calculated for the discharge point of
each subwatershed.
4) Step 3 was repeated with projected land uses at full development (build-out) in each of the
subwatersheds in order to calculate fecal coliform loadings from each subwatershed under fully
developed conditions. The build-out methodology used was as follows:
a) The GIS land use/cover data layers for 1985 and 1990 were analyzed to determine the location
and extent of land areas where development was permitted by zoning regulations in the study
watersheds, but had not yet occurred. This was achieved by first eliminating all land areas
where development had already occurred, and all land areas where future development was
prevented, either by zoning regulations or due to physical constraints (e.g., steep slopes, high
water tables, etc.). The remaining land areas were classified as available for development.
b) A GIS data layer containing development constraints based on zoning regulations and local
by-laws and ordinances (e.g., number and type of structures and minimum frontage area
permitted per land use type) was topographically overlaid onto the data layer containing the
location and extent of land available for development. Some of these data were available in
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digitized GIS data layers from MassGIS. Where data were missing, the following simplifying
assumptions were made:
i. Preservation of upland restricted open spaces was not included in the study
ii. Wetlands were considered "unbuildable"
iii. All agricultural and pasture land was considered developable as residential land
iv. Roads that passed through one type of land use and that would pass through a different
type of land use under build-out conditions were converted to the latter land use type.
The number of residential units were calculated by multiplying the acreage of the residential
category (low, medium, or high density or multi-family) by the MacConnell Land Use
Housing Density values for Massachusetts (as noted above, this was the same method used to
calculate the existing number of residential housing units). The resulting GIS data layer
contained projected land use types, locations, extents, and corresponding numbers, types, and
locations of structures.
c) The resulting GIS data layers were entered into the FecaLOAD model, which estimated
resulting projected fecal coliform loads in the same way as it did for current land use/cover
(using average loading rates for each type of land use and structure, and calculating the
attenuation of fecal coliform based on the distance water from a storm event would pass
through soil, and the buffering capacity of the soil).
STUDY RESULTS AND FINDINGS
• Modeled concentrations of fecal coliform for a 0.5 inch rainfall event were uniformly higher than
concentrations from a 3.0 inch event for both existing as well as build-out scenarios. This was
true for every subwatershed, and is due to the diluting effect of large rain events.
• Modeled concentrations of fecal coliform during rainfall events were not uniformly higher or
lower under build-out conditions in every subwatershed. The magnitude and direction of change
in modeled concentrations from existing to build-out conditions depended on what each land area
was projected to become under full development. For example, one subwatershed characterized
by moderate density residential development dependent on septic systems but projected to become
heavily industrial/commercial with a corresponding decrease in the number of residences on
septic systems was modeled to generate less fecal coliform under build-out conditions than
current development conditions. Conversely, a different subwatershed was projected to have 11
additional septic systems under build-out conditions compared to current development conditions,
with correspondingly higher projected concentrations of fecal coliform. Whether concentrations
increased or decreased in a specific subwatershed depended on current land characteristics and
projected build-out characteristics.
• The most significant source of fecal coliforms common to the three case study communities is
residential land use (i.e., septic systems and domestic animals).
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TYPES OF DATA REQUIRED FOR MODEL
• GIS data layers containing watershed boundaries of the areas to be studied, or, if unavailable,
USGS topographic quad maps (watershed boundaries can be manually digitized into a GIS data
layer).
• GIS data layers containing the geographic location and extent of all soil types in the study area, or,
if unavailable, USDA Soil Conservation Service County Soil Survey maps (soil types can be
digitized manually into a GIS data layer).
• Soil Suitability Ratings (SSR) for each soil type in the areas to be studied (SSR refers to the
ability of a soil type to remove fecal coliform bacteria from contaminated water).
• Digital data on the current extent of sewered areas, land use/land cover types, and zoning.
• Zoning regulations and land use by-laws for all communities that are part of the land areas to be
evaluated.
• Road length (in feet) for all road types.
• Fecal coliform bacteria loading rates from different types of land use/cover and from
domesticated and non-domesticated animals from scientific literature.
• Average number of residential housing units per type of residential land,
DATA ACQUISITION AND LEVEL OF EFFORT
The Massachusetts Bays Program hired an outside consulting firm (Horsley and Witten, Inc.) with
expertise in geographic information systems and water quality modeling to conduct research for this
project. This firm, in turn, hired a sub-contractor to conduct much of the Arclnfo GIS analyses.
Thus, it is clear that this project required a high level of expertise, and could not have been
undertaken without the assistance of skilled consultants.
In addition to technical skills, a large amount of data from disparate sources was required.
Dozens of different types of data were collected from several State and Federal agencies, local
planning departments, and from scientific research organizations, in addition to published scientific
studies (see "Types of Data Required for Model" above). This data was supplemented with field
testing of fecal coliform counts under rainfall events of different magnitudes in order to calibrate the
FecaLOAD model and test the validity of its model predictions. This level of effort is time
consuming and expensive, even though the three study areas combined comprised only a total of
5,481 acres (which, again, is only .0002 (two hundredths of a percent) of the Chesapeake Bay
watershed).
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Geographical Analysis of Bacterial Contamination
REQUIRED COMPUTER AND OTHER RESOURCES
• A GIS is not required to generate the kinds of data used in the FecaLOAD model; it is possible to
generate these data manually. However, the process will be greatly accelerated with use of a GIS,
particularly if the study areas are large. A personal computer or workstation with enough memory
to run Arclnfo GIS (typically at least 16 Megabytes (MB) of Random Access Memory (RAM) and
a 1 Giga-Byte (GB) hard drive is recommended).
• PC or Workstation Arclnfo, a proprietary geographic information system from Environmental
Systems Research Institute, Inc. (ESRI).
• Staff trained in geographic information systems, particularly Arclnfo.
• Microsoft Excel or a similar spreadsheet software program.
FORMAT OF FINAL PRODUCT
The final products are two published (paper) reports, one describing the project, and one
providing additional detail on the methods used, as well as a series of spreadsheet tables containing
projections of fecal coliform levels resulting from current and build-out development conditions in
each of the three watersheds studied and their sub watersheds.
LESSONS LEARNED AND ALTERNATIVE APPROACHES
• Zoning and other land use restrictions or guidelines digitized into geographic information systems
to correspond with affected land areas are not always available for all land areas included in the
study. It may be necessary to manually digitize such data from town assessor's books and/or
make simplifying assumptions that can be applied equally to all land areas of the same type.
ADDITIONAL INFORMATION
Modeling a biological pollutant such as fecal coliform bacteria is inherently difficult due to the
complexities associated with how the pollutant responds to a wide variety of environmental
conditions such as temperature, moisture, sunlight, and soils. Results of the historical modeling
(ground truthing) demonstrated that, in most cases, FecaLOAD is capable of estimating fecal coliform
inputs from land uses within one order of magnitude, its calibration target. In its present form,
FecaLOAD is not designed to estimate concentrations of fecal coliform beyond the limit of the
modeled subwatershed, such as concentrations for the embayment.
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Geographical Analysis of Bacterial Contamination
SOURCES OF INFORMATION AND TEXT IN THIS FACT SHEET
Information and text for this fact sheet were compiled from the following sources:
Costa, J.E., Janik, D., MacGaffey, N., and Martin, D. 1994. Use of a Geographic Information
System to Estimate Nitrogen Loadings to Coastal Watersheds. Buzzards Bay Program Draft
Technical Report.
Horsley and Witten, Inc. 1996. Geographic Analysis of Bacterial Contamination, Ipswich, Beverly,
and Provincetown. Report to the Massachusetts Bays Program. Barnstable, MA.
Horsley and Witten, Inc. 1996. Companion Guidelines for FecaLOAD. Report to the Massachusetts
Bays Program. Barnstable, MA.
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CANE CREEK RESERVOIR WATERSHED STUDY
TITLE OF PROJECT/REPORT:
RESEARCH CONDUCTED BY:
SPONSORING ORGANIZATION(S):
CONTACT INFORMATION:
MAILING ADDRESS:
PHONE NUMBER:
STUDY COMPLETION DATE:
PROJECT LOCATION:
Cane Creek Reservoir Watershed Study. 1996.
The Cadmus Group, Inc.
Orange Water and Sewer Authority.
Edward A. Holland, Director of Planning and
Development.
Orange Water and Sewer Authority; P.O. Box 366;
Carrboro, North Carolina 27510.
(919)968-4421.
August 1996.
Cane Creek Reservoir and Watershed, Orange County,
NC.
INTRODUCTION AND PURPOSE OF STUDY
The purpose of the Cane Creek Watershed study is to aid in developing management plans to
protect the quality of the water supply into the next century. Given the current predominance of
agricultural and forested land in the watershed, proper management of those land use activities is now
the primary concern for protection of the water supply. However, it is expected that over time the
character of land use will shift to residential use and as a result present new challenges to protecting
the water supply.
The Orange Water and Sewer Authority (OWAS A) owns and operates the Cane Creek Reservoir
as a water supply for residents of the towns of Chapel Hill and Carrboro and portions of Orange
County, North Carolina. It is with this authority that OWASA commissioned this study and hired
The Cadmus Group, Inc., to prepare the report. The study focuses on evaluating alternative options
for achieving OWASA's overall water quality goal and objectives and to recommend the best option
or set of options. Another important purpose of the study is to evaluate the effectiveness of existing
watershed supply protection measures, particularly how they will perform over the long term.
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RELEVANCE TO THE CHESAPEAKE BAY PROGRAM
There are two primary reasons why the Cane Creek Watershed study is highlighted in this report:
1) The landscape of the Cane Creek Watershed bears some similarity to portions of the Chesapeake
Bay watershed, in that it is largely comprised of agricultural and forested lands. As such, the build-
out methodology used to determine future changes in the Cane Creek Watershed may be relevant to a
build-out analysis of similar proportions conducted in the Chesapeake Bay.
2) The build-out analyses (at 25 percent and against 100 percent of build-out) were combined with
water quality models to identify the greatest threats to future water quality in the watershed resulting
from increased population and residential development. The methods used to calculate the water
quality impacts associated with various management alternatives may provide useful insight and
background information for build-out analyses in the Chesapeake Bay.
SIZE AND GEOGRAPHIC BOUNDARIES OF STUDY
Cane Creek Watershed is approximately 31.6 square miles (20,227 acres), including the reservoir
surface. The study area is located in the upper Cape Fear Basin in the central Piedmont region of
North Carolina. Approximately 90 percent of the Cane Creek watershed is situated in Bingham
township of southwestern Orange County. The remaining 10 percent, including parts of Toms Creek
and Caterpillar Creek drainage areas is located in Alamance County.
DESCRIPTION OF LANDSCAPE
The watershed is primarily rural and 62 percent of its land remains wooded. Agricultural use,
including four active dairy farms, is significant (currently 24 percent), but decreasing. Pressures for
additional residential development (currently covering about 12 percent of the watershed area),
however, are increasing. Effective in Orange County January 1, 1994, residential lots must be a
minimum of 2 acres and have a maximum impervious surface limit of 6 percent. Up to 1 percent of
the watershed may be used for nonresidential uses such as churches, fire stations, and solid waste
stations.
