United States
             Environmental Protection
              Office Of
              The Administrator
EPA 101/F-90/046
January 1991
Urban Storm Water Runoff
And Ground-Water Quality
                                        Printed on Recycled Paper

                Jayne C. Nussbaum

                November 26, 1990

       Lyndon B. Johnson School of Public Affairs
           The University of Texas at Austin

  National Network for Environmental Management Studies
         U.S. Environmental Protection Agency
                   US. Environmental Protection Agency
                   Region 5 Library (PL-12J)
                   77 West Jackson Blvd., 12th Floor
                   Chicago, IL 60604-3590


This report was furnished to the U.S. Environmental Protection
Agency by  the student identified  on the  cover  page,  under a National
Network for Environmental  Management  Studies  fellowship.

The  contents are essentially  as  received from the  author.  The
opinions, findings,  and conclusions  expressed are  those  of the author
and  not necessarily  those of the U.S. Environmental  Protection
Agency.  Mention,  if any, of company, process, or product names  is
not to be considered as an endorsement by the U.S.  Environmental
Protection  Agency.

Urban storm water runoff is a form of nonpoint source pollution which is intimately tied to
the hydrologic cycle, human activities, and urbanization.  Traditionally, scientific research,
water resource management, and regulations have focused on the effects of urban storm
water on surface water quality, and seldom on ground-water quality. The Safe Drinking
Water Act and other narrowly focused federal legislation, along with state and local laws
and ordinances, provide a legislative patchwork that attempts to protect the nation's
ground-water quality. A clear and enforceable comprehensive federal policy protecting
ground-water quality is needed to provide direction to state and local governments.

The purpose of this report is to provide a summary of information and key references on
urban storm water in relation to ground-water protection for United States Environmental
Protection Agency (EPA) staff and others responsible for protecting ground-water quality.
This report presents a brief overview of the major literature describing: 1) the quality and
chemistry of urban storm water runoff, 2) its effects on ground-water resources, and 3)
current management practices, strategies, and regulations that attempt to reduce ground-
water contamination from urban storm water. Also included is a selected bibliography and
list of contacts at the federal, state, and local levels of government.

This report was made possible by a fellowship grant from the National Network of
Environmental Management Studies Program of the U.S. Environmental Protection
Agency.  This grant provided the author funding for a three month internship at U.S. EPA
Region 10 which fulfilled the internship degree requirement  for a Masters of Public Affairs
from the Lyndon B. Johnson School of Public Affairs. I would especially like to thank
Jonathan Williams at U.S. EPA Region 10 for his invaluable guidance and help in writing
and editing this report.

                          TABLE OF CONTENTS

Chapter Title                                                                 Eag

Executive  Summary                                                        1

1  Introduction                                                             2
      1.1 General Description of Nonpoint Source Pollution                        2
      1.2 General Description of Urban Storm Water Runoff                        2
             1.2.1  Hydrologic Cycle
             1.2.2  Quantity of Urban Storm Water
             1.2.3  Quality of Urban Storm Water
      1.3 Urban Storm Water Runoff and Ground-Water Quality                    6
      1.4 Background                                                        6

2  Quality and Chemistry of Urban Storm Water Runoff                    8
      2.1 Introduction                                                        8
             2.1.1  How Pollutants Are Reported
             2.1.2 Problems Comparing Data
      2.2 Conventional Parameters                                             9
             2.2.1  Physical
             2.2.2 Chemical
             2.2.3  Oxygen Demand
             2.2.4 Nutrients
             2.2.5  Bacteria/Viruses
             2.2.6 Studies
      2.3 Toxicants                                                          16
             2.3.1  Metals
             2.3.2 Organics
      2.4 Factors Affecting Urban Storm Water Quality                            24
             2.4.1  Urban Land Use
             2.4.2 Sources of Pollutants
             2.4.3 Geographic location

3  Urban Storm Water Runoff and Ground-Water Quality                   31
      3.1 Ground-Water Recharge from Urban Storm Water                        31
      3.2  Studies                                                            31
             3.2.1  Nationwide Urban Runoff Program (NURP)
             3.2.2 Long Island. NY NURP
             3.2.3 Fresno, CA NURP
             3.2.4 Spokane, WA
      3.3 Contamination Risks to Ground-Water                                 33

4  Urban Storm Water Quality Management Practices                        35
      4.1 Introduction                                                        35
      4.2 Structural Controls                                                  36
             4.2.1  Detention/Retention
             4.2.2 Infiltration
             4.2.3 Biofiltration
             4.2.4 Oil-water Separators
             4.2.5 Prevention of Erosion on Construction Sites

Chapter Title                                                                 Pape

      4.3 Non-structural Controls                                              42
             4.3.1 Housekeeping
             4.3.2 Primary or Secondary Treatment of Storm Water
             4.3.3 Investigative Monitoring and Site Visits

5  Policies  and Regulations                                                 44
      5.1 Introduction                                                        44
      5.2 Water Quality Act of 1987                                            45
             5.2.1 Section 402
             5.2.2 Sections 401 and 503
             5.2.3 Current EPA Ruling on Urban Storm Water
      5.3 Safe Drinking Water Act                                             46
             1. National Drinking Water Regulations
             2. Underground Injection Control
             3. Sole Source Aquifer Program
             4. Wellhead Protection Program
      5.4 Other Federal Statutes - FIFRA, TOSCA, RCRA, CERCLA                48

6  Conclusions and Recommendation                                       50
      6.1 Introduction                                                        50
      6.2 Assessment of the Water Quality Act of 1987                            50
      6.3 Assessment of the Safe Drinking Water Act                              51
      6.4 Recommendations                                                  52

Appendix A Summary of Analytical Chemistry Findings from NURP                53
             Priority Pollutant Samples.

