5173                                       800R76101
              PLANNING METHODOLOGIES
                    FOR ANALYSIS
                         OF
            LAND USE / WATER QUALITY
                   RELATIONSHIPS
                   TECHNICAL APPENDIX

             U. S. Environmental Protection Agency
                  Washington, D. C. 20460
                      October, 1976

-------
                 EPA REVIEW NOTICE
This report has been reviewed by the Environmental
Protection Agency and approved as satisfying the
terms of the subject contract.  Approval does not
signify that the contents necessarily reflect the
views and policies of the Environmental Protection
Agency, nor does mention of trademarks or commercial
products constitute endorsement or recommendation
for use.

-------
 PLANNING METHODOLOGIES FOR ANALYSIS OF

  LAND USE/WATER QUALITY RELATIONSHIPS


           TECHNICAL APPENDIX
        In partial fulfillment of
       EPA Contract No. 68-01-3551

                 for the

  U.S. ENVIRONMENTAL PROTECTION AGENCY
         Water Planning Division
EPA Project Officer:  William C. Lienesch
              October 1976

-------

-------
                                  PROJECT PARTICIPANTS


                            BETZ  ENVIRONMENTAL ENGINEERS,  INC



                                    Project Director

                                  William K. Davis,  AIP
                             Assistant Vice President B.E.E.



                                 Principal Investigator

                                 Thomas R. Hammer,  Ph.d.
                            Principal Socio-Economic Planner
"^                                  Major Contributors
(Ys,
"^                            Francis X.  Browne,  Ph.d.,  P.E.
^                                   Victor J.  DePallo
f^                                William H. Gammerdinger
                                     James V.  Husted
                                   Thomas G.  May,  P.E.
                                  D. Kelly O'Day,  P.E.
                                   Jacquelyn G.  White

-------
                          CONTENTS


                                                  Page

Introduction                                      A-l

Empirical Analysis                                A-l

Relationships between Pollutant Concen-
trations and Precipitation Variables              A-3

Relationships between Pollutant Loadings
and Watershed Characteristics                     A-12

Application of Loading Relationships in
Reconnaissance Studies                            A-26

Water Quality Aspects of Nonpoint Sources         A-38

Important Considerations in Water Quality
Analysis                                          A-39

Biological Effects of Nonpoint Source
Pollutants                                        A-65

Analysis of Water Quality Data to
Determine Nonpoint Problems                       A-81

Addendum 1                                        A-l02

Bibliography                                      A-104

-------
                       LIST OF TABLES


Table                       Title                      Page

 A-l      Summary of Regression Results for
          Oklahoma Water Quality Data                  A-6

 A-2      COD Concentration, Relative to
          Concentration One Hour After Start
          of Storm                                     A-12

 A-3      Regression Results for BOD Loadings          A-17

 A-4      Regression Results for Other Constituents    A-22

 A-5      Descriptive Data for Hydrologic Sub-
          divisions in Hypothetical Study Area         A-28

 A-6      Estimated BOD Loading for Hypothetical
          Study Area, Based on Standard Oklahoma
          Relationships                                A-31

 A-7      BOD Loadings Based on Alternative
          Oklahoma Relationships                       A-31

 A-8      Summary of Field Data for Hypothetical
          Watershed                                    A-34

 A-9      Tabulation of Annual BOD Loadings
          During Storm Periods, in Pounds              A-36

 A-10     Assessment of Storm Related Constituents     A-44

 A-ll     Effect on Stream Decomposition Rearation
          Rates of Increasing Various Factors          A-49

 A-12     Effects of Storm Events on Decomposition,
          Reaeration and In-Stream Dissolved Oxygen    A-52

 A-l3     Average Values of Oxygen Uptake of
          River Bottoms                                A-54

 A-14     Sediment Accumulation per Unit of
          Net Drainage Area                            A-63
                           VI

-------
                 List of Tables (Continued)
Table                       Title                      Page

 A-15     Macroinvertebrate Response to Dis-
          solved Oxygen Concentrations                 A-67

 A-16     Reported Toxic and Non-Toxic Concen-
          trations of Selected Substances              A-73

 A-17     Determined Synergistic and Antagon-
          istic Effects of Toxic Substances            A-75

 A-18     Concentrations of Chloride Harmful to
          Fish                                         A-81

 A-19     Example Techniques for Analyzing
          Existing Data for Nonpoint Source
          Problems                                     A-8 5

 A-20     Major Nonpoint Pollutant Sources             A-93
                          Vll

-------
                       LIST OF FIGURES
Figure                      Title                      Page

 A-l      Relationships between Pollutant Con-
          centration and Time since Previous
          Storm                                        A-7

 A-2      Estimated Loading Relationships for
          BOD                                          A-18

 A-3      Estimated Loading Relationships for
          COD, TOG and SS                              A-23

 A-4      Estimated Loading Relationships for
          Organic Kjeldahl, Nitrogen, Ammonia
          and Nitrate                                  A-24

 A-5      Hypothetical Urban Area                      A-27

 A-6      Muddy Creek Watershed  (Hypothetical)         A-29

 A-7      Stormwater Constituents and their
          Persistence                                  A-41

 A-8      Stormwater Constituents and their
          Effective Distance                           A-42

 A-9      Trout Mortality to Low Oxygen Levels         A-46

 A-10     Flow as Calculated by Various Pre-
          diction Equations                            A-50

 A-ll     Dissolved Oxygen Profiles of Passaic
          River Following Storm                        A-53

 A-12     BOD and Deoxygenation Rate Constant
          of Effluent Stream Flowing over
          Sludge and Bed                               A-56

 A-13     Mass Curves of Total Oxygen Consumed,
          Oc, by Benthal Deposits                      A-56
                         Vlll

-------
                  TECHNICAL APPENDIX
Introduction

The Planning Methodologies report has dealt with analysis
and control of unrecorded pollution from urban land, ex-
cluding combined sewer overflows.  This technical appendix
presents various supporting materials which have been as-
sembled as part of the project.  Three general aspects of
unrecorded pollution are addressed:  (1) magnitude and var-
iation of loadings; (2) water quality impacts; (3) biolog-
ical effects.  These materials are not intended to represent
a comprehensive overview of the subject; they have been de-
veloped primarily to address the specific issues discussed
in the text.  The overall impression which is conveyed is
that the seriousness of unrecorded pollution is highly
variable among urban areas, and that many aspects of this
problem remain poorly understood, particularly the response
of aquatic biota to transient pollutant inputs.

Empirical Analysis

A substantial body of literature describes unrecorded pol-
lutant loadings and loading relationships for urban basins
in the U.S.  However,  very few of these studies have at-
tempted to provide a balanced characterization of the ef-
fects of urban land on in-stream conditions.  Most studies
of unrecorded pollutant loadings have not attempted to deal
systematically with the land use determinants involved; many
have focused upon very small catchments which may differ
substantially from larger basins in pollutant generation.
The present study has therefore included a modest study of
loading relationships, based upon two existing data sources
which are relatively comprehensive.

One data set analyzed here was obtained by AVCO Corporation
(AVCO, 1970) in a study of stormwater pollution in Tulsa,
Oklahoma.  Storm runoff quality was sampled during a number
of storm periods in each of 15 basins in Tulsa.  The catch-
ments ranged from 64 acres to 938 acres, averaging about 370
acres (0.6 square mile).  These basins provided good ex-
amples of the residential, commercial and industrial land
uses typically found in a medium-sized urban center.  Pop-
ulation density ranged from zero to 14 persons per acre,
with an average between 6 and 7 per acre.  The proportion of
impervious land ranged from 11 percent to 74 percent.  All
but one of the residential basins were served by separate
                           A-l

-------
sanitary sewers.  Varying degrees of storm sewerage were
represented, ranging up to complete replacement of natural
channels by artificial conduits.  Over 400 chemical samples
were taken.  The water quality parameters analyzed in the
present study were:  biochemical oxygen demand (BOD), chem-
ical oxygen demand (COD), total organic carbon (TOC), organ-
ic Kjeldahl nitrogen (OKN), soluble orthophosphate (OP04)
and suspended solids (SS).  Both individual concentrations
and annual loadings of these constituents were available
from the AVCO report.

The second data set was obtained from an ongoing program con-
ducted jointly by the U.S. Geological Survey and the City of
Philadelphia, which has involved monthly sampling of numerous
watersheds in and near Philadelphia since 1970 (Radziul, et
al, 1973).  Many of these watersheds were chosen explicitly
on the basis of land use.  The network thus provided an ex-
cellent representation of urban and suburban land in the
Philadelphia area, with the exception of very high-density
urban development.  Ten of these basins, ranging from 1 to
21 square miles in area and containing no authorized point
discharges, were selected for analysis here.  Although the
U.S.G.S./Philadelphia sampling program was not specifically
oriented toward storm runoff, the available data were con-
sidered adequate to characterize wet-weather conditions and
to compute annual pollutant loadings for the selected water-
sheds.*  Similar use of the data has been reported by other
investigators  (Radziul, et al, 1973).
* Annual loadings were prepared in the following fashion.
  Pollutant concentrations during wet weather and dry
  weather were segregated and related to stream discharge by
  logarithmic regression.  Flow-duration curves, expressing
  percentages of the time that stream flow was within speci-
  fied intervals, were then prepared for wet and dry condi-
  tions at each station, utilizing the continuous stream
  flow records available.   (Wet and dry days were identi-
  fied for this purpose by hydrograph behavior rather than
  precipitation records; the number of wet days in each
  case corresponded roughly to the number of days with
  rainfall exceeding 0.1 inch.)  The estimated pollutant
  concentration corresponding to each level of discharge
  was then multiplied by discharge and by the percent of
  time that discharge was within the given interval; these
  products were summed over all discharge intervals and
  multiplied by appropriate constants to yield an annual
  loading during wet or dry conditions.

                            A-2

-------
Relationships Between Pollutant Concentrations and Pre-
cipitation Variables

It was considered of interest to examine the relationships
between pollutant concentrations and various precipitation
variables, such as the time since start of rainfall, average
intensity of precipitation, and time since the previous
storm.  These relationships bear upon several important
issues involving the origin of pollutants, as discussed in
the text of the Planning Methodologies report.  If pollu-
tants are derived from diffuse materials which build up
gradually on watershed surfaces, the loadings and concentra-
tions observed in a given storm should be positively related
to time since the previous storm.  Individual concentrations
should also be negatively related to time since the start of
rainfall and the average intensity of rainfall (due to re-
duction during a storm in the amount of material available
for transport).  On the other hand, if pollutants are de-
rived from land erosion, or processes resembling land ero-
sion, the only expected relationship with precipitation
variables might be a positive association between pollutant
concentrations and the average intensity of precipitation.

In order to examine these relationships for a representative
sample of urban basins, the Tulsa data were subjected to a
series of regression analysis.  Each observed concentration
of a chemical constituent was related to the following
precipitation variables:

     XI   Time since start of precipitation, in hours

     X2   Amount of precipitation since start of event,
          in inches

     X3   Average intensity of precipitation, in inches
          per hour (from start of rainfall to time of
          sample)

     X4   Time since antecedent rainfall event, in hours

     X5   Amount of antecedent rainfall event, in inches

     X6   Duration of antecedent rainfall event,  in hours

     X7   Average intensity of antecedent event,  in inches
          per hour

     X8   Antecedent precipitation index (an index of soil
          wetness)
                         A-3

-------
Due to the limited number of observations available for each
basin, and the known tendency of pollutant concentrations in
storm water to behave erratically, the chosen procedure was
to develop pooled estimates of relationships by considering
the data for all basins simultaneously.  It was thus neces-
sary to control for variation in pollutant concentrations
due to land use and other characteristics of individual
basins.  This was done by including dummy variables, in a
manner which is explained in Addendum 1.  Prior to the
regression analysis, all variables except the dummy vari-
ables were converted to logarithmic form.  (Unity was first
added to each of the chemical concentrations to prevent
domination of the regression results by low observations.)
A large number of regression analyses were conducted, each
of which involved one of the chemical concentrations as
dependent variable and one or more of the explanatory
factors listed above as independent variables  (in addition
to the dummy variables).  A major objective was to examine
relationships between chemical concentrations and X4, time
since antecedent rainfall event.

Somewhat surprisingly, none of the regression analyses based
on the full sample of observations revealed strong relation-
ships with time since antecedent rainfall.  This was true
regardless of the other independent variables entered along
with X4.  A very mild positive relationship with X4, sig-
nificant at the 5% level but not the 1% level, was observed
for suspended solids.  No other significant relationships
with time since antecedent rainfall were obtained, despite
considerable experimentation.*

An additional group of regression analyses were therefore
conducted utilizing only those observations occurring in the
first four hours since the start of rainfall.  Deletion of
* A similar lack of positive association with X4 was ob-
  served in regression analyses conducted as part of the
  AVCO study  (which did not control for variation in basin
  characteristics).  All regression coefficients applying
  to X4 were negative, although only two were statistically
  significant  (AVCO, Table K-2).
                           A-4

-------
observations with XI greater than 4.0 hours reduced the size
of the sample by approximately half.  It was reasoned that
observations occurring near the beginning of a storm should
be most influenced by time since the previous storm event.
The results of this series of regressions are summarized in
Table A-l.  Statistically significant, but very mild, posi-
tive relationships with time since antecedent rainfall were
obtained for BOD, total organic carbon, and soluble ortho-
phosphate.  These findings are presented graphically in
Figure A-l, which shows the ratio of pollutant concentration
to the value which would occur if time since previous rain-
fall were equal to 100 hours (holding constant all variables
besides X4).  For purposes of comparison, the diagonal line
shows the relationship which would be expected if the sole
pollutant source consisted of easily-transportable materials
which accumulated on watershed impervious surfaces at a
constant daily rate.

A lack of strong association between pollutant concentra-
tions and time since antecedent rainfall has also been
observed by other investigators.  The North Carolina study
cited in the text (Colston, 1974), which involved more than
500 samples of storm runoff from a 1.67-square-mile basin in
Durham, North Carolina, included regression analyses in
which pollutant loading rates were related to the following
variables:  rate of stream discharge, time from storm start,
time from last storm, and time from last hydrograph peak.*
The latter two variables did not contribute significantly to
the explanation of loading rates, and thus they were deleted
from the analysis.  A similar situation was observed in a
study by Weibel, Anderson and Woodward (1964) of runoff from
an urban area in Cincinnati, Ohio.  The authors reported
* In logarithmic regressions where stream discharge is in-
  cluded as an independent variable, use of the pollutant
  loading rate (or rate of flux) rather than pollutant con-
  centration as dependent variable does not affect the re-
  gression coefficients and standard errors obtained for
  the other independent variables.  In effect, both sides
  of the equation are multiplied by discharge  (before tak-
  ing logs), which simply serves to elevate R-square and
  the significance of discharge as an explanatory variable.
                         A-5

-------
                             TABLE A-l

            SUMMARY OF REGRESSION RESULTS FOR OKLAHOMA
                        WATER QUALITY DATA

 Dependent
  Variable   Regression Coefficients for Independent Variables  Multiple
                  (log form), Excluding Dummy Variables	  R-Square


BOD

COD

TOC

OKN

OPO4

SS


-0

-0

-0

-0




Xl
* if
.297
**
.317
**
.283
**
.231

—

—


-0



-0

-0



0
X3
* *
.512

—
**
.211
**
.176

—
**
.460
X4
t
0.085

—
**
0.171

--
**
0.098

—




-0



-0

0

0
X8

—
*
.123

—
**
.097
* *
.158
*
.205


0.

0.

0.

0.

0.

0.


4524

4532

4452

3787

4632

4672
Definitions:   X  = time since start of rainfall
              X^ = average intensity of rainfall

              X. = time since antecedent rainfall
               4

              X0 = antecedent precipitation index
               o
Note:  Single asterisk denotes statistical significance at the
       5% level; double asterisk denotes significance at 1%
       level.  The number of observations ranges from 147 to
       207.

Source:  Analysis by Betz Environmental Engineers, Inc.,
         based upon data from AVCO (1970) .
                                 A-6

-------
                                               .S?   E
 OOt=SdSl :aOJ NOIiVaiN3DNOD Ol
NOIlVaiN3DNOD JlNVimiOd JO OI1V8
                A-7

-------
that "The relationship, if there is one, between the length
of antecedent (dry) interval and runoff loads has not been
evidenced in the data examined thus far."  (p. 923).  The
data included more than 25 rainfall events exceeding 0.1
inch.

Failure to observe strong relationships between pollutant
concentrations and time since previous rainfall is incon-
sistent with the assumptions contained in STORM, and similar
predictive methodologies, which attribute pollutant loadings
to progressive dirt and dust accumulation.  The findings
presented here are also inconsistent with a number of other
empirical studies that have found antecedent rainfall to be
important to pollutant concentrations or loadings (e.g.,
Lager and Smith, 1974, p. 81).  Several possible explana-
tions for this situation are the following:

     Random variation.  Pollutant concentrations during
     storm conditions are heavily influenced by transient
     and random factors  (as evidenced by the fact that less
     than half of total variance was explained in each of
     the Oklahoma regressions).  However, given the large
     numbers of chemical samples analyzed in the Tulsa,
     Durham and Cincinnati studies, it is highly unlikely
     that random variation would obscure relationships with
     previous rainfall if such relationships were strong.
     Municipal street sweeping operations also do not appear
     to be a major explanatory factor.  Most of the Oklahoma
     basins were swept less often than once every six weeks.
     Furthermore, Sartor and Boyd  (1972) have estimated that
     conventional sweeping practices are only 50% effective
     in removing dirt and dust from street surfaces.  If
     particle size is taken into account, Sartor and Boyd
     indicate that sweeping is only 43% and 34% effective
     for BOD and COD, respectively.

     Behavior of loadings versus concentrations.  Pollutant
     loadings, as opposed to concentrations, have not been
     related here to precipitation variables, because load-
     ing estimates for individual storms were not available
     from the AVCO study.  It is conceivable that loadings
     may be more strongly related to time since antecedent
     rainfall than concentrations.  However, since the total
     loading for a storm is simply equal to a constant times
     concentration times discharge, integrated over the dur-
     ation of the storm, loading rates and concentrations
     cannot differ systematically in their relationships to
                         A-8

-------
time since antecedent rainfall unless the runoff rate
is somehow related to antecedent rainfall.  Storms
which follow long dry periods might tend to be rela-
tively heavy  (which would result in high runoff volumes
and total loadings) or relatively short in duration
(which would result in above-average concentrations;
see below).  However, neither of these possibilities
would appear important.  Also, variation in discharge
should be largely controlled in the present equations
by the inclusion of X3  (average intensity of rainfall)
as an independent variable along with X4.

Nonlinear surface pollutant accumulation rates.  As
described in the Planning Methodologies report (pp. 42-
44), there is a strong possibility that dirt and dust
accumulation rates—as opposed to deposition rates—may
be nonlinear, so that the total amount of accumulated
material approaches an upper bound rather than increas-
ing indefinitely.  This finding, by Shaheen (1975),
applies specifically to roadway surfaces.  Its signi-
ficance for overall pollutant yields is somewhat un-
clear, however, because pollutants removed from road-
ways by wind and other mechanisms may remain available
for transport by stormwater (a point which is empha-
sized by Shaheen).  In any case, it appears likely that
nonlinearity of pollutant accumulation rates bears some
responsibility for the failure of pollutant concentra-
tions to be strongly related to time since antecedent
rainfall in some instances.  This is an important point
to note because the available predictive methodolo-
gies—e.g., STORM—presently do not incorporate non-
linear accumulation rates  (as of early 1976).

Pollutant sources besides washoff.  The present find-
ings are probably due to some extent to the role of
pollutant sources which do not involve washoff of
diffuse materials from impervious surfaces.  The two
source classes for which the pollutant yields would not
be positively related to time since antecedent rainfall
are:  (1) erosion and erosion-type processes,  in which
the pollutant yields are not limited by the amount of
material present; and (2)  erratic and continuous dis-
charges which are not rainfall-activated.  The present
findings thus provide some indication that diffuse
materials on impervious surfaces are not overwhelmingly
responsible for pollutant yields from medium-density
areas.
                    A-9

-------
The use of unsubstantiated assumptions about pollutant
buildup on watershed surfaces would lead to significant
forecasting errors in some instances.  For example, suppose
that a stormwater model such as STORM is calibrated for
streams in the Philadelphia area.  In this region, the
annual probability (P)  of observing a period "T" days or
longer without rainfall exceeding 0.1 inch is roughly pre-
dictable by the following expression:
          P = 1 - exp(-40exp(-.17T) .
Based on this formula, there is an even chance that a dry
interval of 33 days or greater will occur in any five-year
period, or that an interval of 24 days will occur in any
given year.  Thus, the critical condition for stormwater
pollution might be defined as a dry interval of perhaps 30
days, followed by a brief storm.  However, the only water
quality data available for calibration of the model might
apply to conditions very different from this.  For example,
a typical three-month sampling period would contain a maxi-
mum dry interval of only 15 days; and this interval might be
followed by a storm that failed to resemble critical con-
ditions in other respects.  Thus, application of the model
to predict the critical pollutant loading or concentration
would require substantial extrapolation beyond the observed
data.  If based upon an assumption of progressive pollutant
accumulation, this extrapolation could involve very serious
error.

Returning to the analysis of the Oklahoma data, the regres-
sion coefficients obtained for variables other than time
since previous storm are also of interest.  Significant
negative relationships with time since start of rainfall
(XI) were observed for BOD, COD, TOC and organic Kjeldahl
nitrogen.*  All of these constituents except COD were also
related negatively to average intensity of precipitation
(X3).  Both types of relationships were consistent with the
pattern normally expected if pollutants are washed from
impervious surfaces.  Negative relationships with antecedent
* Strong negative relationships with time since start cf
  storm were also obrained in the North Carolina regression
  analyses  (Colston, 1974, p. 57).
                         A-10

-------
soil moisture  (X8) were observed for COD and OKN.  No obvi-
ous explanation is available other than the possibility that
high soil moisture was associated with low availability of
organic material, due to removal during previous wet periods.

Suspended solids concentrations reflected the influence of
erosion, being positively related to average intensity of
precipitation and unrelated to time since the start of rain-
fall.  Soluble orthophosphate was an intermediate case,
because no significant relationships with either of these
precipitation variables were observed.  Suspended solids and
soluble orthophosphate were both positively related to
antecedent soil moisture (X8).  This is expected for pol-
lutants yielded by erosion, because soil moisture influences
the quantity of runoff from pervious land.

An important aspect of these relationships is the implied
magnitude of the "first-flush" effect.  Very high pollutant
concentrations often occur in the initial stages of storm
events, due to washoff from watershed surfaces and also the
scouring of accumulated material from catch basins and storm
sewers.  The shock effect of these contaminants upon receiv-
ing stream biota is often cited as one of the most serious
consequences of urban runoff, and has led to the view that
urban stormwater can have disproportionately large environ-
mental impacts relative to the annual pollutant loadings
involved.

The magnitude of the first-flush effect relative to pol-
lutant concentrations occurring later is expressed in the
relationship between pollutant concentration and time since
start of storm.  In the regression results presented above
for Tulsa, and in the Durham and Cincinnati studies cited
earlier, the relationship for COD has been typical of the
strongest relationships observed.  Table A-2 summarizes COD
levels during three time periods, each taken as a ratio to
the concentration which would be observed one hour after the
start of the storm.  The Tulsa and Durham figures have been
derived by evaluating regression equations; the Cincinnati
figures are from a direct tabulation of mean concentrations
(Weibel, et al, 1964, p. 923).

The magnitude of the first-flush effect is perhaps less than
might be expected.  In all cases, average COD concentrations
during the first 15 minutes of storm events are less than
twice the concentrations observed at 1 hour after start of
storm, and are less than 2.5 times as great as the average
                            A-ll

-------
concentrations for all stormwater samples  (not indicated in
Table A-2).   In the Cincinnati case, the average COD con-
centration during the first 15 minutes of storm events is
only 72% greater than the overall average concentration.
The persistence of pollutant loadings after two hours is
also considered significant.  Other investigators have noted
that the magnitude of the first-flush effect tends to be
variable among regions and individual basins (see the forth-
coming Hydroscience report referenced in the text).  The
important point is that the existence of a highly pronounced
first-flush effect should not be automatically assumed.
                       TABLE A-2

     COD CONCENTRATION, RELATIVE TO CONCENTRATION
             ONE HOUR AFTER START OF STORM
                                Time Since Start of Storm
Tulsa, Oklahoma

Cincinnati, Ohio

Durham, North Carolina
 0-15
minutes

  1.90

  1.62

  1.79
 15-30
minutes

  1.26

  1.24

  1.32
120 minutes
 and over

  0.65

  0.69

  0.68
Source:  Weibel, et al  (1964); computations based on data
          from AVCO (1970) and Colston  (1974).
Relationships Between Pollutant Loadings and Watershed
Characteristics

The Tulsa data, the Philadelphia data, and information for
three basins in New Jersey have been utilized to estimate
urban pollutant-generation relationships for various water
constituents.*  The annual loadings of these constituents
* The three New Jersey basins were sampled during 1969-1972
  by the Water Resources Research Institute at Rutgers
   (Whipple et al, 1974).  Annual BOD loadings based on these
  data have been prepared utilizing revised estimates of
  annual runoff quantity.
                            A-12

-------
were related to several indices of human activity and land
condition by multiple regression.  The explanatory factors
which could be considered were seriously constrained by data
availability.  (See the discussion in the text of variables
needed for complete watershed description.)  However, the
simple equations obtained were felt to be instructive and
potentially usable for limited forecasting activities.

A basic requirement for the analysis of pollutant-generation
relationships was that the data should pertain to multiple
watersheds in a given geographic area.  This was considered
necessary in order to control for the effects of regional
factors such as climate.  The Pennsylvania and New Jersey
basins were considered to be in the same region, because
they were separated by less than 100 miles and exhibited
similar loading characteristics.  The overall sample con-
sisted of 13 basins in the Pennsylvania/New Jersey region,
and 13 basins in the Tulsa region.

The quantities analyzed were the annual loadings in pounds
per acre per year of the following water constituents:  BOD,
COD, OKN (organic Kjeldahl nitrogen), NH3  (ammonia), N03
(nitrate),  OPO4 (soluble orthophosphate), and PO4  (total
phosphate).  Unfortunately, comparable data for both sets of
basins were available only for the organic constituents,
BOD, COD and TOC.   The watershed characteristics considered
in the analysis were the following:
     PI - Population density in persons per acre

     P2 - Density of population in dwellings constructed
          before 1940, in persons per acre

     P3 - Density of population in dwellings constructed
          after 1940, in persons per acre

     M  - Median family income  (as reported in 1970 Census
          for the year 1969)

     E  - Employment density in persons per acre

     I  - Impervious surface as percent of watershed area

All of the density measures were gross rather than net
density, i.e., consisted of population or employment divided
by the acreage of the entire watershed.  In preparing pop-
ulation and income data, it was necessary to consult the
                           A-13

-------
1970 U.S. Census, Census Tract Statistics, for all of the
basins studied (although total population was available for
the Tulsa basins from the AVCO study).   Approximation was
required because census tract boundaries generally did not
correspond to drainage area boundaries.  However, nearly all
of the measurements were considered accurate to within 10%.
Separate tabulations of population in dwelling units con-
structed before and after 1940 were prepared using the
Census table which lists number of units by year structure
built.  This distinction is significant to pollutant genera-
tion.

Detailed land use data were assembled for the Pennsylvania
watersheds using census tract information developed by the
Delaware Valley Regional Planning Commission.  Land use data
were also available for the Oklahoma basins from the AVCO
report.  This information was not utilized directly in the
analysis of pollutant loadings, however, due to definitional
differences and other factors.  Total employment in each
basin  (i.e., employment at place-of-work, not place-of-
residence) was estimated on the basis of the land use data,
using a methodology which is discussed later.  Although all
available information was utilized in preparing these esti-
mates, the values for some of the individual basins could be
in error by as much as 25%.  However, test application of
the methodology to large segments of the Philadelphia region
indicates that the overall magnitude of estimates is prob-
ably correct.  Finally, watershed imperviousness was ob-
tained from the AVCO study, previous studies of the Phila-
delphia area, and direct measurement (Hammer, 1973a).

The analysis involved simple and multiple regressions in
which dependent variables expressing pollutant loadings were
related to the above factors as independent variables.  Two
of the fifteen Oklahoma basins studied by AVCO were not
included in this investigation.  One was a basin draining
part of the Tulsa airport; the other was a basin for which
runoff consisted of intermittent overflow from an abandoned
strip-pit.

In cases where constituent loadings were available for both
Oklahoma and Pennsylvania/New Jersey,  the annual loads per
acre were higher on the average for Oklahoma by amounts
ranging from 15% in the case of BOD, to 100% for TOC.  In
view of the descriptions given in the  AVCO report, and the
author's knowledge of the other basins, it is believed that
differences in general cleanliness were partly responsible
                            A-14

-------
for this occurrence.  In any case, it was necessary to
control for these systematic differences in some fashion,
since the factors responsible would clearly not be expressed
in the independent variables.  The adopted procedure \\as
based on the following assumptions:  (1) for any given
values of the independent variables, it was assumed that the
loading of a chemical constituent in Oklahoma would be equal
to the loading which would occur in Pennsylvania/New Jersey,
times a constant factor "k"; and  (2) it was assumed that the
value of "k" for each constituent was equal to the ratio of
observed mean values for the two regions.  The procedure was
to divide the constituent loading for each basin by the mean
loading for that region.  This dimensionless ratio was used
as the dependent variable in all but one of the regression
analyses involving data for both regions.  Such a procedure
is legitimate only when the means of the independent vari-
ables are similar for the regions involved, which was
generally true in the present case.*  Subsequent to the
regression analysis, predictive equations were obtained for
each region by multiplying each of the coefficients in the
regression equation by the mean loading for that region.
* Let Yl and Y2 denote loadings of a given chemical con-
  stituent for the Pennsylvania/New Jersey and Oklahoma
  regions, respectively; and let XI and X2 be correspond-
  ing vectors denoting independent variables.  the first of
  the two assumptions made here is that:  Yl=f(XI) and
  Y2=kf(X2)=f(kX2), where f is a linear function.  Suppose
  that separate linear regressions of this form were con-
  ducted for the two regions, and that the mean values of
  independent variables in the two cases were substituted
  into the regression equations obtained.  Because regres-
  sion equations hold exactly at the means, the following
  relationships would be obtained:  Y'=F(X'l) and Y'2=^
  kG(X'2), where F and G are the estimated functions in
  each case, and primes denote mean values.  If it is
  assumed that k=Y'2/Y'l, the second relationship becomes:
  y"l=G(X'2).  Clearly, the functions F and G cannot be
  approximately the same unless the vectors X'l and X'2
  are similar,  or unless the differences in mean values
  of individual variables are internally compensating.
                           A-15

-------
The findings of the analysis can be summarized as follows.
Strong relationships with watershed characteristics were
identified for a majority of the chemical loadings analyzed.
However, due to the small sample sizes and the existence of
substantial random error, it was considered appropriate to
restrict regression equations to very simple forms.  Popu-
lation density was found to be generally a poor predictor of
pollutant loadings.  The best explanatory variable in almost
all cases was employment density.  Percent imperviousness,
which covers the effects of both residential and non-resi-
dential development, was also found statistically signifi-
cant in a majority of cases when entered as a single inde-
pendent variable.

Experimentation with population-related variables indicated
that two factors are potentially very important:  age of
housing, and income levels.  The role of age of housing
emerged when residential basins were segregated from other
basins  (see below).  Median family income was attributed
substantial importance in a number of regressions when
entered in an interactive form with population density,
(e.g., an independent variable might consist of population
density divided by median family income.  The findings
involving income are not reproduced here because the equa-
tions are not considered reliable and have little practical
usefulness.  The important finding is that medium and high-
income housing constructed since 1940 has minimal impact on
pollutant loadings  (see discussion below).