APPLICABILITY OF METHOD TO OTHER GEOGRAPHIC AREAS AND SCALES
The approach developed by Cadmus certainly can be applied to other geographic areas and scales.
Cadmus designed the approach, including a suite of analytical models, as a useful tool for long-term
watershed management and protection. While the scope of the study focuses solely on the Cane
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Cane Creek Reservoir Study
Creek Watershed, the methods used in the study may be adapted to fit different scenarios in other
areas and at other scales in the Chesapeake Bay.
ALTERNATIVE DEVELOPMENT SCENARIOS CONSIDERED
A total of six different management scenarios were analyzed by Cadmus and evaluated by an
Advisory Committee. To address future watershed conditions, each management scenario was
evaluated at 25 percent and 100 percent of watershed development. The specific scenarios for
protecting future watershed conditions include:
1) Maintaining the Baseline (Current Protection Measures).
2) Construction of Tributary Detention Facilities.
3) OWASA Land Acquisition with 2-acre Zoning.
4) Preservation of Open Space Combined with BMPs. One Option with 10 Percent Preservation
and Another Option with 33 Percent Preservation.
5) Preservation of Open Space Combined with Large-lot Zoning and BMPs.
6) Mandatory Cluster Development.
The report provides a detailed description of each of the management scenarios.
QUESTIONS AND VARIABLES INCLUDED IN STUDY
The study identifies six management objectives and a set of indicators to measure how well
various management scenarios meet objectives. The objectives include: Minimize risks to public
health; minimize loss of reservoir storage capacity due to sedimentation; minimize aesthetically
objectionable taste, odor and color problems in tap water; maintain desirable quality for recreational
and aesthetic enjoyment; minimize impacts on county residents who are not OWASA customers; and
minimize rate increases to OWASA customers. The variables included:
• Total Organic Carbon (TOC) concentration
• Summer median chlorophyll-a (algal concentration)
• Percent of time with chlorophyll-a greater than 40ug/l
• Sedimentation rate
• Water clarity (Secchi depth)
• Dissolved oxygen profile
• Sediment delivery from agricultural land use
• Sediment delivery from residential land use
• Surface flow and sediment delivery from animal operations
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Cane Creek Reservoir Study
• Fish habitat
• Utility costs
• Opportunity cost of changes in property value
METHODOLOGY
The response of indicators to management scenarios and future land use was estimated using
modeling tools. Cadmus developed a steady-state (i.e., average conditions) spreadsheet model of
watershed land use, associated loading of pollutants, lake response, and anticipated impacts on
indicators. Calibration of the spreadsheet model was based on background analyses using more
detailed, time-dependent models including: Agricultural Management and Load Generation;
Generalized Watershed-Scale Nonpoint Loading; In-lake processes (U.S. Army Corps of Engineers
BATHTUB model, etc.).
The spreadsheet planning model is designed to calculate future land use resulting from a
particular management scenario at two points in time: 25 percent of build-out and full build-out (100
percent). The planning model is geographic-based and is organized around six subwatersheds in the
Cane Creek Watershed. It models land use, management, pollution load generation, and pollutant
delivery for each subwatershed.
The spreadsheet planning model included four major components:
• Specify management options and development scenarios
• Estimate future land cover and land use
• Calculate runoff and load resulting from future land cover and land use in each subwatershed
• Estimate the impacts of reservoir water quality and other quantitative indicators.
Each management scenario was evaluated in two stages. First, Cadmus provided a quantitative
assessment of predicted indicator values for each scenario and presented the results to the advisory
committee. The committee then ranked the scenarios based on the indicator results, assessments
reflecting uncertainty of meeting predicted results and potential for unintended results and other
qualitative factors.
STUDY RESULTS AND FINDINGS
• Existing water quality in the reservoir is generally acceptable and in compliance with all
applicable water quality standards, but is not pristine.
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Cane Creek Reservoir Study
• Modeling analyses indicate that development regulations and practices currently in place are not
sufficient to protect water quality from anticipated new residential development.
• The greatest threats to future water quality are posed by increases in algal blooms, manganese
concentrations, and total organic carbon levels, low dissolved oxygen concentration, reduced
water clarity and microbial pathogens.
• No single management scenario can meet all of the objectives identified in the study. The
committee must consider a combination of the four preferred options identified during the study
process.
TYPES OF DATA REQUIRED FOR MODEL
Types of data required for the models used in this study include current data on the quantitative
environmental variables discussed earlier in this summary.
DATA ACQUISITION AND LEVEL OF EFFORT
The level of effort performed by Cadmus to acquire the data for this study included:
• Coordinate projects and meetings
• Collect data
• Review and interpret existing waters quality data
• Estimate nonpoint pollutant loadings under existing conditions
• Evaluate water quality impacts of existing nonpoint pollution loads
• Evaluate water quality impacts of future nonpoint pollution loadings
• Formulate alternative management strategies for watershed protection
• Identify and evaluate in-lake methods for enhancing water quality
• Evaluate water quality impacts of alternative management strategies
• Evaluate regulatory, financial, and institutional requirements of the recommended watershed
protection plan
• Prepare final report summarizing watershed protection plan
REQUIRED COMPUTER AND OTHER RESOURCES
• PC or Workstation Arclnfo, a proprietary geographic information system developed by ESRI
• Staff trained in the use of GIS
• Microsoft Excel or a similar spreadsheet software program.
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Cane Creek Reservoir Study
FORMAT OF FINAL PRODUCT
The format of the final product includes a report, Cane Creek Reservoir Watershed Study-Draft
Report, August 1996, The Cadmus Group, Inc.: Durham, NC.
As referenced in the report, Cadmus also developed a spreadsheet planning model to estimate
impacts on watershed objectives from different management scenarios. This model may be a useful
tool in advancing efforts to perform a build-out analysis for portions of the Chesapeake Bay
watershed.
LESSONS LEARNED AND ALTERNATIVE APPROACHES
One of the major lessons learned through the study process and identified during the advisory
committee's evaluation of the various management scenarios was that no single management option
would effectively meet all of the objectives defined. As a result, the final watershed management
plan will be developed with additional public outreach and input and will most likely reflect a revised
version of at least one of the preferred management scenarios.
ADDITIONAL INFORMATION
In addition to the build-out analysis and the identification of preferred management scenarios,
several steps were identified by the advisory committee that are needed to complete the development
of an effective watershed management plan for Cane Creek Watershed. These steps include:
• Public review of the results of the study.
• Impact analysis of preferred management scenarios conducted by OWAS A and local county
planners in Orange County.
• Decision and implementation support from OWAS A Board of Directors.
• Documentation of the plan of action to provide long-term reference and communication of
implementation details.
SOURCES OF INFORMATION AND TEXT IN THIS FACT SHEET
Information and text for this fact sheet were compiled from the following source:
Orange Water and Sewer Authority. 1996 (draft). Cane Creek Reservoir Watershed Study. Carrboro,
NC.
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IV. EVALUATING BUILD-OUT ANALYSIS AND WATER
QUALITY MODELING METHODOLOGIES FOR
POTENTIAL USE BY THE CHESAPEAKE BAY PROGRAM
A total of fourteen build-out analysis/water quality modeling case studies are presented in this
report. Five are presented as in-depth summaries in the main body of the document, and the
remaining nine are presented as two-page Fact Sheets in Appendix B. All contain useful information
about alternative methods that have been used to conduct build-out analyses. In addition, the five in-
depth summaries also include information on water quality and environmental modeling
methodologies that have been applied to land use output data sets from build-out analyses. There are
numerous similarities and differences between the fourteen studies summarized in this report. Each
has its own strengths and weaknesses. For those interested in understanding the commonalities and
differences, strengths and weaknesses between the methods used in these studies, there is no
substitute for actually reviewing the summaries and Fact Sheets, in addition to other relevant sections
of this report. However, a rough comparison between some common build-out analysis and water
quality/environmental modeling methodologies is provided below as well as some suggestions on
how to meaningfully evaluate these and other build-out analysis and water quality/environmental
modeling methodologies. The comparisons and suggestions are provided to help the reader determine
the degree to which each methodology or model would meet the needs of a particular situation or
organization.
EVALUATION CRITERIA
A number of considerations should be thoroughly evaluated when determining the most
appropriate build-out analysis and/or water quality modeling techniques to use for any particular
situation. These considerations can be presented as key criteria to guide the decision-making process.
Potential approaches should be evaluated against these criteria to ensure that the selection of final
techniques is based on the most relevant information available.
There are various criteria that could be used to evaluate different build-out analysis and water
quality/environmental modeling methodologies. Three criteria, designed to aid the reader in
conducting a simple analysis of any methodology or model, are suggested in this section. These
criteria were developed by the Chesapeake Bay Program. The criteria are: 1) Accuracy in predicting
environmental impact; 2) Cost; and 3) Computer and staff resources required. After a general
discussion of these criteria and the techniques that may be used in applying the methodologies, a
matrix is presented that compares some common build-out analysis and water quality/environmental
modeling methodologies using the criteria.
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Evaluating Methodologies
The following criteria are discussed in terms of both build-out analysis and water
quality/environmental modeling methodologies. A summary of some common types of
methodologies is presented following this discussion. Table 2 defines the types of build-out analysis
and water quality modeling methodologies used in the studies summarized in this report. In addition,
these methodologies are evaluated in Tables 3 and 4.
Accuracy in Predicting Environmental Impact
Different types of models are better at simulating actual changes in land use or pollution loads
than others. In general, complex models that take into account more variables are more successful at
simulating true conditions than simplified models that rely on many averages and simplifying
assumptions. For example, a build-out analysis methodology that incorporates land use data at the
parcel level (i.e., specific information about the type of land use and number of structures at the
individual land parcel ownership level), will produce a forecast of future land use patterns that is
more precise than a methodology that relies on satellite-derived images that lump many land use
types into broad categories and that typically can not distinguish land features at a resolution higher
than 30 square meters.
Similarly, a full-scale detailed water quality model, such as the Chesapeake Bay Program's HSPF
Watershed Model (described in Appendix A) will more accurately simulate the transport and fate of
pollutants from land to receiving water than will a simple spreadsheet-driven model that cannot
simulate the many physical and biological processes that occur in watersheds. It is important to note,
however, that exceedingly high levels of precision may not be necessary to adequately serve the
purposes of every build-out analysis. There are times when simplified models are perfectly adequate
for generating information that will be used for "ball park" estimates of future water quality impacts
resulting from development. This concept is explored more thoroughly in the section,
"Considerations When Selecting a Methodology."
Discussed below are some key elements in determining the accuracy of build-out analysis and
water quality/environmental modeling methodologies:
Scale
The scale that a model operates on refers to the minimum area of land that the model recognizes
in its functions. Some models can simulate land use or physical and biological processes down to the
square foot, while others may refer to an acre as the smallest unit of measure. Large scales (e.g.,
square meter) are useful when the study area is small and generalizations or averages would render
differences between land areas within the overall study with less clarity. Small scales (e.g., acres) are
March, 1998 68
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Evaluating Methodologies
useful when the study area is large, averages provide adequate information, and collection of highly
detailed large scale data would create a volume of information so large as to impede thorough and
accurate analysis.
Recognition of Distinct Land Use Types
For reasons related to, yet distinct from, the scale used in the model, some build-out analysis
methodologies are more suitable for recognizing differences between land use types than are others.
Take, for example, a methodology that employs a geographic information system (GIS) to compile
and analyze land use data. Current land use data derived from aerial photographs has been found to
more accurately delineate between high-density and low-density residential developments than data
derived from low resolution satellite images that lump all types of development into one category.
Input Data
In general, the more distinct types of relevant data included in a model, the better the model is at
simulating actual processes. For example, a build-out analysis model that incorporates only Census
Bureau Block Group population projections is likely to be less successful at predicting future land
development patterns than one that also incorporates projected household size (residents per
household), the average amount of land consumed by an average housing unit (average "lot size"),
and other variables that influence land development patterns. Other types of relevant input data can
include the amount of land in the study area under management programs such as agricultural best
management practices (BMPs); physical variables such as temperature, rainfall, and slope of land
areas; and other variables such as biological diversity, species richness and minimum habitat size
requirements.
Output Data
Before selecting any model, it is essential to clearly identify the questions that need to be
answered in the study. If the question is, "How much additional nitrogen will enter a water body
given projected development patterns in the year 2010?", the model chosen should provide the
information necessary to answer that question. But not all studies are carried out with few, easily
answered questions in mind. Sometimes the questions are more vague, such as "What kind of
environmental impact would result from the addition of 150,000 residents to our region?" In such
cases, every attempt should be made to break larger questions into smaller, more quantifiable ones.
In addition, a model should be selected that will generate enough data to answer all of the important
questions. If the mandate of a study is necessarily general, it may make sense to format the model
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Evaluating Methodologies
used to generate as many types of output data as possible, so that the necessary information will be
there when more refined questions are asked.
Cost/Resource Considerations
Cost can be measured in both dollars and time. If the staff involved in a project are paid (i.e., not
volunteers), then time also generates cost in dollars. Certain build-out analysis/water quality
modeling methodologies are costlier than others to implement, in terms of finances, staff time, or
both. For example, the Chesapeake Bay Program's HSPF Watershed Model (discussed in Appendix
A) requires a team of over six individuals to operate, and depends on data analysis by an off-site
super computer. In contrast, the water quality model developed by the Buzzards Bay Program
(reviewed earlier in this report) can be operated by one individual using a standard commercially
available computer spreadsheet program.
In general, the more sophisticated a build-out analysis or water quality model is, the more
expensive it is to obtain, tailor to local conditions, and operate. In any proposed project, the cost of
the models used must be weighed against the level of precision necessary to meet the project's
objectives.
Ease of Meeting Computer and Staff Requirements
Directly related to cost are the characteristics of the computer and staff resources required to
perform the build-out analysis or apply the water quality model selected. This is a measure of the
level of required computer power and staff and expertise. Before deciding upon a methodology, the
organization or person(s) making the decision should carefully investigate whether it will have the
required computer hardware and software and skilled staff necessary to implement the methodology.
The case studies presented in this report will give the reader a sense of the resources required to apply
the methodologies that have been implemented by other organizations.
In general, if an organization does not have the sophisticated computers or software applications
necessary for the type of analysis it wishes to use, and/or staff qualified to operate such systems, it
may contract with an outside consulting firm that does have those resources. If the organization is a
government agency, it may also seek assistance from another agency with adequate resources. If the
type of analysis desired will be needed by the organization on a regular basis, it may be more cost
effective and efficient to purchase the hardware, software, and hire skilled operators as permanent, in-
house technical staff.
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EVALUATION OF MODELS PRESENTED IN THIS REPORT
Presented below in Table 2 are definitions of the types of build-out analysis and water quality
modeling methodologies used by the studies summarized in this report. In addition, Tables 3 and 4
contain a preliminary evaluation of the different types of build-out analysis and water
quality/environmental modeling methodologies presented in this report. The following evaluation
refers to common types of methodologies used, rather than to any of the specific methodologies
described in the case studies presented in this report. The methodologies presented in the case studies
are all modified versions of the basic methodologies described below, as indicated in Table 2.
Basic Build-Out Analysis Methodologies
The following general definitions apply to build-out analysis methodologies for purposes of
interpreting Tables 3 and 4. Full descriptions of each methodology appear in chapter two.
Parcel-Level, Manual
This method involves a process of manually drawing potential roads, structures, and other types
of development onto paper maps until all developable land areas are consumed. Due to the time
required to draw developments by hand, this method is only feasible for relatively small areas, such as
a town or small county. However, it is an inexpensive method that requires little or no resources
aside from paper maps and traditional drafting tools.
Summed Area, Manual
Using a planimeter or other device to measure areas zoned for development on paper maps, the
researcher sums the total acreage available for development in the study area and then divides this
number by an average that represents typical housing unit lot size plus a percentage representing
required land that must be reserved for frontage and infrastructure. The result is an estimate of the
total number of new residential lots that would be developed under build-out conditions. This
method is particularly appropriate for land areas too large to feasibly examine using the parcel-level
method, or when a rough average is appropriate to answer the questions posed by the study.
Geographic Information System
This method is the fastest of the three ways to conduct a build-out analysis. The method is
essentially the same as the summed area method described above, but the calculation of total area is
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Evaluating Methodologies
conducted using a geographic information system (GIS), rather than a human being. This is
particularly useful when the land area is large and would require many hours of calculation by hand.
Basic Water Quality/Environmental Modeling Methodologies
The following general definitions apply to water quality/environmental modeling methodologies
for purposes of interpreting Tables 2, 3, and 4. Full descriptions of each methodology appear in
chapter two.
Simple Models
Simple models tend to be less sophisticated and require less expertise and resources to create and
operate than watershed models. In fact, a simple water quality model can often be one of several
components of a watershed model. Typically, water quality models consist of a list of coefficients
that translate an acre of land into a quantity of water pollution, based on the type of land and quantity
of water or time involved. They may also incorporate highly simplified coefficients to simulate
pollutant transport and fate, such as the degree to which a land use type serves as a pollutant source or
sink, the proximity of each land area to the nearest downslope water body, and the buffering potential
of the intervening land areas.
Mid-Range Models
Mid-range models fall somewhere in between simple and detailed models. Typically, they are
more sophisticated versions of simple (also called "spreadsheet") models. The added sophistication
is often comprised of a geographic information system interface that modifies land use pollutant
loadings based on the location of the land area in question in relation to other land areas and water
bodies. For more detail on all three types of models, refer to chapter 2.
Detailed Models
Detailed computerized models, called watershed models, simulate watershed hydrology and water
quality for various pollutants. Watershed models simulate processes that occur in a watershed, and
produce output data such as surface water flow rate, quantity of sediment per unit of time, and
nutrient and pesticide concentrations. Watershed models are usually complex and require a team of
computer programmers and other technicians to calibrate and operate, as well as powerful computers
and computer programing languages.
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Table 2. Types of Build-Out Analyses, and Water Quality Models Presented in This Report
Title of Report,
Analysis, or Model
Growth Management for Watershed
Protection in Maryland
Use of a Geographic Information
System to Estimate Nitrogen Loading
to Coastal Watersheds
Biodiversity and Landscape
Planning: Alternative Futures for the
Region of Camp Pendleton,
California
Geographic Analysis of Bacterial
Contamination, Ipswich, Beverly,
and Provincetown
Cane Creek Reservoir Watershed
Study
Ground Water Supply Protection and
Management Plan for the Eastern
Shore of Virginia
Living With the River: A
Development Management Plan for
the Severn River Watershed to the
Year 2020
U.S. 301 Transportation Study
Technical Report: Land Use and
Growth Management
Build-out Analysis of the Thomas
Jefferson Planning District
Lancaster County Comprehensive
Plan: Growth Management Plan
U.S. EPA Clean Lakes Report for the
Occoquan Watershed
Alternative Futures for Monroe
County, Pennsylvania
Hillsdale Lake Watershed Population
and Land Use Projections, 1990 -
2010, for the Hillsdale Lake Nutrient
Study
Buildout Analysis on a GIS
Type of Build-Out
Analysis
Geographic Information
System
Parcel-Level, Manual and
Geographic Information
System
Geographic Information
System
Geographic Information
System
Summed Area, Manual and
Geographic Information
System
Summed Area, Manual
Parcel-Level, Manual
Summed Area, Manual
Geographic Information
System
Summed Area, Manual and
Parcel-Level, Manual
Summed Area, Manual
Geographic Information
System
Parcel-Level, Manual and
Summed Area, Manual
Geographic Information
System
Type of Water Quality
Model
Detailed
Simple
(Not applicable —
analysis was of habitat
loss, not water quality)
Simple
Simple and Detailed
Simple
(None used)
(None used)
(None used)
(None used)
Detailed
(None used)
(None used)
(None used)
Page Location in
this Report
14
28
39
52
61
B-l
B-3
B-5
B-7
B-9
B-ll
B-13
B-15
B-17
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COMPARISON OF BUILD-OUT ANALYSIS AND WATER QUALITY/ENVIRONMENTAL
MODELING METHODOLOGIES FOR LARGE AND SMALL LAND AREAS
The following tables present a matrix that allows for a rough comparison of the some common,
generic build-out analysis and water quality/environmental modeling methodologies. A number of
things should be kept in mind when reviewing these tables: 1) The scale of comparison (1 = lowest, 5
= highest) is in terms of how each methodology compares to the other methodologies in the tables,
not to an absolute scale. Thus, a methodology scoring 5 in accuracy is not necessarily perfectly
accurate; it is simply at least as accurate as any of the other methods in the table; and 2) The
difference between the "Cost/Resources Considerations" column and the "Ease of Meeting
Computer/Staff Requirements" column is that the former refers to the cost of undertaking such an
analysis in both dollars and hours typically required, and the latter refers to the level of power of the
computers required to run the model, and the level of technical training required of the staff operating
the model.
Note: These tables provide a quick summary of the methodologies included in this report. The
information is intended to allow for a rapid, general evaluation of different kinds of models in
common use. As noted earlier, the criteria used were developed by the Chesapeake Bay Program.
The scores applied to each methodology, which reflected the degrees to which it met the criteria, were
also developed by the CBP. For these reasons, the reader is strongly encouraged to read all of the in-
depth summaries and Fact Sheets included in this report in order to gain a thorough understanding of
available methodologies and their uses.
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Table 3. Evaluation of Methodologies for SMALL2 Land Areas
Methodology
Build-Out
Analysis
Water Quality
Parcel-Level, Manual
Summed Area, Manual
Geographic Information
System
Detailed Models
Simple Models
Mid-range Models
Accuracy
5
3
3 or 5*
5
2
3
Cost/
Resource
Considerations
4
4
4
1
4
3
Ease of Meeting
Computer/Staff
Requirements
5
5
3
1
4
3
Scale: 5 = highest, 1 = lowest.
* Accuracy is high when GIS is configured to assign development to land areas to maximize the number of parcels that
could be accommodated.
Table 4. Evaluation of Methodologies for LARGE3 Land Areas
Methodology
Build-Out
Analysis
Water
Quality
Parcel-Level, Manual
Summed Area, Manual
Geographic Information
System
Detailed Models
Simple Models
Mid-range Models
Accuracy
5
4
4-5
5
1
2
Cost/
Resource
Considerations
1*
1*
4
2
4
3
Ease of Meeting
Computer/Staff
Requirements
5
4
3
1
4
3
Scale: 5 = highest, 1 = lowest.