BOD was analyzed in somewhat greater detail than the other
constituents because the most observations  (26 basins) were
available in this  case.  The findings, which are summarized
in Table A-3 and Figure A-2, are considered to have general
relevance for other pollutant loadings.  The equations
describing relationships with imperviousness and employment
density are presented in the first line of Table A-3 and in
the upper two graphs of Figure A-2.  Employment density was
a relatively stronger explanatory variable, and would have
dominated the regression results if entered along with
imperviousness in  a multiple regression.  As was typical for
most constituents, the constant term in the predictive
equations for BOD  was lower when imperviousness was the
independent variable than when employment density was used.
This is logical because low imperviousness always implies
low employment density, whereas the reverse is not neces-
sarily  true.
                            A-16

-------


































m
f
^C

w
1-4
1






























































co
o
z
Q
a

a
o
CQ

a;
o

CO
E-i
J
O
1

2
O
M
CO
CO
w
p£
o
§




























l^
id
3
tr
CO
i
K
10
to
o>
c
in
3
O
•rH
to
0)
rH
j3
n)
•H
(-1
id


•P
G
(1)
•o
G
a)
a
(U
•o
G
H

M
O

CO

f*

G 1 *
>i-H
O W
rH C
CX 0)
g Q
u3
*
rH
rH
cn
o
o





^
^J
•H
to
C
01
D

G
0
•H
+J
id
rH
3
a
O
a.


o to
^* CP
CTl G
rH-iH
1 rH
•P rH
10 01
O 3
CM Q

00
in
rH
o

o




4C
to
^3 tJl
•* G

rH rH
| rH
0) 01
£§
G
id g
4J H
10 (U
C E*
O
U
*
vo
0
ON
o
•
o

^j* co ^3* in
vo m o^ vo
TJ* r^ ro vo
• • • •
o o o o


1(1 01 (0
C C G 1
0) -rl -H -H X
CT tfl U) W W
G (d id (d I
•H pa m m M
•d o
Id l~t — 1 rH JQ
O rH i-H i-H (d
j < < «; j
Q
§.
i-H tN ro ^*
CO
CO
vo
•
o

























*
r^
^*
cn
o
n

























cn
vo
•
fN|
rH


|
g
cn M tj>
G to 1 C 10
•rl C Vl TH G
-P -H O 4J -rt
Vi to £} VH to
O id id O id
a>w r3 cun

in
                                  o
                                  G
                                  id
                                  U
                                 -•H
                                 VM
                                 •H
                                  C

                                 •H
                                  (0

                                  (0
                                  o>
                                 4J
                                  O
                                  c
                                  01
                                 •o
                                  a
                                 •rH
                                  to
                                  id
                                  3
                                  o
                                 •a
<*>
in
0)
4J
4J
id
0)
0
G
id
O
•rl
MH
G
•rl
to
^
id
o
•H
4J
to
•rl
4J
id
4J
to
to
01
4J
0
01
•a
to ai
01 H
4J
to <*>
Id rH
01 01
•H f:
G
co m

.,
01
4J
O















O
G
H

*
to
M
ginee
pa
rH
Itf
4J
S
§
•rl
G
M
N
-4J
n

0)
o
3
0
CO
A-17

-------
            ALL BASINS
    ALL  BASINS
Ul
\ 50
Ul
U
^ 40
CO
Z 30
O
1"
a
-• 10
o
o
« 0
c
p
« 60
<
Ul
>: so
Ul
B£
«{ 40
CD
g 30
O
2 20
o
§,o
O
O
01 0
(
L
« 60
I 50
IU
_e
^40
•i
Z 30
O
S 20
1,0
O
2 „




X/


Ok

/
/


ahom
..'*'
^.



aX*
X
/N.J.


/
X
x



> 20 40 60 80 10
ERCENT OF AREA IMPERVIOU
ALL BASIN

Industrial
Okla
Pa./N.J.^
X jf



Areas: X
XX
^k
,-^x ^
^"^N

00 tn O
BOD LOADING IN LB./ACRE/YEAR
— . >O U> *• in &
O O O O O O C
/ x^X
X
X .. ^
•'"" ^^
s^
Non-Industrial Areas:
[Okla.
^Pa./N.J.

) 25 50
PERCENT OF AREA IM
ABOR-EXPORTING ARE;
PRE
Pa.

.•"
$£.

1940
Oklav
/N.J.
y


\
^US
\/


_• "••
\194C
l\>k|
>a.
ING:
X*
;X


TOST
HOU
3.
N.J.
.'' A
X

— ••'
IING:

	 .... j, _j
(/> m
73
o S
v>
1 IB./ACRE/YEAR
J > in O-
> 0 0 0 S
I
1 20
2 10
0
o
10 0



__..-•"
^


Oklahoma.
***** ^*
<
-------
The other BOD regressions involved partitioning the sample
of observations according to the predominant type of urban
development present.  Basins which were primarily residen-
tial were defined as "labor-exporting" areas according to
the following criteria:  (1) employment in the basin was
less than 0.4 times basin population  (i.e., was less than
the approximate number of workers residing in the basin);
and (2) the total acreage of commercial and industrial land
use was less than half the acreage of residential land.  For
all basins in the present sample, these two criteria were
equivalent, although this might not always be true in gen-
eral.   Basins for which the above criteria did not hold were
designated "labor-importing" areas.  These were in turn
classified either "industrial" or "commercial" according to
which land use was predominant in terms of acreage.*  In the
third regression listed in Table A-3, an imperviousness
variable was utilized which consisted of total impervious-
ness for basins designated industrial, and zero for all
other basins.  This variable was entered in a multiple
regression along with the overall imperviousness variable,
and was found significant at the 1% level with a positive
coefficient.  The implication is that a pollutant yield per
acre of impervious surface is significantly higher for
industrial areas than other areas.  The estimated relation-
ships for Oklahoma and Pennsylvania basins are graphed in
the middle section of Figure A-2.**
*  For present purposes, industrial land use will include
   construction, manufacturing, utilities, bulk wholesaling
   and rail and truck transportation.  Commercial land use
   will include retail trade, finance, and all personal and
   professional services except education, public adminis-
   tration and cemeteries.

** Note that these results apply to the entire impervious
   portion of industrial basins, not just the impervious
   area of industrial establishments  (which was not
   measured separately).  Since the latter was typically
   no more than half of total impervious surface, the im-
   pact of industrial land per se is probably greater
   than indicated in the graph.
                           A-19

-------
A regression dealing only with labor-exporting basins
yielded the results shown in the fourth line of Table A-3
and in the lower left section of Figure A-2.  Population in
dwellings constructed before 1940, and population in post-
1940 dwellings, were entered as separate variables.  The
former was statistically significant (i.e., significantly
different from zero) at the 1% level; but the coefficient
for population in post-1940 dwellings was smaller than its
standard error.  A joint test indicated that the two coef-
ficients were significantly different at the 2% level.  If
interpreted literally, the regression results would indicate
that the marginal BOD of residential population is more than
five times as great for pre-1940 housing as for post-1940
housing.  A regression relating BOD loads to employment
density for labor-importing areas is described in the last
line of Table A-3 and in the lower right section of Figure
A-2.  In spite of the small sample size in this case, a
strong positive relationship was obtained, with a substan-
tially greater slope than was estimated on the basis of the
full sample.

It was decided, on the basis of these BOD results and simi-
lar analyses for other constituents, that the best general
procedure would be to relate each constituent to impervious-
ness and employment density in separate univariate regres-
sions.  Use of the resulting relationships for predictive
purposes would then involve averaging the two loading esti-
mates yielded by these relationships.  For example, a 40%
impervious basin in Oklahoma with 2.5 employees per acre
would be expected to yield:  (30 + 26)/2 = 28 pounds of BOD
per acre per year (based on the upper two graphs in Figure
A-2).  This approach was favored for three reasons:   (1) the
use of additional predictive variables would complicate the
relationships and would not be justified in terms of in-
creased accuracy; (2) employment and impervious surface are
relatively unambiguous variables, in comparison with land
use measurements; and (3) in intensively developed areas,
imperviousness is subject to an upper bound  (i.e., 100%)
whereas employment density is not.  Due to this fact, and
the above-mentioned characteristic of constant terms, the
loading estimates obtained as averages in the above fashion
are believed to reflect the actual loading characteristics
of urban land over a wide range of development intensity.

In the case of BOD, which is somewhat more difficult to
estimate accurately than other constituents  (e.g., COD), the
loadings predicted by this methodology for the sample basins
                            A-20

-------
are within 15% of their true values half the time, and with-
in 30% of their true values 80% of the time.  This is felt
to be reasonable accuracy given that the other factors shown
in the lower portion of Figure A-2 are not considered.

The estimated loading relationships for COD, organic carbon,
and suspended solids are shown in the upper portion of Table
A-4 and in Figure A-3.  In each of these cases, employment
density explains more than half the variation in observed
loadings/ and imperviousness explains slightly less than
half.  The suspended solids relationships are based on the
Oklahoma data only.  One of the Oklahoma basins contained a
large amount of construction activity at the time of the
AVCO study.  The suspended solids loading from this basin
was more than three times as great as the next highest
loading,  and seven times as great as the average.  This
basin was eliminated from the present sample when analyzing
suspended solids because there was insufficient information
to deal systematically with construction impact.  The esti-
mated relationships are thus intended to apply to suspended
solids yields from developed urban land.

Loading relationships for organic Kjeldahl nitrogen, ammonia
and nitrate are depicted in Figure A-4.  OKN is the only
constituent for which imperviousness was found to be a
stronger explanatory variable than employment density.  For
ammonia,  there was not a significant relationship between
annual loading and percent impervious.  However, such a re-
lationship did appear to exist for industrial basins alone.
This situation is depicted in Figure A-4 (although the
number of industrial basins was not sufficient for regres-
sion analysis).  For nitrate, the only relationship observed
was a mild positive association with population density in
sewered dwelling units.  (The one Pennsylvania basin con-
taining a significant number of dwellings with on-site
disposal was deleted.)  A relationship pertaining to nitrate
yield from dwellings with on-site sewage disposal was avail-
able from previous research in Chester County, Pennsylvania,
which is within the region covered by the present study
(Howard and Hammer, 1973).   This relationship, converted to
population units, is presented in the lower portion of
Figure A-4.  Its difference from the estimated relationship
for sewered population is striking, especially because soils
in the area studied are generally considered suitable for
on-site waste disposal.  Finally, no significant relation-
ships with watershed characteristics were observed for
                           A-21

-------














































•si-
1
<

W
rH
03
<
EH







































































W

^
W
g
H
EH
CO
Z
o
o

PS
H
X
EH
O

U
0
fn

CO
EH
r3
D
CO
s
Z
0
H
CO
W
w
OH
u
K










































tn
cu
JQ
10
•H
M
10
>

4J
c
0)
•a
c
H.
cu
'O
C
H

M
O
VIH

to
4J
C
01
•H
o
•rH
m
MH
0)
O
O

C
0
•H
to
10
0)
rl
en
0)
us



















































c
o
•H
4J
10
rH
3
CU
0
p.



























+J
c:
0)
i
><
o
rH
a
i




jj
c
10
| J
4-1
05
C
O
O




























0>
)H
(0
tr
CO
i
a



',..-
f
01
CO

>.
4J
•H
to
C
01
a



U)
U]
0)
c
to
3
o
-rH
1-1
01
a
4

i->
C
01
U
\4
01
PJ






>
-p
•rl
to
C
0)
Q







g
M
0)
EH






























in rH rH >» «»  in
H O 00
• • •
O O VO
VO





in ^r vo o
O «3 rH *T
10 CM r~ T CM M
O O O O ^3" rH
Tf in
•» rH



o
8
^^
c w
o w
J5 S
rl
10 Ul
CJ T)
•H
U rH >,
•H O rH
C CO C
10 0
tn "O
rl 01 (0
O TJ H
C 0
rH 01 .C
10 CU tO
Q 4J U) rH
O O 3 .*
U EH CO O





rH ai in f»
in r- T r«
T TT V ro
o o o o









•It
CO
CM
cn
•
rH











«
*
in
o\
n
o
o











*
*
T «
r~ oo
vo o
rH in
• *
O 0





i >i
rH rH rH
x: - c c
. -~ ~
rH itf rH mnj ron)
01 O C K -r( O -H
•n~ O Z C Z C
f«S »- (0 — 10
C (0 > >
O 01 g 10 rH 0) H
•.H en O --H >i -P >i
cox; c to (0 to
(0 IH (0 O C rl C
CT'-I-' r-l EC -PC
IH -H A: e cu -H 01
O Z O < fc Z P<
0)
u
c
10
u
•rt
in
•H
C
O»
**^
10

09
U
4J
O
C
01
•O

r^
to
-H
rt
0)
4J
to
10


01
rH

OP
in
V
A
4J

4J
0)

0)
O
C
10
U
•rt
IM
•H
C
t>»
•H
10
rH
10
O
•H
•P
m
•rl
•P
10
ll
to

to
0>
4J
0
CU
T3
l>
pK
U)
•rl
Vj
01
-p
to
10

01
rH
tp
c
•H
CO


••
01
4->
1










































































rH
0)
>
0)
rH

dp
rH

0)
X!
4->

4J
10
































































U
C
H

%
10
rl
01
01
g
•rl
CJ1
C
H

H
10
4J
C
CU
2
o
rl
•H
>
c
U

N
4J
CU
CQ


••
01
u
rl
0
O
to
A-22

-------
                 COD
POUNDS/ACRE/YEAR
_ 10 W A 0
§o o o c
o o o c



.»
x^

Okla
^
x


lomo
X
X>«


#*
x
^
insylv

/'

/
ania

       0   20   40   60   80   100
          PERCENT IMPERVIOUS
                                             500
        10         15
 ,UFNT rtR A,cr:E
                 TOC
POUNDS/ACRE/YEAR
_. _ K.
A. 0> K> O~ C
3 O O O O O



X**
— -

0

x
Pen

kloho
X
X
*-"-
isylva

ma^x

^
nia

X*'



       0   20   40   60   80  100
          PERCENT  IMPERVIOUS
                                             200
POUNDS/ACRE/YEAR
_
O-
O
_.
M
O
                                              80  —
                                              40  —
                                                                      njylvania
        10        15
'.>)£,••:!  PiR ACRE
                  ss
POUNDS/ACRE/YEAR
w » >o >o C
0 O 0 0 C
3 O O O O C



.•
/*

Okla
t
.••''


homa
x



..•**



\/




       0   20   40   60   80  100
          PERCENT IMPERVIOUS
                                            1500
POUNDS/ACRE/YEAR
o Jo
0 0 0 0
O O O O
            Figure JU ESTIMATED  LOADING RELATIONSHIPS FOR Cii-1 v    ... .:•
SOURCE: Betz Environmental Engineers Inc.
                                 A-23

-------
                     OKN
       OKN
POUNDS/ACRE/YEAR _ POUNDS/ACRE/YEAR POUNDS/ACRE/YEAR
K> .ft 9> 00 O —
300000 o »o *. o eo o o — w w .&,  «-» _



X*
<»*-



..•*



**
.''Okl



/'
ihom


^»*

3


POUNOS/ACRE/YEAR
) 20 40 60 80 100
PERCENT IMPERVIOUS
AMMONIAfNHa)



/


'a.: ln<
lasins
/
w
Pa.: ft


ustric
Only
^
II OtF



r
er Ba

/


sins

at
IU
IU
ot
^
V)
a
z
O
a.
) 20 40 60 80 100
PERCENT INPERVIOUS
NITRATE

/



/
Pa.:0we!lii


-— — • -"
Pa. = S«werc


igs with On Sit* Dispos
„ "•
	 • 	 *
d Dwellings

3
4
3
2
1
0
(
10
8
6
4
2
0
(


^<
.-•**'


0*
L-""bklahoi




10


) 5 10 If
EMPLOYMENT PER ACRE
AMMONIA(NH3)



//
^

^
.Xf*enn


X
X
tylvania


) 5 10 1.
EMPLOYMENT PER ACRE

al
	 	 	



                    2.5        5.0        7.5        10.0
                                POPULATION PER ACRE
12.S
15.0
Fifire A 4  ESTIMATED  LOADING RELATIONSHIPS  FOR  ORGANIC  KIELDAHL  NITROGEN, AMMONIA, AND  NITRATE

SOURCE: Beti Environmental Engineers Inc.
                                              A-24

-------
soluble orthophosphate or total phosphate.  The mean annual
loadings per acre for these constituents were 2.61 and 3.71,
applying to Oklahoma and Pennsylvania, respectively.

Overall, the regression results are remarkably consistent.
The major finding is the greater importance attributed to
economic activity than to population, except in the case of
nitrate.  Employment density and imperviousness were both
statistically significant in explaining the annual loadings
of five constituents:  BOD, COD, TOC, SS and OKN.  In all of
these cases, the regression coefficient for employment
density was four to six times as large as the coefficient
for imperviousness.  A formula has been developed as part of
this study which relates imperviousness to population and
employment densities (see the discussion below of planning
applications).   If this formula is substituted into the
regression equation containing imperviousness, and this
equation is averaged with the employment density equation,
the result is a linear equation for each constituent which
relates loadings to employment density and population den-
sity.  The ratio of coefficients for the latter two vari-
ables in this equation ranges from 4.6 for BOD, down to 3.7
for organic Kjeldahl nitrogen.  Thus, the equations would
indicate that each additional employee in a watershed in-
creases pollutant yields by roughly four times as much as
each additional resident.  This finding has clearly been
influenced, however, by the fact that approximately three-
fourths of the total residential population in the basins
studied lived in post-1940 dwelling units.

There are a number of possible explanations for the great
importance attributed to age of housing in the regression
results.  This finding appears to be due in part to associ-
ations between age of housing and various socioeconomic
characteristics, which are in turn correlated with cleanli-
ness, age and condition of automobiles, and other factors
that directly affect pollutant generation.  Some other
possibilities which have been mentioned are:  physical
deterioration of streets and buildings; existence of more
dense vegetation in older areas; and negative associations
between age of housing and air quality.  A potentially very
important factor is condition of the sanitary sewer system.
Sewer leaks and bypasses can be highly significant pollutant
sources in older neighborhoods.  Deterioration of sewer
pipes causes leakage of wastewater, and also results in
infiltration/inflow problems which necessitate creation of
bypasses.  In any case, an important question is whether
                           A-25

-------
these different • ;  between pollutant yields for new  and old
development  arc  !ue strictly to former construction prac-
tices/ or wheLlji.-r  we can expect progressive increases  in
pollute,'-  j  ;   to occur for recently constructed  develop-
ment.
Studi
Given
present ••:<.'
directi-y .
study :- >  -<
easter:   ij
ships •.;-.-. r
stand," •'•.:'-,
recorn.iiL,,
region L_>
and to i-j.
ef f ir i 'T '
examf ~* •:  ^.
cedure,
inf oiTfi-:; \  1
r e so i.ir •:<./.-
tended '!.'.
appro;- '.'£•

The ir- r.£,K
show*.  IT
than a ir'T
A lar--, .  (
Creek,, v, .
load: r/., i
a ma i o :  r
larly  :  ":
deprc-s ',c,j
treat -r.-^
expe-. L..C
The
           L
flow-,-,  < h-
propc ;:' ' <:•'-.  o
area:-1,   ' - J t
othe/  i > • ; -. •
litt..-.  -i  . .
                f Beading Relationships in Reconnaissance
a-I. .ion which  appears  to exist among pollutant
u'-ban areas  in  the U.S.,  the relationships
ho previous  section  are not considered to be
cable for prediction purposes outside the
r which they were estimated (i.e., Tulsa and
Ivania/New Jersey).   However,  the relation-
.•' ful in reconnaissance studies to establish
 ''parison for field  data.  The objective of
 i cudies is  to  characterize subareas of a
1 ',ant yields relative to expected loadings,
 • and isolate high-yield source areas as
 possible.   The following is a hypothetical
  Justrates  various  aspects of such a pro-
''. ;cctive in  this case is to extract as much
 possible from  field data, given limited
.•"/". t. a collection. This emphasis is not in-
v  (-hat minimal  data  collection programs are
 -:nses where greater resources exist.

•.tipple involves  the hypothetical urban area
 • A-5.  A metropolitan area of somewhat less
 rr^ople is situated  at the head of an estuary.
'! of the urbanized region is drained by Muddy
M-.c-rs the estuary from the west.  Organic
  estuary during storm periods are known to be
    For several days after a storm, particu-
 *  i storm, dissolved oxygen in the estuary is
.: I, ve to normal  dry-weather levels.  Upgraded
  r,ting waste disposal plants—which will be
, •  case to meet secondary standards--is not
 .  inate this post-storm DO problem.

: -'.:on of the urban  area is served by combined
.0  !"he known  importance of combined sewer over-
i -,. jial planning  agency is devoting a large
; t." study grant to  SWMM modeling of these
..derate funding is  available for study of
, '•:.lorded sources, about which relatively
                            A-26

-------
                                                .MAJOR
                                                DRIVER
                                           IM
                              WASTE TREATMENT PLANTS:
                                       O Industrial
                                       • Municipal
  Fifvre A-5 HYPOTHETICAL URBAN AREA
SOURCE: Betz Environmental Engineers Inc.
               A-27

-------
A reconnaissance procedure has been  chosen as the most
efficient means of assessing unrecorded pollution outside
the combined  sewer area.  The hydrologic subdivisions uti-
lized in carrying out this procedure for the Muddy Creek
watershed are shown in Figure A-6, which is an enlargement
of Figure A-5.   Eight areas are  shown,  ranging in size  from
3,000 to 5,000 acres.   (In an actual situation, more subdi-
visions might be desired.)  Characteristics of these areas
are summarized in Table A-5.  The  southern portion of the
Muddy Creek watershed contains substantial industrial devel-
opment.  A new industrial park is  located in areas 5 and 7,
whereas area  8 contains older industrial development.
Relatively new suburban housing  is located in areas 2,  3 and
5.  Areas 4,  6 and 8 contain older housing, plus substantial
commercial development, particularly in area 6.  Two munici-
pal treatment plants are located in  the watershed, a large
regional facility in area 6, and a smaller plant in area 8.
Industrial dischargers are located in areas 5 and 8.
  Hydrologic
 Subdivisions
     1

     2

     3

     4

     5

     6

     7

     8
                          TABLE A-5

            DESCRIPTIVE DATA FOR HYDROLOGIC SUBDIVISIONS
                   IN HYPOTHETICAL STUDY AREA

                                  Densities  (#/Acre)
 Area   Popu-  Employ-  Popu-  Employ-
in Acres  lation  ment    lation   ment
3,000
4,000
3,000
5,000
4,000
4,000
5,000
5,000
33,000
9,000
32,000
18,000
55,000
16,000
36,000
15,000
40,000
221,000
0
4,000
3,000
10,000
8,000
16,000
15,000
25,000
81,000
3.0
8.0
6.0
11.0
4.0
9.0
3.0
8.0

0.0
1.0
1.0
2.0
2.0
4.0
3.0
5.0

 Percent
Imprevious
(Estimated)

   14

   27

   23

   36

   22

   39

   18

   40
 Source:  Betz Environmental Engineers,  Inc.
                             A-28

-------
RURAL LAND
           (
                                                                    COMBINED
                                                                   SEWER AREA
              \
                                                            IM
                                               WASTE TREATMENT PLANTS:
                                                       O INDUSTRIAL
                                                       • MUNICIPAL
               Him A-6 MUDDY CREEK WATERSHED (HYPOTHETICAL)
                  SOURCE: Betz Environmental Engineers Inc.
                                       A-29

-------
The planning agency has chosen 5-day BOD as the index of
organic loadings, due to the availability of BOD data for
the estuary and for treatment plant effluents.   No water
quality or streamflow data initially exist for the Muddy
Creek watershed.  Three or four persons can be made avail-
able for field sampling during storms; but only one current
meter is available for measurement of discharge.

A first step is to compute the expected BOD loadings from
the eight hydrologic subdivisions, based on the information
given in Table A-5 and the relationships presented in Figure
A-2 of this report.  The Oklahoma relationships are utilized
in this case, although the choice is unimportant in practice
since the Pennsylvania relationships are proportional.  The
resultant loading estimates are presented in Tables A-6 and
A-7.  Table A-6 is based on the standard relationships in-
volving imperviousness and employment density,  presented in
the upper portion of Figure A-2.  Table A-7 is based on the
alternative relationships shown in the lower portion of
Figure A-2, which consider age of housing and the existence
of industrial areas.  The total estimated BOD loading from
the urbanized portion of the Muddy Creek watershed is almost
exactly the same in the two cases, although some significant
differences exist for individual hydrologic subdivisions.
The discussion hereafter will refer just to Table A-7.

Top priority is assigned to measurement of pollutant loads
at point A, which subtends the entire Muddy Creek watershed
outside the combined sewer area  (see Figure A-6).  An ini-
tial sampling network is established at points A, B, C and
D, to characterize pollutant loads from the Muddy Creek
watershed as a whole, from the tributary basins of Pebble
Brook and Dead Run, and from the 30 square miles of largely
rural land subtended by point D.  Arrangements are made at
these and the other stations to record water stage as part
of sampling procedures, using either a staff gage or an
overhead reference point such as a bridge railing.

The first storm event sampled is a frontal storm involving
somewhat less than one inch of rain in two hours.  The storm
is known not to resemble critical conditions for the estu-
ary, but is favorable for research purposes because the
rainfall is uniform throughout the region and because ad-
vance warning is adequate for deployment of the field crew.
Sampling is conducted for eight hours at points B and C, and
for four additional hours at A and D.  Water samples are
taken and  stage  is recorded several times each hour.  The
                           A-30

-------
                          TABLE A-6

     ESTIMATED BOD LOADING FOR HYPOTHETICAL STUDY AREA,
          BASED ON STANDARD OKLAHOMA RELATIONSHIPS*
Hydrologic
Subdivision

    1
    2
    3
    4
    5
    6
    7
    8
              BOD Loading in Ib/Acre/Year
             Based on    Based on
             Impervi-   Employment
             ousness     Density    Average
       19
       25
       23
       29
       23
       30
       21
       30
            21
            23
            23
            25
            25
            30
            28
            33
             20
             24
             23
             27
             24
             30
             24
             32
                                    Estimated Annual
                                      BOD Loading
                                       in Pounds
      60,000
      96,000
      69,000
     135,000
      96,000
     120,000
     120,000
     160,000

     856,000
Source:  Betz Environmental Engineers, Inc.
                       TABLE A-7

           BOD LOADINGS BASED ON ALTERNATIVE
                OKLAHOMA RELATIONSHIPS*
Hydrologic
Subdivision
Number  Type*
           BOD Loading in Ib/Acre/Year
  1
  2
  3
  4
  5
  6
  7
  8
R
R
R
R
I
N
I
I
Popu-
lation

  17
  20
  22
  33
Impervi-
ousness

  17
  23
  21
  27
  28
  29
  25
  43
                         Employ-
                          ment
                    19
                    25
                    22
                    28
Average

  17
  22
  21
  30
  24
  27
  24
  35
  Annual
  Loading
in Pounds

  51,000
  88,000
  63,000
 150,000
  96,000
 108,000
 120,000
 175,000

 851,000
*  The standard relationships are shown in the upper two
   graphs of Figure A-2; the alternative relationships are
   shown in the middle and lower graphs.

** Land Use Types:  R, labor-exporting; I, labor-importing/
   industrial; N, labor-importing/non-industrial.  For the
   labor-exporting areas,  the following percentages of
   population are assumed to live in pre-1940 dwellings:
   20% for Area 1, 20% for Area 2, 50% for Area 3, and 80%
   for Area 4.

Source:  Betz Environmental Engineers, Inc.
                      A-31

-------
current meter is used to measure discharge repeatedly at
points A and B, which are adjacent.  Based on water stage
data, and the actual discharge measurements at points A and
B, the shape of the flow hydrograph at each station is
roughly determined.  This is used to form discharge-weighted
composites of the BOD samples  (i.e./ each composite sample
is assumed to represent an equal volume of water).   Roughly
five composite samples are prepared for each station:  one
or two representing rising stage, one representing peak
stage, and two representing falling stage.  The roughly 20
composite samples obtained in this fashion are analyzed for
BOD in the lab; and the concentrations are averaged for each
station.  The results are shown in the upper portion of
Table A-8.

Determination of the total volume of storm runoff from vari-
ous areas is problematic because discharge hydrographs are
available only at points A and B.  The eight-hour period of
maximum flow at point B is defined as the storm period.  The
last two hours of this period are not included for point D,
since travel time from D to A is approximately two hours.
Base flow during the storm period is not distinguished from
surface runoff.  Total discharge during the storm period
amounts to roughly 200 acre-feet at point B, and 860 acre-
feet at point A.  Runoff from hydrologic subdivisions 2
through 6 is estimated by assuming 0.02 acre-feet per acre,
as observed at point B (areas 7 and 8).  A lower value is
assumed for area 1.  Runoff from the rural area is then
obtained as a residual.  The resulting runoff volumes, shown
in Table A-8, are known to be subject to error.  This is
usually not critical in reconnaissance studies, however, as
long as total runoff from the study area is known,  and the
figures for subdivisions are reasonably consistent.

The remaining columns of Table A-8 show the estimated BOD
loading at each station during the storm period, the esti-
mated load from point sources during this period, and the
net load due to land drainage.  The net loads for the urban
portion of the Muddy Creek watershed, and for basins 1, 3, 5
and 6 taken together, are' estimated by subtraction.  The
loadings from various areas are then divided by the corres-
ponding annual loadings estimated from the Oklahoma rela-
tionships  (from Table A-7).  This is done in order to
control for general land characteristics when making in-
ternal comparisons among loadings.
                           A-32

-------
As indicated by the last column of Table A-8, the lowest BOD
load on a relative basis is yielded by areas 2 and 4, sub-
tended by point C.  The highest relative load is produced by
the area consisting of subdivisions 1, 3, 5 and 6.  With
regard to subdivision 6, one possibility is that the load-
ings from the municipal and industrial dischargers are not
represented correctly.  The volumes of municipal effluent
released during the storm period are known from treatment
plant records; but effluent strength may be a variable
factor.  Arrangements are therefore made for systematic
effluent sampling by treatment plant operators during future
storm periods.

In the next storm sampled (storm 2 in Table A-8), station D
is replaced by stations F and E.  Stations A, B and C are
retained, in order to corroborate the findings made in the
first storm.  Discharge measurements are again conducted at
stations A and B.  Discharge-weighted average BOD concen-
trations and runoff volumes are obtained in a fashion simi-
lar to that described earlier, except that somewhat dif-
ferent assumptions are employed due to different storm
characteristics.  The findings are reported in the central
portion of Table A-8.  As indicated in the right-hand
column, subdivisions 5 and 6 appear to be the high-yield
areas, relative to expectations.  (However, the loading
estimate for area 6 is not considered highly reliable be-
cause it was obtained as a difference between larger num-
bers.)  The municipal treatment plant in area 6 is also
found to contribute a larger BOD loading than previously
thought, due to relatively high wastewater volume and
inefficient treatment during the storm period.

The network of stations is changed again when sampling the
third storm.  Stations A and C are retained, due to the need
to accumulate as much data as possible for the whole basin
(point A), and the desire to use C as a "baseline" case.
Adequate stream flow rating curves have been developed for
points A and B using data from the first two storms, so that
the current meter can now be used to measure discharge at
point F.  Points G and H have been added in order to inves-
tigate a suspected source of pollutant loadings in part of
basin 6, namely, an antiquated separate sewer system which
links to the combined sewer area.