* The cost of undertaking a build-out analysis on a very large area without the assistance of a GIS is so high as to be
essentially infeasible.
For purposes of this table, a "small" land area is one for which it would be feasible to obtain land parcel-level data,
such as from town assessor's offices.
For purposes of this table, a "large" land area is one for which it would be infeasible to obtain land parcel-level
data, requiring a more general analysis based on numerous averages and assumptions.
March, 1998
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Evaluating Methodologies
Additional Considerations When Selecting a Methodology
The following are additional considerations when evaluating a build-out analysis or water quality
modeling methodology for its potential use in a project:
Determining Type and Number of Development Scenarios
The answers to the following questions will help determine the types of data necessary for model
input, as well as the most appropriate build-out methodology.
• Will the study include a full build-out scenario (i.e., all land fully developed), or some number of
partial build-out scenarios (e.g., 50 percent developed, 75 percent developed, etc., or build-out
under varying population levels)?
• Is the goal of the study to determine how much land will be developed when the land area is fully
developed, regardless of when that will occur, or would it be more useful to project development
at some specific future date, such as ten years in the future?
Data Requirements
A careful inventory of the kinds of data that will be required for the project prior to the start of the
project will help determine whether the available models can be used effectively. If key input data
can not be obtained at present, it may make sense to delay the start of the study until further
background research can generate the necessary data. Some of the key data types that should be
considered in this context are:
• Demographic
• Cartographic
• Natural Resources (including species habitat)
• Management Practices (including agricultural best management practices)
• Infrastructure (e.g., sewage lines, roads, wastewater treatment plants, etc.)
• Pollutant loading rates per land use type
• Existing Land Use
These are just some of the potential model inputs that may be required by the models an organization
may be considering for use. A careful evaluation of model data needs should be conducted prior to
the start of a study in order to determine whether all necessary data is available.
March, 1998 76
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Evaluating Methodologies
Manual Versus Computer-Aided Spatial Analysis
As noted above, it is possible to conduct a simple build-out analysis using hard-copy (paper)
maps and common planning tools such as pencils and planimeters to measure areas on maps in terms
of actual physical space. However, this type of analysis is infeasible for large land areas due to the
amount of time that would be required to conduct the analysis by hand. In such cases it is more
appropriate to use a geographic information system to conduct most analyses. If computer-aided
analysis will be required, the cost of such analysis should be recognized up front.
Scale
If the land area to be analyzed is small (e.g., a town or small county), it is necessary to select a
methodology capable of recognizing and modeling small units of area, such as square meters. This is
not true for analyses of large areas, such as a large watershed encompassing several towns and
counties. In such cases, a methodology that incorporates simplifying assumptions and averages in
order to facilitate rapid analysis may be perfectly appropriate.
Required Resources
The amount of resources necessary to undertake the analysis should be commensurate with the
objective of the final product. In situations where a rapid and general analysis of a land area would
be appropriate for initial planning purposes, it would not make sense to expend a great deal of money
or staff time on a model that produces highly refined, sophisticated results. Conversely, if the
analysis will be used to make large-scale and long-term decisions that will impact the environment
and the quality of life of residents in the study area for decades to come, it may make sense to make a
significant investment in a more sophisticated model. At a minimum, the following resource
requirements should be carefully evaluated before a model is selected:
• Required computer hardware and software
• Level of staff technical expertise
• Length of time required to complete study
• Financial cost of completing the study
User Applicability
Who will ultimately conduct the analysis? Who will use the results of the analysis? These are
two critical questions to ask when considering build-out analysis/water quality modeling
methodologies. The answers will help determine how sophisticated the model needs to be, how
March, 1998 77
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Evaluating Methodologies
expensive it could be, and what types of information it should generate. It may make sense to
consider the resources and needs of the following types of organizations:
• State governments
• County governments
• Local governments
• Multi-jurisdictional efforts like the Chesapeake Bay Program
• Non-profits
• Academic institutions
March, 1998 . 78
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APPENDIX A
Evaluation of the Potential Application of the Chesapeake
Bay Program HSPF Watershed Model to Build-Out Analyses
-------
Appendix A
EVALUATION OF THE POTENTIAL APPLICATION OF THE CHESAPEAKE BAY
PROGRAM HSPF WATERSHED MODEL TO BUILD-OUT ANALYSES
One of the questions posed at the outset of this project (at the July workshop) was, to what extent
could the Chesapeake Bay Program's Hydrologic Simulation Program-Fortran (HSPF) Watershed
Model assist in conducting build-out analyses on land areas within the Chesapeake Bay watershed?
The Watershed Model is the primary tool used by the Chesapeake Bay Program to help signatories to
the 1987 Chesapeake Bay Agreement and its 1992 amendments meet tributary-specific nutrient
reduction goals. Following is a description and an evaluation of the Watershed Model in terms of its
potential utility, if it were to be used in conjunction with a build-out analysis.
Background Information on the Watershed Model
The Chesapeake Bay Program Watershed Model is a computer model written in Hydrologic
Simulation Program-Fortran (HSPF) code that simulates the transport of point and nonpoint nutrient
loads, flow and sediment from throughout the watershed to the Chesapeake Bay. Point source
nutrients and flow are released directly into rivers and streams from sources such as municipal
wastewater treatment plants and industrial plants. Nonpoint source nutrients, flow and sediment are
washed off of various land use types (e.g., agricultural, urban) throughout the watershed into rivers
and streams. The Watershed Model then simulates the transport of these point and nonpoint nutrient
and sediment loads to the Chesapeake Bay via rivers and streams.
The model was first developed in 1987 and is currently in its fourth phase of development.
Refinements have been made during each phase, from the development of more detailed input data to
the incorporation of simulations that more accurately capture the actual environmental processes
taking place on different land use types and within river and stream channels.
One of the key strengths of the Watershed Model is its ability to predict water quality impacts
from different scenarios. Scenarios are used by managers as a "what if?" tool; they are designed to
simulate management alternatives and the potential results such alternatives might have. Of the types
of scenarios commonly run in the Watershed Model, there are several related to land use. For
example, the forest scenario estimates nutrient loads delivered to the line separating the tidal and non-
tidal portions of the Chesapeake Bay, or fall line, from an entirely forested watershed. This scenario
can be used to assess the difference between an entirely forested watershed and other scenarios, such
as nutrient loads delivered from existing land use in 1990.
The WSM represents the entire drainage area of the Chesapeake Bay as a series of land segments
connected via a network of rivers and streams, called reaches or tributaries. Within each model
March, 1998 A-l
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Appendix A
segment, eight different land use categories are simulated providing surface and subsurface nonpoint
nutrient loadings to the reach draining that segment. These land use categories are:
• conventional tillage cropland,
• conservation tillage cropland,
• hay land,
• forested land,
• pasture,
• manure acres (a subset of pasture),
• pervious urban land, and
• impervious urban land.
Criteria the Watershed Model Must Meet to Perform Build-Out Analyses:
The following discussion highlights key criteria that determine the appropriateness of the
Watershed Model for use in conjunction with build-out analyses.
Size of Land Area
Build-out analyses may be conducted on relatively small land areas (county to town size areas) as
well as medium or large land areas. In order to be useful, the Watershed Model must be applicable
for use on a range of land area sizes.
Delineation
Build-out analyses will most likely be applied both to areas that follow political as well as
hydrological boundaries. The Watershed Model must be able to accommodate both types of
boundaries.
Input Data
Once a build-out analysis tool is in place, analyses will be conducted by changing data inputs and
observing the resultant changes in nutrient loads and their sources. To facilitate the design and
execution of such scenarios, the input data and their modification to simulate different conditions
(e.g. changes in land use, number of septic systems, etc.) should be relatively straightforward.
March, 1998 A-2
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Appendix A
Accessibility
In order to be most accessible to the broadest range of users, a build-out analysis tool should be
available in a PC-compatible format.
Geographic Display
A straightforward or hard-coded link between the output from the build-out analysis tool and a
geographic information system (GIS) or other geographic display tool will greatly enhance the ability
to communicate large amounts of information efficiently and to discern geographic patterns or trends
in development or nutrient load sources.
Environmental Impact
Build-out analyses, when combined with models that measure the environmental impact of
different land use types, can be conducted in order to estimate the potential environmental impacts of
varying development scenarios. An effective build-out analysis/water quality modeling tool will
quantify the effects of increased development (increased runoff from impervious surfaces, increased
point and/or nonpoint nutrient loads, fragmented habitat) on environmental parameters such as in-
stream water quality and species distribution and/or abundance.
Evaluation of the Watershed Model as a Build-Out Analysis Tool
Challenges hi Applying the Watershed Model to Build-Out Analysis
The following discussion provides an overview of three key challenges to applying the Watershed
Model to build-out analysis scenarios.
Simulation Format
The Watershed Model simulates one acre of each land use type and then multiplies through by
acres in that land use type in a given segment to obtain total loads by segment. In other words, land
use types within a given segment are in effect aggregated so that one cannot simulate different land
use distributions within a simulation unit (e.g., forest buffers within a segment). These kinds of
calculations can be done using attenuation factors ~ the amount by which you would expect a given
load to be reduced were it routed through a buffer ~ once agreement is reached on what attenuation
rates are.
March, 1998 A-3
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Appendix A
Toxics
In many build-out analyses, researchers may wish to estimate potential impacts to the toxic load
delivered to water bodies from alternative development scenarios. This is currently not possible with
HSPF. The current application of the Watershed Model simulates nutrients and flow. HSPF has
modules for the simulation of toxics, but these are not currently used in the Watershed Model. The
toxics simulation modules were applied in a Bay Program study, but toxics data availability was a
limitation.
Simulation of Urban Land
The majority of land in the Chesapeake Bay Watershed is forest and cropland. More resources
have therefore been allocated to improve the Watershed Model code for the simulation of edge of
stream loads for these land uses (AGCHEM NITR implementation in 1995, AGCHEM FOREST
implementation in 1996) than for the simulation of urban land. Urban edge of stream loads were
calibrated based on a regression relating percent impervious cover to nutrient loads.
Watershed Model Performance with Respect to Build-Out Analysis Criteria
The following discussion evaluates the potential performance of the HSPF Watershed Model in
conjunction with conducting a build-out analysis. Model performance is discussed in the context of
the criteria developed above.
Size of Land Area
The Watershed Model is most effectively applied on large land areas. However, it can be used on
land areas as small as one acre.
Delineation
The edge of stream portion of the Watershed Model can be applied to any land configuration,
following political or hydrological boundaries. The reach simulation, however, should include all
load sources to the given reach in order to give the best representation of the processes taking place
within that reach. This means that hydrologic boundaries should be used for effective reach
simulation.
March, 1998 A-4
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Appendix A
Input Data
Land use data are specified in the input deck and are easily modified from one scenario to another.
External nutrient loads, such as point sources, atmospheric deposition and septic loads, are input to
the model as time series data in a very specific format. They are easily multiplied by factors, and
more intricate changes can be made to the time series themselves.
Accessibility
HSPF is currently available and being used in a PC format. However, the size of the input and
output data files and the nature of the simulation require a powerful, dedicated machine to execute
model runs.
Geographic Display
The geographic display of model output is done on a regular basis by the modeling team. This
process could conceivably be streamlined and automated. The resolution of the geographic display is,
however, limited by the size of the simulation units or segments.
Environmental Impact
The Watershed Model can quantify changes in water quantity and quality as a result of changing
development patterns, but cannot speak to resulting changes in species distributions or aspects of
habitat quality other than water quality.
Potential Role of the Watershed Model in Build-Out Analyses
The calibrated Watershed Model edge of stream nutrient loads per unit area could be used to test
the impact of changing land use patterns without requiring a model run. The new land use
distributions would be determined and multiplied by the appropriate unit load (Ib/acre) to obtain a
total load from a given land use type within the study area. Attenuation factors simulating the impact
of buffers could also be applied in this manner, i.e. they could be developed on a segment basis and
applied to the edge of stream loads without requiring a model run. For areas above the fall line, the
proportion of the load that reaches the fall line can be determined using fall line transport factors.
Fall line transport factors summarize the processes (sedimentation losses, scour, chemical and
biological transformations) that take place within reaches as nutrients are transported from their point
of origin to the fall line. Lb/acre loads are available for each land use type and for each model
segment. Fall line transport factors are available for each model segment. Areas smaller than a
March, 1998 * A-5
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Appendix A
Watershed Model segment would use the loading rates and transport factors of the segment within
which they are located. Areas spanning two or more model segments would use the loading rates and
transport factors of each of the segments in the appropriate proportion (based on land use
distribution). Use of the full HSPF-based Watershed Model in build-out analyses is possible but may
not be cost-effective depending on the requirements of the specific study. Results of Watershed
Model runs, such as edge of stream loads and transport factors, could be very useful in performing
build-out analyses, but model runs for the entire Chesapeake Bay watershed may not be particularly
useful. However, the Watershed Model could be combined with detailed land use data for a sub-
watershed to perform build-out analyses at that level of detail. The key input would be detailed data
on projected land use for the area selected.
March, 1998 A-6
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APPENDIX B
Build-Out Analysis/Water Quality Modeling Fact Sheets
-------
FACT SHEET # 1
VIRGINIA EASTERN SHORE GROUND WATER SUPPLY MANAGEMENT
TITLE OF PROJECT/
REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S):
CONTACT
INFORMATION:
MAILING ADDRESS:
PHONE NUMBER:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS
OF STUDY AREA:
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
Ground Water Supply Protection and Management Plan for the Eastern Shore
of Virginia. 1992.
Horsley Witten Hegemann, Inc., formerly of Rockville, MD.
U.S. Environmental Protection Agency for the Virginia State Water Control
Board and the National Oceanic and Atmospheric Administration for the
Virginia Council on the Environment's Coastal Resources Management
Program. Prepared for Eastern Shore of Virginia Ground Water Study
Committee, Accomack, VA.
Horsley and Witten, Inc. (formerly Horsley Witten Hegemann, Inc.)
Consultants in Waters Resources and Land Planning.
3179 Main Street, Barnstable, MA 02630.
(508) 362-5570.
May 5, 1992
Virginia's Eastern Shore, located within the Chesapeake Bay watershed, has a
total area of approximately 537,000 acres, of which about 38 percent (206,000
acres) are wetlands and coastal islands that are unsuitable for development.
Approximately 53 percent of the total area is used for forestry and agricultural
purposes and the remaining 9 percent consists of residential use (3.2 percent),
commercial/industrial use (0.6 percent), public lands (2.4 percent) and other
uses (2.3 percent).
The purpose of the study was to investigate the impacts of existing and
potential land uses on ground water quality on the Eastern Shore. The
investigation focuses on a specific recharge area defined in the study.
The development scenarios considered in this study include potential
residential build-out analyses for each of the two counties within the study area
(Northampton and Accomack Counties).
Zoning requirements for each of the two counties located within the study
area.
Soils data from the Natural Resources Conservation Service, formerly the
Soil Conservation Service, to determine development potential of land.
Existing land use types and percentages.
March, 1998
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BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
Researchers used U.S. Geological Survey (1:25,000 scale) topographic
quadrangles and county land use district maps (1:25,000 scale) to delineate the
recharge area and the area targeted for future development. Existing land uses
were documented as well as the potential for future land development. A
computerized spreadsheet program (Microsoft Excel) was used to perform the
necessary calculations for build-out scenarios in each of the two counties being
studied. The total number of possible future units was calculated by taking the
total land area within each land use category minus 15 percent for roads and
poorly drained soils and dividing that number by the permitted number of lots
per acre allowed under current and recommended zoning regulations.
The scope of the study did not require the development of or use of a water
quality assessment model. However, the results of the study were used in a
nitrogen loading model to determine maximum nitrogen loading under the
planned densities and land use types for both counties and loading that would
result from future development scenarios and land use patterns.
The potential for development of low-density residential units within the study
area exceeded the current number of units in both counties. However, the
realization of this potential is unlikely at this time since development of the
Eastern Shore study area is not expected to increase dramatically in the near
future. Opportunities exist to implement management tools now that will
control future development and protect ground water.
The study methodology and results are included in the Ground Water Supply
Protection and Management Plan for the Eastern Shore of Virginia. Contact
the consultant that conducted this study for further details and information
about the computer programs, software packages and mapping devices used in
the study.
The source of information and text for this fact sheet is cited above under "Title
of Project/Report" and "Research Conducted By."
March, 1998
B-l
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FACT SHEET # 2
SEVERN RIVER WATERSHED DEVELOPMENT MANAGEMENT PLAN
TITLE OF
PROJECT/REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION^):
CONTACT
INFORMATION:
MAILING ADDRESS:
PHONE NUMBER:
STUDY COMPLETION
DATE:
GEOGRAPHIC
CHARACTERISTICS OF
STUDY AREA
(LOCATION, SIZE,
BOUNDARIES,
LANDSCAPE
FEATURES):
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
Living With the River: A Development Management Plan for the Severn
River Watershed to the Year 2020. 1993.
Dodson Associates and Land Ethics
The Severn River Commission
The Severn River Commission, Dodson Associates and Land Ethics
The Severn River Commission, c/o Anne Arundel County Office of
Planning and Zoning, Heritage Office Center 2664 Riva Road, Annapolis,
MD 21404.
Dodson Associates, P.O. Box 160, Ashfield, MA 01330.
Land Ethics, 1400 16th Street, Suite 300 N.W., Washington, D.C. 20036.
Land Ethics, (202) 939-3410.
December 1993.
The Severn River Watershed, as part of the larger Chesapeake Bay
Watershed, encompasses approximately 78 square miles and includes 50
sub-watersheds. It is located entirely within Anne Arundel County,
Maryland and includes the majority of the City of Annapolis, Maryland.
The Severn River is a tidal tributary of the Chesapeake Bay with a relatively
small contribution of fresh water from upstream drainage. The River and its
watershed have supported a long history of fishing, farming and human
settlement. Land use in the Watershed is comprised of 20 percent
residential, 10-15 percent commercial/industrial, and 15 percent open space
or under cultivation. Approximately 50 percent of the watershed is forested.
The purpose of the study was to determine the extent and impact of present
and future development in the Severn River watershed through the years
2000 and 2020 and provide recommendations for ensuring balanced use and
sustainable development.
Two buildout scenarios were developed using population projections for the
entire watershed to the years 2000 and 2020.
March, 1998
B-3
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DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
• Existing regulatory and physical constraints to current development in
the watershed (e.g., zoning laws, presence of wetlands and steep slopes,
protected areas). Sources of data include the Anne Arundel County
General Development Plan, the Generalized Comprehensive Zoning
Map, the Critical Area Program, the Forest Conservation Plan, Habitat
Assessment Manual, Subdivision Regulations and Erosion and Sediment
Control regulations).
• Census data and demographic projections. Sources of information
include the 1992 population and housing projections for the years 2000
and 2020, provided by the Anne Arundel County Office of Planning and
Code Enforcement and the State of MD Office of Planning.
• Projected market conditions
The method used to develop the build-out scenarios for 2000 and 2020
initially involved mapping two sets of information: development constraints
and development probabilities within the Watershed. To map the
development constraints, researchers considered a set of factors ranging
from areas where development is permanently prohibited in the Watershed
(e.g., areas zoned for open space, highways, areas with slopes greater that 30
percent) to areas with minimal constraints (i.e., areas where no physical or
regulatory barriers exist). To map development probability, researchers
identified and ranked areas in the Watershed according to physical and
regulatory limitations, market demand and demographic projections. These
maps, in addition to an analysis of census projections provided the
cornerstone of the build-out analyses. A total of four maps (at a scale of
1:2,000) were produced by Dodson Associates and Land Ethics that reflect
development constraints and probabilities for both years. Using these maps
and census data as a foundation, researchers developed build-out projections
for 2000 and 2020. Produced at the same scale, two build-out maps, one for
each year, reflect the projected pattern of development under existing
regulations and likely future development trends. Maps illustrating
recommended development for each of the years were also produced.
The build-out analyses for 2000 and 2020 reveal that the majority of the
development projected for the Severn River Watershed will occur in upland
areas. This makes sense considering that 90 percent of the tidal area has
experienced some level of development. The study provides
recommendations about how and where future development should take
place, issues that need to be addressed and various tools that may be used to
accomplish manageable growth. The study also provides recommendations
on how to alleviate some of the environmental concerns resulting from
existing development. This study was published as a written report for the
Severn River Commission. Contact the Commission or consultants for
copies of the report and inquiries about the preparation of the build-out and
other maps.
The source of information and text for this fact sheet is cited above under
"Title of Project/Report." and "Research Conducted By."
March, 1998
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FACT SHEET #3
US 301 TRANSPORTATION STUDY
TITLE OF
PROJECT/REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S):
CONTACT
INFORMATION:
MAILING ADDRESS:
PHONE NUMBER:
• US 301 Transportation Study Task Force Final Report. 1996;
• US 301 Task Force Final Recommendations. 1996.; and
• US 301 Transportation Study Technical Report: Land Use and Growth
Management. 1997.
• US 301 Transportation Study Task Force Final Report was prepared by
the Task Force in cooperation with the Maryland Department of
Transportation;
• US 301 Task Force Final Recommendations was prepared by the Task
Force; and
• US 301 Transportation Study Technical Report: Land Use and Growth
Management was prepared by Douglas R. Porter, Planning and
Development Consultant in cooperation with Edwin Thomas, Robert G.
Kramer & Associates and Parsons, Brinckerhoff, McQuade and Douglas.
The Governor's Office of the State of Maryland and the Maryland
Department of Transportation.
Heidi Van Luven, US 301 Transportation Study Project Manager
State Highway Administration, Maryland Department of Transportation.
P.O. Box 717, Mailstop C301, Baltimore, MD 21203-0717.
(800) 548-5026.
STUDY START DATE: US 301 Transportation Study, initiated in 1992.