The third storm is a convective shower in which rainfall is
distributed unevenly over the region.  The estimated runoff
volumes at points C, G and H are therefore very approximate.
The data for points G and H are nevertheless valuable in
                         A-33

-------





























a
W
X
a.
u

H

lJ
(tjj
u
H
EH
H
33
EH
O
a.
CO X

fg
o;
w o

m
rt <
EH EH
ft.
d

o
t ~\
w
H
FT,

CM
O

«
i

D
w































•O
10
o -o o
4J 11 rj

O U rH
•H 11 10
4J a, 3
10 X C
c: w c
tu
tr
to
•o c
10 O-H
O -P 10
r-l H
0) Q
-P 3
G) t3 TJ
z c
•a c
10 -H 01
O O 0)
-H1 & O
u
063
ooo

CM




tN OJ
^r oo
M O
0 0







o o o o

IT! rH CTl f*

CO ** rH «H
"


o o o o
•<* •*
OO P*






•0*0)
H 1
O O 0)

O 3 0




* «
o o o o
vo O 00 O
CO tN rH tN





C
a o
O-H | ^
CO 4-> Q) 'd
id rH en tu
Q) V* \ \4 4->
cr, -P D> 10 .G
lO f^ S -C O1
H <1) O -H
<1) U C OJ 0)
> C -H -H S
< o a
u —






0 o O O
• • • •
r- en •f  rH -H
OJ O >
rH r) -H
0) T3 13
X 3
W

rH
HI
M
3

c
01 m
3 rH
Q, rH
10
CO CO 1" r-l
1 - - 3
•H r* CN P4
cn
G C
H O
rH -H
a-p
E 10
10 4-1
W tfl

Ifl
4J
10
a
< m u Q
•a
a)
s

•H
rH
01
a





               00    P-




               00    O
                    o
                    in
       p* eft
       in m
       O rH
       O O
o o
vo in
*r m
OOOOO


O3 rs| 00 CTi O
     000
     o% vo m
o o
oo in
             o m o o o
             o r-   o o
             ooooo
             o TO o ^ o
                                         o o
                                         o o
                                           OOOOO
             OOOOO
             ooinoo
             •o
             c
             10
             o.     m

             CO 00 «*• fl
•o
c
10
rH

rH
10
3


to
3
rH
ft
1
rH

•o
•o c
X- fi 10
4J 10 rH
U rH
10 rH
a-H 10
— 10 M
rl 3
U3 3 r4
rl
01 01
3 -O 3
rH G rH
a 10 a.
i i

        H
        0)
        to
        XJ
        o
        o
        EH
        UJ
               T)
                a)

                >
               •H


                (U
               Q
T3

ID

>

rl

HI

to

XI

O
                          O
                          EH
                          OJ
                                                                0)  o
                                                                u  w
     A-34

-------
revealing a significant difference in average BOD concen-
trations, which would suggest that the sewer system problem
is important.

The sampling program thus indicates that basin 5 and the
southeast portion of basin 6 are relatively high-yield
areas.  These areas receive primary attention in later
reconnaissance activities, which include direct inspection
of streams and land areas.  In addition, the industrial
discharge in basin 5 (about which little has been known
other than the information in discharge permits)  is moni-
tored directly in later storms and non-storm periods.

The data presented in Table A-8 can be used to estimate
annual pollutant loadings for the various subdivisions,
although it is understood that the resulting figures are
approximate.  Annual loadings are computed directly for
stations A and C, which have been monitored in all three
storms.  The overall discharge-weighted average BOD concen-
trations in the two cases are 6.134 mg/1 and 3.853 mg/1,
respectively.  Independent estimates are prepared of stream
discharge during all storm periods in a typical year; these
amount to 43,300 acre-feet for station A and 9,000 acre-feet
for station C.  The estimated annual BOD loadings produced
during storm periods are thus 722,000 pounds and 94,000
pounds, respectively.

The loading estimates prepared for other subdivisions per-
tain only to land drainage, not point sources.  In the
estimation process, the loading from subdivisions 2 and 4 is
used as a benchmark for extrapolating from observed data to
annual loading values.   For example, the ratio of the land
drainage loading from subdivision 5 to the loading from sub-
divisions 2 and 4 was:   4,000/3,800 = 1.05 in storm 2, and
1,330/1,360 = 0.98 in storm 3.  The average of these fig-
ures, 1.02, is multiplied by the annual load of 94,000
pounds for subdivisions 2 and 4 to yield a value of 96,000
pounds for subdivision 5.  Similar computations are carried
out for other areas.  In the case of subdivisions 1 and 3
(which contain low-density residential development similar
to area 2) no direct data are available from the monitoring
program.  Thus, the ratio used for extrapolation purposes is
based on the loading figures presented in Table A-7.  The
results of these computations are given in the first column
of Table A-9.
                         A-35

-------
                       TABLE A-9

           TABULATION OF ANNUAL BOD LOADINGS
            DURING STORM PERIODS, IN POUNDS
                     Estimated    "Baseline"
Land Drainage         Annual        Loading       Loading
  Loadings            Loading    (Theoretical)   Objective*

Subdivisions 1 & 3     45,000       45,000         36,000

Subdivisions 2 & 4     94,000       94,000         75,000

Subdivision 5          96,000       38,000         45,000

Subdivision 6         120,000       43,000         54,000

Subdivisions 7 & 8    177,000      117,000        109,000

Total, Land Drainage  532,000      337,000        319,000

Rural land and
Point Sources         190,000

     Total            722,000
* The loading objective for each area is equal to the actual
  loading, minus 75% of the difference between actual and
  baseline loadings, minus 20% of the baseline loadings
  (see text).
Some insight into the loading reductions achievable by var-
ious types of controls can be gained by computing "baseline"
loading values, again utilizing the loading from subdivi-
sions 2 and 4 as a reference point.  As indicated earlier,
subdivisions 2 and 4 are characterized by relatively clean
surface conditions, no point sources, and no known discrete
sources of stormwater pollution.  The loading from this
area thus provides a rough indication of the pollutant-
generation levels which could possibly be achieved in other
areas through general cleanup measures and site-specific
controls.  The estimated BOD yield from subdivisions 2 and
                         A-36

-------
4 is first divided by the loading predicted in Table A-7
(238,000 pounds, based on the Oklahoma relationships).  The
resulting ratio is 0.395, indicating that annual loadings in
the study area run about 40% of the levels predicted by the
Oklahoma relationships.  This ratio is then applied to the
other annual loading figures in Table A-7 to yield the
"baseline" estimates shown in the second column of Table
A-9.  These are the loadings which theoretically would be
observed  (without point sources) if all land conditions
resembled subdivisions 2 and 4, given the existing dif-
ferences in factors such as population, employment, and im-
perviousness.

The deviation between actual and baseline conditions tends
to be a good indicator of the relative importance of site-
specific pollutant sources in an area.  Control of these
sources can often be achieved at low public cost once their
presence is established.  In the present case it is assumed
that the planning agency places a high priority upon detec-
tion and control of high-yield sources.  A first-cut esti-
mate of the effectiveness of controls is obtained by assum-
ing that site-specific corrective measures can potentially
reduce the loadings from subdivisions 5 through 8 by amounts
equal to 75% of the difference between present and baseline
loadings.  In addition, it is anticipated that general im-
provement in land management practices such as rubbish re-
moval and street sweeping will reduce loadings from all
areas by amounts equal to 20% of baseline.  Given these
assumptions, the loading objectives shown in the right-hand
column of Table A-9 are established.

If the loading objectives were met, the total BOD yield of
Muddy Creek due to urban land drainage would decline from
532,000 pounds per year to 319,000 pounds per year, a reduc-
tion of 40%.  The bulk of the reduction (about 150,000
pounds) would be due to the implementation of site-specific
controls.  These hypothetical figures would not be a suf-
ficient basis for determining whether urban runoff control,
along with point source abatement, would produce satis-
factory conditions in the estuary.  However, such computa-
tions provide helpful insights into the stormwater control
problem.
                         A-37

-------
Water Quality Aspects of Nonpoint Sources

The remaining portion of the appendix was assembled to help
the reader understand some important aspects of water quali-
ty response to nonpoint source pollutants.  It does not
detail all, or even most, of the considerations which must
go into analyzing and monitoring water quality.  Several
subjects are discussed; some rather well known but worthy of
repeating, and others which can often be overlooked or
underemphasized.  The discussion assumes the reader will
have a relatively sound understanding of steady-state water
quality problems.

The methodologies for nonpoint analysis presented in the
body of the report stressed quantitative analysis of exist-
ing water quality data, collection of additional water
quality data through a well-structured sampling program, and
analysis techniques such as mass balances, nomagraph method-
ologies, etc.  Computer modeling approaches were deempha-
sized.  It is felt that this overall approach is appropriate
for 208 water quality management studies which have a limit-
ed time and budget for ranking nonpoint problems and recom-
mending controls.

Most likely, the important outputs from the nonpoint element
of 208 programs following the proposed approach will be:

     1.   Determine what kinds of nonpoint problems exist,
          their extent and severity

     2.   Rank nonpoint problems based upon water quality
          impairment and probability control

     3.   Recommend general "Best Management Practices" for
          selected sources

     4.   Present preliminary site-specific recommendations
          on significant nonpoint sources

     5.   Develop a long-term program for further study of
          unresolved nonpoint problems along with a specific
          monitoring program to aid future analysis and help
          gage pollution control progress
                         A-38

-------
The recommended approach relies heavily on a thorough under-
standing of water quality, especially the impact of nonpoint
sources on water quality.  Unlike many approaches currently
in use, the proposed methodology does not concentrate on
loads delivered to receiving waters, but instead focuses on
the reaction of the receiving water to nonpoint loads.  If a
structured water quality monitoring and analysis program in-
dicates no significant water quality problems due to non-
point sources, then it does not appear appropriate to commit
resources to developing estimates of Ibs per day of pol-
lutant from various land uses and watersheds.  Likewise,
computer modeling of storm water would appear unwarranted.

Important Considerations in Water Quality Analysis

This section attempts to provide an overview of the water
quality impact of nonpoint source pollutants and describe
several selected phenomena which occur after nonpoint pollu-
tants are discharged to the receiving water.  The section is
organized as follows:

     Time Frame for Analyzing Water Quality Impacts

     Decomposition and Reaeration at High Flow

     Influence of Benthic Deposits on Water Quality

     Types of Water Bodies and Significance to Nonpoint
     Sources

     Some Comments on Probable Control Recommendations
     Time Frame for Analyzing Water Quality Impacts:  The
appropriate time frame for analyzing nonpoint water quality
impacts is the "worst case condition."  This condition will
vary from watershed to watershed and also will depend on the
pollutant under study.  Substantial pollutant loads are
washed into the receiving water during a storm and this may
cause transient water quality problems.  However, many pol-
lutants cause long-term problems; in this case, worst case
conditions would be defined as the sequence of activities
(e.g., storms) which resulted in the long-term water quality
problem.
                         A-39

-------
It is suggested that investigation of the persistence and
time frame associated with some storm-related pollutants may
show that single storm analysis can be abandoned in favor of
seasonal or annual runoff loads (generally a much simpler
approach than storm-by-storm analysis).   Rather than proceed
directly to sophisticated modeling approaches, consideration
of existing data and the persistence of pollutants may allow
cost-effective short-cuts.

1.   Pollutant Persistence and Impact Distance

     Figure A-7 graphically presents the relative persis-
     tence of various stormwater constituents.  Such con-
     stituents as floating solids, bacteria and viruses,
     have a relatively short persistence, ranging from hours
     to days.  Those constituents which directly affect
     dissolved oxygen have a persistence span ranging from
     hours to months.  Other constituents (e.g., suspended
     solids, nutrients, dissolved solids and metals) can
     remain in the aqueous system for relatively long peri-
     ods of time (e.g., for years).  Many of these con-
     stituents can settle out and accumulate in the benthic
     layers.  These materials can be continually released or
     remain in the sediments until they become resuspended
     by turbulent conditions during high flow periods.
     Metals, pesticides and certain suspended solids can
     accumulate in the systems of aquatic plants and animals
     and have a cumulative, long-range toxic effect on
     aquatic biota.

     The area affected by various stormwater-related con-
     stituents varies depending on such factors as the con-
     stituent's lifespan, stream's transport capability, and
     various other factors relating to stream hydraulics.
     Because of this, various areas of the stream network
     can be affected in different ways by a single storm.
     Figure A-8 schematically presents the relative distance
     affected by various stormwater constituents.  Those
     constituents with relatively short persistence, such as
     floatables and bacteria, affect a relatively small
     area, ranging from extremely local to within a few
     miles downstream of the discharge point.  The affected
     downstream area depends on stream transport factors.
     Impoundments and low stream velocities tend to impede
                           A-40

-------
        10
        SECONDS

        106
        10'
         10
         _L
         FLOATABLES
           BACTERIAL AND VIRUS
                        DISSOLVED OXYGEN
                                        SUSPENDED SOLIDS
                                                    NUTRIENTS
                                           I
                                                             DISSOLVED SOLIDS
                                                                 HETALS--
                                               PERSISTENT
                                               ORGAN ICS
                                         I
HOUR
DAY
MONTH
YEAR
                                                                  DECADE
                              WEEK
                  SEASON
             Figure A-7 STORMWATER CONSTITUENTS AND THEIR PERSISTENCE
SOURCE:  Eugene Driscoll,  "Instream Impacts  of Urban  Runoff," a  paper  delivered
         at the Urban Stormwater Management  Seminar,  Atlanta, Georgia,  November
         **-6, 1975
                                      A-41

-------
       HYDRAULIC  DESIGN
                 FLOATABLES
                          BACTERIA
                                SOLIDS
                                 DISSOLVED OXYGEN



fGEN


JTRIENTS


METALS/ORGAN ICS



T.D.S.
     10
       -2
10
  -1
                                10
                           10
10
               LOCAL
                                                REGION
                                                               BASIN
     Figure A-8 STORMWATER CONSTITUENTS AND THEIR EFFECTIVE DISTANCE
SOURCE:  Eugene Driscoll,  "Instream Impacts  of  Urban  Runoff," a paper delivered
         at the Urban Stormwater  Management  Seminar,  Atlanta, Georgia, November
         <»-6,  1975
                                  A-42

-------
transport and thereby localize the effect of most
constituents.  Constituents with longer lifespans, such
as nutrients, metals and organics, can eventually
affect the entire downstream portion of the stream
network.

Significance of Nonpoint Assessment and Water Quality
Criteria

Table A-10 provides an assessment of stormwater-related
constituents.  Each constituent is described by its
particular persistence, area affected, scope and sig-
nificance.  Examination of the table indicates that
annual loading rates may be acceptable in dealing with
several storm-related pollutants.  Other constituents
should be dealt with on a storm-by-storm basis if a
transient problem is caused by the pollutant of inter-
est.  Investigation of existing water quality data, if
extensive enough, will often indicate that no transient
problems exist.  Analysis of biologic data is often
helpful in this regard.  BOD is a parameter that re-
ceives significant attention and, because it has a
short persistence, an attempt is often made to model
the transient BOD/DO event.  Modeling may be appropri-
ate in dense urban areas, combined sewered watersheds,
etc.; it may not be cost-effective in suburban areas
with fast moving streams.  This consideration is dis-
cussed further in the next section.  The persistence
and impact distance of nonpoint pollutants also affect
the selection of applicable water quality criteria.
Generally, existing criteria are based primarily on
long-term problems likely to occur during summer low
flow periods (when point sources are the dominant
load).  These criteria may or may not be applicable to
nonpoint sources.

Heavy runoff can produce two types of water quality
conditions:

a.   Pollutant concentration in the stream can be
     diluted due to large volumes of relatively clean
     runoff.
                     A-43

-------
navigation ,
tics
"sS
a 4>

0 B
II

Q) M
0i jj
.§•§
a
3
*
N
10
JS
5
1

rH
10
•H
4>
B
O
4J
&



B
O
•H
4J
41
rH
a
41
•o

8
and aesthetii
a
o
•H
XI
8
rH
5
C

•H
^1
41
01
•o



o
^J
id
u
•H
t
O

^J
41
1
n
h
S
S
u
•H
rH
3
a
a
o
•H
XI
0

O H
•H XI
X 3
SH
a


IT
iH
0
•rt
X
O

41
rH
•H
n
a
a
                          6      i      6






o
rH
1
i
E<
M
E-i
01
z
8
Q
W
EJ
S
a
8
CO
0
iH
^
o.
o
CO
1
t)
•H
> -H
•H C
•O 01
B >
•H 41

O
4>
a
rH
3
•0
•H
•H C

•H Q)

8
a
rH
id
3 —

-rt —
'O 01
•H 01

en
B
•H
•O
id
o
rH

rH
I

id

en
B
•H
•O
<0

1
B
S

Oi
B
•H
•0
o
H

rH
id
3

jjj

O>
B
•H
•O
id
0
rH

rH
B
§

fH
o
01
ca

co

S
B
•H
HI


41 -C
XI 10 4>
Id 41 U

S iw
CU H


ens
B id
*>-H <»
01 > M
id o -t>
fc. X 01
IB
XI
1
to



cnE
B IB
» -H 41
0 > H
rH O -P
co £ ca
rH
rH
id
U
O
rH
B
•H
n
id
XI
i
n




rH
IB
O
O
rH
B
•H
n
IB
XI
i
n




rH
id
§
rH
B
•H
a
5

•8
n




rH
id
O
3
•S
•H
J
1
B

n
JS
41
•O
^
1
B
m
id
XI
•§
•H

B
•H
1

B
CQ
id
XI
1
n
9
•H

1
B

a
a)
A

fi
n
id
XI
i
a

g
B
41

U
•H
U)
U
41
0.
















n
41
B
id

>H 3
OrH
rH
O
o.

41
U

1
at
3



rH
id

b
41
41
M
41

id 4>

4)

H id
O M
i! id
01 P.
s

J\
B
•H

10
O
rH
Cu
m
5
B


1
CO
Q
•a

CO
41
CO
•3
^
•H
^»
JJ

ffj
•H
r4
01
4J
U
Id
m
CO
5
B


1
CQ
•3















Q
§

CO
id
41

1
CO
id
•O


o
•o
•H
rH
O
01
41
rH
f^
id
4)
rH
4J
JJ
01
01
m
id
01

i
n
5
B
g









a
41
C
41
-rl
^j
41
3
m
u
10
01

1
n
5
B





n
u
-H
B


O
V.
n
rH
10
JJ
S
n
hi
id
41

i
a
5
B
g

"o
CO

•o
0)

rH
O
n
n
•rt
a

rH
10

e




















in
•o
•H
O
                                                                                              -
                                                                                            O    «1  O T3  41
                                                                                            g o c  n 4)-a
                                                                                            B -4J »  Q.CO
                                                                                           •H    o  a s  o
                                                                                              MT3  Id Id *>
                                                                                            on      u
                                                                                           4J 0) rH  +J    4)
                                                                                               Id-H
                                                                                            0)    I  01    M
                                                                                           •H  i       ra  a
                                                                                            O    OlrH i  O
                                                                                            1-1 C -O  IB 01  W
                                                                                              •H .H  3 rH  (X
                                                                                            i co 3  -a .a  a
                                                                                              n i  -H o  a
                                                                                           rH 0 6  > fc
                                                                                            IB  i  —i  -H a o>
                                                                                            o xi n  Q    M
                                                                                            O 3 id  C
-------
     b.    Pollutant concentration can be increased by highly
          contaminated runoff.

     For the long-duration pollutants shown in Figure A-7
     (heavy metals, nutrients, etc.) either condition may
     produce problems.  The concern should not be so much
     with the peak loadings which occur with heavy runoff,
     but rather with the long-term, average loads.  For
     these types of pollutants, steady-state water quality
     criteria may be appropriate (when applied to average
     conditions rather than peak storm conditions).

     If the first condition is applied to the short-term
     pollutants listed in Figure A-7 (BOD and bacteria) then
     runoff is unlikely to cause a problem because these
     pollutants will decay and be assimilated in the stream.
     If the short-term pollutant concentration increases
     (Condition 2) a transient problem may occur.*

     If, for example, a dissolved oxygen sag occurs due to
     BOD decomposition, a decision must be made on whether
     this sag is harmful and nonpoint controls are neces-
     sary.  Comparison of the low DO with steady-state DO
     criteria is not appropriate because the criteria  (say
     4.0 mg/1)  is generally based upon aquatic life reaction
     to several consecutive days of low DO levels.  Post-
     storm DO levels may drop below 4.0 mg/1 for several
     hours and then recover to 5-6 mg/1.  The decision on
     whether a problem exists should be based on the impact
     of the short-term sag on aquatic life.  Biological
     assessment can aid in this determination.  Also, re-
     search, as depicted in Figure A-9, may lend itself to
     assisting in establishing water quality criteria appli-
     cable to short-term storms.  The figure shows the mor-
     tality of trout as a function of short-duration DO
     levels.  The figure is an example of how bioassay data
     based on laboratory tests may be presented; it does not
* See following section for detailed discussion of BOD/DO
  relationship.
                         A-45

-------
  show antagonistic effects of other pollutants.  Never-
  theless,  information similar to that  shown in the figure
  could be  applied to establish short-term DO conditions as
  follows:*
  a.
Establish percent mortality acceptable;  this would
have to be  linked to storm frequencies.

Determine DO/time relationship of worst  storm
(i.e., runoff)  condition occurring once  a year.
This can be  approximated by examining  existing data
or receiving water modeling.  For example,  assume
that this worst case condition results in a minimum
DO of 1.0 mg/1  for 50 minutes.

Referral to  Figure A-9 indicates that  a  value of
1.0 mg/1 for only 30 minutes causes  80%  mortality.
         <
         H
         
-------
     Decomposition and Reaeration at High Flow:  Depending
on the physical characteristics of the receiving stream,
climatic conditions, and the storm-related BOD load, the
stream's dissolved oxygen levels may increase or decrease.
The following paragraphs indicate that in relatively small,
fast moving streams, BOD from storm runoff probably is not a
problem.  If the BOD is not decomposed by the time it
reaches slower moving downstream water bodies  (e.g., estu-
aries, impoundments), DO depletion problems may occur, de-
pending on the assimilative capacity of the downstream body.

Both decomposition and reaeration rates are affected by a
number of variables.  The following paragraphs list a number
of these factors and briefly describe the general impact of
each factor on decomposition and reaeration rates.  Special
emphasis will be placed on those factors directly related to
storm events.

The biological decomposition of organic matter is commonly
conceptualized by the following equation:
where:
     Lt = BOD at time t

     L0 = initial (ultimate) BOD

     Ki = overall deoxygenation rate (day  )

     t  = time since discharge (days)
The amount of decomposable matter in the stream is usually
measured in terms of biochemical oxygen demand (BOD)  which
is defined as the amount of dissolved oxygen consumed in the
bacterial oxidation of decomposable matter.

Reaeration can be defined as the replenishment of dissolved
oxygen.  This is basically a chemical and physical process,
although some biological processes may come into play.  Re-
aeration can be considered as a function of molecular diffu-
sion and the following stream characteristics:  depth, velo-
city, slope and channel irregularity.  The reaeration rate
is used to calculate the stream DO deficit which is commonly
conceptualized by the following equation:
                         A-47

-------
            -K2t
     D  = D e
      t    o
where:

     Dt = DO deficit at time t

     D0 = initial DO deficit

     K2 = reaeration rate  (day"1)

     t  = time  (days)
The reaeration rate  (K2) is considered a function of stream
geometry.


          (C,) (u) 2
      2    (H)C3


where:

     K«       = reaeration rate

     u        = stream velocity

     H        = stream depth  (ft)

     C-i,Co/Co = empirical constraints
While the decomposition is basically the biological process,
reaeration can be termed a physical and chemical process.

Table A-11 lists general factors which affect the decomposi-
tion (K^) and reaeration (K2) rates and indicates the gen-
eral impact of each parameter on these rates.  Both temper-
ature and turbulence effect decomposition and reaeration.
Flow has a negative impact on reaeration and can increase or
decrease the decomposition rate depending on whether the
runoff concentration is higher or lower than the in-stream
concentration.  The table also indicates that the in-stream
BOD concentration directly affects the decomposition rate.
                            A-48

-------
The ultimate allowable BOD loading generally increases as
flow increases or as temperature decreases.  This is under-
standable since an increase in flow will generally improve a
stream's assimilative capacity due to increased dilution
while a decrease in temperature will lower the decomposition
rate, and therefore, allow larger BOD loads without deplet-
ing additional DO.  Figure A-10 graphically presents the
relationship between the reaeration rate (1^) and flow.  A
number of researchers have developed specific reaeration
equations based on observations in various types of streams.
These various equations have been plotted against flow to
reflect the wide range of reaeration rates that have been
observed in different types of streams for different flow
periods.  It should be noted that most of the reaeration
rates are observed to decrease as flow increases.
                         TABLE A-11

             EFFECT ON STREAM DECOMPOSITION AND
       REAERATION RATES OF INCREASING VARIOUS FACTORS
                          Effect on           Effect on
                        Decomposition        Reaeration
Factor Increased            Rate	           Rate

Temperature              Increase            Decrease

Turbulence               Increase            Increase

Flow                     Decrease*           Decrease

BOD Concentration        Increase            No direct effect

Dissolved Oxygen         Increase            Decrease
Concentration


* Assuming dilution of in-stream BOD concentration

Source:  Betz Environmental Engineers,  Inc.
                            A-49

-------
    1.00

   0.90

   0.80

   0.70

_  0.60
'>»
2  0.50
 o
it:
   0.40

   0.30

   0.20

   0.10
T      I      I      I      I      I      I      I
                  -6AMESON
                       ''CONNOR 8 DOBBINS
                        OWENS, EDWARDS  a GIBBS
                     -LANGBEIN &  DURHAM
  -CHURCHILL, ELMORE a  BUCKINGHAM
              I
       I
I
I
I
I
I
      0      100   200   300   400   500   600   700   800   900  1000

                                  FLOW (cfs)


     Figure A-10 KA vs. FLOW AS CALCULATED BY  VARIOUS PREDICTION EQUATIONS
      Source:   Whipple,  et al,  1974
                              A-50

-------
Table A-12 presents various factors directly attributable to
storms and their impact on decomposition rate, reaeration
rate, and the likely overall impact on the DO concentration
in slow and fast moving streams.  The overall impact of a
storm on the dissolved oxygen concentration will vary de-
pending on the physical characteristics of the stream.

For streams exhibiting moderate to fast velocities, the DO
profile during a storm would reflect an initial upward surge
in the dissolved oxygen profile due to the highly oxygenated
runoff entering the system.  This initial pulse is generally
followed by a gradual return to the pre-storm DO level.  In
moderate to fast moving streams, most of the additional BOD
entering the stream is flushed from the system before it has
a chance to exert an oxygen demand on the stream.  In slower
moving streams, the DO profile would be similar, except that
the return-to-normal stage would also include a possible
dissolved oxygen sag below the pre-storm level due to the
exertion of material that had not been flushed from the
system.

An illustration of this dissolved oxygen sag is provided in
Figure A-ll which plots the dissolved oxygen concentration
and the corresponding stream flow observed during three
typical storms on the Passaic River at Little Falls, New
Jersey.  All three storms indicate an initial surge of dis-
solved oxygen followed by a gradual sag.  The dissolved
oxygen usually continues to decline below the level which
prevailed at the beginning of the storm, reaching a minimum
value 4-9 days after the hydrograph peak.  The DO concentra-
tion then recovers while the hydrograph is still falling.
This general path was observed for 80% of the recorded
storms at Little Falls occurring between May and October
1971 to 1973.  The Passaic River is a lethargic stream
containing numerous benthic deposits.  One explanation of
the dissolved oxygen sag is that oxygen demanding material
is scoured from these benthic deposits and resuspended
during the course of the storm, and exerts a DO demand
during the post-storm period as stream velocities return to
normal.

     Influence of Benthic Deposits on Water Quality;  The
above example indicates that benthic deposits can have sig-
nificant impacts on a stream's dissolved oxygen levels.
Benthic deposits can also be sources of nutrients, heavy
metals and other deleterious parameters.  In the above case,
it was indicated that the DO depletion was from the resus-
pension of deposits by high flows following a storm.  Ben-
thic deposits may also cause oxygen depletion during low
                           A-51

-------













z
H

O

a




4-1
O
10
i-
H
1-4.
1-1
Ifl
M
O
^
O






C
o
-H
4-1
«
c
C 01
o u
c
o
u

s


CT
c
•H
4J
10
Ifl
fa


CT
C
•H
^
Q
£
§
rH
CO

CN
m

EH
   O
   CO
   CO
   H
2 Q
O _
K

CO

2
     CO
°§
CQ H
U <
   U
W
   2
   O
   CO
   o
   8
                       C
M
U
C
•H





0)
CO
Ifl
0)
1-1
U
0)
•a

0)
ca
a
01
u
01
•a

01
to
(0
0)
H
0
c
•H






a
o
CQ
«M
IM
O
C
3
«
















































Q
o
C CQ
ifl
51
0)
M M
01 -P
£ CO

-H C
J3-H








a>
CO
10
01
M
U
e
•H





0)
CO
Ifl
<0

O
0)
•a

0)
to
fd
0)
u
c
•H

0)
Ifl
10
0)
M
O
C
•H









0)
O
C
01
1-1
3
•2
3
EH
Q)
4J
10
-H
•O
01

•H

O
a





0)
rH
X)
-H
CO
CO
O
a

u
01

-H
13

O
C

0)
to
id
0)
M
u
c
•H











cr
c
•H
M
3
O
O
CO




4J
O
Ifl
t
•H






0)
to
Ifl
0)
M
O
01
;d



4J
o
«
O4

•H





















\









01
ca
10
01
u
c
•H
^
a
M
o
04
e
0)
4-1







0)
rH
XI
CO
CO
O
o.

0)
H
XI
-H
to
to
O
O4









*
o
Q

M-t
*W
0
3
«
























0)
CO
Ifl
0)
u
0>
•o

0)
ca
10
0)
M
u
c
•H



















0)
4J
Ifl
•H
•a 4J
0) U
i io
It-
•H
o
c




01
0) «0
rH Ifl
XI 0)

ca u
ta 01
O TJ
04
4J
u
01 4J
tl U
•H ifl
•a 04
6
O-H
C!
01
a) ca
r-t 10
X) 0)
•H H
ca u
ca a
O-H
a






to
-H
01
4J
CJ
10
CQ

IM
M-i
g
3

01
4J
(0
•H
•a -P
Q) O
E (ti
E QJ
•H e
•H
O
c




0)
0) ca
H 10
n a)
•H M
CO U
CO 01

§4
4J
U
01 4J
H U
•H Ifl
rO O4
^
O-H
d
o
c
•H

r-l
ifl
0
o





ca
4J
•H
m
•a o
01 O4
4J 01
10 T3
r-l
0) U
M-H


Ui C
0 01
•P XI
CO
                                                                                            o
                                                                                           •H
                                                                                           •P
                                                                                            10
                                                                                            10
                                                                                            8
                                                                                                 g




                                                                                                 o


                                                                                                 rl

                                                                                                  *.
                                                                                                 >1
                                                                                                 H
                                                                                                 rH
                                                                                                 Ifl
                                                                                                 M
                                                                                                 0)


                                                                                                 I
                                            A-52

-------
     6O-
  ~ 50-
   a
   a
  40-

  S-O-

 JOOO-

1 2000-

 woo-

                               PASSAIC RIVER AT  LITTLE FALLS
                               STORM OF:  8/1/73  -f 8/14/73
     ,  OItJ45S7«»«flWT»14
                                PASSAIC  RIVER AT LITTLE  FALLS
                                STORM OF:   7/29/71 - 8/12/71
                               "V
      *
-------
flow, steady-state conditions by releasing organic nitrogen
and ammonia from the benthic layer, which then undergoes
decomposition in the stream.  Table A-13 presents typical
oxygen uptake rates of sediment deposits.