COMPLETION DATE:
GEOGRAPHIC
CHARACTERISTICS OF
STUDY AREA
(LOCATION, SIZE,
BOUNDARIES,
LANDSCAPE
FEATURES):
• US 301 Transportation Study Task Force Final Report, November 1996
• US 301 Task Force Final Recommendations, adopted July 17,1996
• US 301 Transportation Study Technical Report: Land Use and Growth
Management, January 1997.
The study area of the US 301 Transportation Study includes five counties in
Maryland and a portion of the District of Columbia. The area stretches east
into Maryland from the District of Columbia to the Chesapeake Bay and
from US 50 to the Potomac River on the state border. The area is part of the
Washington/Baltimore Consolidated Metropolitan Area, which encompasses
13 counties, Washington, D.C., the City of Baltimore, four additional cities,
and several smaller municipalities. The landscape of the study area varies
widely in character, ranging from high density urban development including
industrial and commercial enterprises to mostly rural and wooded areas,
with waterfront development, located further away from the major urban
areas.
March, 1998
B-5
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PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
The purpose of the US 301 Transportation Study was to initiate a
collaborative planning process to determine and relate future transportation
needs, associated land use patterns and environmental concerns. The
Maryland Department of Transportation had abandoned an earlier study for
an eastern bypass of Washington, D.C. following strong opposition from
environmental and other groups concerned with the effect of the proposed
interstate-type highway improvement on spreading suburban development
and its impact on sensitive environmental resources, including the
Chesapeake Bay.
In order to determine the optimal combination of potential transportation
improvements, related land use patterns and environmental protection
measures, the task force evaluated a range of alternative transportation
improvements and programs in the context of several alternative future land
use patterns. The land use alternatives considered included: A "current
plans" alternative based on the regional land use projections for 1990 to
2020 made by the Metropolitan Council of Governments (MWCOG);
"market-driven" and "policy-driven" alternatives.
The primary data requirements for the study included population,
employment and housing projections for each county within the study area.
The data were compiled by MWCOG. Other requirements included an
understanding of county and municipal planning policies and regulations,
county comprehensive plans and zoning ordinances.
Consultants to the task force used a set of evaluation measures to identify
the significant effects of the patterns of land use "inputs" to a travel
forecasting model for each land use alternative. The land use "inputs"
included allocations of households and jobs among the counties,
development and rural areas and transportation analysis zones (TAZs). The
evaluation measures included: percent of new households and jobs in
development areas; total additional acres developed; acres of farmland,
forest and sensitive areas preserved; and jobs/housing ratio by county.
A wide range of conclusions were drawn for future land use alternatives and
transportation improvements within the study area. In general, the task force
recommended that local land use plans and policies, among other things,
minimize the amount of land consumed and environmental resources
impacts. To accomplish this, the task force recommended that longer-term
options such as the protection of rights-of-way, and establishment and
expansion of hiker/biker facilities, ridesharing programs and telecommuting
incentives. The Final Report and Technical Report listed above provide
useful references to background documents and further details about the
study.
The sources of information and text for this fact sheet are cited above under
"Title of Project/Report" and "Research Conducted By."
March, 1998
B-6
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FACT SHEET #4
THOMAS JEFFERSON PLANNING DISTRICT COMMISSION
TITLE OF PROJECT/
REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION^):
CONTACT
INFORMATION:
MAILING ADDRESS:
WEB SITE:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS
OF STUDY AREA:
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
Build-out Analysis of the Thomas Jefferson Planning District. 1996.
Thomas Jefferson Planning District Commission; locality planning staffs; and
the Piedmont Environmental Council.
Thomas Jefferson Planning District Commission; Virginia Environmental
Endowment; Federal Highway Administration Intermodel Surface
Transportation Efficiency Act funding administered through the Virginia
Department of Transportation.
Mr. John Potter, GIS Planner.
Thomas Jefferson Planning District Commission; P.O. Box 1505;
Charlottesville, VA 22902-1505.
http://monticello.avenue.gen.va.us/Gov/TJPDC
Tjpdc@monticello.avenue.gen.va.us
(804)979-7310.
1996.
The Thomas Jefferson Planning District encompasses approximately 2,180
square miles, located in central Virginia. It includes the counties of Albemarle,
Greene, Louisa, Fluvanna, and Nelson, as well as the city of Charlottesville.
Common landscape features include rivers, flood plains, farms, forests,
wetlands, mountains, valleys, and urban and suburban development. Two of
the counties contain parts of Shenandoah National Park, and one contains part
of George Washington National Forest.
To assess the development potential of the Thomas Jefferson Planning District.
The study estimated the maximum amount of land that could be developed in
the Planning District given current zoning regulations. It did not predict the
date at which maximum development would be reached.
Data required included: Pertinent land records from the State Computerized
Information System (CIS); the percentage of the total block acreage under
environmental constraints from steep slopes, poor soils, and flood plains; total
March, 1998
B-7
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BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
Tms FACT SHEET:
development rights for each census block; location and extent of soil types that
preclude septic systems; location and extent of slopes in excess of 25 percent.;
and USGS 1 "=24,000" quadrangles.
1) All counties provided the Planning District with copies of pertinent land
records from the "Computerized Information System" (CIS).
2) For each county, the percentage of the total block acreage under
environmental constraints from steep slopes, poor soils, and flood plains
was determined.
3) This percentage was removed from each Census block in the rural areas.
4) Applicable zoning ordinances were applied.
5) Development rights already used were subtracted from the total.
6) Total development rights were aggregated for each census block.
The Commission used the VIRGIS system developed at the Virginia
Polytechnic Institute's Department of Agricultural Engineering. VIRGIS is
raster based, which allows for multiple overlays in less time than that required
for a vector based system.
The product was the paper report cited at the beginning of this fact sheet, in
addition to various GIS data layers used in their preparation.
The source of information and text for this fact sheet is cited above under "Title
of Project/Report," "Research Conducted By," and "Contact Information."
March, 1998
B-8
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FACT SHEET # 5
LANCASTER COUNTY COMPREHENSIVE PLAN: GROWTH MANAGEMENT PLAN
TITLE OF PROJECT/
REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S):
CONTACT
INFORMATION:
MAILING ADDRESS:
WEB SITE:
PHONE NUMBER:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS
OF STUDY AREA:
PURPOSE OF STUDY:
Lancaster County Comprehensive Plan: Growth Management Plan. 1993.
Lancaster County Planning Commission.
Lancaster County Planning Commission. Plan was approved by the Lancaster
County Board of Commissioners.
Ronald Bailey, Planning Director
Lancaster County Planning Commission.
Lancaster County Planning Commission, 50 N. Duke Street, P.O. Box 83480
Lancaster, PA 17608-3480.
http://www.co.lancaster.pa.us
(717) 299-8333 Fax: (717) 295-3659.
April 1993.
Lancaster County, located due west of Philadelphia, is among one of the fastest
growing counties in Pennsylvania. This growth is primarily the result of three
main industries: agriculture, business-industry, and tourism. The County is the
most productive non-irrigated county in the U.S., exceeding the agricultural
production of 10 States. Agricultural zoning has been applied to over 280,000
acres in 36 of the County's 41 townships - 72 percent of the 390,000 acres in
farm use. Over 15,000 acres constituting 170 farms are preserved, most in
perpetuity. The County is rich in natural resources, including the Susquehanna
River and its tributaries, scenic vistas, woodlands, wetlands and a diversity of
wildlife species. Suburban sprawl continues to threaten the landscape, with
approximately 3,000 acres of lost agricultural land per year. The City of
Lancaster is the largest municipality in the County.
The purpose of the Growth Management Plan is to provide a process for
municipal officials to follow in guiding and influencing the pattern, location,
and timing of growth within the municipalities of Lancaster County. The
primary goal of the Plan is to promote the direction of future growth in
Lancaster County to existing urban areas and away from the County's
agricultural and natural resource lands through the establishment of Urban
Growth Boundaries (UGBs).
March, 1998
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ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
To achieve the goal of the Growth Management Plan, the Lancaster County
Planning Commission developed three "visions" for the future of Lancaster
County based on established UGBs: a County-wide Vision, and Urban Vision,
and a Rural Vision. The County-wide vision calls for growth to be directed to
urban areas where there is a full range of public services available to support
residential and economic development. The Urban Vision calls for future
growth in suburban areas, adjacent to the City of Lancaster and boroughs, to
occur primarily on an infill basis and using innovative new development
patterns. The Rural Vision calls for supporting agriculture as the backbone of
the local economy, by encouraging villages to continue to function as
community and service centers, and by protecting resource lands for uses which
are compatible with their carrying capacities.
The primary data requirements for developing the Visions for Lancaster County
included projections of population growth and housing needs, Comprehensive
Plans, knowledge of existing zoning ordinances, existing municipal boundaries
and a breakdown of various land uses within the County.
The County Planning Commission developed a four-step process for defining
the UGBs. First, proposed urban growth areas were selected, each centered on
one or more boroughs or the City of Lancaster. Second, 20-year population
projections were made for each impacted municipality. Based on those
projections, average household size, and other factors, the land use needs for
each municipality were calculated. Finally, selection of the appropriate areas
for inclusion were made and the recommendations taken to the municipalities
for approval. Rural land use designations, according to the Plan, should be
based upon the identification of areas suitable for agriculture, resource
conservation and preservation uses outside of UGBs, as illustrated on the
County-wide Future Land Use Map. Municipal Comprehensive Plan maps are
to be generally consistent with the County-wide map.
Aside from promoting the use of UGBs to direct future growth in Lancaster
County toward existing urban areas and away from rural areas, the
Commission emphasized the importance of intergovernmental coordination and
offered strategic guidance on making that a reality in Lancaster County. The
Growth Management Plan offered some useful tools and techniques for
managing growth at the local level, especially for municipalities located in
Pennsylvania. In addition to the Growth Management Plan there are three
additional components of the Lancaster County Comprehensive Plan: the
Policy Plan, the Action Plan and the Regional Plans.
The sources of information and text for this fact sheet are cited above under
"Title of Project/Report" and "Research Conducted By."
March, 1998
B-10
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FACT SHEET #6
OCCOQUAN WATERSHED WATER QUALITY STUDY
TITLE OF PROJECT/
REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S):
CONTACT
INFORMATION:
MAILING ADDRESS:
WEB SITE:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS
OF STUDY AREA:
PURPOSE OF STUDY:
U.S. EPA Clean Lakes Report for the Occoquan Watershed. 1994.
Northern Virginia Planning District Commission (NVPDC) Environmental and
Land Use Services Division in association with the Occoquan Watershed
Monitoring Laboratory (OWML).
U.S. Environmental Protection Agency. Report prepared for the Occoquan
Watershed Policy Board.
Kimberly Davis, NVPDC, Environmental Services.
NVPDC, 7535 Little River Turnpike, Suite 100, Annandale, VA 22003-2937.
http://www.nvpdc.state.va.us
nvpdc @ dgsys .com
(703) 642-0700 Fax: (703) 642-5077.
June 1994.
The Occoquan Watershed is located in the Northern Virginia suburban region
lying to the south and west of Washington, D.C. It is bounded by the Potomac
Estuary to the east and Bull Run Mountain to the west. At the location of the
Occoquan High Dam, the basin drains 570 square miles. The landscape of the
Watershed is characterized by low, rolling hills interspaced by steep-sloped
gorges within which lie Civil War battlefields, regional parks, rural farms,
numerous road systems and urban concentrations. The landscape that once
supported a large agricultural economy continues to evolve into residential,
commercial and light industrial development as suburban sprawl reaches out
from the greater Washington, D.C. area.
The primary purpose of the Clean Lakes Report is to support the continuance
of watershed management activities in the Occoquan Watershed. The specific
objective of the report was to review the impacts of past, present and future
land use on water resources (i.e., water supply, surface and ground water
quality) of the Watershed. The study discussed the impacts that population
growth and changing land uses have had on the Watershed's hydrology, levels
of nonpoint source pollution entering the water supply and on biological
resources.
March, 1998
B-ll
-------
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
The study did not focus on examining alternative development scenarios for the
Watershed. However, it did review changes in land use from the late 1970s to
the present and considered projections of land use for the year 2005.
Land use projections for 2005 were based upon individual jurisdictional
comprehensive plans and estimates of population growth for the jurisdictions.
The NVPDC and OWML conducted extensive research and monitoring of
nonpoint source pollution to surface waters, excluding the reservoir
(temperature, dissolved oxygen, hydrogen ion activity and alkalinity,
conductance and total dissolved solids, suspended solids, nitrogen, phosphorus,
degradable organic matter, and synthetic organic chemicals). For the reservoir,
separate data were collected (temperature, dissolved oxygen, secchi depth,
alkalinity, nitrogen, phosphorus, N.P. ratio, chlorophyll-a, phytoplankton,
synthetic organic chemicals, trace metals in fish tissue, and synthetic organic
compounds in fish tissue).
The Occoquan Basin Computer Model was used to analyze the effects of land
use changes on pollutant loads delivered to receiving waters, including the
Occoquan Reservoir and pollutant transformation with those waters. The
model was developed from the Hydrocomp Simulation Program (Hydrocomp
1977) and the EPA Nonpoint Source Program (Donigan and Crawford, 1976).
The model uses a nonpoint submodel to determine the nonpoint loadings and
a module called LANDS to simulate surface runoff, subsurface interflow and
groundwater flow to the stream segment. A module called CHANNEL accepts
the inflows from LANDS and point source discharges and routes the flow
through the stream segment. A module call QUALITY calculates advective
transport, diffusion, chemical transformation, algal growth, nutrient uptake and
mass balance for the simulation of BOD, DO, suspended sediment, nitrogen
species, phosphorus species and chlorophyll-a.
The Clean Lakes Report discussed the use of land use controls and best
management practice (BMP) requirements for existing and future management
of the Occoquan Watershed. With land use (zoning controls) in place, future
efforts at improved conditions will focus on improved BMP coverage,
operation, efficiency and maintenance. The report did not offer specific
recommendations for alternative land uses. However, it did discuss the use of
BMPs to mitigate future impacts to water quality in the Watershed.
The full citations for the Hydrocomp Simulation Program and the EPA
Nonpoint Source Program models were not included in the report. However,
the contact name given at the beginning of this fact sheet may be able to
provide additional assistance. Also, visit the NVPDC's Web site for additional
information and updates on the Occoquan Basin Computer Model.
The source of information and text for this fact sheet is cited above under "Title
of Project/Report" and "Research Conducted By."
March, 1998
B-12
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FACT SHEET #7
ALTERNATIVE FUTURES FOR MONROE COUNTY, PENNSYLVANIA
TITLE OF
PROJECT/REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION^):
CONTACT
INFORMATION:
MAILING ADDRESS:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS OF
STUDY AREA:
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
Alternative Futures for Monroe County, Pennsylvania. 1994.
Harvard University Graduate School of Design.
U.S. Environmental Protection Agency Region El, the Monroe County
Commissioners, the Monroe County Conservation District, the Monroe
County Planning Commission, and the USDA Forest Service, Pacific
Northwest Research Station.
Carl Steinitz, Professor of Landscape Architecture and Planning, Harvard
University Graduate School of Design.
Harvard University, Graduate School of Design, Department of Landscape
Architecture; Gund Hall; 48 Quincy Street; Cambridge, MA 02138.
December 1993 (report date).
Monroe County, PA is located within a 100 mile radius northwest and west
of Philadelphia and New York City, respectively. The county is
approximately 30 miles long from north to south and 35 miles across from
east to west. The county, which rests on the Pocono Plateau, possesses
unique landscape features as a result of the glaciation that occurred
approximately 10,000 years ago. Characterized by the scenic Poconos
mountains and valleys, the county consists of wetlands, unique bogs, open
water, and a mix of maple, oak, hemlock and pine forests supporting a
diversity of biological resources.
The purpose of the study was to investigate future land use alternatives for
Monroe County, Pennsylvania. The study provided a synthesis of the
County's most pressing landscape and planning issues and examined a range
of six alternatives for the County. It was prepared as an educational guide
for Monroe County planning officials and citizens and students and
professionals of landscape planning.
Six possible alternative land use scenarios were developed for Monroe
County for the year 2020:
• Plan-Trend Alternative: Illustrated the continuation of existing
development practices permitted by the Monroe County Comprehensive
Plan.
• Build-Out Alternative: Assumed that the forces of free market
development will lead to the suburbanization of Monroe County in the
March, 1998
B-13
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DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
THIS FACT SHEET:
same way that so many other metropolitan suburbs have developed, with
low density housing spread over the landscape.
• Township Alternative: This scenario incorporated high density
development in existing subdivisions and new development near town
centers and plans for conservation of natural areas outside township
boundaries.
• Southern Alternative: Focused development patterns in the County to
reflect conservation of fragile and threatened natural resources in the
northern portion and environmentally responsible growth in the
southern, more suburban and agricultural, portion of the County.
• Spine Alternative: Concentrated development along a central corridor
between the two major growth areas and preserved the rural character of
the remainder of the County.
• Park Alternative: Envisioned conserving all of the currently
undeveloped land in Monroe County.
Six central processes formed the basis for the evaluation of the current
condition of Monroe County and the assessment of the alternative land use
scenarios. Described as separate landscapes, researchers collected data to
describe Monroe County in terms of the geologic, biologic and visual
landscape; and incorporated demographics; economics; and politics.
A geographic information system (GIS) was developed to display each of
the landscapes described above. Data were collected from a variety of
sources including the Environmental Protection Agency, the U.S. Census
Bureau, the U.S. Geological Survey, The Nature Conservancy and Cornell
University. Several new digital data sets were also compiled at Harvard
University.
Each of the six alternative land use scenarios were analyzed and synthesized
using a combinations of several software packages including: ARC/INFO
and Arc View (ESRI, Inc., Redlands, CA); Imagine (ERDAS, Atlanta, GA);
and Map Factory (Thinkspace, Inc., London Ontario). After each alternative
scenario was configured, the POLYTRIMS (Center for Landscape Research,
University of Toronto, Ontario) program was used to produce view maps for
each alternative.
The study provided an overview of how each alternative land use scenario
would impact each of the six "landscapes" described above. For example,
the Plan-Trend and Build-Out scenarios would have the most devastating
impact on the natural resources of Monroe County, while the Park
alternative would ensure enhanced protection of such resources (e.g., surface
and groundwater quality). This study is published as a written report and
includes references to many of the maps used.
The source of information and text for this fact sheet is cited above under
"Title of Project/Report" and "Research Conducted By."
March, 1998
B-14
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FACT SHEET #8
HILLSDALE LAKE WATERSHED POPULATION AND
LAND USE PROJECTIONS, 1990-2010
TITLE OF
PROJECT/REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S):
CONTACT
INFORMATION:
MAILING ADDRESS:
E-MAIL ADDRESS:
PHONE NUMBER:
STUDY COMPLETION
DATE:
GEOGRAPHIC
CHARACTERISTICS OF
STUDY AREA
(LOCATION, SIZE,
BOUNDARIES,
LANDSCAPE
FEATURES):
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
Hillsdale Lake Watershed Population and Land Use Projections, 1990-2010,
for the Hillsdale Lake Nutrient Study.
Johnson County Planning Office, Johnson County Unified Wastewater
District and James M. Montgomery, Consulting Engineers, Inc.
Johnson County Planning Office.
Dean Palos.
110 South Cherry, Olathe, KS 66061.
dean.palos@jocoks.com
(913) 764-8484 ext. 6260.
October 1990 (report date).
The project's geographic (watershed) boundaries include portions of the
cities of Gardner, Spring Hill, Wellsville, and all of Edgerton. Portions of
Miami, Johnson, Douglas and Franklin counties and the southern part of
Johnson County Industrial Airport. The study area totals 95,334 acres (149
square miles) and includes portions of several cities and counties. The study
was undertaken in an inland watershed encompassing multiple jurisdictions.
The watershed is almost entirely rural and is made up of predominantly
farmland, streams and forest cover, in addition to Hillsdale Lake. U.S.
Interstate 35 runs through the entire watershed from Northeast to Southwest,
just north of Hillsdale Lake.
The goal of this build-out analysis was to predict the effects of future growth
on the water quality of Hillsdale Lake using population projections and land
use projections in conjunction with nutrient loading data. The analysis was
prompted by a concern for the water quality of the lake and the amount of
discharge from local sewage treatment facilities and runoff in the watershed.
For the area of Hillsdale Lake Watershed that encompasses Miami County,
three development scenarios were developed at rural residential densities.
For each scenario, the ultimate development in terms of residential units and
persons are included in the report.
March, 1998
B-15
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DATA REQUIREMENTS:
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
Tms FACT SHEET:
Three projections were made based on: 1) A regional model, 2) Local
Comprehensive Plans, and 3) Building permit histories.
The goal of this study was to project population growth and land use change
over a twenty year period of time. Thus, the types of information required
included population statistics from the U.S. Bureau of Census, and types of
existing land use (e.g., residential, commercial, and industrial). The data
obtained for the study were obtained from existing information, surveys and
interviews with local officials knowledgeable of the watershed's
development trends and potential. Population data were obtained from U.S.
Census of Bureau Housing Count Statistics. Existing land use data were
compiled from 1988 Johnson County aerial photos, special field surveys and
from planning consultants in Miami County. A review was also made of the
comprehensive plans for two of the towns and of available, recent and
historical building permit records.
Three population projections were made (A, B, and C), each based on these
different methods. Population Projection A was based on the Mid-America
Regional Council (MARC). Projection B was derived from the Edgerton
and Gardner comprehensive plans. Projection C was based upon building
permits issued within the watershed and assumptions about growth.
A published report, Hillsdale Lake Watershed Population and Land Use
Projections 1990-2010, for the Hillsdale Lake Nutrient Study. 1990.
Consultants, at the time the report was issued, were in the process of
developing a computer model to project the degree of pollution in Hillsdale
Lake that would result from increased residential development.
Population Projection "C" was recommended for use for the study of
Hillsdale Lake, because of the quality of the information in comparison to
that used in Projections A and B. Projection C offered the most current and
geographic data, based on building permit issuance. The population in the
watershed is expected to grow over the twenty year period by approximately
20% every ten years. The largest changes in land use will be the result of an
increase in rural residential uses. This occurs because of the large lot size of
those types of units ranging from one unit per one acre in Spring Hill to one
unit per 17 acres in parts of Miami County.