Ogumrombi and Dobbins  (1970), showed that two major proces-
ses exert oxygen demand on the water:

     1.   Addition of BOD from benthic deposits.  The rate
          of this addition is designated as La  (mg/l/day).

     2.   The removal of DO to satisfy the BOD of organic
          material within the top aerobic layer.  The net
          rate of removal is designated as DJ-,  (mg/l/day) .

The authors presented data which indicated that both La and
DJ.J decrease with time.  This is depicted in Figure A-12,
which shows BOD and the oxygenation rate of the supernatent
effluent stream.
                         TABLE A-13

      AVERAGE VALUES OF OXYGEN UPTAKE OF RIVER BOTTOMS
Bottom Type and Location

Sphaerotilus -  (10 gm dry wt/m^)
Municipal sewage sludge-outfall
  vicinity
Municipal sewage sludge - "Aged"
  downstream of outfall
Cellulosic fiber sludge*
Estuarine mud
Sandy bottom
Mineral soils
Uptake (gms 02/m  - day)
	@ 20°C	
                 Approx.
  Range          Average
   2-10.0

   1-2
   4-10
   1-2
 0.2-1.0
0.05-0.1
1.5
7
1.5
0.5
0.7
* Calculated from reported uptake values of 2-5 and 3.5
  gms/m2/day at
Source:  Thomann, R. J., "Systems Analysis and Water Quality
         Management," McGraw-Hill, 1972.
                         A-54

-------
Review of Ogumrombi and Dobbins data demonstrates that
sludge depth has a significant impact on both parameters,
whereas retention time does not.  The effect of depth can be
seen from Figure A-13, which shows a mass curve of total
oxygen consumed.  The total oxygen is the sum of the oxygen
demand by the benthic deposits plus the oxygen consumed
through decomposition of the BOD added to the supernatent
water.

Let us use Figure A-13 in a hypothetical example to demon-
strate the significant impacts of controlling the oxygen
demand of benthic sources.  Suppose that we have a stream in
which benthic demand is a significant component of the total
oxygen demand and control of benthic sources is being in-
vestigated.  Let us further assume that the benthic problem
is a long-term one and that the 36-day values presented in
the figure are the parameters of interest.  Our existing
sludge depth is 7.62 centimeters and exerts the total oxygen
demand of 27 milligrams per square centimeter.  Computations
indicate that we must reduce the oxygen demand of the ben-
thic layer to 16 milligrams per square centimeter.  The
figure shows that in order to cut the oxygen demand by a
factor of less than half, the sludge depth must be cut by a
factor of 3 (down to 2.54 centimeters).

Other conclusions pertinent to the study of benthic demands
are:

     1.   On the average, La appears to be about 28% of D^
          in terms of mg/l/day.

     2.   The value of La and DJ-J for a fresh sludge deposit
          which is not continuously being replenished are
          gradually reduced with time.

     3.   Both La and DJ-, increase with increase in depth of
          sludge deposits; however, they do not vary in
          direct proportion to the depth of the deposit.
          The values of these parameters per unit depth de-
          crease as the depth of the deposit increases.

     4.   When the environment in the supernatent water is
          aerobic, La and D]-> are independent of the concen-
          tration of DO in the supernatent water;  however,
          in an anaerobic environment, the value of DJ-, is
                          A-55

-------
   3.01
 e
 X
 8
 • to
   0.0
        I   I   I   I   I   I   I   1   1    I   I   I
                                    ~   I
                        LIQUID

                  6) I-MT JO* C 100
                  Qp) U.IIMATC lire BOO
                   X CAICUI.ATIO FROM MCASURED 5-DAT BOD
                   b CAICUIATCD  FROM SMOOTH CUFVf OF f-DAV BOO
                   O MtAWIICD J-DAY BOO
                                   10  II  12  13  U
                         DAYS
 Figure A-12    BOD AND DEOXYGENATIONJATE CONSTAJH
            OF EFFLUENT STREAM FLOWING OVER  SLUDGE
            AND  BED (7.62  CM SLUDGE DEPTH )
Source:   Ogurombi and Dobbins, 1970
   31.0
   36.0
   3 CO
 „ "•«
 5 30.0
 £ 21.0
 51 20.0
 6 n.o
 „  '••»
 I H.O
 u
 ^ 12.0
 J 10.0
   ».[)
  3
   t.o
   2.0
\   \  I   1  I   I   I  I   T
                          I   T  I   1  1   I  I   I
          I   II	I	I  I   I  I   I   I  I   I  I   I  I   I   I
               *  10  I?  I* 16  It  20  22  24 26  2t  30  32  M 3ft
 Figure A- 13  MASS CURVES OF TOTAL OXYGEN CONSUMED,
            Oc,  BY BFN1HAL DEPOSITS
   o REACTOR J    A REACTOR II SLUDGE DEPTH  7.62  CM
   •REACTOR III  v REACTOR IV, SLUDGE DEPTH 2.54 CM
Source:   Ogurombi and Dobbins, 1970
                       A-56

-------
          limited by the rate at which the DO is applied to
          the supernatent water, while the values of La are
          relatively unaffected.

A later article  (Fillos and Molof, 1972) supported most of
the findings of Ogumrombi and Dobbins.  Some of their con-
clusions were:

     1.   A critical sludge depth of 3-4 inches exists; at
          depths greater than this, oxygen uptake rate is
          independent of depth.

     2.   BOD, PO^ and NH3 are released more rapidly as
          supernatent DO drops below 2-1.5 mg/1.*

     3.   The conclusion on BOD differs from the earlier
          study.  The more recent study concluded that al-
          though D]-, was generally dominant, La became a
          major factor affecting the oxygen economy of the
          stream when DO was greater than 1.5 mg/1.

Fillos and Swanson (1975) studied the release rate of nu-
trients from river and lake sediments.  The authors indicate
that release of nutrients, such as ammonia and phosphorus,
may be sufficient to maintain the eutrophic state of waters
long after external sources have been eliminated.

Benthal deposits were collected and analyzed from Muddy
River and Lake Warner, both in Massachussetts.  Phosphate
and iron releases were found to be heavily dependent on the
presence of a thin aerobic layer on the benthic blanket.
Anaerobic conditions resulted in a sudden increase in phos-
phorus and iron releases.  The orthophosphate release rate
from Muddy River sediments averaged 9.6 mg/day/sq meter (_as
P)  under aerobic conditions.  Lake Warner demonstrated the
following orthophosphate release rates:

     Aerobic (avg) 1/2 mg/day/sq meter

     Anaerobic (max)  26 mg/day/sq meter
* This may be very important in nutrient analysis of im-
  poundments where DO at bottom may be close to zero.
  Another ramification is that lower DO (below 2 mg/1)
  results in more release of BOD and NH^,  which further
  exacerbates the DO situation.


                            A-57

-------
Ammonia levels were not found to vary with aerobic/anaerobic
conditions.

The following release rates were reported for ammonia nitro-
gen (as N):

     Muddy River    15 mg/hr/sq meter

     Lake Warner     5 mg/hr/sq meter

It is clear from this study that short-duration intermittent
anaerobic conditions in the immediate overlying water are
capable of causing dramatic increases in the release rates
of nutrients from sediments.  Such anaerobic conditions may
be localized and may result from the oxygen demand of the
sediments themselves.  Therefore, in any lake management
procedure, the sediments must be treated as intermittent
sources of nutrients and as a continuous sink for oxygen.

     Types of Water Bodies and their Significance;  Pollu-
tant effects on water chemistry and aquatic ecology will
vary significantly, depending on the type of water body the
pollutant is discharged into.  The three water bodies dis-
cussed below--streams, lakes, impoundments--each have hy-
draulic, ecological and physical differences which affect
the fate of pollutants.  The stream discussion which follows
focuses on free-flowing streams rather than estuaries.
Estuaries, being influenced by tidal action, may have pol-
lutant transformation taking place which have characteris-
tics similar to streams and impoundments and unique to estu-
aries.

This discussion will deal primarily with the mechanisms of
pollutant transport and transformation of sediment and
nutrients.  Discussion of these pollutants will indicate the
kinds of phenomena that occur when other types of pollutants
are discharged to these waters.

1.   Streams

     The fate of the sediments entering cannot be determined
     a priori without knowing the characteristics of the
     basin.  Slope, water velocity, particle type and size
     all play an important role in sediment transport.  At
     best, a few generalities can be made.
                          A-58

-------
     a.    As velocity increases,  the distance of transport
          increases

     b.    Larger and more dense particles settle out fdrst

     c.    Sedimentation occurs in pool areas

     d.    Turbulence will act to  maintain particles in sus-
          pension*

     The interaction between water velocity and sediment
     transport is a complex relationship.  In general, as
     the velocity increases the rate of settling decreases;
     simultaneously, bank scour may also increase,  causing
     an increase in the total solids being transported in
     the stream.  According to Leopold (1968) a stream 2 ft.
     deep and 11 ft. wide carrying 55 cfs at bankfull stage
     would have to increase to 3  ft. by 20 ft. to accommo-
     date a 2.7 times increase in maximum flow.  An increase
     of this magnitude could occur as a result of develop-
     ment.  These figures indicate that even if erosion were
     controlled during development, impervious surfaces
     could cause increases in flow that would result in
     higher sediment loadings, at least temporarily.
     Sedimentation problems could also occur as a result of
     shifting substrates and thereby cause a loss of certain
     aquatic species.

     An example of the difficulty of relating suspended
     solids data to sedimentation is provided by Hoak
     (1959).   At Braddock, PA. the mean suspended solids
     load in the Monongahela River is 1,924 tons/day; the
     volume about 345 acre-ft/mile.  If the sediment load
     settled and stayed at this point the channel would be
     filled in in a little less than one year (Hoak, 1959).
     This example indicates that  sedimentation occurs, but
     constant shifting of this material also occurs.
* There is some evidence to suggest turbulence may in some
  cases increase agglutination of particules,  increasing
  settling capacity.   Turbulence can also result in sus-
  pended matter becoming dissolved.  See Hoak, 1959.
                          A-59

-------
     A more general idea of where sedimentation problems
     will occur in a stream can probably be determined from
     information on soil types and by locating pool areas
     where water velocities decrease (the latter from on-
     site observation and topography maps).

     Much of the transport of nutrients in streams is close-
     ly associated sediment transport.   Phosphorus in par-
     ticular is readily adsorbed onto soil particles.
     Nitrogen is also transported on soil particles but
     tends to be more soluble.  The fate of these nutrients
     in the stream beds is dependent on several factors.
     Phosphorus and nitrogen in forms associated with par-
     ticulate matter will disperse according to the mechan-
     isms of particle dispersion.  The dissolved fractions
     will either be immediately absorbed by aquatic vegeta-
     tion or carried downstream.  Factors affecting this
     process are:

          water velocity and turbulence
          microorganisms and vegetation
          turbidity
          temperature
          particle size and type
          channel characteristics
          temperature

     The dynamics of phosphorus in streams is discussed in
     greater detail by Ryden et al (1972).

     Assuming no additional inputs of nutrients, concentra-
     tions decrease as materials proceed downstream.  This
     is due to uptake by organisms and dilution by the en-
     trance of cleaner water—assuming the other inputs are
     in fact cleaner.

     The extent to which nutrients settling out affect the
     stream depends on the particular situation.  During
     storm conditions with accompanying high flows, sediment
     material often becomes resuspended, which essentially
     acts as a new input into the stream.
2.    Lakes
     Determining the amount of sedimentation occurring in
     lakes is even more difficult than in stream systems.
     Although it may be assumed that lakes act as a settling
     basin for incoming streams, and therefore, essentially
                            A-60

-------
all entering suspended matter eventually settles on the
bottom, this information does not solve the problem.
Nonpoint sources are generally from diffuse sources of
runoff that are difficult to measure.  Even where in-
puts can be measured, current patterns and eddies which
may not be constant make it difficult to determine
where sedimentation will occur.  Lake turnover may
resuspend solids, creating further impacts.  The ini-
tial point of entry is usually a major sedimentation
point due to the abrupt decrease in velocity at this
point.  However, it may not be the only area affected.

The dynamics of nutrients in lakes and reservoirs is
incompletely understood.  In an essentially closed lake
system, the nutrients entering remain in the system;
they are either utilized by the vegetation, settle out,
or remain in solution.  Which path is taken depends on
the water body characteristics and the nutrient form.
Nitrates and phosphates in solution are readily avail-
able for plant growth.  This is also true of ammonia
which can be utilized as a nitrogen source by many
types of aquatic vegetation.  Ammonia may also be
oxidized to nitrate before being incorporated into
plant biomass.

Nutrients associated with particulate matter tend to
settle out and become part of the sediments, but a num-
ber of factors may affect this process.  Turbulence
will tend to keep particles suspended and may also re-
sult in nutrients going into solution.  Current pat-
terns and eddies may cause suspended matter to settle
out far from the point of input, making impacts dif-
ficult to determine.

To what extent nutrients tied up in the sediments are
available to aquatic life is not definitely known.
Phosphates in particular tend to form very stable com-
plexes with elements such as iron and aluminum.  Some
evidence suggests that sediment runoff into reservoirs
and lakes may actually reduce dissolved ortho-phosphate
levels by forming complexes that precipitate due to the
rapid equilibrium between water and sediments  (Heine-
mann, in Ackermann et al, 1973).  However, these sedi-
ments could later supply phosphorus to aquatic organ-
isms when the sediments are stirred up during turnover,
turbulence, or even by bottom feeding fish such as carp
and catfish.
                       A-61

-------
3.   Impoundments

     In impoundments, calculations of sedimentation can be
     as difficult to obtain as sedimentation estimates for
     lakes.  Although the amount of sediment existing through
     the discharge stream may be measurable, problems simi-
     lar to those found in lakes remain.  Assuming that the
     entrance and exit of suspended solids can be determined,
     it is then necessary to consider retention time in the
     impoundment and whether the impoundment stratifies and
     undergoes turn-over, resuspending solids.

     In spite of the complexities involved, a number of
     studies have been done on sedimentation in reservoirs.
     From these studies a few general trends have been ob-
     served:

     a.   There is an inverse relationship between size of
          reservoir and rate of filling in.

     b.   Particules tend to be deposited in a gradation of
          particle sizes along the longitudinal axis of the
          reservoir.  Coarser and heavier particles are
          dropped in the headwater and finer sediments are
          deposited toward the dam.   (Note:  This is af-
          fected by:  water level, temperature and dissolved
          minerals, mineral composition of the sediments,
          especially clay-sized fraction; volume relation-
          ship of reservoir storage capacity and influent
          water; configuration of basin; and amount of
          sediment previously deposited.)

     The factors affecting sedimentation in reservoirs are
     discussed in greater detail by Glymph  (in Ackerman et
     al, 1973).  Data on reservoir sedimentation in the
     United States are provided by Bendy et al (in Ackermann
     et al, 1973).  These data support the generally held
     hypothesis that, as drainage area increases, sediment
     yields decrease.  Therefore, the greatest sedimentation
     problems tend to occur in small upland reservoirs.  A
     summary of sediment accumulation data for the reser-
     voirs surveyed is presented in Table A-14.

     There are some differences in nutrients between natural
     lakes and impoundments, although the basic principles
     apply.  Impoundments are not a closed system and many
     nutrients may be removed due to greater concentrations
     near the bottom.  There may also be a greater input of
                          A-62

-------








































H
A

W

m
rig
EH





























































rf
1


U
r r»
s
2
H
g
Q
EH
H
52

fe
^
H
O

K
U
ft.

Z
O
H
£H
5
D
•G
Q
o
o


EH


H
Q
W
CO


















•P
C
01
g
•H
•o *
0) C
W O

>-H 4J
id id
3 H
G y
< §
o
c u
id <
•H
•a
s





4J
G
'
|
SS












0)
M
rtj

(V
01
rd
•H
m
Vi
Q









CM
e

x^
n
g

n
o
•H



O4
•H
e

\i i

0
id



CM
g
"\
n
g
m
0
rH


CM
.,H
g

4J
O
id



0]
^4
•H
o
K
<0
m
01
a










ts
g
«%













(N
•H
€






Q\ 00 iH CO
ro ro rsj rH
• • • •
0 O 0 O









CN rn o *» r*
00 f*l 00 *S* Ol
o o o o o








^t o\ TJ* •<)• 10
r^ vo r~ ro CM
0 O O 0 O







ic in in >H n
in ^« m r-- m
rH rH rH O O








00 O 00 CA CO
^f r- r-i oo o
VD 1^ H r-l








O
• • • en in
CN m in in -
rH CM CM CM CN

O O O O O

^d &* C5 O^ O^
. in
CM in 
id
•H
id
•a

4J
01
c
z
4J
c
o

•o
01
m
id

0)
id

n
a)
4J
id


0
•H
4>
id
•rH
3
g
U
O
id

jj
C
g
•H
•O
01
n

rH
a
3
C
5
*













































^^
CO
r*
en

^
Hi
idl

•Pi
oil

^
c
id
1
0)

o

—
^
Hi
ml




s
c
01
a


••
0)
o
IH
O

A-63

-------
     nutrients into a reservoir system because of the drain-
     age pattern.  Rivers characteristically carry higher
     concentrations of nutrients than lakes.  By damming a
     river, these higher concentrations are retained in the
     system.  The addition of nonpoint sources of nutrients
     to such a system could accentuate the buildup if flows
     are never high enough to flush the system.

     Some Comments on Probable Controls:  A recent paper by
Barker (1974)  offers several ideas on implementation con-
straints of nonpoint controls and how they might affect the
study of nonpoint problems.  They are presented here to give
a perspective; adoption of Barker's convictions may have
significant ramifications on the type of nonpoint analysis
pursued.

Barker turns his focus beyond the investigation of nonpoint
pollution sources to the implementation and enforcement of
justifiable controls.  In doing so, he argues that, because
of implementation constraints, we can usually determine the
control recommendations which will be coming from 208 pro-
grams after all the nonpoint study, assessment and analysis
is completed.   Barker's conclusions are indeed controversial
and, by his own admission, "perhaps in excess."  However,
they are valuable in that they run counter to the conven-
tional wisdom and may force rethinking of some preconceived
notions.

The following points summarize some of Barker's conclusions:

     1.   Nonpoint controls for agriculture will consist of
          the same principles the Soil Conservation Service
          has espoused since the 1930s unless the economic
          structure of farming is drastically redefined.

     2.   The only practical controls for most urban runoff
          problems are related to sediment and erosion.

     3.   Mathematical modeling of nonpoint wastes is a very
          inexact science and may not be a cost-effective
          approach.

     4.   Legal defense of recommended control measures is
          extremely important because it is likely that
          controls will be challenged by an uncooperative
          developer or land owner.  Thus, it is imperative
          that nonpoint recommendations be based upon accur-
          ate supportive data and an acceptable methodology.
                           A-64

-------
Biological Effects of Nonpoint Source Pollutants

A clear understanding of the biological impacts of nonpoint
source pollutants is necessary to adequately assess the
severity of the nonpoint problem.  Determining water quality
criteria applicable to nonpoint phenomena and the nonpoint
pollutant reduction goal also require a thorough knowledge
of pollutant impact on water ecology.

Unfortunately, little information is available on the speci-
fic effects of nonpoint source pollution on the biological
systems of water bodies.  Although there are special circum-
stances associated with nonpoint source pollution, the
source of an adverse input has no effect on the response of
the organisms involved.  Therefore, general responses of
organisms to various pollution substances associated with
nonpoint source will be discussed.  In addition, the special
aspects associated with nonpoint pollution will be con-
sidered in these discussions.

The following discussion will focus on the biological impact
of six conditions/pollutants which are associated with non-
point sources:

     Low Oxygen Conditions

     Flow Effects

     Suspended Solids

     Nutrients

     Toxic Substances

     Road Salts

     Responses to Low Oxygen Conditions:  A decrease in dis-
solved oxygen is one of the problems that frequently accom-
panies nonpoint source pollution.  The effect of this de-
crease on aquatic biota depends on the amount of the de-
crease, the type of organism, the duration of the oxygen
depression, and whether other adverse conditions accompany
the oxygen drop.

The responses of fish to short term low oxygen conditions
are not well defined.  Doudoroff and Warren (1962) sum-
marized previous studies and concluded that little mortality
                          A-65

-------
would be expected at concentrations near and above 3.0 mg/1,
even for prolonged periods, provided other harmful agents
were-not present.  A concentration of 2.0 mg/1 may be cri-
tical for sensitive forms, but at low temperature, concen-
trations as low as 1.0 mg/1 may be tolerated by acclimatized
fish.   The key factors affecting tolerances appear to be
conditioning of the organism, temperature, and the presence
or absence of other adverse factors.  Fish have been found
to grow little, or not at all, in the presence of abundant
food at reduced oxygen concentration even though these
levels could be tolerated for long periods of time (Doudo-
roff and Warren/ 1962).   Specific species were not named in
the above summary.

In another study, carp and buffalo were reported in water
carrying as little as 2.2 mg/1 dissolved oxygen; however, a
variety of fish species were found only where a minimum of
4.0 mg/1 was present.  The greatest variety of fish were
present in waters carrying 9.0 mg/1 dissolved oxygen (Ellis,
1957) .

It is apparent from the available information that many fac-
tors affect the response of fish to a decrease in dissolved
oxygen.  Acclimatization was a factor in Doudoroff's find-
ings (1962).  This means fish gradually exposed to a gradi-
ent of low dissolved oxygen concentration will have a better
chance of surviving than fish in an environment where the
dissolved oxygen undergoes a sudden drop, which is fre-
quently the case in nonpoint source pollution.  Temperature
is also a critical factor, with high temperatures accentu-
ating the effects of oxygen stress.  The presence of other
factors, such as suspended matter and toxic substances, that
frequently accompany low dissolved oxygen conditions, also
reduce tolerances to oxygen stress.

Seasonal factors must also be considered.  High temperature,
low flow periods would be more critical than low tempera-
ture,  high flow periods.  Oxygen-demanding substances would
also be more critical during spawning seasons because of the
greater susceptibility of hatchlings and fry to oxygen
stress.

The response of invertebrates to low oxygen conditions is
affected by the same factors as those affecting fish re-
sponse.  Table A-15 lists the results of laboratory studies
conducted in Montana and Utah.  It is apparent that re-
sponses of different species, or even the same species from
                          A-66

-------




























ai
z
o
H
H EH
M <
Z «

&4 Z
(A H
U U
* Z
Id U
< Z
2 U
03 O
a o

> Q


O J
S 0
u to
< w
2 M
Q

O





















































n

o
«
IH
>w

g

01
fl
0
c
&






























I



M
3
O
£
1



















c
01 H
U ID

41 -r<
a. >
n
• 3
(0
(U
u -o
01 01
Q.-P
co n
01
S"tO
>
c i?
to 'O
0! —


1 *-
•H n
h to
3 %
M —

• •
^ 19


01
0^
c
CO
a.


\
C tr
s B
E O
Q
tn
a) oi

O ro
<1> O
a o
W J

n
HI
•H (U
o a
01 >
O.E-
m
m
-H
o -a
to tn
ID
z

01
a*
c
10
a



\
C tn
« E
01
zs










OJ


0




(NO








v m
HH

H"
1 1
cr>v
vo





f>] ^*
IDH



00 fM
II •
inv
1 1
vo
• •
^S-fM


CT| 00
V tN

«£
C 
t 1
CO

m


wm
^r m

a
C
a


O *J
S D



ID
01 0)

41 td
w J


'


tN

in
l
00

rH






fl

ID
Ul
01
-P ^^
QJ (n
O Ql
^J H
11 rH

0) >1


U —




010
•* in








OH

r4
1 1
O vo
tflH





IAOD
CO V



CO tN

<« in
i i
tN **




OH
«• n

a
c



i *"




91

a
J


"


CO
1

1
r-






00

CM


en
(Q 
-------
different localities, exposed to different laboratory con-
ditions are highly variable.

Temperature can be extremely critical in determining toler-
ance.  It has been estimated that aquatic organisms at an
environmental temperature of 10°C can withstand a reduced
oxygen concentration about 2.4 times as low as at a temper-
ature of 15.6°C.  Changes in flow are believed to have
similar effects on survival at different oxygen concentra-
tions.  One study demonstrated that a gradual reduction in
oxygen with a water flow of 0.06 ft/sec produced a 50 per-
cent stonefly mortality, while similar conditions with a
water flow of 0.25 ft/sec produced no mortality (Gaufin,
1973).

     Flow Effects:  The physical aspects of the increase in
water volume and velocity are important considerations; how-
ever, these aspects are difficult to separate from the chem-
ical considerations.  Flow and suspended solids are particu-
larly interrelated.  An increase in flow can cause stream
bank scouring that results in an increase in suspended
solids concentrations without an external source of solids.
The effects of bank scour on the biota of a stream is essen-
tially the same as suspended solids entering from surface
runoff.

The increase in velocity alone also affects the biota.
Aquatic plants and animals are pulled off the substrate and
washed downstream.  The type of substrate also affects the
degree of scouring.  Small stones, gravel, or sand sub-
strates are easily disrupted, while large rocks are less apt
to be moved and may provide refuge for mobile aquatic organ-
isms.  The time for recovery or recolonization following a
storm depends on the degree of scouring, the time of year
and type of organisms.  During the active growing season—
spring—more rapid recovery would occur than in the fall.
Although it is impossible to precisely predict how long it
will take a stream to recover, an approximate recovery time
may be from 2 to 4 weeks under normal circumstances.

     Suspended Solids;  Suspended solids  (SS) can have a
detrimental effect on aquatic communities.  The turbidity
caused by SS can inhibit light penetration that is necessary
for photosynthesis, causing a decline in vegetation.  The
abrasiveness of the particles can damage plant bodies, and
as the particles settle, attached vegetation is smothered.
                           A-68

-------
Settleable solids blanket animals, plants and their habi-
tats, either killing the organism or rendering the habitats
unsuitable for occupation.  Suspended solids also serve as a
transport mechanism for pesticides, heavy metals, and other
toxic substances which are readily sorbed onto soil par-
ticles.

Macroinvertebrate and fish species can be directly and indi-
rectly affected by SS.  Changes in habitat may occur because
of destruction of vegetation that eliminate species, or food
sources may be eliminated (Hynes, 1974).  Suspended solids
may directly affect species due to abrasion on delicate mem-
branes and gill structures.

The specific biological effects depend on the nature of the
suspended solids.  If the solids have a high organic con-
tent, a high BOD may be associated with the SS.  In addi-
tion, different particle types have different settling
characteristics and these properties along with the flow
will determine the zone of influence of the entering solids.

It has also been demonstrated that subtle changes in sub-
strate type can affect aquatic organisms.  Rocky substrates
characteristically support the most diverse communities.
One of the main reasons is apparently the availability of
interstitial habitats that are utilized by many species
(Brussen and Prather, 1974) .   Even a small degree of sedi-
mentation can fill these spaces and eliminate or reduce
species populations.  The extent of the change is dependent
primarily on the degree of sedimentation.

EPA has proposed a maximum limit of 80 mg/1 SS in fresh
water (EPA, 1973) .  There is no evidence that concentrations
of suspended solids less than 25 mg/1 have any harmful ef-
fects on fisheries  (EPA, 1973).  Waters containing 25 to 80
mg/1 should be capable of supporting good to moderate fish-
eries, whereas concentrations greater than 80 mg/1 are
unlikely to do so.

     Nutrient Enrichment:  The main effect of nutrient en-
richment is to increase aquatic vegetation.  To what extent
plant biomass will increase is difficult to determine be-
cause the question of what constitutes a limiting concentra-
tion of nitrogen, or phosphorus has never been adequately
answered.  Sawyer (in Harms and Southerland, 1975)  reported
that concentrations of 0.01 mg/1 of soluble phosphorus and
0.30 mg/1 of inorganic nitrogen were sufficent to support
                           A-69

-------
algal blooms in Wisconsin lakes when other environmental
factors were optimum.  Sylvester (in Harms and Southerland,
1975) reported limiting concentrations of 0.01 mg/1 phos-
phorus and 0.2 mg/1 nitrogen for Green Lake in Seattle,
Washington.

For streams, Mackenthus (in Harms and Southerland, 1975)
recommended that total phosphorus concentrations not exceed
0.1 mg/1 (as P) in streams and should not exceed 0.05 mg/1 P
in streams entering a lake or reservoir.  However, a study
by the Federal Water Pollution Control Administration re-
ported that total phosphorus concentrations exceeded 0.05
mg/1 P in 48 percent of the U.S. rivers sampled.  A Public
Health Service study reported that an average of 77 percent
of the stations sampled on U.S. rivers contained at least
0.1 mg/1 P04 (0.03 mg/1 as P) and 60 percent contained ni-
trate concentrations greater than 1.4 mg/1 NO^  (Harms and
Southerland, 1975).

It should also be pointed out that the 0.01 mg/1 of soluble
phosphorus limiting concentration reported by Sawyer (in
Harms and Southerland, 1975) and Sylvester is the detection
limit for the Standard Methods colorimetric analysis custom-
arily employed.  There is little information on the effects
of concentrations below this limit in water quality analy-
ses.  Perhaps the real answer lies in the following state-
ment:  "At this time, no procedure for evaluating nutrient
supplies and detecting growth-limiting factors in lakes and
streams seems to have been developed to the point of general
reliability and usefulness"  (Gerloff, 1969).

Established "threshold" concentrations are best used as a
point of reference to indicate whether a given nutrient con-
centration may present potential or existing problems.  A
single parameter value is not sufficient to determine whether
excessive aquatic growth will occur.

The form the nutrients take is important in determining ef-
fects on water quality.  Ryden et al  (.1972) discussed the
effects of different forms of phosphorus.  It was pointed
out that much of the phosphorus that is exported from water-
sheds may be in biologically unavailable forms, such as
apatite.  The percentage of biologically unavailable forms
is often related to soil type or the soil horizon exposed to
erosion.  Phosphorus in erosion from the lower soil horizon
is to a great extent apatite.  The difference between dis-
solved and particulate forms of phosphorus is also impor-
tant.  Measurements of total phosphorus concentration do not
                            A-70

-------
indicate how much phosphorus is readily available to aquatic
vegetation.  For this reason, dissolved phosphorus measure-
ments are better indicators of immediately available phos-
phorus.

A large percentage of the nutrients associated with nonpoint
source are associated with soil particles.  An immediate al-
gal response following runoff of this type would probably
not occur.  Whether these nutrients would become available
at a later time depends on the chemical and biological
characteristics of the water (see discussion of suspended
solids).   Nutrients entering in a dissolved state may be
more immediately available, although a lag phase of two
weeks was reported between the discharge of storm water into
a lake and a large increase in phytoplankton biomass.  How-
ever, an almost immediate increase in metabolic activity was
noted  (Knauer, 1975).  This delay in biomass increase may be
due to two factors:  (1) the growth rate of the organisms,
and  (2) the time required for biotic recovery following high
flow or storm conditions.

     Toxic Substances:   The toxicity of any substance is de-
pendent on several factors:

     Concentration of the metal

     Type of organism

     Type of metal compound

     Synergistic and antagonistic effects

     Physical and chemical characteristics of the water body

Because of the complexities involved, no single value can be
used as an absolute to predict the effects of a toxic sub-
stance in a water system.  The concentrations and quantities
entering the system are frequently difficult to quantify,
particularly where nonpoint sources are concerned.  It is
also difficult to determine the mixing characteristics and
transport mechanics in the water body.  Assuming these as-
pects can be dealt with, the toxicity of most substances to
aquatic life is not clearly defined.