The sources of information and text for this fact sheet are cited above under
"Title of Project/Report," "Research Conducted By," and "Contact
Information."
March, 1998
B-16
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FACT SHEET # 9
BUILD-OUT ANALYSIS ON A GEOGRAPHIC INFORMATION
SYSTEM (GIS)
TITLE OF
PROJECT/REPORT:
RESEARCH
CONDUCTED BY:
SPONSORING
ORGANIZATION(S) :
CONTACT
INFORMATION:
MAILING ADDRESS:
E-MAIL:
PHONE NUMBER:
STUDY COMPLETION
DATE:
LANDSCAPE
CHARACTERISTICS OF
STUDY AREA:
PURPOSE OF STUDY:
ALTERNATIVE
DEVELOPMENT
SCENARIOS
CONSIDERED:
DATA REQUIREMENTS:
Buildout Analysis on a GIS.
Edward (Ted) Lyman.
Ted Lyman in fulfillment of the requirements for his Master of Science
Degree at the University of Vermont.
Ted Lyman.
P.O. Box 1318, Williamsburg, VA 23187.
Ted @ infotech .ts .wm.edu
(757)221-1420.
June 1996.
A total of three geographic areas were evaluated as part of this study. They
included:
• The City of Woodstock in Oxford County, Ontario, Canada
• The City of Charlottesville, Virginia and five surrounding counties (all
located in the Thomas Jefferson Planning District)
• San Diego County, California, including the county and the 18 cities
within its boundaries.
The purpose of the study was to evaluate, through a review of four case
studies, how a geographic information system (GIS) can be used as a tool to
determine the build-out potential of an area and how the information may be
used to influence policy decisions about future development.
Only the full build-out potential for each specific area was examined. No
other alternative development scenarios were included.
As a first step in developing the GIS, each case began with an inventory of
existing land resources and knowledge of existing land use regulations.
Even though the specific objectives of each case study varied and the quality
March, 1998
B-17
-------
BRIEF DESCRIPTION OF
BUILD-OUT METHOD
AND/OR WATER
QUALITY MODEL
USED:
GENERAL
CONCLUSIONS AND
PRODUCTS:
SOURCE(S) OF INFOR-
MATION/TEXT FOR
Tms FACT SHEET:
and quantity of available information was inconsistent from case to case, the
data requirements for developing a GIS and performing a build-out analysis
for all four studies was more or less similar. The other major data
components included:
• Land use information, zoning maps
• Physical and regulatory constraints
• Current census data and rates of growth in housing
• Building records for residential construction activity.
The build-out methods used in each of the case studies differed from one
another in the application of variables and the selection of basic geographic
units. However, each produced a reasonable forecast of what a full build-
out would look like under existing regulations and constraints. The GIS
used in the case studies ranged from a singularly focused search for
developable land to one that managed multiple models of growth
forecasting. There was some variability among the case studies in the
hardware selected, but the GIS application in each case was ARC/INFO
(ESRI, Redland, CA).
Woodstock used data from an existing, parcel-based county land
information system (form of GIS) and development constraints data as the
basis for buildout analysis. Woodstock was able to identify vacant land, by
parcel, that could be used to meet anticipated growth. The build-out method
used in the Charlottesville case relied on the aggregation of data from tax
parcel records into larger census blocks. This method was problematic in
that the census block, zoning and parcel boundaries did not always coincide.
The San Diego case study used a nested hierarchy of coverages in which
boundaries did not overlap. They used the Traffic Analysis Zone (a subset
of the census block and the smallest geographical unit of analysis for the
regional system) and general land-use plan for each municipality to identify
vacant lands and development potential.
The study revealed potential applications of GIS as a build-out analysis and
planning tool. GIS can be used to identify and illustrate the potential of
future development in a geographic region by allowing planners to develop a
spatial framework in which numerous variables (e.g., land use, physical
constraints, existing development, mapping of ecological resources) can be
graphically represented together. While none of the case studies reviewed
by Mr. Lyman used a GIS to produce alternative development scenarios, the
tool can be a powerful method of identifying options available to planners
and communities and is highly functional in evaluating possible
development alternatives.
The report prepared by Mr. Lyman is not a sufficient reference for
replicating the methods used to perform a build-out in the four case studies.
However, the report provides an excellent comparison of the studies and
offers literature references for obtaining details on the other case studies.
The sources of information and text for this fact sheet are cited above under
"Title of Project/Report," "Research Conducted By," and "Contact
Information."
March, 1998
B-18
-------
APPENDIX C
Relevant Literature
-------
RELEVANT LITERATURE
Buzzards Bay Project. 1992. Managing Nitrogen to Sensitive Embayments. Fact Sheet. Marion, MA.
Buzzards Bay Project. 1991. Buttermilk Bay Nitrogen Management Strategy. Fact Sheet. Marion, MA.
Chesapeake Bay Program. 1994. Mission Statement. Land, Growth and Stewardship Subcommittee.
Annapolis, MD.
Chesapeake Bay Program. 1996. Priorities for Action for Land, Growth and Stewardship in the
Chesapeake Bay Region. Land, Growth and Stewardship Subcommittee. Annapolis, MD.
Chesapeake Bay Program. 1996. Adoption Statement on Land, Growth, and Stewardship. Chesapeake
Executive Council. Annapolis, MD.
Costa, J.E., D. Janik, N. MacGaffey, and D. Martin. 1994 (draft). Use of a Geographic Information
System to Estimate Nitrogen Loading to Coastal Watersheds. Technical Report. Buzzards Bay
Project. Marion, MA.
Costa, J.E., B.L. Howes, A.E. Giblin, and I. Valiela. 1992. Monitoring Nitrogen and Indicators of
Nitrogen to Support Management Action in Buzzards Bay. In Ecological Indicators. D.H.
McKenzie, D.E. Hylact, and V. Janet McDonald (eds.), Vol. 1. Elsevier Press, London. Pp 499-531.
Dodson Associates and Land Ethics. 1993. Living With the River: A Development Management Plan for
the Severn River Watershed to the Year 2020. Prepared for the Severn River Commission.
Annapolis, MD.
Horsley and Witten, Inc. 1996. Geographic Analysis of Bacterial Contamination, Ipswich, Beverly, and
Provincetown. Report to the Massachusetts Bays Program. Barnstable, MA.
Horsley and Witten, Inc. 1996. Companion Guidelines for FecaLOAD. Report to the Massachusetts
Bays Program. Barnstable, MA.
Horsley and Witten, Inc. (formerly Horsley, Witten and Hegemann, Inc.) 1992. Ground Water Supply
Protection and Management Plan for the Eastern Shore of Virginia. Barnstable, MA.
Johnson County Planning Office. 1990. Hillsdale Lake Watershed Population and Land Use
Projections, 1990-2010, for the Hillsdale Lake Nutrient Study. Olathe, KS.
Lacy, J. 1992. Manual of Build-Out Analysis. Center for Rural Massachusetts, Department of
Landscape Architecture and Regional Planning, University of Massachusetts, Amherst, MA.
Lancaster County Planning Commission. 1993. Lancaster County Comprehensive Plan: Growth
Management Plan. Lancaster, PA.
Lyman, E. 1996. Buildout Analysis on a GIS. (Masters of Science thesis). University of Vermont:
Burlington, VT.
March, 1998 C-l
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Maryland Office of Planning. 1997. Developing Growth Management Options for Maryland's Tributary
Strategies. Growth and Watershed Planning Series. (March 28 draft). Baltimore, MD.
Maryland Office of Planning. 1995. Growth, Resource Lands and Watersheds: The Need for Integrated
Planning and Management. Baltimore, MD. Fact sheet.
Maryland Office of Planning. 1995. An Integrated Watershed Planning Tool for Land Use Management
and Nonpoint Source Pollution Control. Baltimore, MD. Fact sheet.
Northern Virginia Planning District Commission. 1994. U.S. EPA Clean Lakes Report for the Occoquan
Watershed. Prepared for the Occoquan Watershed Policy Board. Vienna, VA.
Orange Water and Sewer Authority. 1996 (draft). Cane Creek Reservoir Watershed Study. Carrboro,
NC.
Porter, D.R. and Edwin Thomas, Robert G. Kramer & Associates and Parsons, Brinckerhoff, McQuade
and Douglas. 1997. US 301 Transportation Study Technical Report: Land Use and Growth
Management. Baltimore, MD.
Schiffman, I. Alternative Techniques for Managing Growth. Berkeley, California: Institute of
Government Studies, University of California at Berkeley, 1990, c!989.
Southern California Association of Governments. Open Space and Conservation. In DRAFT Regional
Comprehensive Plan. Los Angeles: California, December 1993.
Steinitz, C. (ed.). 1996. Biodiversity and Landscape Planning: Alternative Futures for the Region of
Camp Pendleton, CA. Research supported by the Strategic Environmental Research and
Development Program. Harvard University: Cambridge, MA.
Steinitz, C. 1994. Alternative Futures for Monroe County, Pennsylvania. Harvard University:
Cambridge, MA.
Steinitz, C. A Framework for Theory and Practice in Landscape Planning. GIS Europe (July 1993).
Tassone, J.F., R. E. Hall, N.S. Edwards, and D.M.G. Weller. 1996. Integrated Watershed Planning and
Management: Growth, Land Resources and Nonpoint Source Pollution. Published in the
Proceedings of the Watershed '96 Conference, Baltimore, MD.
Thomas Jefferson Planning District Commission. 1996. Build-out Analysis of the Thomas Jefferson
Planning District. Charlottesville, VA.
US 301 Transportation Study Task Force and the Maryland Department of Transportation. 1996. US 301
Transportation Study Task Force Final Report. Baltimore, MD.
US 301 Transportation Study Task Force. 1996. US 301 Task Force Final Recommendations. Baltimore,
MD.
U.S. Environmental Protection Agency. 1991. Modeling of Nonpoint Source Water Quality in Urban
and Non-urban Areas. Office of Research and Development, Washington D.C.
March, 1998 C-2
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FOR ADDITIONAL INFORMATION
Additional information about build-out analyses and water quality and environmental modeling can be
obtained in the following ways:
• Consult the literature presented in the previous section.
• Contact the Chesapeake Bay Program's Land, Growth and Stewardship Subcommittee Liaison
(Menchu Martinez) by dialing 1-800-968-7229 (1-800-YOUR-BAY), Extension 704.
• Investigate the following World Wide Web sites:
http://www.chesapeakebay.net/bayprogram/ (Chesapeake Bay Program Home Page)
http://www.op.state.md.us/ (Maryland Office of Planning)
http://www.nvpdc.state.va.us (Occoquan Reservoir Study)
http://www.epa.gov/nep/nepbroc.html (National Estuary Program Home Page)
http://www.gsd.harvard.edu/brc/brc.html (Camp Pendleton Study)
http://monticello.avenue.gen.va.us/Gov/TJPDC (Thomas Jefferson Planning District Commission)
http://www.co.lancaster.pa.us (Lancaster County Planning Commission)
http://www.nvpdc.state.va.us (Northern Virginia Planning District Commission)
March, 1998 C-3
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