The majority of the information available on the effects of
toxicity on aquatic organisms is based on bioassay tests
which are carried out under controlled conditions that sel-
dom occur in nature.  This type of information is useful
                           A-71

-------
only as long as the limitations are considered.  To use the
results of bioassay tests as absolutes in determining
whether a given concentration will be harmful in a natural
environment is inappropriate.  Typical bioassay tests do not
measure behavioral modifications that may affect productivi-
ty or the possibility of lowering an organism's resistance
to other adverse impacts, such as disease and/or parasites.
Bioassay information is, however, useful for indicating po-
tential problem areas.

Table A-ll gives an indication of the range of concentra-
tions that have been reported as harmful or non-harmful to
specific aquatic organisms.  The problems involved in mea-
suring toxicity are illustrated by the conflicting results
that have been reported  (Table A-16).  The discrepancies do
not necessarily reflect "right" or "wrong" answers, or even
good or bad testing techniques, but rather the existence of
unmeasured variables in testing procedures.  In addition,
threshold values recommended by EPA are given in the text.
In most cases, these values are well below recorded acute
lethal concentrations and are designed to prevent possible
chronic effects and behavioral modifications.

Although most of the available toxicity information is for
individual rather than combinations of substances, pre-
liminary studies indicate acute toxicities for mixed solu-
tions may be predictable if the TL5Q (50% toxicity level) is
known for the individual substances.  In order to obtain a
predictive three-day Tl^g for mixed effluents the concentra-
tion of each toxic substance found in the effluent was ex-
pressed as the proportion of the expected three-day TL5Q and
these values were then summed to give a predicted Toxicity
Index.  Agreement was found to be good between predicted and
measured results (Lloyd in Biological Problems in Water
Pollution, 1962) .  However, synergistic or antagonistic
effects could greatly affect the accuracy of this procedure.
Table A-17 summarizes synergistic and antagonistic effects
of selected toxicants.

1.   Aluminum

     There is little information on the abundance or toxici-
     ty of aluminum.  Aluminum may have greater toxicity
     than has been assumed  (EPA Water Quality Criteria,
     1972, March 1973).  Its presence in streams may be a
     result of industrial wastes, but a more likely source
                          A-72

-------
                              TABLE  A-16

             REPORTED TOXIC AND NON-TOXIC CONCENTRATIONS

                        OF SELECTED SUBSTANCES
Substance
Concentrations
   (mg/1)	  Exposure
             Organism
                                                          Water Type
Ammonia
      oxic
     Non-toxic
                 0.3-0.4
                 0.3-1.0
                 2.0-2.5
                 3.4
                 1.5

                 4.3
                           trout fry
                           fish
                1-4 days   goldfish
                96 hr TL   bluegill sunfish soft water
                        m" rainbow trout    20 C.
                1 hr
                           roost varieties
                            of fish
                           minnows
Aluminum
     Toxic
     Non-toxic

CadmiTjm
     Toxic
   •0.10         1 week     stickleback
   5.0          5 min.     trout
   5.0          48 hrs     fingerling rain- pH9
                            bow trout
   0.05            -       fish             pH7

   1.0          5 min.     trout
     Chronically
      safe       0.03-0.06
     Reduced re-
      production 0.0005
Chromium
     Toxic
     Non-toxic
   0.01-10      7 days     rainbow trout
   0.01-10      2-6 days   fathead minnows
   0.01-10      96 hrs     bluegill sunfish

                           fathead minnows  hard water
                            bluegill sun-   (.200 mg/1 as
                            fish             Ca COj)

                3 weeks    crustaceans
                            (daphnia)
   17 to 118    96 hrs     fish
   0.05            -       invertebrates
   0.032-6.4       -       algae

   7.1             -       carp
  35.3             -       goldfish
Copper
     Tox
     Non-toxic
                 0.015.3.0
                 0.1-1.0
                 O.OQ6
                                         fish, crusta-    soft
                                          ceans, mollusks,
                                          insects, phyto-
                                          plankton, and
                                          zooplankton
                           most fish
                           fish, crusta-
                            ceans  (Daphnia)
                            hardness  (45
                             mg/1  as
                             Ca Co3)
      Dxic
                 2.5
                 0.05-1.0
                120-136 hr brook trout
                           fish
     Non-toxic
   0.02
   0.25
   0.40
27 days

96 hr
                                         trout
                                         bluegi.lls
                                         bluegills
                           A-73

-------
TABLE A-16
(continued)
REPORTED TOXIC AND NON-TOXIC CONCENTRATIONS
OF SELECTED SUBSTANCES
Concentrations
Substance
Lead
Toxic








Non- toxic


Mercury
Toxic




Non- toxic

(mg/1)

0.2
0.34


0.5-7.0 and
0.4-0.5

482 and 442

0.62
0.7


0.004-0.02
0.01
0.05-0.1
1.0
10-20
0.2

Exposure

-
48 hr TL
in

96 hrs
LC50

96 hrs
LC50
48 hr
3 weeks


-
80-92 days
6-12 days
96 hrs
>10 days
_

Organism

fish
stickleback,
Coho salmon

fathead minnow,
and brook trout

fathead minnow.
and brook trout
trout
minnows ,
sticklebacks

freshwater fish
minnows
fish
fish
fish
tench, carp.
rainbow trout,
Water Type

soft
1000-3000 mg/1
dissolved
solids

soft (20-45
mg/1 CaCo3-

hard
_
soft


-
-
-


_

char, fish, food

Nickel
Toxic


Non-toxic

Reduced re-
production
Zinc
Toxic











Non- toxic



reduced re-
production


5
26-43

0.030

0.095


0.01-0.4

0.5

1.0
3.0

4.0
0.87

33.0

0.13

3.0

0.10



96 hr
LC50
96 hr
LC50
3 weeks

3 weeks


-

3 days

24 hr
8 hr

3 days
96 hr
LC50
96 hr
LC50
20 days

10 days



organisms

fathead minnows
fathead minnows

crustaceans,
(daphnia)
crustaceans,
(daphnia)

young rainbow
trout
fingerling rain-
bow trout
sticklebacks
fingerling rain-
bow trout
rainbow trout
fathead minnows

fathead minnows

brown trout
fingerlings
fingerling rain-
bow, trout
crustaceans
(daphnia)


soft (20 mg/1
as CaCo,)
hard (200-360
as CaCo,)
soft (45Jtng/l
as CaCo )
soft (45Jmg/l
as CaCo,)

-

soft

soft
soft

hard
soft (20 mg/1
as CaCo,)
hard (360 mg/1
as CaCOj)
hard

hard

soft (45 mg/1
as CaCo3)
Source:   McKee  and Wolfe, 1963; EPA, Water Quality  Criteria,
         1972,  March 1973
                           A-74

-------
                        TABLE A-17

      DETERMINED SYNERGISTIC AND ANTAGONISTIC EFFECTS
                    OF TOXIC SUBSTANCES
Constituent


Ammonia


Cadmium

Chromium

Copper
Cyanide




Lead

Mercury

Nickel

Zinc
   Synergistic
     Effects


High pH, low DO,
cyanide

Zinc, cyanide

Low DO

Chromium, mercury,
zinc, cadmium,
low DO
Low pH, high tem-
perature, low DO,
ammonia, zinc,
cadmium

Low DO

Copper
Copper, low DO,
cyanide
Antagonistic Effects
CO,
Hardness
Hardness (alkalinity),
temperature, dissolved
oxygen, turbidity,
carbon dioxide,  magne-
sium salts, phosphates,
sodium

Copper, nickel,  hard-
ness
Hardness



Hardness

Calcium
Source:  McKee and Wolf, 1963; EPA Water Quality Criteria,
         1972, March 1973
                           A-75

-------
     is wash water from water treatment plants.  Many of the
     aluminum salts are insoluble and therefore likely to
     settle out rapidly (McKee & Wolf, 1963).  The suspended
     precipitate of ionized aluminum is toxic and concen-
     trations in this form greater than 0.1 mg/1 would be
     deleterious to growth and survival of fish (EPA Water
     Quality Criteria, 1972, March 1973).
2.    Cadmium
     Although many forms of cadmium are highly soluble, the
     carbonate and hydroxide forms are insoluble.  There-
     fore, at high pH, cadmium will tend to precipitate.
     High concentrations of cadmium has been found to occur
     in areas of high population density (Andelman, 1974 -
     in Singis, 1974).  Available data indicate the lethal
     concentration varies from about 0.01 to 10 mg/1, de-
     pending on the test animal, type of water, temperature
     and time of exposure.  Indications are that cadmium
     reacts synergistically with other substances, such as
     cyanide  (McKee & Wolf, 1963).  This metal is considered
     an extremely dangerous cumulative poison.  EPA  (Water
     Quality Criteria, 1972, March, 1973) recommends that
     aquatic life be protected where cadmium concentrations
     exceed 0.03 mg/1 in water with a total hardness above
     100 mg/1 as CaCo3 or 0.0004 mg/1 in waters with a
     hardness of 100 mg/1 or less.
3.    Chromium
     The toxicity of chromium is highly dependent on the or-
     ganism, temperature, pH and synergistic or antagonistic
     effects.  Although fish are relatively tolerant of
     chromium salt, many invertebrates are extremely sensi-
     tive.  There is no conclusive evidence that the hexa-
     valent form is more toxic to fish than the trivalent
     form (McKee & Wolf, 1963).  However, the evidence tends
     to be conflicting and it may depend to a great extent
     on the organism and the compound.  The apparent "safe"
     level for fish  (less than 17 mg/1) is moderately high,
     and the recommended EPA  (Water Quality Criteria, 1972,
     March,  1973) upper limit of 0.05 mg/1 was selected in
     order to protect mixed aquatic populations.
                          A-76

-------
4.    Copper
     Copper salts occur in surface water only in trace
     amounts and their presence in concentration above 0.05
     mg/1 is generally considered a result of pollution
     (McKee & Wolf, 1963).  Although the chloride, nitrate
     and sulfate of the cuprous ion are soluble in water,
     the carbonate, hydroxide, oxide and sulfide are not.
     Therefore,  at a pH of 7 or above, the cupric ions will
     rapidly precipitate  (McKee & Wolf, 1963).

     In hard water, copper toxicity is reduced by the pre-
     cipitation of copper carbonate or other insoluble com-
     pounds.  Synergistic reactions are believed to occur
     between copper and chlorine, zinc, cadmium and mercury.
     In contrast, evidence suggests copper decreases the
     toxicity of cyanide  (McKee & Wolf, 1963).

     The factors influencing the lethal toxicity of copper
     to  fish include hardness, dissolved oxygen, tempera-
     ture,  turbidity, carbon dioxide,  magnesium salts and
     phosphates  (EPA Water Quality Criteria, 1972, March
     1973).   The implications that copper is particularly
     toxic  to algae and mollusks should be considered for
     any given body of water; however, the criteria (safe-
     to-lethal ratios 0.1 to 0.2) that apply to fish will
     protect these organisms as well.   The safe-to-lethal
     ratio  of 0.1 should be multiplied by the 96-hour LC5Q

     of the most sensitive important species in the locality
     to determine a recommended safe concentration of cop-
     per to protect aquatic life (EPA Water Quality Cri-
     teria,  1972, March 1973).

     Cyanide

     The toxicity of cyanide is highly dependent on pH.  As
     the pH decreases, toxicity increases; however, it has
     been reported that in the pH range of 6.0  to 8.5, there
     is little effect on toxicity.   In natural  water,  cyan-
     ides deteriorate or are decomposed by bacterial action.
     Degradation is unaffected by temperatures  in the range
     from 10° to 35°C but is greatly reduced at lower or
     higher temperatures  (McKee & Wolf, 1963).

     The toxicity of cyanide is increased by elevated tem-
     peratures (a 10°C increase produces two- to three-fold
                         A-77

-------
     increases in toxicity),  low dissolved oxygen, zinc and
     cadmium.   The toxicity of cyanide is lower for in-
     vertebrates than for fish (McKee & Wolf, 1963).
6.    Iron
     Iron is less toxic than most other heavy metals.  Ex-
     tremely high concentrations in unbuffered water can
     lower the pH to toxic levels, but the deposition of
     iron hydroxide precipitate is more likely to harm fish
     by coating gills or smothering fish eggs.  Ninety-five
     percent of U.S. water supporting good fish life have
     iron concentrations of 0.7 mg/1 or less  (McKee & Wolf,
     1963).
7.    Lead
     The carbonate, hydroxide and sulfate salts are rela-
     tively insoluble; therefore, lead generally settles out
     fairly rapidly except in soft waters.  Lead toxicity
     increases with a reduction in dissolved oxygen.  EPA
     (Water Quality Criteria, 1972, March, 1973) recommends
     that the concentration of lead should not exceed 0.03
     mg/1 at any time or place in order to protect aquatic
     life.
8.    Mercury
     Although elemental mercury is insoluble in water, many
     of the salts are quite soluble.  Mercuric ions are con-
     sidered highly toxic to aquatic life  (Table A-16).  The
     toxicity of mercuric salts is increased by the presence
     of trace amounts of copper (McKee & Wolf, 1963).

     There is not sufficient data available to determine the
     levels of mercury that are safe for aquatic organisms
     under chronic exposure.  Since experiments on sublethal
     effects are lacking, the next most useful information
     available is on the lethal effects following moderately
     long exposures of weeks or months.  As exposure  time
     increases, lower concentrations of mercury become
     lethal.  Data are not available on the residue levels
     that are safe for aquatic organisms  (EPA Water Quality
     Criteria, 1972, March 1973).  According to the Food and
     Drug Administration, mercury residues should not exceed
     0.5 micrograms per gram of total mercury in edible
                          A-78

-------
     portions of fresh water fish.  EPA (Water Quality Cri-
     teria, 1972, March, 1973)  suggests that this level be
     the guideline to protect predators in aquatic food
     chains.
9.    Nickel
     Although nickel as a pure metal is insoluble in water,
     many nickel salts are highly soluble.  Nickel is one of
     the least toxic metals.  Although 0.8 mg/1 has been
     reported as lethal to sticklebacks, fish have been
     found living in water with concentrations of 13-18 mg/1
     of nickel (McKee & Wolf, 1963).  The safe-to-lethal
     ratio for nickel is 0.01 for the protection of fish.
     This application factor should be applied to the 96-
     hour LC5Q °f *-he most sensitive important species in
     the locality to determine the recommended concentration
     of nickel safe to aquatic life (EPA Water Quality Cri-
     teria, 1972, March 1973).
10.   Zinc
     Zinc salts such as zinc chloride and zinc sulfate are
     highly soluble in water; however, salts such as zinc
     carbonate, zinc oxide and zinc sulfide are insoluble in
     water.  Therefore, the compound present is important in
     determining whether zinc will settle out or remain in
     solution.

     Zinc is toxic to aquatic organisms.   The acute lethal
     toxicity of zinc is greatly affected by water hardness.
     The sensitivity of fish to zinc varies with species,
     age and condition of the fish, as well as with the
     physical and chemical characteristics of the water.
     Acclimatization to zinc has been reported for some
     fish.   Calcium is especially antagonistic to zinc
     toxicity.   In soft water, zinc and copper react syner-
     gistically, but this does not hold in hard water.
     Toxicity is also thought to increase in the presence of
     cyanide and as dissolved oxygen concentrations de-
     crease.  The safe-to-lethal ratio for zinc (0.005), if
     multipled by the 96-hour LC,-Q of the most sensitive
     important species in the locality, will determine the
     recommended concentration of zinc safe to aquatic life
     (EPA Water Quality Criteria, 1972, March 1973).
                          A-79

-------
     Sublethal Effects;  In addition to direct toxicity,
sublethal effects must also be considered.  If a substance
causes avoidance, interference with sensory mechanisms, or
prohibits reproduction, aquatic organisms gradually will be
eliminated, even though dramatic die-offs do not occur.

Young Atlantic salmon are reported to avoid copper and zinc
at concentrations one-fiftieth the incipient lethal level.
Low levels of copper have also been reported to interfere
with odor cues necessary for salmon to return to home
streams for spawning (Sutterlin, 1974).

Avoidance behavior may be beneficial if a substance is tem-
porary and localized and can prevent sudden die-offs of
mobile organisms.  However, where chemical senses are inter-
fered with, organisms may be restricted in feeding and re-
productive processes which may cause gradual reduction or
total elimination of species.

     Road Salts:  The biological effects of road salts on
aquatic organisms have received little attention.  One study
reported direct and indirect effects on lake benthic or-
ganisms.  The increase in salinity directly eliminated
dipteran larvae, and the decrease in oxygen concentration
that occurred because of the density changes eliminated
several oligochaete species  (Judd, n.d.).

The effects of adding salts to freshwater can be predicted
to a great extent on the basis of reactions of freshwater
organisms to marine and estuarine environments.  Freshwater
organisms cannot survive in salt water environments because
of the change in osmotic pressure that affects fluid bal-
ance.  Although specialized species that can tolerate wide
ranges of salinity exist, adaptation to the intermittent
input of salt associated with nonpoint source runoff would
be unlikely.  Chloride concentrations in freshwater support-
ing good fish life are below 9 mg/1 in 50 percent, and below
170 mg/1 in 95 percent, of the waters  (McKee & Wolf, 1963).
Concentrations reported as harmful to fish are presented in
Table A-18.
                          A-80

-------
                         TABLE A-18

         CONCENTRATIONS OF CHLORIDE HARMFUL TO FISH


     Cl Concentrations  (mg/1)            Type of Fish

             400                         Trout

            2000                         Some fish

            4000                         Bass, Pike, Perch

          4500-6000                      Carp eggs

          8100-10,500                    Small Bluegills


     Source:  McKee & Wolf, 1963


Analysis of Water Quality Data to Determine Nonpoint Problems

In many areas, the extent and severity of nonpoint problems
is often unknown.  This is usually due to past concentration
on point sources and inadequate water quality data.  This
obviously makes it extremely difficult to set priorities and
develop a coherent strategy for analyzing nonpoint problems
and establishing controls.

It is often possible to use existing water quality data to
help focus on specific pollutants and certain watersheds and
stream segments where nonpoint problems appear most severe.
The remainder of the 208 nonpoint program can then concen-
trate on the major problems that have been identified.  Un-
doubtedly, additional data collection will also be required
to better define existing nonpoint problems.  This section
covers these two crucial areas of nonpoint analysis; analy-
sis of existing data and collection of additional data.  The
presentation is organized by the following topics:

     Analysis of Existing Data:  An Example

     Use of Steady-State Models in Nonpoint Source Analysis

     Analysis of Biological Data for Nonpoint Analysis

     Development of a Nonpoint Source Sampling Program
                          A-81

-------
     Analysis of Existing Data:  An Example;  In areas where
a good water quality network has been in existence for
several years, a surprisingly large amount of information on
the location and severity of nonpoint problems can be ob-
tained by proper analysis of the data.  The objective of
this subsection is not to detail the techniques for nonpoint
analysis but merely to indicate the types of analyses which
may be used to shed light on major nonpoint problems.  A
recent study on the Passaic River in New Jersey (Berger/Betz,
1975) is used as an example of what innovative evaluation of
existing data might yield.

1.   The Setting

     The example used was taken from a recent water quality
     management study of the Northeast New Jersey metropoli-
     tan area (Berger/Betz, 1975).  The major stream in the
     study area is the Passaic River, a slow moving stream
     which is heavily used for water supply and waste as-
     similation throughout its length.  The analysis which
     follows was for the free flowing portion of the stream;
     the estuary portion was not included in the analysis
     because of the magnitude of combined sewer overflows
     into the estuary, insufficient data, and the complica-
     tions of data interpretation caused by tidal fluctua-
     tions.

     The Freshwater Passaic covers a drainage area of 806
     square miles and is the third largest drainage area in
     the State of New Jersey.  Average annual rainfall over
     the area is about 47 inches.  The majority of the
     Freshwater Passaic is geographically located in the New
     England Upland Province.  Topography is generally flat.
     Population in the basin is over 600,000  (population
     density over 700 people per sq mi).  Land uses in the
     basin are:
               1970 Land Use            % of Total Area

          Single Family Residential          23.5
          Multi Family Residential            1
          Industrial                          3.5
          Commercial                          1.5
          Public and Quasi Public             5
          Conservation, Recreation
          and Vacant                         65.5
                          A-82

-------
     The analysis was structured to gain information on
     three broad types of nonpoint sources.  The following
     quotation (Berger/Betz, 1975) defines the three cate-
     gories :

          "An important distinction of nonpoint sources
          exists among storm-activated sources, continuous
          sources and erratic sources.  Storm-activated
          sources involve contaminant loads derived from the
          land surface and delivered to the stream system by
          surface runoff.  These pollutant loadings can
          result in transient water quality problems during
          storm periods, and also can contribute to long-
          term problems due to the settling out of material
          in benthic deposits.  Annual nonpoint source pol-
          lutant yields tend to be dominated by loadings
          derived during storm periods—although these
          loadings are not necessarily most important in
          terms of problems created.

          "Continuous nonpoint sources generally involve
          contamination of the groundwater reservoir which
          feeds the stream system more or less continuously
          over time and space.  Continuous sources tend to
          have relatively less impact on water quality dur-
          ing storms than during nonstorm periods, due to
          the much greater dilution of effluents during
          storms; thus, continuous nonpoint sources are
          analyzed primarily as a low-flow problem.

          "Erratic sources, such as unauthorized dumping and
          accidental spills, are difficult to evaluate
          without direct monitoring of individual source
          area.  Their impact is usually established only on
          an average long-term basis, usually in combination
          with other types of sources."

2.    The Analysis

     BOD, dissolved oxygen and sediment data were deemed
     adequate for analysis; heavy metal and nutrient data
     were extremely sparse and not appropriate for rigorous
     analysis.  Monthly parameter values were available on
     several stations located along the freshwater Passaic
     and its  tributaries.  A continuous recording station
                          A-83

-------
     existed at the most downstream station,  yielding daily
     data on DO,  temperature,  pH and conductivity.*  Data
     from a summer survey conducted to calibrate a low flow
     model were also available.

     The analysis consisted of mass balance techniques,
     annual load computations  and plotting of data.  The
     analysis was divided into four separate techniques,
     each used for defining different portions of the non-
     point source problem:

          Low Flow Mass Balance

          Annual BOD Loads

          DO Response to Storm Loadings

          Annual Sediment Loads

     The purpose of each technique, parameters analyzed,
     etc., are summarized in Table A-19.

3.    The Results

     Details of the analysis techniques can be found in the
     original report (Berger/Betz, 1975).   The results of
     the analysis yielded the  following conclusions:

     a.   Based on the low flow mass balance, nonpoint
          problems occurring during low flow conditions
          (benthic deposits, polluted groundwater inflow,
          unreported point sources) were prioritized.
          Various sections of  the river and its tributaries
          were identified as having especially severe prob-
          lems.  The results were used to better define a
          nonpoint source sampling program.

     b.   The annual BOD load calculations, which tend to be
          dominated by storm period loads, were used to
          locate areas having significant storm-activated
* Hourly data was not utilized in the analysis, but it was
  available through USGS.
                          A-84

-------
                         TABLE A-19

       EXAMPLE TECHNIQUES FOR ANALYZING EXISTING DATA
                FOR NONPOINT SOURCE PROBLEMS
Technique

Low Flow Mass
Balance
Condition

Low Flow
Data Analyzed   Purpose
Annual BOD
Loadte
Dissolved
Oxygen
Response
to Storm
Loadings
Annual
Sediment
Loads
All flow con-
ditions used
to calculate
annual load
Storm Condi-
tions
All flow con-
ditions used
to calculate
annual loads
CBOD & NBOD*
values from
summer survey
data collected
for low flow
model calibra-
tion

CBOD values
published for
several sta-
tions in USGS1
annual "Water
Quality Re-
cords"
To identify areas
with significant
steady-state or
continuous non-
point source
problems.
To identify areas
with abnormally
high nonpoint BOP
loads.  This is
strongly related
to storm runoff
loads as opposed
to steady-state
nonpoint sources.
Daily DO values To determine tran-
published for
the most down-
stream station
in the network
sient impact of non-
point sources on DO
and make preliminary
determination of
what causes DO depres-
sion after storm.
Sediment values To test hypothesis
for several     of significant
stations in     benthic deposition.
USGS'  annual
"Water Quality
Records"
* CBOD B carbonaceous BOD; NBOD B nitrogeneous BOD

Source:  Berger/Betz, 1975
                    A-85

-------
     sources.   Two stream segments were identified with
     extremely high nonpoint loads, it was suspected that
     discrete  sources,  such as spills, material storage
     yards,  bypasses from sanitary sewers, pump stations and
     treatment plants,  may be the cause of some of the high
     readings.  A sampling program was designed to collect
     additional data on the significant problem segments.
     It is hoped that future sampling will identify discrete
     sources,  which are usually easier to control than
     distributed runoff sources.

     c.   Analysis of daily dissolved oxygen values at the
          last downstream station revealed that DO levels
          increased shortly after the start of a storm but
          declined over a period of several days to below
          the  level which prevailed at the beginning of the
          storm (plots of this phenomena have already been
          presented in Figure A-10).   The DO response
          appeared to be explained by assuming that the DO
          was  depressed by organic material which was washed
          into the stream by runoff and by the scouring of
          benthic deposits.  Because of the characteristics
          of the Passaic (extremely slow velocities) it is
          unlikely that benthic deposits can be sufficiently
          controlled by runoff control measures to signifi-
          cantly alleviate the post-storm DO depression.

     d.   The  sediment mass balances were computed to gain
          perspective on the benthic deposit accumulations.
          Analysis indicated that nearly half of the annual
          sediment input to the main river segment settles
          out  rather than leaves the basin.

     Use of Steady-State Models in Nonpoint Source Analysis:
Steady-state water quality models cannot adequately handle
transient events associated with some nonpoint sources.
However, use of steady-state models can aid in the assess-
ment of several nonpoint sources.  As indicated in the
previous section, the actual data collected for model cali-
bration can be used for mass balances  (in the example given
in the previous section, this technique located areas of
significant steady-state loads).

Nonpoint sources which may be handled by steady-state model-
ing include:
                          A-86

-------
            Source

     Landfill leachate

     Marshes
     Pervious lagoons
     Salt water intrusion
     Areas of septic tank
     malfunctioning
     Acid mine drainage
   Typical Parameters

BOD/DO, nutrients, heavy
metals
BOD/DO, nutrients
BOD/DO, nutrients
Chlorides

BOD/CO, nutrients
Heavy metals
These pollutant sources can be handled in steady-state
modeling by adjusting certain modeling parameters to reflect
loads from nonpoint sources.  Benthic loads are generally
handled specifically in the benthic demand components of the
model.  Distributed sources, such as septic tank areas,
marshes, etc., can be handled by adjusting the incremental
runoff loads in the model.  Sources such as lagoons and
landfills may be addressed either as a point source or a
distributed source, depending on the characteristics of the
groundwater flow system and the length of the model reaches.

Considerable skill and experience is needed in adapting and
calibrating steady-state models to accurately reflect actual
conditions.  It is possible to miscalibrate a model and
develop water quality predictions which are grossly in
error.  The only safeguard to prevent this from happening is
to collect adequate calibration data and perform model
calibration with experienced modelers.

     Analysis of Biological Data:  The assessment of bio-
logical data offers a tool for the investigation of nonpoint
sources which is often neglected or under-utilized.  Reli-
ance on only chemical and physical data does not yield a
complete picture of water quality.  Because of the general
lack of sufficient chemical data and the complexity of
interpreting physical and chemical data as they relate to
the health or quality of a stream, it may be cost effective
to place greater emphasis on biological parameters.

Aquatic organisms and communities can be used as natural
pollution monitors.  When an aquatic community undergoes a
stress, such as pollution, the community structure can be
affected.  This change can be monitored and the long-term
effects can be measured and analyzed.  Because aquatic or-
ganisms respond to their total environment and reflect long-
term conditions, they can often provide a better assessment
                          A-87

-------
of stream quality and environmental damage than can other
monitoring methods.  Some organisms tend to accumulate or
magnify toxic substances, pesticides, radionuclides and a
variety of other pollutants.  Organisms also can reflect the
synergistic and antagonistic interactions of point and
nonpoint source pollutants occurring within a specific re-
ceiving water system.

Chemical analyses can only indicate the water quality at the
time the sample is collected, and unless extensive sampling
is done, variation in different areas of the water will not
be determined.  Even if adequate chemical data were avail-
able, the problem would still remain:  interpret its signi-
ficance to aquatic ecology.  For example, suppose a stream
which demonstrates a sharp DO decline to 3 mg/1 after storm
periods (rainfall greater than 0.5 inches).  This level is
generally maintained for 6 hours; DO then recovers to 5.5
mg/1.  Apparently, storm runoff is causing the DO drop, but
is this drop causing a problem?  If a biological survey
indicates that the fish and other aquatic species desired
for the stream are relatively unaffected then the answer may
be negative.*  At least the problem could not be termed
critical and the remaining nonpoint program could be modi-
fied accordingly.

In evaluating the condition of an aquatic system, many
factors must be considered.  The available information must
be evaluated on the basis of habitats surveyed, season, and
flow regime.  The guidelines discussed in the following
paragraphs must be used with the above point in mind.

Biological sampling programs for the detection of nonpoint
problems are presented in a later section of this appendix.
The following discussion assumes that the data has already
been collected and must be evaluated.

The concept of indicator, or sensitive organisms is fre-
quently employed in evaluating water quality.  While this
concept, in conjunction with community structure, is the
* The storm runoff could be causing deleterious loads of
  nutrients or heavy metals which cause problems down-
  stream.  This is neglected in the above example.
                          A-88

-------
basis for biological surveys, a number of limitations must
be acknowledged when evaluating water quality on the basis
of the presence or absence of certain organisms.

First, many factors besides water quality affect the distri-
bution of organisms.  In streams, velocity and substrate are
two important factors.  Although the presence of certain
organisms usually indicates good water quality, their ab-
sence may be due to factors other than poor water quality
(Hawkes, 1974).  An English study, Report of the River Pol-
lution Survey, found that 98% of the length of a fast-moving
stream was classified as first class quality, biologically
and chemically.  Only 6% of the length of a slow-moving
stream was first class biologically and chemically, while
65% was ranked as third class biologically but first class
chemically (Hawkes, 1974).  The difference in biological
condition was due to unsuitable habitats, not chemical or
physical water quality.

A second limitation of indicator systems is that they have
been developed on the basis of organic pollution, which may
not always be the main consideration for nonpoint source
analysis.  Organisms differ in their respective tolerances
to different forms of pollution.  For example, stoneflies
which are considered the most intolerant of organic pollu-
tion were found to be among the most tolerant organisms in
heavy metal-polluted Welsh rivers (Hawkes, 1974).  However,
suspended solids and BOD, two parameters associated with
organic pollution, are also concerns in nonpoint source
pollution.  Therefore, existing information on organisms
tolerant of organic pollution can be applicable to nonpoint
source pollution.

As long as the limitations of the information are realized,
the concept of indicator organisms can be very useful in
assessing the effects of nonpoint source pollution.  Al-
though the presence or absence of a single species does not
define water quality, the presence of large numbers of cer-
tain species, or absence of whole groups of organisms, can
be indicative of water quality conditions.

Palmer  (1969) lists 80 algae species tolerant of organic
pollution.  The list was part of a compilation based on 269
reports from 165 authors.  Rankings were determined by
assigning a score of 1 or 2 for each species reported as
tolerant to organic pollution.  A 2 was assigned if the
species was reported to tolerate large amounts of organic
                          A-89

-------
pollution.  Hart and Fuller (1974) listed invertebrate
species found at pH values less than 4.5 and greater than
8.5 and adverse oxygen and BOD conditions (DO less than 4
mg/1 and BOD greater than 5.9 mg/1).  Use of the species
lists contained in the cited publications can aid in assess-
ing water quality conditions.

In addition to the concept of indicator organisms, community
structure is also considered in evaluating aquatic systems.
Characteristically, aquatic systems with good water quality
have a greater number of species than systems with poorer
quality water.  There are some exceptions to this pattern,
but it generally holds true.  Species distribution is also
important.  Polluted waters are usually dominated by a few
species with numerous individuals while other species present
have very few individuals.  Good quality waters usually have
a more equal distribution of individuals per species.

Numerous methods have been devised for analyzing biological
data.  The following is a classification for streams that
provides a means for general and specific evaluation.  The
classification is based upon combining aspects of community
structure with the indicator organism concept.  Although
there are exceptions to this pattern, it provides a general
overview of expected conditions.

The biological organisms are divided into the following
seven categories:
     Category

        1
        2

        3

        4
               Description

Blue-green algae and the green algae
genera Stigeoclonium, and Tribonema; the
bdelloid rotifers plus Cephalodella
megalocephala and Proales decipiens

Oligochaetes, leeches and pulmonate snails

Protozoa

Diatoms, red algae, and most of the
green algae

All rotifers not included in column one,
plus clams, prosobranch snails, and tri-
cladid worms
                          A-90

-------
        6           All insects and Crustacea

        7           All fish
After the data have been categorized, the sampling stations
thought to be affected by nonpoint source pollution are com-
pared to an unaffected station or the control; or compared
to a standard that has been set up for a geographical region.

The number of species in each category for the control sta-
tion or standard is set as equal to 100%.  The percentage of
species for each of the categories is then computed for the
affected stations.  For example, if the control station had
10 species in Category 1 and the impact station had 5 spe-
cies in Category 1, the value for the impact station would
be 50%.  The resulting patterns are defined as follows:

     Healthy:  The algae are mostly diatoms and green algae,
     such as Cladophora crespata and glomerata, and the
     insects and fish are represented by a great variety of
     species.  There are numerous protozoa, but they do not
     fall into a set pattern.

     Categories 1 and 2 tend to vary greatly, depending on
     ecological conditions in the area.  Categories 4, 6 and
     7 are all above the 50% level.

     Semi-healthy:  The pattern is irregular, indicating the
     balance found in a healthy station has been disrupted
     but not destroyed.  Often a single species will be
     represented by a disproportionately large number of
     individuals.  This condition may be defined as follows:

     1.   Either or both categories 6 or 7 below 50%, and
          categories 1 or 2 under 100%.

     2.   Either category 6 or 7 below 50%, and categories
          1, 2 and 4 100% or over:  or categories 1 and 2
          100% or over and category 4 having large numbers
          of some species.

     Polluted:  The overall balance of the community is up-
     set.  However, conditions are favorable for some spe-
     cies in categories 1 and 2.  This conditions is defined
     as follows:
                          A-91

-------
     1.   Either or both of categories 6 and 7 are absent,
          and categories 1 and 2 are 50% or better.. .

     2.   Categories 6 and 7 are both present, but below
          50%; then categories 1 and 2 must be 100% or more.

     Very Polluted:  Conditions are definitely toxic to
     plant and animal life, with many groups absent.  This
     condition is defined as follows:

     1.   Categories 6 and 7 are absent, and category 4 is
          below 50%.

     2.   Category 6 or 7 is present, then 1 or 2 is less
          than 50%.

Although this level of information is not available in many
cases, this classification provides an overall picture of
the types of organisms and general community structure
characteristic of different ecological conditions (Patrick
1949).

     Development of a Nonpoint Source Sampling Program;
Additional data will be required in almost all 208 areas to
further define nonpoint source problems.  The data may be
used for problem assessment, model calibration, etc., and
thus is critical to adequate nonpoint source evaluation.
Since the time span of initial 208 work is relatively short,
it is unlikely that all, or even most, of the questions con-
cerning nonpoint pollution can be answered by additional
data; a long-term sampling program based upon "best guess"
priorities is probably the best strategy for sampling.

The following paragraphs do not present the methodology for
developing a nonpoint sampling program.  Rather, important
considerations are reviewed and an overview is presented
which may help in establishing study area specific programs.

1.   The Nonpoint Source Sampling Framework

     A partial listing of major nonpoint sources is pre-
     sented in Table A-20.  This list includes storm-acti-
     vated sources and sources which operate more or less
     independently of hydrologic conditions.  The analysis
     of these sources involved two elements:
                          A-92

-------
                         TABLE A-20

              MAJOR NONPOINT POLLUTANT SOURCES


Surface Runoff  (including intermittent point sources)

     Combined sewer overflows
     Other urban runoff  (including storm sewers and sanitary
          sewer bypasses)
     Suburban runoff  (including storm sewers and sanitary
          sewer bypasses)
     Runoff from other developed land—e.g., highways
     Agricultural runoff:  cropland
     Pastureland, feedlots, other ag. land
     Runoff from construction sites
     Silviculture and surface mining operations

Sources Involving Groundwater Contamination

     On-site waste disposal systems
     Leachate from landfills and other residual waste
          disposal activities
     Agriculture, including agricultural specialities
     Acid mine drainage
     Lagoons (municipal and industrial)
     Spray irrigation

Factors Affecting Water Quantity

     Salt water intrusion
     Hydrographic modifications:
          Impoundment s
          Channelization
          Impervious surface

Miscellaneous Sources

     Unauthorized discharges, dumping
     Accidental spills, overflows,  leakages (e.g., lagoons,
          pipelines)
     Port operations
     Recreational water use
                             -93

-------
     a.    Pollutant  generation

     b.    Receiving  water  response

     Generally,  neither  the  nature  nor  extent  of  water
     quality  problems  resulting  from  storm-period pollutant
     loadings is well  defined.   The sampling program must
     therefore carefully balance the  needs  of  pollutant
     generation and  receiving water response.

     Pollutant generation  refers to the quantity  of  pollu-
     tants yielded to  the  surface water system, including
     the  timing of pollutant loads  and  their relationship to
     hydrologic conditions.  Receiving  water response refers
     to the actual problems  created by  nonpoint source
     loadings in surface waters. Analysis  of  receiving
     water response  must consider:

     a.    Pollutant  routing  under various  flow conditions

     b.    In-stream  processes  such  as:

          decomposition
          photosynthetic activity
          reaeration
          precipitation  of materials  into  the  benthos

     c.    Characteristics  of all water  bodies  being  affected
          by  a given nonpoint  source.

     It appears that a cost-effective approach to nonpoint
     source impacts  focus  upon the  limiting conditions  for
     design of control measures.  That  is,  although  a given
     pollutant source in a given basin  may contribute to
     several  different types of  problems,  detailed quanti-
     tative analysis need  be provided only for those sources
     causing  the problems.  These sources  will require  the
     most stringent  control  measures.  An  extremely  impor-
     tant goal of the sampling program and initial analysis
     will be  to identify these conditions,  and thus  to  nar-
     row  the focus of subsequent activities.

2.    The  Type Problem Approach to Nonpoint Source Questions

     The  "Type Problem Approach" is suggested  as  an  orderly
     and  logical method  of investigating nonpoint source
                          A-94

-------
effects.  The major nonpoint pollutant sources in Table
A-20 can be conveniently organized into four major
classes of problems:

a.   General non-storm quality factors

b.   Site-specific nonpoint sources

c.   Transient storm problems

d.   Long-term storm effects

The four separate types of problems can be attached by
four supplementary measurement programs which, taken
together, provide a unified overview of the major pos-
sible categories of problems.

a.   General Non-storm Quality;  General non-storm
     quality factors include geochemically-related
     natural background changes and changes attribut-
     able to man's activities.  Quality problems may be
     related to dissolved oxygen, nutrients or toxic
     materials.  A low flow sampling program for
     steady-state model calibration (a usual component
     in many 208 studies) will provide the basic input
     to the definition of regionalized incremental
     runoff quality factors.  Major deviations in
     quality not attributable to point sources will
     serve to flag that area as a nonpoint source
     special interest area.

     The role of benthic demands on water quality is
     generally not well established.  The low flow
     sampling should include a general characterization
     of the nature and depth of sediments at each loca-
     tion.  The objective is to produce a benthic map.
     Benthic demands appearing in the modeling analysis
     will be of special concern.  Such areas should be
     subsequently investigated in detail through field
     surveys to verify their existence, extent, depth,
     uptake rate and other characteristics.

b.   Site-Specific Sources:  Site specific nonpoint
     sources are those which have clearly defined
     source areas such as:
                     A-95

-------
Landfills
Spray irrigation fields
Lagoons of various types
On-site disposal areas, i.e., septic tank con-
centrations

To a significant degree such locations are amen-
able to a regulatory action.  Their actual impact
on the receiving water quality is often not well
known, especially for sites installed before the
current complex environmental monitoring require-
ments were adopted.  A major requirement of the
nonpoint work element is the establishment of
nonpoint source priority lists.  The case of land-
fills is illustrative of the priority dilemma.

Landfills are generally too numerous in the study
area to be considered individually in any data
effort.  There is usually little information as to
whether specific landfills have a significant
impact on surface water quality.  The magnitude of
the problem should be determined, as suggested
below, along with its hydrogeologic and seasonal
variations.  The same types of questions apply to
other site-specific sources.

Assuming that monitoring all site-specific sources
is not possible, it is proposed that a sampling
approach involving the monitoring of the seasonal
performance of a number of representative and
critical site-specific sources be adopted.  Ques-
tions concerning the seasonal variation of loads
as they directly affect surface water quality can
be answered by sampling from high water spring
conditions through dry summer conditions.

This approach would provide assistance in develop-
ing pollutant generation relationships and in
identifying current and potential surface and
groundwater quality problem areas.  It would also
be an important aid in establishing priorities for
the extent of the particular problem and the
allocation of the 208 project resources to be
devoted to their solution.
                A-96

-------
c.   Transient Storm Problems:  Transient storm prob-
     lems may be investigated in terms of three broad
     effects:

     dissolved oxygen variations
     nutrient, toxics and heavy metals washoff
     the integrated effects on the major downstream
          water bodies (e.g., estuaries)

     Dissolved oxygen levels are of concern because
     they exert an intermediate effect on a stream's
     fishery resources.  During a storm, two oxygen
     forces are activated.  The first is the effect of
     cloud cover in reducing photosynthesis.  This may
     be especially important when clouds persist for
     several days with slow moving storm systems.  A
     high initial biomass to flow ratio would aid in
     the oxygen depression.  The second effect is the
     elevation of dissolved oxygen levels due to in-
     creased reaeration from raindrop impact and in-
     creased turbulence due to higher flows.

     The relative magnitude of these two forces deter-
     mines whether the net effect is an elevation or
     depression of dissolved oxygen levels.  The rela-
     tionship of these effects to critical levels is
     not well documented for most streams.  It is pro-
     posed that a sampling program involving a recon-
     naissance level study of dissolved oxygen levels
     during storm events on area tributaries be adop-
     ted.  This is an important part of problem assess-
     ment because, generally, it is not even known
     whether there is indeed a problem that must be
     addressed by 208 planning.

     The establishment of pollutant-generation rela-
     tionships is generally a central aspect of the 208
     approach.  Washoff rates for nutrients, toxics and
     heavy metals must generally be established for
     various land uses.  The storm sampling should in-
     clude sampling for important parameters; this will
     permit a limited verification of the SWMM/STORM
     pollutant-generation methodology.

     The assessment of tributary storm effects on estu-
     aries or other major downstream water bodies is an
     extremely complicated task because it must bridge
                     A-97

-------
the gap between the process of pollutant genera-
tion and the actual amount of pollutants being
delivered by the tributaries into their receiving
waters.

Two approaches to this problem may be appropriate.
Within the framework of the reconnaissance samp-
ling network, stations should be chosen to repre-
sent segments upstream and downstream from rela-
tively flat uniform reaches having no tributary
inputs.  The net difference in the stream load
across the reach would represent the effect of
possible sediment resuspension, sediment depo-
sition, or bank and channel scouring.  The second
approach would involve an analysis of the dif-
ferences between the SWMM/STORM-generated pollu-
tant loads and those that were actually measured
in the course of the sampling program.

A major potential problem in the verification of
the modeling results is that the inherent errors
in the pollutant generation algorithms have the
potential of being of the same or greater magni-
tude than the effect that the modeling process is
trying to detect.  This means that interpretation
of the modeling results will have to be made
judiciously.  A major accomplishment would be the
development of reliable relationships between pol-
lutant generation and pollutant delivery.  This
would permit modifications of SWMM/STORM outputs
to reflect more accurate water impacts.

Long-Term Storm Effects - Dissolved Oxygen:  Long-
term residual effects of storms may have a signi-
ficant effect on steady-state water quality con-
ditions through the mechanism of benthic demand.
The exact role of benthic demand in controlling
water quality is not well defined on most of the
study area streams.

Benthic deposits may be particularly troublesome
behind river impoundments or slow, flat portions
of the river.  If benthic problems are suspected,
the sampling program should investigate in detail
the oxygen relationships in impoundments.  This
involves systematic measurement of dissolved
                A-98

-------
          oxygen and the use of light and dark respirometers
          to measure the benthic oxygen uptake rate.   Mea-
          surements should be made before and after storms.
          This will help determine long-term stream re-
          sponses to nonpoint pollutants washed in from
          tributary streams.  Data should also be collected
          during relatively stable streamflow sequences to
          determine possible changes in benthic demand due
          to steady-state accumulations.  This program
          should help resolve questions concerning the
          relative effects of storm washoff, bottom resus-
          pension and steady-state accumulation.

          Another sampling program may be necessary to de-
          termine the relative importance of diurnal  dis-
          solved oxygen variations.  Many times,  steady-
          state modeling without accounting for diurnal
          effects may be a gross misstatement of  the  on-
          going stream processes.  If diurnal problems are
          suspected, there is a need to establish the rela-
          tive importance of the periphyta, rooted aquatics,
          in controlling the phyotosynthesis/respiration
          balance in local streams.

3.    Biological Monitoring

     Biological monitoring provides an effective  means by
     which to evaluate water quality because biological data
     are generally the best indicators of the overall con-
     ditions of a water body.  This type of monitoring seems
     especially appropriate when one considers that water
     quality standards are partially designed to  protect
     biological organisms.

     For purposes of biological monitoring, a station will
     normally encompass areas, rather than points, within a
     reach of river or area of lake, reservoir or estuary
     that adequately represent a variety of habitats  typ-
     ically present in the body of water being monitored.
     Unless there is a specific need to evaluate  the  effects
     of a physical structure, it will normally be advisable
     to avoid areas which have been altered by a  bridge or
     weir, are located within a discharge plume,  etc.  Thus,
     biological sampling stations may not always  coincide
     with chemical or sediment stations.
                          A-99

-------
Several types of biological monitoring programs can be
used, depending on the suspected problem and the needed
information.  Three examples that might be used are
listed below.

a.   Short-term Survey:  Site examinations made once or
     only a few times to determine quickly the bio-
     logical quality of the area and the possible
     causes for the condition.

b.   Long-term monitoring:  Sampling is conducted at
     regular intervals over a period of time.  This
     method offers the opportunity to measure seasonal
     variations and fluctuations caused by random
     events.

c.   Specific Parameter Monitoring:  Selected organisms
     or groups (such as plankton, fish or inverte-
     brates) are monitored for changes in numbers,
     size, condition, etc., and extrapolations are made
     about water quality.

If transient pollution problems following a storm are
suspected, the following biological sampling may yield
valuable information on the extent and severity of the
problem:

     Conduct three surveys, one during a dry period, a
     second directly after a period of heavy rainfall,
     and the third approximately a month after a heavy
     rainfall.  The first set of samples provide base-
     line information on the quality of the stream or
     lake.  The second set will indicate the immediate
     effects of scouring and runoff materials.  The
     third set will provide information on the extent
     of recovery following storm conditions and whether
     the effects are long-term.  For each survey, a
     comparable area relatively unaffected by runoff
     would also have to be sampled to provide a control,

Ideally, permanent biological collections are made and
identification to species level are established where
possible.  Constraints of time and money often make
this level of study impossible.  Although modifications
of this program are possible, it must be emphasized
that the information obtained will also be reduced
accordingly.
                     A-100

-------
More superficial surveys can be conducted that provide
an overview of the condition of the system.  A general
idea of biological quality can be gained by an experi-
enced biologist making on-site field observations.  The
latter, in spite of limitations, would probably provide
sufficient information for determining whether there
was an existing nonpoint source pollution problem.  A
major disadvantage of a superficial survey is the lack
of a permanent or quantitative record for future com-
parison.

Comparable lakes or streams unaffected by point or non-
point sources should be studied for purposes of com-
parison.  In actuality, these conditions are difficult
to find.  Frequently, reaches of the stream or parts of
the lake under study can be found which are not in-
fluenced by pollution; they can be used as comparative
controls.  It must be emphasized that similarity be-
tween habitats is essential in making any comparisons
between different areas.
                     A-101

-------
                      ADDENDUM 1
The regression analyses relating chemical concentrations to
precipitation variables utilized the following functional
form:
                  b-L  b~       b
          Y = bX   X   -  •  -X  n
     or, ln(Y +1) = In bo + b^lnX.^ + .  . .  + b  (In XR)


     where:    Y is a chemical concentration;

               X-,,. .  . ,Xn are precipitation variables; and

               bo, bj,. .  ., bn are coefficients to be

               estimated.


The objective was to control for effects of basin charac-
teristics on Y by allowing the "constant term"  (In b )
to assume different values for different basins.  This was
done by inserting dummy variables into the logarithmic form
of the regression.  Each was simply a variable with a value
of unity for all observations pertaining to a given basin,
and zero for all other observations.  There was thus one
dummy variable corresponding to each basin.  These could be
entered into the regression as ordinary independent vari-
ables; the regression coefficient obtained for each would
be, in effect, an estimate of  (In bQ) for the given basin.

A minor complication was that the full set of dummy vari-
ables could not be entered along with a conventional con-
stant term since these would be redundant  (resulting in
singularity of the covariance matrix).  For convenience, the
ordinary constant term was retained, and the first dummy
variable was deleted.  The regression equation was therefore
the following:
                        A-1Q2

-------
     In(Y + 1) = Inb0 + a2D2 + '  '  'amDm


                 + b^lnX-^ + . .  . + bn(lnXn)


          where:  D_ , .  .   . , Dm are dummy variables; and

                  a~ / .  .   ./ am are additional parameters

                  to be estimated.


The appropriate constant term for a given basin could then
be obtained as the sum of  In b ,  as estimated in the regres-
sion, and the regression coefficient for the dummy variable
pertaining to that basin.   The predictive equation for
basin "i" was thus the following:
Y = -
              (b0 exp(ai))
                                     bn
In all regressions cited here, the set of dummy variables
as a whole made a statistically significant contribution
(at the 1% level) to the explanation of the dependent
variable.  The regression coefficients and significance
tests for individual dummy variables are not of major in-
terest and therefore are not reproduced here.
                         A-103

-------
                     BIBLIOGRAPHY
Abt Associates, Inc.  "Preventive Approaches to Urban Storm-
     water Management" (Report forthcoming).  Prepared for
     U.S. Environmental Protection Agency by Abt Associates,
     Cambridge, Massachusetts, 1976.

Ahl, T.  "Effects of Man-induced and Natural Loading of
     Phosphorus and Nitrogen on the Large Swedish Lakes."
     Verhandlungen Internationale Vereinigung fuer Theo-
     retische und Angewandte Limnologie, 19:1125-1132, 1975.

American Public Works Association.  "National Characteriza-
     tion, Impacts and Critical Evaluation of Stormwater
     Discharges, Nonsewered Urban Runoff and Combined Sewer
     Outflows,  (Final Report Draft)."  Prepared for the U.S.
     EPA, Washington, D.C., August 1975.

American Public Works Association.  "Water Pollution Aspects
     of Urban Runoff."  Prepared for Federal Water Quality
     Control Administration, 1969.

Amy, G., et al.  "Water Quality Management Planning for
     Urban Runoff."  Prepared for U.S. Environmental Pro-
     tection Agency by URS Research Company, EPA 440/9-75-
     004, NTIS PB 241 689, 1974.

Anderson, D. G.  "Effects of Urban Development on Floods in
     Northern Virginia."  U.S. Geological Survey Open File
     Report, 1968.

Andersen, D. R.  "Water Quality Models for Urban and
     Suburban Areas."  Nebraska Water Resources Research
     Institute, University of Nebraska, Lincoln, Nebraska,
     1974.

"Applications of Stormwater Management Models."  Handout
     at EPA seminar at University of Massachusetts, Amherst,
     July 28-August 1, 1975.

Aron, G., et al.  "A Method for Integrating Surface and
     Ground Water Use in Humid Regions."  Pennsylvania State
     University, Institute for Research on Land and Water
     Resources, Research Publication No. 76, University
     Park, Pennsylvania, 1975.
                          A-104

-------
AVCO Economic Systems, Inc.  "Storm Water Pollution from
     Urban Land Activity."  Prepared for U.S. Department of
     the Interior by AVCO Economic Systems, Inc., Washing-
     ton, D.C., 1970.

Bansal, M. K.  "Deoxygenation in Natural Streams."  Water
     Resource Bulletin, Vol. 11, No. 3, pp. 491-501, 1975.

Battelle Columbus Labs.  "Development of the Arizona
     Environmental and Economic Trade-off Model."  Prepared
     for the state of Arizona Department of Economic Plan-
     ning and Development, Columbus, Ohio, March 31, 1973.

Beck, Alan M.  "The Ecology of Stray Dogs, a Study of Free
     Ranging Urban Animals."  York Press, Baltimore, Mary-
     land, 1973.

Benjes, H. H., et al.  "Storm-Water Overflows from Combined
     Sewers."  Journal of the Water Pollution Control
     Federation, Vol. 33, No. 12, pp. 1251-1259, 1961.

Benzie, W. J., and Courphaine, R. J.  "Discharges from
     Separate Storm Sewers and Combined Sewers."  Journal of
     the Water Pollution Control Federation, Vol. 38, No. 3,
     pp. 410-421, 1966.

Berger, Lewis and Associates.  "Section 303(e)  Water Quality
     Management Basin Plan, Northeast New Jersey Urban
     Area." Prepared for New Jersey Department of Environ-
     mental Protection, 1975.

Betson, R. P., and McMaster, W.  M.  "Non-point Source
     Mineral Water Quality Model."  Journal of the Water
     Pollution Control Federation, Vol. 47, No.  10, pp.
     2461-2473, 1975.

Biesecker, James E., and Liefeste, D. K.  "Water Quality of
     Hydrologic Benchmarks:  An Indicator of Water Quality
     in the Natural Environment."  USGS Circular 460-E,
     1975.

Biggar, J. W., and Corey, R. B.   "Agricultural Drainage
     of Eutrophication."  Eutrophication; Causes, Conse-
     quences, Correctives.   National Academy of  Sciences,
     Washington,  D.C., 1969.
                         A-105

-------
Black, Crow and Eidsness, Inc.  "Storm and Combined Sewer
     Pollution Sources and Abatement."  U. S. Environmental
     Protection Agency, NTIS PB 201 725, 1971.

Blackman, W. C. , Jr., et al.  "Mineral Pollution in the
     Colorado River Basin."  Journal of the Water Pollution
     Control Federation, Vol. 45, No. 7, pp. 1517-1557,
     1973.

Blackwood, K. R.  "Runoff Water Quality of Three Tucson
     Watersheds."  U.S. Environmental Protection Agency,
     NTIS PB 240 287, 1974.

Bowman, H. R., Conway, J. G. and Asaro, F.  "Atmospheric
     Lead and Bromine Concentrations in Berkeley, Cali-
     fornia, 1963-1970."  Environmental Science and Tech-
     nology, Vol. 6, No. 6, pp. 556-560, 1972.

Branch, Melville C., City Planning and Aerial Information.
     Harvard University Press, Cambridge, Massachusetts,
     1971.

Brandes, Charles E.  "Methods of Synthesis for Ecological
     Planning."  Master's Thesis, University of Pennsyl-
     vania, Philadelphia, 1973.

Brandstetter, A.  "Comparative Analysis of Urban Stormwater
     Models."  Pacific Northwest Laboratories, Battelle
     Memorial Institute, Richland, Washington, 1974.

Brown, H. E.  "A System for Measuring Total Sediment Yield
     from Small Watersheds."  Water Resources Research, Vol
     6, pp. 818-826, 1970.

Brown, H. J., et al.  "Empirical Models of Urban Land Uses:
     Suggestions on Research Objectives and Organization."
     Columbia University Press, New York, New York, 1972.

Brown, J. C., Shaw, C. M. and Read, N. P.  "Nutrients and
     Suspended Sediments for Forested Watersheds in the
     East-Central Sierra Nevada."  University of Nevada,
     Reno, Nevada, n.d.
                         A-106

-------
Brown, J. C.,  Skau, C. M. and Howe, W. R.  "Nutrient and
     Sediment Production from Forested Watersheds."  Paper
     No. 73-201, Presented at the Annual Meeting of the
     American Society of Agricultural Engineers at Lexing-
     ton, Kentucky, June 17-20, 1973.

Brown, R., et al.  "Empirical Models of Urban Land Use:
     Suggestions on Research Objectives and Organization."
     Columbia University Press, New York, New York, 1972.

Brusven, M. A. and Phathen, K. V.  "Influence of Stream
     Sediments on Distribution of Macrobenthos."  Journal of
     Entomological Society of British Columbia (Canada),
     Vol. 71,  pp. 25-32, October 1974.

Bryan, E.H.  "Concentrations of Lead in Urban Storm Water."
     Journal of the Water Pollution Control Federation, Vol.
     46, No. 11, pp. 2419-2421, 1974.

Bryan, E. H.,  "Quality of Stormwater Drainage from Urban
     Land Areas in North Carolina."  Water Resources Re-
     search Institute1 of North Carolina, Raleigh, North
     Carolina, 1970.

Burm, R. J., Krawczyk, D. F. and Harlow, G. L.  "Chemical
     and Physical Comparison of Combined and Separate Sewer
     Discharges."  Journal of the Water Pollution Control
     Federation, Vol. 40, No. 1, pp. 112-126, 1968.

Burm, R. J. and Vaughan, R. D.  "Bacteriological Comparison
     Between Combined and Separate Sewer Discharges in
     Southeastern Michigan."  Journal of the Water Pollution
     Control Federation, Vol. 38, No. 3, pp.  400-409, 1966.

Cahill, T. H., Imperato, P. and Verhoff, F. H.  "Evaluation
     of Phosphorus Dynamics in a Watershed."  Journal of the
     Environmental Engineering Division, Proceedings of the
     American Society of Civil Engineers, Vol. 100, EE2, pp.
     439-458,  1974.

Cairns, J., and Dickson, K. L. , eds.  "Biological Methods
     for the Assessment of Water Quality."  American Society
     for Testing and Materials, Philadelphia, Pennsylvania,
     1973.
                         A-107

-------
Carey, G. H., et al.  "Urbanization, Water Pollution,
     and Public Policy."  Center for Urban Policy Research,
     Rutgers University, New Brunswick, New Jersey, 1972.

Catanese, A. J.  "Scientific Methods of Urban Analysis."
     University of Illinois Press, Chicago, Illinois.  1972.

Cherkauer, D. S.  "Urbanization Impact on Water Quality
     During a Flood in Small Watersheds."  Water Resources
     Bulletin, Vol. 11, No. 5, pp. 987-998, 1975.

Chen, C. N.  "Evaluation and Control of Soil Erosion in
     Urbanizing Watersheds."  Proceedings of the National
     Symposium on Urban Rainfall and Runoff and Sediment
     Control, University of Kentucky, Lexington, Kentucky,
     1974.

Chow, T. J. and Earl, J. L.  "Lead Aerosols in the Atmos-
     phere, Incremental Concentrations"  (Report).  Science,
     Vol. 169, p. 577, 1970.

Chun, M. J., Young, R. H. F. and Anderson, G. K.  "Waste-
     water Effluents and Surface Runoff Quality."  Water
     Resources Research Center, Technical Report No. 63,
     Honolulu, Hawaii, 1972.

Clark, L. J., Guide, V. and Pheiffer, T. H.  "Nutrient
     Transport and Accountability in the Lower Susquehanna
     River Basin - Summary and Conclusions."  U.S. Environ-
     mental Protection Agency, Region III, Annapolis Field
     Office Technical Report No. 60, EPA 903/9-74-014, 1974.

Cleveland, J. G., et_ al.  "Storm Water Pollution from Urban
     Land Activity."  Combined Sewer Overflow Abatement
     Technology, Water Pollution Control Research Series,
     U.S. Environmental Protection Agency, 1970.

Cleveland, J. A., Reid, G. W. and Harp, J. F.  "Evaluation
     of Dispersed Pollutional Loads from Urban Areas."  NTIS
     PB 263 746, n.d.

Colston, N. V., Jr.  "Characterization and Treatment of
     Urban Land Runoff."  Prepared for U.S. Environmental
     Protection Agency, EPA 670/2-74-096, 1974.
                         A-108

-------
Colston, N. V., Jr.  "Pollution from Urban Land Runoff."
     University of North Carolina Water Resources Research
     Institute at North Carolina State University, Durham,
     North Carolina, 1974.

Colston, Newton V., Jr. and Tafuni, Anthony N.  "Urban Land
     Runoff Considerations."  Urbanization and Water Quality
     Control, W. Whipple, Jr., ed., American Water Resources
     Association, Minneapolis, Minnesota, 1975.

Commonwealth of Pennsylvania, Department of Environmental
     Resources.  "Technical Manual for Sewage Enforcement
     Officers."  Harrisburg, Pennsylvania, 1974.

Corey, G. H., et al.  "Urbanization, Water Pollution, and
     Public Policy."  Center for Urban Policy Research,
     Rutgers University, New Brunswick, New Jersey, 1972.

Coughlin/ Robert E., Berry, David and Hammer, Thomas R.
     "Environmental Study of the Poquessing Watershed."
     Regional Science Research Institute, Philadelphia,
     Pennsylvania,  1976.

Coughlin, R. E. and Hammer, T. R.  "Environmental Study of
     the Wissahickon Watershed within the City of Phila-
     delphia."  Regional Science Research Institute, Phila-
     delphia, Pennsylvania, 1973.

Coughlin, Robert E. and Hammer, Thomas R.  "Stream Quality
     Preservation Through Urban Development."  Prepared for
     U.S. Environmental Protection Agency by the Regional
     Science Research Institute, Philadelphia, Pennsylvania,
     EPA-R5-73-019, 1973.

Cowan, W. F. and Lee, G. F.  "Leaves as a Source of Phos-
     phorus."  Environmental Science and Technology, Vol. 7,
     No. 9, p. 853, 1973.

Crecelius, E. A. and Piper, D. Z.  "Particulate Lead Con-
     tamination Recorded in Sedimentary Cores from Lake
     Washington, Seattle."  Environmental Science -and Tech-
     nology, Vol. 7, pp. 1053-1067, 1973.

Crim, R. L. and Lovelace, N. L.  "Auto-Qual Modeling Sys-
     tem."  U.S. Environmental Protection Agency, Region
     III, Annapolis Field Office Technical Report #54, 1973.
                         A-109

-------
Daines, R. H., Motto, H., and Chitko, D. M.  "Atmospheric
     Lead:  Its Relationship to Traffic Volume and Proximity
     to Highways."  Environmental Science and Technology,
     Vol. 4, p. 318, 1970.

de Gueare, T. V. and Ongerth, J. E.  "Empirical Analysis
     of Commercial Solid Waste Generation."  Journal of the
     Sanitary Engineering Division, Proceedings of the
     American Society of Civil Engineers, Vol. 97, SA6, pp.
     843-850, 1971.

Digiano, F. A. and Coler, R. A.  "Definition of Procedures
     for Study of River Pollution by Non-point Urban Sour-
     ces."  U.S. Environmental Protection Agency, NTIS PB
     237 972, 1974.

Dillion, P. J. and Kirchner, W. B.  "The Effects of Geology
     and Land Use on the Export of Phosphorus from Water-
     sheds."  Water Research  (Great Britain), Vol. 9, pp.
     135-148, 1975.

Dow Chemical Company.  "An Economic Analysis of Erosion and
     Sediment Control Methods for Watersheds Undergoing
     Urbanization."  Prepared for the U.S. Department of the
     Interior, 1972.

Dudley, John G. and Stephenson, D. A.   "Nutrient Enrichment
     of Ground Water from Septic Tank Disposal Systems."
     Upper Great Lakes Regional Commission, 1973.

Dugan, G. L. and McGaughey, P. H.  "Enrichment of Surface
     Waters."  Journal of the Water Pollution Control
     Federation, Vol. 46, No. 10, pp. 2261-2280, 1974.

Dunbar, D. D. and Henry, J. G. F.  "Pollution Control
     Measures for Stormwaters and Combined Sewer Overflows."
     Journal of the Water Pollution Control Federation, Vol.
     38, No. 1, pp. 9-26, 1966.

Durbin, Timothy, Jr.  "Digial Simulation of the Effects of
     Urbanization on Runoff in the Upper Santa Ana Valley,
     California."  U.S. Department of the  Interior, Geo-
     logical Survey Water-Resources Investigations 41-73,
     1974.
                          A-110

-------
Ecology and the Economy...A Concept for Balancing Long
     Range Goals."  Urban and Rural Lands Committee.  Paci-
     fic Northwest River Basin Commission, November, 1973.

Edwards, D.  "Some Effects of Siltation Upon Aquatic
     Macrophyte Vegetation in Rivers."  Hydrobiologia, Vol.
     34, No. 1, pp. 29-37, 1969.

Elfers, K. and Hufachmidt, M. M.  "Open Space and Urban
     Water Management Phase 1:  Goals and Criteria."
     University of North Carolina, Water Resources Research
     Institute, Report No. 104, Chapel Hill, North Carolina,
     1975.

Elgmork, K., et al.  "Polluted Snows in Southern Norway
     During the Period 1968-1971."  Environmental Pollution,
     Vol. 4, No. 1, p. 41, 1973.

Emery,  R. M.,  Moon, C. E. and Welch, E. B.  "Enriching
     Effects of Urban Runoff on the Productivity of a
     Mesotrophic Lake."  Water Research (Great Britain),
     Vol. 7, pp. 1506-1516, 1973.

Engineering-Science, Inc.  "Comparative Costs of Erosion
     and Sediment Control Construction Activities."  Pre-
     pared for U.S. Environmental Protection Agency, EPA
     430/9-73-016, 1973.

Engman, E. T.   "Partial Area Hydrology and its Application
     to Water Resources."  Water Resources Bulletin, Vol.
     10, No. 3. pp. 512-521, 1974.

Engman, E. T.  and Ragowski, A. S.  "A Partial Area Model
     for Storm Flow Synthesis."  Water Resources Research,
     Vol. 10,  No. 3, pp. 464-472, 1974.

"Environmental Management for the Metropolitan Area -
     Part II:   Urban Drainage."  U.S. Army Corps. Seattle
     District, 1974.

"EPA Prepares Effluent Guidance for 21 Industries for
     Permit Program."  Environment Reporter, Vol. 3, No. 37,
     pp. 1053-1057, 1973.
                         A-lll

-------
Espey, W. H. Jr., and Winslow, D. E.  "Urban Flood Fre-
     quency Characteristics."  Journal of the Hydraulics
     Division, American Society of Civil Engineers, Vol.
     100, HY2, pp. 279-293, 1974.

"Eutrophication: Causes, Consequences, Correctives."
     Proceedings of a Symposium, National Academy of Sci-
     ences, Washington, D. C., 1969.

"Evaluation of the Effects of Urbanization on Aquatic
     Ecology and Hydrologic Regimes."  Hydrocomp, Inc., PB-
     247 095/3WP, Palo Alto, California, 1975.

Field, R.  "Coping with Urban Runoff in the United States."
     Water Research (Great Britain), Vol. 9, pp. 499-511,
     1975.

Field, R.  "Urban Pollution and Associated Effects of
     Street Salting."  Edison Water Quality Research Lab,
     National Environmental Research Center, Cincinnati,
     Ohio, Environmental Protection Agency, Edison, New
     jersey, 1972.

Field, R. and Knowles, D.  "Urban Runoff and Combined
     Sewer Overflow."  Journal of the Water Pollution
     Control Federation, Vol. 47, No. 6, pp. 1352-1369,
     1975.

Field, R. and Lager, J. A.  "Urban Runoff Pollution Control,
     State-of-the-Art."  Journal of the Environmental
     Engineering Division, Proceedings of the American
     Society of Civil Engineers, Vol. 101, EEl, pp. 107-125,
     1975.

Field, R. and Wiezel, P.   "Urban Runoff and Combined Sewer
     Overflow."  Journal of the Water Pollution Control
     Federation, Vol. 45, No. 6, pp. 1108-1115, 1973.

Fellos, John and Molof, Alan H.  "Effect of Benthal Deposits
     on Oxygen and Nutrient Economy of Flowing Waters."
     Journal of the Water Pollution Control Federation, Vol.
     44, No. 4, pp. 644-662, 1972.
                         A-112

-------
Fillos, John and Swanson, William R.  "The Release Rate of
     Nutrients from River and Lake Sediments."  journal of
     the Water Pollution Control Federation, Vol. 47, No. 5,
     pp. 1032-1042, 1975.

Floyd, C. F. and Rowan, M. J.  "Implications of Zoning as
     an Urban Water Management Measure."  Department of Real
     Estate, University of Georgia and Environmental Re-
     sources Center, Georgia Institute of Technology, 1976.

Foehrenbach, J.  "Eutrophication."  Journal of the Water
     Pollution Control Federation, Vol. 45, No. 6, pp. 1237-
     1244, 1973.

Franklin Institute Research Laboratories.  "Selected Urban
     Storm Water Runoff Abstracts."  U.S. Environmental
     Protection Agency, 11024 EJC, 1970.

Frey, J. C., Gamble, H. B. and Sauerlender, 0. H.  "Eco-
     nomics of Water Supply Planning and Management."
     Institute for Research on Land and Water Resources
     Publication No. 90, Penn State University, University
     Park, Pennsylvania, 1975.

Fruh, G. E.  "The Overall Picture of Eutrophication."
     Journal of the Water Pollution Control Federation, Vol.
     39, No. 9, pp. 1449-1463, 1967.

Gambell, A. W.  "Sulfate and Nitrate Content of Precipita-
     tion Over Parts of North Carolina and Virginia."  U.S.
     Geological Survey Professional Paper 475C, C209, 1963.

Gannett, Fleming, Corddry and Carpenter, Inc.  "Storm Water
     Management Alternatives."  From final report on Watts
     Branch Storm Water Management Study to Montgomery
     County, Maryland Department of Environmental Planning,
     1975.

Gaufin, A. R.  "Water Quality Requirements of Aquatic
     Insects."  U.S. Environmental Protection Agency, EPA
     660/3-74-004, 1973.

Gburek, W. J. and Brogan, J. G.  "A Natural Non-Point
     Phosphate Input to Small Streams."  Northeast Watershed
     Research Center, University Park, Pennsylvania, n.d.
                         A-113

-------
Gizzard, T. J. and Jennelle, E. M.  "Will Wastewater
     Treatment Stop Eutrophication of Impoundments?"
     Presented at the 27th Purdue Industrial Waste Con-
     ference, West Lafayette, Indiana, 1972.

Graham, F. H., Costello, L. S. and Mallon, H. J.  "Estima-
     tion of Imperviousness and Specific Curb Length for
     Forecasting Stormwater Quality and Quantity."  Journal
     of the Water Pollution Control Federation, Vol. 46, No.
     4, pp. 717-725, 1974.

Grossman, D., Hudson, J. F. and Marks, D. H.  "Waste
     Generation Models for Solid Waste Collection."  Journal
     of the Environmental Engineering Division, Proceedings
     of the American Society of Civil Engineers, Vol. 100,
     EE6, pp. 1219-1230, 1974.

Grava, Sigurd.  Urban Planning Aspects of Water Pollution
     Control.  Columbia University Press, New York, New
     York, 1969.

Guy, H. P.  "Research Needs Regarding Sediment and Urbani-
     zation. "  Journal of the Hydraulics Division, Proceed-
     ings of the American Society of Civil Engineers, Vol.
     93, HY6, pp. 247-254, 1967.

Guy, H. P.  "Residential Construction and Sedimentation at
     Kensington, Maryland."  Federal Inter-Agency Sedimenta-
     tion Conference, AR5 Miscellaneous Publication 970,
     1965.

Guy, H. P. and Ferguson, G. E.  "Sediment in Small Reser-
     voirs Due to Urbanization."  Journal of the Hydraulics
     Division, Proceedings of the American Society of Civil
     Engineers, Vol. 88, No. HY2, pp. 27-37, March 2962.

Hagarman, James.  Personal Conversation in Philadelphia,
     Pennsylvania, April 29, 1976.

Haith, D. A.  "Land Use and Water Quality in New York
     Rivers."  Journal of the Environmental Engineering
     Division, Proceedings of the American Society of Civil
     Engineers, Vol. 102, EEl, pp. 1-15,  1976.
                         A-114

-------
Hammer, Thomas R.  "Stream Channel Enlargement due to
     Urbanization."  Water Resources Research, Vol. 9, No.
     6, 1973.

Hammer, T. R.  "Effects of Urbanization on Stream Channels
     and Stream Flow."  Regional Science Research Institute,
     Philadelphia, Pennsylvania, 1973a.

Hammer, T. R.  "Water Quality Determination in a Suburban!z-
     ing Basin:  Brandywine Creek, Pennsylvania."  Regional
     Science Research Institute Discussion Paper No. 78,
     Philadelphia, 1974.

Hanes, R. E., Zelazny, L. W., and Blaser, R. E.  "Effects
     of De-icing Salts on Roadside Plants and Water Sup-
     plies."  Department of Agronomy, Virginia Polytechnic
     Institute, Blackburg, Virginia, 1967.

Harbridge House.  "Key Land Use Issues Facing EPA."  Pre-
     pared for U.S. Environmental Protection Agency, NTIS
     PB, pp. 235-345, 1974.

Harkin, John M., Jawson, M. D., and Baker, F. G.  "Cause
     and Remedy of Failure of Septic Tank Seepage Systems."
     Proceedings, Second National Conference on Individual
     Onsite Wastewater Systems, National Sanitation Founda-
     tion, Ann Arbor, Michigan, pp. 119-124, 1976.

Harms, L. L, and Southerland, E. V.  "A Case Study in Non-
     Point Source Pollution in Virginia."  Virginia Water
     Resources Research Center Bulletin No. 88, Virginia
     Polytechnic Institute, Blacksburg, Virginia, 1975.

Hartt, J. P.  "A Study of Pollution Loadings from Urban
     Runoff."  Water Pollution Research in Canada, Vol. 8,
     pp. 16-25, 1973.

Hawkes, H. A.  "Water Quality:  Biological Considerations."
     Chemistry and Industry, pp. 990-1000, December 21,
     1974.

Hawkins, R. H. and Judd, J. H.  "Water Pollution as Affected
     by Street Salting."  Water Resources Bulletin, Vol. 8,
     No. 6, pp. 1246-1252, 1972.
                         A-115

-------
Heaney, J. P. and Sullivan, R. H.  "Source Control of
     Urban Water Pollution."  Journal Water Pollution
     Control Federation, Vol. 43, No. 4, pp. 571-579, 1971.

Heaney, J. P., et al.  "Urban Stormwater Management Model-
     ing and DecTs ion-Making."  Prepared for U.S. Environ-
     mental Protection Agency, National Environmental
     Research Center, NTIS PB 242 290, 1975.

Keeps, D. P. and Mein, R. G.  "Independent Comparison of
     3 Urban Runoff Models."  Journal of the Hydraulics
     Division, Proceedings of the American Society of Civil
     Engineers, Vol. 100, HY7, pp. 995-1009, 1974.

Heerdegen, R. G. and Reich, B. M.  "Unit Hydrographs for
     Catchments of Different Sizes and Dissimilar Regions."
     Institute for Research on Land and Water Resources,
     Reprint Series No. 44, Pennsylvania State University,
     University Park, Pennsylvania, 1974.

Helly, Walter.  Urban Systems Models.  Academic Press,
     New York, New York, 1975.

Henningson, Durham and Richardson, Inc.  "Combined Sewer
     Overflow Abatement Plan."  Draft Report for the U.S.
     Environmental Protection Agency, 11024 FEG, Des Moines,
     Iowa, 1973.

Hergert, S. L.  "Urban Runoff Quality and Modeling Study."
     Prepared for U.S. Environmental Protection Agency, NTIS
     PB, 237 141, 1972.

Hiemstra, L. A. V.  "Joint Probabilities in the Rainfall-
     Runoff Relation."  Institute for Research on Land and
     Water Resources, Reprint Series No. 14, Pennsylvania
     State University, University Park, Pennsylvania, 1969.

Hill, D. E. and Thomas, H. F.  "Use of Natural Resources
     Data in Land and Water Planning."  The Connecticut
     Agricultural Experiment Station, Bulletin 733, New
     Haven, Connecticut, 1972.

Hoak, R. D.  "Physical and Chemical Behavior of Suspended
     Solids."  Sewage and Industrial Wastes, Vol. 31, No.
     12, pp. 1401-1408, 1959.
                         A-116

-------
Hobble, J. E. and Likens, G. E.  "The Output of Phosphorus
     Dissolved Organic Carbon, and Fine Particulate Carbon
     from Hubbard Brook Watershed."  Limnology and Ocean-
     ography, Vol. 18, No. 5, pp. 734-742, 1973.

Halsworth, E. G. and Adams, W. A.  "The Heavy Metals,Content
     of Rainfall in the East Midlands."  Environmental
     Pollution  (Great Britain), Vol. 4, p. 231, 1973.

Holzer, Thomas L.  "Limits to Growth and Septic Tanks."
     Paper Presented at Conference on Rural Environmental
     Engineering, Warren, Vermont, 1973.

Horbeck, J. W.  "Storm Flow from Hardwood-Forested and
     Cleared Watersheds in New Hampshire."  Water Resources
     Research, Vol. 9, No. 2, 1973.

Horton, J. P.  "Street Cleaning Effectiveness: Vacuum
     Sweepers."  The APWA Reporter, pp. 20-22, April 1976.

Hossain, A., Delleur, J. W. and Rao, R. A.  "Evaporation
     Infiltration and Rainfall-Runoff Processes in Urban
     Watersheds."  Water Resources Research Center, Tech-
     nical Report No. 41, Purdue University, West Lafayette,
     Indiana, 1974.

Howard, W. T. and Hammer, T. R.  "Water Quality Impacts of
     Unsewered Housing."  Regional Science Research Insti-
     tute Discussion Paper No. 66, Philadelphia, Pennsyl-
     vania, 1973.

Howells, D. H.  "Water Quality Dimensions of Water Resources
     Planning."  Journal of the Hydraulics Division, Pro-
     ceedings of the American Society of Civil Engineers,
     Vol. 101, HY2, pp. 277-284, 1975.

Huber, Wayne C., et al.  "Storm Water Management Model
     User's Manual - Version II."  Prepared for U.S. Environ-
     mental Protection Agency, 1975.

Huff, D. D., et al.  "Simulation of Urban Runoff Nutrient
     Loading, and Biotic Response of a Shallow Eutrophic
     Lake."  Institute for Environmental Studies, University
     of Wisconsin, Madison, Wisconsin, 1974.
                         A-117

-------
Hwang, C. P., Huang, P. M. and Lackie, T. H.  "Phosphorus
     Distribution in Blackstrip Lake Sediments."  Journal of
     the Water Pollution Control Federation, Vol. 47, No. 5,
     pp. 1081-1085, 1975.

Hydrologic Engineering Center, U.S. Army Corps of Engineers.
     Urban Storm Water Runoff Model Storm Computer Program
     Users Guide, 1975.

Hydrologic Engineering Center, U.S. Army Corps of Engineers.
     "FY 1972 Annual Report on the Quality of Urban Storm
     Runoff Entering the San Francisco Bay."  1972.

Hydroscience in U.S. EPA.  Areawide Assessment Procedures
     Manual, report forthcoming.

Hynes, H. B. N.  The Ecology of Running Waters.  University
     of Toronto Press, Toronto, Ontario, 1970.

International Business Machines, Inc.  "IBM Scientific
     Computing Symposium, Land and Air Resource Management."
     White Plains, New York, 1968.

Interstate Sanitation Commission.  "Combined Sewer Overflow
     Study for the Hudson River Conference."  New York, New
     York, 1972.

Jaworski, N. A. and Hetling, L. J.  "Relative Contributions
     of Nutrients to the Potomac River Basin from Various
     Sources."  U.S. Department of the Interior, Federal
     Water Pollution Control Administration, Chesapeake
     Technical Support Laboratory, Technical Report No. 31,
     1970.

Johnson, R. E., Rossano, A. T. Jr. and Sylvester, R. 0.
     "Dustfall as a Source of Water Quality Impairment."
     Journal of the Sanitary Engineering Division, Pro-
     ceedings of the American Society of Civil Engineers,
     Vol. 92, SA1, pp. 245-268, 1966.

Jordan, R. A. and Bender, M. E.   "An in situ Evaluation of
     Nutrient Effects in Lakes."  Prepared  for U.S. Environ-
     mental Protection Agency by Virginia Institute of
     Marine Science, Gloucester Point, Virginia, EPA-R3-73-
     018, 1973.

Judd, J. H.  "Lake Stratification Caused by Runoff from
     Street De-icing."  Water Research  (Great Britain), Vol.
      4, pp.  521-532,  1970.
                         A-118

-------
Judd, John A.  "Effect of Salts from Street Runoff on
     Benthic Organisms."  University of Wisconsin, Great
     Lakes Center, Milwaukee, Wisconsin, 1967.

Kaufman, W. J.  "Chemical Pollution of Ground Waters."
     Journal of the American Water Works, Vol. 66, pp. 152-
     159, 1974.

Kerr, R. L., et al.  "Analysis of Rainfall - Duration -
     Frequency for Pennsylvania."  Institute for Research on
     Land and Water Resources Research, Publication No. 70,
     Penn State University, University Park, Pennsylvania,
     1970.

Keup, L. E.  "Biology of Water Pollution."  W. M. Ingram and
     K. M. Mackenthum, Eds., U.S. Department of the In-
     terior, Federal Water Pollution Control Administration,
     1967.

Khanna, S. D.  "Effects of Highways on Surface and Sub-
     surface Waters."  Public Works, Vol. 104, pp. 1171-
     1182, 1973.

King, D. L. and Ball, R. C.  "Comparative Energetics of a
     Polluted Stream."  Limnology and Oceanography, Vol. 12,
     No. 1, pp. 27-33, 1967.

Klein, L. A., £t al_.  "Source of Metals in New York City
     Wastewater."  Journal of Water Pollution Control
     Federation, Vol. 46, p. 2653, 1974.

Kluesener, J. W. and Lee, G. F.  "Nutrient Loading from a
     Separate Storm Sewer in Madison, Wisconsin."  Journal
     of the Water Pollution Control Federation, Vol. 46, pp.
     920-936, 1974.

Knauer, D. R.  "The Effect of Urban Runoff on Phytophankton
     Ecology."  Verhandlungen, Internationale Vereinigung
     fuer Theoretische und Angewandte Limnologie.  Vol. 19,
     pp. 893-903, 1975.

Kothand Araman V.  "Water Quality Characteristics of Storm
     Sewer Discharges and Combined Sewer Overflows."
     Illinois State Water Survey, Illinois Department of
     Registration and Education, Circular 109, Urbana,
     Illinois, 1972.
                         A-119

-------
Kramer, J. R.,  Herbes, S. E. and Allen, H. E.  "Phosphorus:
     An Analysis of Water, Biomass, and Sediment."  Nutri-
     ents in Natural Waters, Wiley-Interscience, New York,
     New York,  1972.

Kreisal, James F.  "Rural Wastewater Research."  Proceed-
     ings, Second National Conference on Individual On-site
     Wastewater Systems, National Sanitation Foundation, Ann
     Arbor, Michigan, pp. 145-157, 1976.

Krenkel, P. A., Cawley, W. A. and Minch, V. A.  "The
     Effect of Impounding Reservoirs on River Waste Assimi-
     lative Capacity."  Journal of the Water Pollution
     Control Federation, Vol. 37, pp. 1203-1217, 1965.

Kuhner, J. and Shapiro, M.  "Discussion of 'Urban Runoff
     Pollution Control - State-of-the-Art1, by R. Field and
     J. A. Lager."  Journal of the Environmental Engineering
     Division,  Proceeding of the American Society of Civil
     Engineers, Vol. 102, EEI, pp. 220-223, 1976.

Kuo, Chin Y.  "Evaluation of Sediment Yield Due to Housing
     Construction:  A Case Study."  Department of Civil
     Engineering, Old Dominion University, Norfolk, Vir-
     ginia.

Lager, J. A. and Smith, W. G.  "Urban Stormwater Management
     and Technology:  An Assessment."  U.S. Environmental
     Protection Agency, National Environmental Research
     Center, EPA 670/2-74-040, 1974.

Lamonds, A. G.   "Chemical and Biological Quality of Lake
     Dicie at Eustis, Flordia, with Emphasis on the Effects
     of Storm Runoff."  U.S. Geological Survey, NTIS PB 239
     014, Tallahassee, Florida, 1974.

La Valle, P. D.  "Domestic Sources of Stream Phosphates in
     Urban Streams."  Water Research  (Great Britain), Vol.
     9, pp. 915-927, 1975.

Lazrus, A. L.,  Lorange, F. and Lodge, J. R. Jr.  "Lead and
     other Metal ions in United States Precipitation."
     Environmental Science and Technology, Vol. 4, p. 55,
     1970.
                         A-120

-------
Leclerc, G.  "Methodology for Assessing the Potential Impact
     of Urban Development on Urban Runoff and the Relative
     Efficiency of Runoff Control Alternatives."  PhD The-
     sis, Massachusetts Institute of Technology, 1973.

Lee, G. F.  "Role of Phosphorus in Eutrophication and
     Diffuse Source Control."  Water Research (Great Brit-
     ain), Vol. 7, pp. 111-128, 1973.

Leopold, L. B., Wolman, M. G. and Miller, J. P.   "Fluvial
     Processes in Geomorphology."  W. H. Freeman and Com-
     pany, San Francisco, California, 1964.

Leopold, L. B.  "Hydrology for Urban Land Planning - A
     Guidebook on the Hydrologic Effects of Urban Land Use."
     U.S. Geological Survey Circular 554, 1968.

Likens, G. E., ed.  "Nutrients and Eutrophication:  The
     Limiting Nutrient Controversy."  Special Symposia (Vol.
     1), American Society of Limnology and Oceanography,
     Allen Press, Lawrence, Kansas, 1972.

Likens, G. E.  "The Runoff of Water and Nutrients from
     Watersheds Tributary to Cayuga Lake, New York."
     Cornell University Water Resources and Marine Sciences
     Center, Technical Report No. 81, Ithaca, New York,
     1974.

Likens, G. E.  "The Chemistry of Precipitation in the
     Central Finger Lakes Region."  Cornell University Water
     Resources and Marine Sciences Center, Technical Report
     No. 50, Ithaca, New York, 1972.

Loehr, R. C.  "Characteristics and Comparative Magnitude
     of Nonpoint Sources."  Journal of the Water Pollution
     Control Federation, Vol. 46, No. 8, pp. 1849-1872,
     1974.

Mallory, C. W.  "The Beneficial Use of Storm Water."  U.S.
     Environmental Protection Agency, EPA-R2-73-139, 1973.

Man-Made Lakes:  Their Problems and Environmental Effects.
     W. C. Ackermann, G. F. White and E. B. Worthington,
     eds., American Geophysical Union, Washington, D. C.,
     1973.
                         A-121

-------
Mansue, L. J. and Commings, A. B.  "Sediment Transport by
     Streams Draining into the Delaware Estuary."  Water-
     Supply Paper 1532-H, U.S. Government Printing Office,
     Washington, D.C., 1974.

Mantri, V. and Kaushik, K.  "A Model of Time-Varying,
     Non-Uniform Flow in Open Channels."  Part II, 1975.

Manuel, A. D., Gustafson, R. H. and Welch, R. B.  "Three
     Land Research Studies."  National Commission on Urban
     Problems, Report No. 12, 1968.

Marsalek, J., et al.  "Comparative Evaluation of Three
     Urban Runoff Models."  Water Resources Bulletin, Vol.
     11, No. 2, pp. 306-328, 1975.

Martin, D. M. and Gaff, D. R.  "The Role of Nitrogen in the
     Aquatic Environment."  Academy of Natural Sciences,
     NTIS PB 213 496, Philadelphia, Pennsylvania, 1972.

Maryland Department of Water Resources, Burton C. Becker
     and Thomas R. Mills.  "Guidelines for Erosion and
     Sediment Control Planning and Implementation."  Pre-
     pared for U.S. Environmental Protection Agency, EPA R2-
     72-015, 1072.

McBean, E. A. and Loucks, D. P.   "Planning and Analysis of
     Metropolitan Water Resources System."  Cornell Uni-
     versity Water Resources and Marine Science Center,
     Technical Report No. 84, NTIS PB 235 257, Ithaca, New
     York, 1974.

McCuen, R. H.  "Flood Runoff from Urban Areas."  Water
     Resources Research Center, Technical Report No. 33,
     University of Maryland, College Park, Maryland, 1975.

McElroy, A.  D., et al.  "Interim  Report on Loading Functions
     for Assessment of Water Pollution from Nonpoint Sour-
     ces."   Prepared for U.S. Environmental Protection
     Agency  by Midwest Research Institute, Kansas City,
     Missouri, 1975.

McElroy, A.  D., Chiu, S. Y. and Aleti, A.  "Analysis of
     Nonpoint  Source Pollutants in the Missouri Basin
     Region."  U.S. Environmental Protection Agency, EPA
     600/5-75-004, 1975.
                         A-122

-------
McElroy, A. D., et al.  "Water Pollution from Non-Point
     Sources."  Water Research (Great Britain), Vol. 9, pp.
     675-681, 1975.

McHarg, Ian L.  "Design with Nature."  Doubleday/Natural
     History Press, Garden City,  New York, 1969.

McPherson, M. B., Orlob, G. T., Kibler, D. F. and Chen,
     C. W.  "Management of Urban Storm Runoff."  NTIS PB 234
     316, May 1974.

Meta Systems, Inc.  "Land Use Environmental Quality Rela-
     tionship."  Prepared for U.S. Environmental Protection
     Agency under contract 68-01-2622, 1975.

Metcalf and Eddy, Inc., University of Florida and Water
     Resources Engineers.  "Storm Water Management Model."
     (4 volumes).  Prepared for U.S. Environmental Protec-
     tion Agency, 11024DOC, 1971.

Metcalf and Eddy, Inc.  "Storm Water Problems and Control
     in Sanitary Sewers."  Prepared for the U.S. Environ-
     mental Protection Agency, 11024 EQG, 1971.

Metcalf and Eddy, Inc.  "Wastewater Engineering - Collection
     - Treatment - Disposal."  McGraw-Hill Inc., New York,
     New York, 1972.

Middlebrooks, E. J.  "Modeling the Eutrophication Process."
     D. H. Falkenborg and T. E. Moloney, eds., Ann Arbor
     Science Publishers, Inc., Ann Arbor, Michigan, 1974.

Miller, Fred P. and Wolf, D. C.  "Renovation of Sewage
     Effluents by the Soil."  Proceedings of the Second
     National Conference on Individual Wastewater Systems,
     National Sanitation Foundation, Ann Arbor, Michigan,
     pp. 87-101, 1976.

Miller, John C.  "Nitrate Contamination of the Water-Table
     Aquifer by Septic Tank Systems in the Coastal Plain of
     Delaware."  Water Pollution Control in Low Density
     Areas, University Press of New England, Hanover, New
     Hampshire, pp. 121-133, 1975.
                         A-123

-------
Miller, R. Adam, Troxell, J. and Lopold, L. B.  "Hydrology
     of Two Small River Basins in Pennsylvania before
     Urbanization."  U.S. Geological Survey Professional
     Paper 701-A, 1971.

Miller, W. L. and Erickson, S. P.  "Systematic Development
     of Methodogies in Planning Urban Water Resources for
     Medium Size Communities."  Purdue University Water
     Resources Research Center, Report No. 39, West Lafay-
     ette, Indiana, 1973.

Mills, D. M. and Watson, P. S.  "Regional Environmental
     Assessment Procedure."  University of Pennsylvania,
     Philadelphia, Pennsylvania, 1974.

Minneapolis-St. Paul Sanitary District.  "Dispatching
     System for Control of Combined Sewer Losses."  Prepared
     for the U.S. Environmental Protection Agency, 11020
     FAQ, 1971.

"Models for Managing Regional Water Quality."  R. Dorfman,
     H. Jacoby and H. A. Thomas, eds.  Harvard University
     Press, Cambridge, Massachusetts, 1972.

Moore, Charles A. and Silver, Marshall L.  "Nutrient Trans-
     port by SedimentWater Interaction."  Water Resources
     Center Research Report, Illinois University, Urbana,
     Illinois, 1973.

Morrow, N. L. and Brief, R. S.  "Elemental Composition of
     Suspended Matter in Metropolitan New York."  Environ-
     mental Science and Technology, Vol. 5, No. 9, 1971.

Murray, T., et al.  "Honey Hill:  A Systems Approach for
     Planning Multiple Use of Controlled Water Areas."
     Department of Los Angeles Research Office, Harvard
     University, Cambridge, Massachusetts, 1971.

"National Conference on Managing the Environment."  Spon-
     sored by the U.S. Environmental Protection Agency,
     1973.

National Water Monitoring Panel.  "Model State Water Moni-
     toring Program."  Environmental Protection Agency, EPA
     440/9-74-002, 1975.
                         A-124

-------
Newton, C. D., et al.  "Street Runoff as a Source of Lead
     Pollution."  Journal of the Water Pollution Control
     Federation, Vol. 46, No. 5, pp. 9991000, 1974.

"Non-Point Sources of Water Pollution."  Proceedings of a
     Southeastern Regional Conference at Virginia Poly-
     technic Institute, Virginia Water Resources Research
     Center, Blacksburg, Virginia, 1975.

Norton, J. L.  "The Identification and Measurement of
     Chlorinated Hydrocarbon Pesticides Accumulated from
     Urban Runoff."  Prepared for U.S. Environmental Pro-
     tection Agency by the Oklahoma Water Resources Research
     Institute, NTIS PB 226 307, 1973.

Norvell, W. A. and Frink, C. R.  "Water Chemistry and
     Fertility of TwentyThree Connecticut Lakes."  Con-
     necticut Agricultural Experiment Station, New Haven,
     Connecticut, 1975.

"NOX Emissions from Stationary Combustion Sources."
     Journal of Environmental Engineering and Design, p.
     641, June 1974.

"Nutrients in Natural Waters."  H. E. Allen and J. R.
     Kramer, eds.  John Wiley and Sons, New York, New York,
     1972.

Ogumrombi, Joseph A. and Dobins, William E.  "The Effects
     of Benthal Deposits on the Oxygen Resources of Natural
     Streams."  Journal of the Water Pollution Control
     Federation, Vol. 42, No. 4, pp. 538-552, 1970.

Ohio-Kentucky-Indiana Regional Council of Governments.  "A
     Method for Assessing Rural Non-Point Sources and its
     Application in Water Quality Management."  Cincinnati,
     Ohio, 1975.

Oliver, B. G., Milne, J. B. and La Barne, N.  "Chloride
     and Lead in Urban Snow."  Journal of the Water Pollu-
     tion Control Federation, Vol. 46, No. 4, pp. 766-771,
     1974.

"Organisms and Biological Communities as Indicators of
     Environmental Quality - A Symposium."  Sponsored by
     Ohio Biological Survey, Ohio Environmental Protection
     Agency and U.S. Environmental Protection Agency at Ohio
     State University, 1974.
                         A-125

-------
O1Shaughnessy, J. C. and McDonnell, A. J.  "Criteria for
     Estimating Limiting Nutrients in Natural Streams."
     Pennsylvania State University Institute for Research on
     Land and Water Resources Research, Publication No. 75,
     University Park, Pennsylvania, 1973.

Palmer, C. L.  "Feasibility of Combined Sewer System."
     Journal of the Water Pollution Control Federation, Vol.
     35, No. 2, pp. 162-167, 1963.

Palmer, C. M.  "A Composite Rating of Algae Tolerating
     Organic Pollution."  Journal of Phycology, Vol. 5, No.
     1, pp. 78-82, 1969.

Palmer, C. L.  "The Pollutional Effects of Storm-Water
     Overflows from Combined Sewers."  Sewage and Industrial
     Wastes, Vol. 22, No. 2, pp. 154-165, 1950.

Papadakis, C. N. and Preul, H. C.  "Testing of Methods for
     Determination of Urban Runoff."  Journal of the Hy-
     draulics Division, Proceedings of the American Society
     of Civil Engineers, Vol. 99, HY9, pp. 1319-1335, 1973.

Papadakis, C. N. and Preul, H. C.  "Urban Runoff Model."
     Journal of the Hydraulics Division, Proceedings of the
     American Society of Civil Engineers, Vol. 98, HY10, pp.
     1789-1804, 1972.

Parmele, L. H. and McGuinness, J. L.   "Comparisons of
     Measured and Estimated Daily Potential Evapo-transpira-
     tion in a Humid Region."  Journal of Hydrology  (Nether-
     lands) , Vol. 22, pp. 239-251, 1974.

Patri, T., et al.   "Early Warning System:  The Santa Cruz
     Mountains Regional Pilot Study."  Department of Land-
     scape Architecture, College of Environmental Design,
     University of  California, Berkeley, California, 1970.

Patrick, Ruth.   "A  Proposed Biological Measure of Stream
     Conditions  Based on a Survey of  the Conestoga Basin,
     Lancaster County, Pennsylvania."  Proceedings of the
     Academy of  Natural Sciences of Philadelphia, Vol. 101,
     Philadelphia,  Pennsylvania, December 17, 1949.

Pheiffer, T. H.  and Lovelace, N. L.   "Application of Auto-
     Qual Modeling  System to the Patuxent River Basin."
     U.S. Environmental Protection Agency, Annapolis Field
     Office  Technical Report No. 58,  EPA-903/9-74-013, 1973.
                         A-126

-------
Pitt, R. E. and Amy, G.  "Toxic Materials of Street Surface
     Contaminants."  NTIS PB 224-677, August 1973.

Pitt, R. E. and Amy, G.  "Toxic Surface Analysis of Street
     Surface Contaminants."  Prepared for the U.S. Environ-
     mental Protection Agency, 11034 FUJ, EPA R2-73-283,
     1973.

Plews,  Gary D.  "The Adequacy and Uniformity of Regulations
     for Onsite Wastewater Disposal - A State Viewpoint."
     Proceedings,  Second National Conference on Individual
     Onsite Wastewater Systems, National Sanitation Founda-
     tion, Ann Arbor, Michigan, pp. 139-144, 1976.

Plymouth Architectural and Planning Associates, Inc., and
     Betz Environmental Engineers, Inc.  "Workshop on Storm
     Water Management."  Prepared for Pennsylvania Depart-
     ment of Community Affairs, 1975.

Poertner, H. G.  "Practices in Detention of Urban Stormwater
     Runoff."  American Public Works Association, Chicago,
     Illinois, 1974.

Pollution Ecology of Freshwater Invertebrates.  C. W. Hart
     and S. L. H.  Fuller, eds.  Academic Press, Inc., New
     York, New York, 1974.

Pravoshinsky, N. A.  "Description of the Drainage of Street
     Flushing."  Soviet Hydrology, Selected Papers, Issue
     No. 2, pp. 168-170, 168, 1968.

Preul,  H. C.  "Contaminants in Ground Water near Waste
     Stabilization Ponds."  Journal of the Water Pollution
     Control Federation, Vol. 40, No. 4, pp. 659-669, 1968.

Processes, Procedures and Methods to Control Pollution
     Resulting from all Construction."  U.S. Environmental
     Protection Agency, Office of Air and Water Programs,
     EPA 430/9-73-00 7, 1973.

Putnam, A. L.  "Effects of Urban Development of Floods in
     the Piedmont Province of North Caroline."  U.S. Geo-
     logical Survey Open File Report, 1972.

Putnam, D. and Olson, T. A.  "An Investigation of Nutrients
     in Western Lake Superior."  School of Public Health,
     University of Minnesota, 1960.
                         A-127

-------
Quart, Edison L. , Young, R. H. F., Burbank, N. C. Jr. and
     Lau, L. S.  "Effects of Surface Runoff into the South-
     ern Sector of Kaneoke Bay."  Water Resources Research
     Center, University of Hawaii, January 1970.

Radziul, J. V., Cairo, P. R. and Sraoot, G. S.  "Does
     Stormwater Damage?"  Water Pollution Control Associa-
     tion of Pennsylvania Magazine, pp. 26-36, September-
     October 1975.

Radziul, J. V., Cairo, P. R. and Smoot, G. S.  "Does Storm-
     water Pollute?"  Water Pollution Control Association of
     Pennsylvania, 45th Annual Conference, Penn State Uni-
     versity, University Park, Pennsylvania, August 1973.

Ragan, R. M. and Dietemann, A. J.  "Impact of Urban Storm-
     water Runoff on Stream Quality."  Urbanization and
     Water Quality Control, American Water Resources Associ-
     ation, Minneapolis, Minnesota, 1975.

Randall, Clifford W., et al.  "Characterization of Urban
     Runoff in the Oceogran Watershed of Virginia."  Urbani-
     zation and Water Quality Control, American Water Re-
     sources Association, Minneapolis, Minnesota, 1975.

Rao, R. A. and Chenchagya, B. T.  "Probabilistic Analysis
     and Simulation of the Short Time Increment Rainfall
     Process."  Purdue University Water Resources Research
     Center, Technical Report No. 55, West Lafayette,
     Indiana, 1974.

Rao, R. A. and Rao, R. G. S.  "Analysis of the Effect of
     Urbanization on Rainfall Characteristics - I."  Purdue
     University Water Resources Research Center, Technical
     Report No. 50, West Lafayette, Indiana, 1974.

Rao, R. A. and Rao, R. G. S.  "Comparative Analysis of
     Estimation Method in Non-Linear Functional Models of
     the Rainfall-Runoff Process."  Purdue University Water
     Resources Research Center, Technical Report No. 56,
     West Lafayette, Indiana, 1974.

Reed, L. A.  "Sediment Characteristics of Five Streams
     Near Harrisburg, Pennsylvania, before Highway Con-
     struction." Geological Survey, Open File Report 74-410,
     Harrisburg, Pennsylvania, 1974;  Government Printing
     Office, Washington, D.C., 1976.
                         A-128

-------
Reeves, Mark and Miller, Edward E.  "Estimating Infiltration
     for Erratic Rainfall."  Water Resources Research, Vol.
     11, No. 1, pp. 102-110, 1975.

Remson, I., Fungarolc, A. A. and Lawrence, A. W.  "Water
     Movement in an Unsaturated Sanitary Landfill."  Journal
     of the Sanitary Engineering Division, Proceedings of
     the American Society of Civil Engineers, Vol. 94, SA2,
     pp. 307-317, 1968.

Responses of Fish to Environmental Changes.  W. Chavin, ed.
     Charles C. Thomas, Inc., Springfield, Illinois, 1973.

Rho, J. and Gunner, H. B.  "Micro Floral Response to
     Aquatic Weed Decomposition."  University of Massa-
     chusetts, Department of Environmental Sciences, Am-
     herst, Massachusetts, n.d.

Rickert, D. A., Hines, W. G. and McKenzie, S. W.  "Methods
     and Data Requirements for River-Quality Assessments."
     Water Resources Bulletin, Vol. 11, No. 5, pp. 1013-
     1039, 1975.

Roesner, L. A.  "A Storage, Treatment Overflow and Runoff
     Model for Metropolitan Master Planning."  Applications
     of Stormwater Management Models - 1975, EPA manual,
     1975.

Roesner, L. A.  "Quality Aspects of Urban Runoff."  Water
     Resources Engineers, Walnut Creek, California, n.d.

Roesner, L. A., et al.  "A Model for Evaluating Runoff-
     Quality in Metropolitan Master Planning."  American
     Society of Civil Engineers, Urban Water Resources Re-
     search Program, Technical Memo. No. 23, 1974.

Rogowski, A. S.  "Variability of the Soil Water Flow
     Parameters and their Effect on the Computation of
     Rainfall Excess and Runoff."  International Symposium
     on Uncertainties in Hydrologic and Water Resources
     Systems, Pennsylvania State University, University
     Park, Pennsylvania, n.d.

Rovers, F. A. and Parquhai, A.  "Infiltration and Landfill
     Behavior."  Journal of the Environmental Engineering
     Division, Proceedings of the American Society of Civil
     Engineers, Vol. 99, EE5, pp. 671-690, 1973.
                         A-129

-------
Ross, Hardies, O'Keefe, Babcock and Parsons, Inc.  "EPA
     Authority Affecting Land Use."  Prepared for U.S.
     Environmental Protection Agency, NTIS PB 235 331, 1974.

Ruane, R. J. and Fruh, E. G.  "Effects of Watershed Develop-
     ment on Water Quality."  Journal of the American Water
     Works Association, Vol. 65, No. 5, pp. 358-363, 1973.

Ruskin, A. J., ed.  "Aqueous Environmental Chemistry of
     Metals."  Ann Arbor Science Publishers, Inc., Ann
     Arbor, Michigan, 1974.

Ryden, J. C. , Syers, J. K. and Harris, R. F.  "Nutrient
     Enrichment of Runoff Waters by Soils, Phase 1: Phos-
     phorus Enrichment Potential of Urban Soils in the City
     of Madison."  University of Wisconsin Water Resources
     Center, Madison, Wisconsin, 1972.

Salvato, Joseph A., Jr.  Environmental Engineering and
     Sanitation.  John Wiley and Sons, Inc., New York, New
     York, 1972.

Salvato, Joseph A., Jr.  "Problems and Solutions of Onlot
     Sewage Disposal."  Proceedings of the Second National
     Conference on Individual Onsite Wastewater Systems,
     National Sanitation Foundation, Ann Arbor Michigan, pp.
     39-46, 1976.

Sankowski, Stephen J.  "Magnitude of Frequency of Floods
     in New Jersey with Effects of Urbanization."  U.S.
     Geological Survey, Special Report 38, 1974.

Sarme, P. B. S., Delleur, J. W. and Rao, A. R.  "A Program
     in Urban Hydrology, Part II:  An Evaluation of Rainfall
     Runoff for Small Urbanized Watersheds and the Effect of
     Urbanization on Runoff."  Prepared for U.S. Environ-
     mental Protection Agency, NTIS PB 198 043, 1969.

Sartor, J. D. and Boyd, G. B.  "Water Pollution Aspects of
     Street Surface Contaminants."  A study by the URS Re-
     search Company for the U.S. EPA  (EPA-R2-72-081), Wash-
     ington, D.C., November 1972.

Sartor, J. D., Boyd, G. B. and Agandy, F. J.  "Water Pol-
     lution Aspects of Street Surface Contaminants."
     Journal of Water Pollution Control Federation, Vol. 46,
     No. 3, pp. 458-467, 1974.
                         A-130

-------
Schultz,  J. M.  "Pollutional Characteristics of Stormwater
     Runoff from Urban, Serai-Urban and Rural Watersheds in
     the West Lafayette, Indiana Area."  Purdue University
     Department of Civil Engineering, M.S. Thesis, West
     Lafayette, Indiana, 1969.

Seattle,  Municipality of Metropolitan.  "Maximizing
     Storage in Combined Sewer Systems."  Prepared for the
     U.S. Environmental Protection Agency, 11022 ELK, 1971.

"Sediment Sources and Sediment Yields."  Journal of the
     Hydraulic Division, Proceedings of the American Society
     of Civil Engineers, Vol. 96, HY6, pp. 1283-1329, 1970.

"Sediment Transportation Mechanics:  Erosion of Sediment."
     Journal of the Hydraulics Division, Proceedings of the
     American Society of Civil Engineers, Vol. 88, HY4, pp.
     109-27, 1962.

Selected Urban Storm Water Runoff Abstracts.  U.S. Environ-
     mental Protection Agency, 1968-1970.

Shaheen,  Donald G.  "Contributions of Urban Roadway Usage to
     Water Pollution."  Prepared for the U.S. Environmental
     Protection Agency, EPA report No. 600/2-75-004, 1975.

Shaheen,  D. G.  "Passenger Cars are Big Water Polluters,
     Biospherics Finds.:  Chemical and Engineering News,
     Vol. 51, No. 27, p. 10, July 1973.

Shakla, S. S. and Leland, H. V.  "Heavy Metals: Review of
     Lead."  Journal of the Water Pollution Control Federa-
     tion, Vol. 45, No. 6, pp. 1319-1331, 1973.

Shannon,  E. E. and Brezonik, P. L.  "Relationships between
     Lake Trophic State and Nitrogen and Phosphorus Loading
     Rates."  Environmental Science and Technology, Vol. 6,
     No.  8, pp. 719-725, 1972.

Sikard, L. J. and Keeney, D. R.  "Laboratory Studies on
     Stimulation of Biological Denitrification."  Proceed-
     ings of the National Home Sewage Disposal Symposium,
     American Society of Agricultural Engineers, St. Joseph,
     Missouri, pp. 64-73, 1975.

Singer, P. C.  "Trace Metals and Metal Organic Interactions
     in Natural Waters."  Ann Arbor Science Publishers, Ann
     Arbor, Michigan, 1973.
                         A-131

-------
Snodgrass, William J. and O'Melia, Charles R.  "Predictive
     Model for Phosphorus in Lakes."  Environmental Science
     and Technology, Vol. 9, No. 10, pp. 937-944, 1975.

Soltero, R. A., Wright, J. C. and Horpestad, A. A.  "Effects
     of Impoundment on the Water Quality of the Bighorn
     River."  Water Research (Great Britain), Vol. 7, pp.
     343-354, 1973.

Spiegelman, Robert.  "Review of Techniques of Regional
     Analysis, with Particular Emphasis on Applicability to
     Regional Problems."  Stanford Research Center, Palo
     Alto, California, 1962.

Spooner, C. S., Promise, J. and Graham, P. H.  "A Demonstra-
     tion of Areawide Water Resources Planning for Metro-
     politan Washington,  (Draft)."  EPA, Washington, D.C.,
     n.d.

Sridharan, N. and Lee, G. F.  "Phosphorus Studies in Lower
     Green Bay, Lake Michigan."  Journal of the Water
     Pollution Control Federation, Vol. 46, No. 4, pp. 684-
     696, 1974.

Stankowski, Stephen J.  "Population Density as an Indirect
     Indicator of Urban and Suburban Land-Surface Modifica-
     tions."  U.S. Geological Survey, Geological Survey
     Research Professional Paper 800-B, pp. B219-B224, 1972.

Steinitz, C., et al.  "A Comparative Study of Resource
     Analysis Methods."  Department of LA Research Office,
     GSD, Harvard University, Cambridge, Massachusetts, July
     1969.

Sutherland, R. and McCuen, R., R.  "A Mathematical Model for
     Estimating Pollution Loadings in Runoff from Urban
     Streets."  Preprint from Proceedings of the Interna-
     tional Conference on Mathematical Models of Environ-
     mental Problems, Southampton U.K., 1975.

Sutterlin, A. M.  "Pollutants and the Chemical Senses of
     Aquatic Animals - Perspective and Review."  Chemical
     Senses and Flavor, Vol. 1, pp. 167-178, 1974.

Sylvester, R. 0. and DeWalle, F. B.  "Character and Sig-
     nificance of Highway Runoff Waters, A Preliminary
     Appraisal."  Washington State Highway Commission, Y-
     1441, 1972; NTIS PB 220-083, December 1972.
                         A-132

-------
Tao, P. C. and Delleur, J. W.  "Models of the Stochastic
     and Chronologic Structure, Prediction and Simulation of
     Runoff Sequences - Application to the Lower Ohio
     Basin."  Purdue Water Resources Research Center, West
     Lafayette, Indiana, 1975.

Tarzwell, Clarence M., ed.  "Biological Problems in,Water
     Pollution."  Third Seminar, Robert A. Taft Sanitary
     Engineering Center, Cincinnati, Ohio, 1962.

Task Group Report.  "Sources of Nitrogen and Phosphorus
     in Water Supplies."  Journal of the American Water
     Works Association, Vol. 59, pp. 344-366, 1967.

Terstries, M. L. and Stall, J. P.  "Urban Runoff by Road
     Research Lab Method."  Journal of the Hydraulics
     Division, Proceedings of the American Society of Civil
     Engineers, Vol. 95, HY6, pp. 1809-1834, 1969.

Tholin, A. L. and Keiber, C. J.  "The Hydrology of Urban
     Runoff."  Journal of the Sanitary Engineering Division,
     Proceedings of the American Society of Civil Engineers,
     Vol. 85, SA2, pp. 47-106, 1959.

Thomann, R. J.  Systems Analysis and Water Quality Manage-
     ment.  McGraw-Hill, New York, New York, 1972.

Thompson, G. B., et al.  "Variations of Urban Runoff
     Quality and Quantity with Duration and Intensity of
     Storms - Phase III."  Texas Tech University Water
     Resources Center, Lubbock, Texas, 1974.

Toebes, G. H. and Chang, T. P.  "Simulation Model for the
     Upper Wabash Surface Water System."  Purdue University
     Water Resources Research Center, West Lafayette,
     Indiana, 1973.

Torno, H. C.  "A Model for Assessing Impact of Stormwater
     Runoff and Combined Sewer Overflows and Evaluating
     Pollution Abatement Alternatives."  Water Research
      (Great Britain), Vol. 9, pp. 849-852, 1975.

Tourbier, Joachim.  "Water Resources as a Basis for Compre-
     hensive Planning and Development of the Christina River
     Basin."  Prepared for U.S. Department of the Interior
     by Water Resources Center, University of Delaware,
     Newark, Delaware, 1973.
                         A-133

-------
Tourbier, J. and Westmacott, R.  "Water Resources Protection
     Measures in Land Development" - A Handbook, Water
     Resources Center, University of Delaware, Newark, Dela-
     ware, pp. 14-16, April 1974.

Tuffey, T. J., Hunter, J. V. and Matulewich, V. A.  "Zones
     of Nitrification."  Water Resources Bulletin, Vol. 10,
     No. 3, pp. 555-564, 1974.

Turner, Collie and Braden, Inc.  "Storrnwater Management
     Report."  (Draft)  Prepared for New Castle County,
     Delaware by Turner, Collie and Braden, Inc., Houston,
     Texas, 1975.

URS Research Company.  "Water Quality Management Planning
     for Urban Runoff."   (Draft)  Prepared for U.S. En-
     vironmental Protection Agency, Contract No. 68-01-1846,
     August 1964.

Urban Land Institute.  "Residential Stormwater Model."
     Washington,  D. C.

"Urban Hydrology for Small Watersheds."  U.S. Department
     of Agriculture, Soil Conservation Service, Central
     Technical Unit, Hydrology Technical Note 1, 1973.

Urban Stormwater Management Modeling and Decision Making.
     Prepared for National Environmental Research Center by
     Florida University, PB 242-290, 1975.

Urban Systems Research and Engineering, Inc.  "Evaluation
     of the Use of Existing and Modified Land Use Instru-
     ments to Achieve Environmental Quality."  Urban Systems
     Research and Engineering, Inc., Cambridge, Massachu-
     setts, 1975.

U.S. Department of Agriculture.  "Predicting Rainfall-
     Erosion Losses from Cropland East of the Rocky Moun-
     tains."  Agricultural Research Service, Agriculture
     Handbook No. 282, 1965.

U.S. Department of Agriculture, Soil Conservation Service.
     "Soil Survey - Montgomery County, Pennsylvania."
     Government Printing Office, Washington, D.C., 1967.

U.S. Environmental Protection Agency.  "Characterization and
     Treatment of Urban Land Runoff."  EPA 670/2-74-096,
     December 1975.
                         A-134

-------
U.S. Environmental Protection Agency.  "Methods for Identi-
     fying and Evaluating the Nature and Extent of Nonpoint
     Sources of Pollutants."  EPA-430-73-014, Washington,
     D.C., 1973.

U.S. Department of Housing and Urban Development.  "Urban
     and Regional Informations Systems."  Government Print-
     ing Office, Washington, D.C.

Uttormark, Paul D.,  Chapin, John D. and Green, Kenneth M.
     "Estimating Nutrient Loadings of Lakes."  Water Re-
     sources Center, EPA 660/3-74-020, Madison, Wisconsin,
     1974.

Vice, R. B., Guy, H. P. and Ferguson, G. E.  "Sediment
     Movement in an Area of Suburban Highway Construction,
     Scott Run Basin, Fairfax County, Virginia."  U.S.
     Geological Survey, Water Supply Paper 1591-E, 1969.

Viessmar, W.  "Assessing the Quality of Urban Drainage."
     Public Works, Vol. 100, No. 10, pp. 89-92, 1969.

Vitale, A. M. and Sprey, P. M.  "Total Urban Water Pollution
     Loads:  The Impact of Stormwater."  Prepared for U.S.
     Environmental Protection Agency by Enviro Control,
     Inc., Rockville, Maryland, NTIS PB 231 730, 1974.

Walker, W. G., et al.  "Nitrogen Transformations During
     Subsurface Disposal of Septic Tank Effluent in Sands I:
     Soil Transformations."  Journal of Environmental Qual-
     ity, Vol. 2, pp. 475-480, 1973.

Walker, W. G., et al.  "Nitrogen Transformations During
     Subsurface Disposal of Septic Tank Effluent in Sands
     II:  Ground Water Quality."  Journal of Environmental
     Quality, Vol. 2, pp. 521-525, 1973.

Walker, William H.  "Groundwater Nitrate Pollution in Rural
     Areas."  Ground Water, Vol. 11, No. 5, pp. 19-22, 1973.

Wall, J. P., et al.   "Wisconsin Lakes Receiving Sewage
     Effluent."  Wisconsin Water Research Center, Technical
     Report 73-1, EPA R-801-863, 1973.

Wallace, Douglas A.  and Dague, Richard R.  "Modeling of
     Land Runofi Effects on Dissolved Oxygen,"  Journal of
     the Water Pollution Control Federation, Vol. 45, Mo. 8,
     pp. 1795-1809,  1973.
                         A-135

-------
Wallis, I. G.  "Options for Improving Water Quality."
     International Journal of Environment Studies, Vol. 6,
     pp. 107-120, 1974.

Warner, Maurice L. and Preston, Edward H.  "A Review of
     Environmental Impact Assessment Methodologies."  Pre-
     pared for U.S. Environmental Protection Agency, Office
     of Research, EPA 600/5-74-002, April 1974.

"Waste Lube Oils Pose Disposal Dilemma."  Environmental
     Science and Technology, Vol. 6, No. 1, p. 25, 1972.

"Water Pollution Aspects of Urban Runoff."  Prepared for
     the Federal Water Pollution Control Administration,
     U.S. Department of Interior, by the American Public
     Works Association, Government Printing Office, Wash-
     ington, D.C., 1969.

"Water Quality Criteria 1972."  Ecological Research Series,
     R3.73.033, Washington, D.C., March 1973.

"Water Quality Management for Urban Runoff."  U.S. Environ-
     mental Protection Agency.  NTIS PB 241 689.

"Water Quality Management Planning for Urban Runoff."  U.S.
     Environmental Protection Agency, EPA 440/9-75-004,
     1975.

"Water Quality Models for Urban and Suburban Areas."
     Prepared for U.S. Environmental Protection Agency, NTIS
     PB 238 622, University of Nebraska, Lincoln, Nebraska,
     1974.

Water Resources Center, University of Delaware.  Water
     Resources Protection Measures in Land Development - A
     Handbook.  University of Delaware Water Resources
     Center, 1974.

Water Resources Council.  "A Summary Analysis of 19 Tests
     of Proposed Evaluation Procedures on Selected Water and
     Land Resources Projects."  1970.

Weibel, S. R., Anderson, R. J. and Woodward, R. L.  "Urban
     Land Runoff as a Factor in Stream Pollution."  Journal
     of the Water Pollution Control Federation, Vol. 36, No,
     7, pp. 914-924, 1964.
                         A-136

-------
Weibel, S. R.  "Urban Drainage as a Factor in Eutrophica-
     tion."  Eutrophication:  Causes, Consequences, Correc-
     tives.  Proceedings of a Symposium, National Academy of
     Sciences, Washington, D.C., 1969.

Weibel, S. R., et al.  "Pesticides and Other Contaminants
     in Rainfall and Runoff."  Journal of the American Water
     Works Association, Vol. 58, No. 8, pp. 1075-1084, 1966.

Weibel, S. R., et al.  "Treatment of Urban Stormwater
     Runoff."  Journal of the Water Pollution Control Feder-
     ation, Research Supplement, Vol. 40, No. 5, Part 2, R
     162-R170, 1968.

Welb, D. M., et al.  "Variation of Urban Runoff Quality with
     Duration and Intensity of Storms - Phase II."  NTIS No.
     PB-223 930, 1973.

Werner, R. G.  "Water Quality-Limnological Concerns about
     Forest Fertilization."  Forest Fertilization Symposium
     Proceedings, College of Engineering Science and Forestry,
     S.U.N.Y. Warrensburg, New York Campus, 1973.

Werschmeir, W. H. and Smith, D. D.  "Predicting Rainfall
     Erosion Losses from Cropland East of the Rocky Moun-
     tains."  Agricultural Handbook 282, U.S. Government
     Printing Office, Washington, D.C., 1965.

Weston, Roy F., Inc.  "Combined Sewer Overflow Abatement
     Alternatives."  Prepared for U.S. Environmental Pro-
     tection Agency by Roy F. Weston, Inc., West Chester,
     Pennsylvania, 11024 EXF, 1970.

Weston, Roy F., Inc.  "Lancaster County Planning Commission
     Storm Drainage Study."  Roy F. Weston, Inc., West
     Chester, Pennsylvania, 1970.

Whipple, William Jr.  "Urban Runoff:  Quantity and Quality."
     Proceedings of a Research Conference at Rindge, New
     Hampshire, American Society of Civil Engineers, New
     York, New York, 1974.

Whipple, William Jr., ed.  "Urbanization and Water Quality
     Control."  American Water Resources Association, Min-
     neapolis, Minnesota, 1975.
                         A-137

-------
Whipple, William Jr.,  et al.  "Unrecorded Pollution and
     Dynamics of Biochemical Oxygen Demand."  Rutgers
     University, Water Resources Research Institute, New
     Brunswick, New Jersey, 1974.

Whipple, William Jr. and Hafschmidt, M. M.  "Reorientation
     of Urban Water Resources Research."  Rutgers University
     Water Resources Research Institute, New Brunswick, New
     Jersey, 1976.

Whipple, W. Jr. and Hunter, J. V.  "Non-Point Sources and
     Planning for Water Pollution Control."  Presented at
     the 48th Annual Water Pollution Control Federation
     Convention, Miami Beach, Florida, 1975.

Whipple, W., Hunter, J. V. and Yu, S. L.  "Unrecorded
     Pollution from Urban Runoff."  Journal of Water Pol-
     lution Control Federation, Vol. 46, No. 3, pp. 873-885,
     1974.

Wilber, William G. and Hunter, Joseph V.  "Contributions of
     Metals Resulting from Stormwater Runoff and Precipita-
     tion in Lodi, New Jersey."  American Water Resources
     Association, pp.  45-58, June 1975.

Wilber, William A. and Hunter, Joseph V.  "Heavy Metals
     in Urban Runoff."  Rutgers University Department of
     Environmental Science, New Brunswick, New Jersey, 1975.

Wiley, Morris A.  The Petroleum Industry and Cost Effective
     Water Quality Planning: I:  Assessments of PL  92-500
     and II:  Improvement of Cost Effectiveness.  Presented
     at a Symposium on Urbanization and Water Quality
     Control at Rutgers University, New Brunswick,  New
     Jersey, 1975.

Williams, J. R.   "Sediment Yield Prediction with Universal
     Equation Using Runoff Energy Factor."  USDA Resource
     Service, Oxford, Mississippi, November 28-30,  1972.

Williams, J. R. and Berndt, H. D.   "Sediment Yield  Computed
     with Universal Equation."  Journal of the Hydraulics
     Division, Proceedings of the American Society  of Civil
     Engineers, Vol. 98, HY12, pp.  2087-2098, 1972.
                         A-138

-------
Williams, L. G., Joyce, J. C. and Monk,  J.  T.  Jr.   "Stream-
     Velocity Effects on the Heavy Metals Concentration."
     Journal of the American Water Works Association,  Vol.
     65, No. 4, pp. 275-279, 1973.

Williams, J. R.  "Sediment Routing for Agricultural Water-
     sheds."  Water Resources Bulletin,  Vol.  11, No.  5,  pp.
     965-974, 1975.

Wischmeier, W. H., Johnson and Cross.  "A Soil Erodibility
     Nomograph for Farmland and Construction  Sites."
     Journal of Soil Water Conservation, Vol.  26,  pp.  189-
     193, 1971.

Wischmeier, W. H. and Smith, D. D.   "Rainfall  Energy and
     its Relationship to Soil Loss."  Transactions of  the
     American Geophysical Union, Vol. 39, No.  2, 1958.

Wolman, G. Gordan.  "Stream Standards:   Dead  or Hiding?"
     Journal of the Water Pollution  Control Federation,  Vol.
     46, No. 3, 1974.

Wolman, M. G. and Schick, A. D.  "Effects of  Construction
     on Fluvial Sediment: Urban and  Suburban  Areas of  Mary-
     land."  Water Resources Research, Vol. 3,  No.  2,  pp.
     451-462, 1967.

Wulkowicz, G. M. and Saleem, Z. A.   "Chloride  Balance  of
     an Urban Basin in the Chicago Area."   Water Resources
     Research, Vol. 10, No. 5, pp. 974-982, 1974.

Yen, Ben Chie.  "Methodologies for Flow  Prediction in
     Urban Storm Drainage Systems."  Prepared  for  U.S.
     Environmental Protection Agency, NTIS  PB  225-480,  1973,

Young, R. A. and Wiersma, J. L.  "The Role  of  Rainfall
     Impact on Soil Detachment and Transport."  Water  Re-
     sources Research, Vol. 9, No. 6, pp. 1629-1636,  1973.

Young, C. E.  Current Research on Land Application of
     Waste Water and Sludge.  Penn State University,  Insti-
     tute for Research on Land and Water Resources,  Uni-
     versity Park, Pennsylvania, 1975.

Yu, S. L., Whipple, W. and Hunter, J. V.  "Assessing
     Unrecorded Organic Pollution from Agricultural, Urban
     and Wooded Lands."  Water Research  (Great Britain),
     Vol. 9, pp. 849-852, 1975.
                          7i_1 TQ       ftU.S. GOVERNMENT PRINTING OFFICE: 1976 7ZO-117/87<)i

-------