Appendix B Bibliography                                                     57

Appendix C List of Contacts                                                  61

                         List of Tables and Figures
Table 2-1.

Table 2-2.

Table 2-3.

Table 2- 4.

Summary of Major Conventional Parameters of Urban
Storm Water Compared to Water Quality Standards and
Secondary Waste Water Effluent

Summary of Minor Conventional Parameters of Urban
Storm Water Compared to Water Quality Standards.

Summary of Metals Found in Urban Storm Water
Compared to Water Quality Standards.

Sources of Urban Storm Water Pollutants.




Figure 1.

Figure 1-2.

Figure 2-1.

Figure 2-2.

Figure 2-3.
Hydrologic Cycle.

Typical Changes in Runoff Volume Resulting
from Paved Surfaces.

Comparison of Ranges of Metals Concentrations Found in
Urban Storm Water to the National Primary Drinking
Water Regulations (NPDWR).

Comparison of Ranges of Metals Concentrations Found in
Urban Storm Water to the National Primary Drinking
Water Regulations (NPDWR).

Comparison of Ranges of Metals Concentrations Found in
Urban Storm Water to the National Secondary Drinking
Water Regulations (NSDWR).






                           EXECUTIVE SUMMARY
Urban storm water runoff is a form of nonpoint source pollution which is intimately tied to
the hydrologic cycle, human activities, and urbanization. Pollutants such as nutrients,
heavy metals, and pesticides are commonly found in urban storm water. The quality and
chemistry of urban storm water is highly variable and dependent on many factors,
including rainfall characteristics and land use.  Urban storm water pollutants can have both
short and long term ecological and human health effects, and thus represent a major
environmental concern.

Traditionally, scientific research, water resource management, and regulations have
focused on the effects of urban storm water on surface water quality (rivers, lakes, and
estuaries), and seldom on ground-water quality. The Clean Water Act of 1987 and the
current EPA ruling regarding the issuance of National Pollution Discharge Elimination
System permits for urban storm water discharges are only for those point discharges into
surface water bodies.and not ground water. In the last few years more notice has been
given to possible ground-water contamination  from urban storm water because of
increasing urbanization and dependence on ground water for drinking water. However,
there is no comprehensive national legislation or policy that protects ground water quality.

The Safe Drinking Water Act and other narrowly focused federal legislation, along with
state and local laws and ordinances, provide a legislative patchwork that attempts to protect
the nation's ground water quality. To fill the void, some states are using the National
Drinking Water Regulations as ground-water quality standards for lack of federal
standards. Other federal programs such as the Sole Source Aquifer Program are severely
limited in their scope and effectiveness in protecting ground-water quality. A clear and
enforceable comprehensive federal policy protecting ground-water quality is needed to
provide direction to state and local governments. This could take the form of a broad
policy of nondegradation of the existing quality of a given aquifer or a specific set of
ground-water quality standards similar to the National Drinking Water Regulations.

The purpose of this report is to provide a summary of information and key references on
urban storm water in relation to ground-water protection for United States Environmental
Protection Agency (EPA) staff and others responsible for protecting ground-water quality.
This report presents a brief overview of the major literature describing: 1) the quality and
chemistry of urban storm water runoff,  2) its effects on ground-water resources, and 3)
current management practices, strategies, and regulations that attempt to reduce ground-
water contamination from urban storm water. Also included is a selected bibliography and
list of contacts at the federal, state, and local levels of government

                                 CHAPTER  1


1.1  General Description of Nonpoint  Source  Pollution

Nonpoint source water pollution is typically defined as pollution that originates from
sources that are diffuse and difficult to pinpoint. Another broad definition of nonpoint
source pollution is when the rate of materials entering receiving waters (such as sediments,
nutrients, or toxicants generated from land use or the atmosphere) exceeds natural levels
(Novotny and Chesters, 1981, p. 541). In contrast to point source pollution (such as
municipal wastewater effluent), nonpoint source pollution is intermittent, highly variable,
and closely related to human alterations to the landscape and the watershed hydrology of an

Nonpoint pollution sources fall into two broad categories related to land use, rural and
urban.  Rural sources include agriculture, logging, and mining activities. Urban sources
include street litter, automobiles, animal wastes, combined sewer overflows, street salting,
construction, and industrial activities.

Nonpoint source pollution is hard to identify and monitor, and its full impact is not yet well
known. Nevertheless, pollutants from nonpoint sources can have both short and long term
ecological and human health effects, and thus represent a major environmental concern.
Two examples of short term  or "shock" effects are fish kills due to the input of oxygen
consuming organic material that drastically decrease dissolved oxygen levels and closures
of shellfish beds due to bacterial contamination from combined sewer overflows. Long
term cumulative effects include the eutrophication of surface waters from nutrient
overloading or possible contamination of a drinking water aquifer. Another concern is the
accumulation of pollutants in sediments and their possible continual release into receiving

1.2  General Description of Urban  Storm Water Runoff

Urban storm water runoff usually consists of surface runoff from such nonpoint sources as
streets, parking lots,  and yards; but it may also have point source contributions from
accidental spills and  leaks or illegal dumping of commercial and household wastes into
storm drains. Urban runoff commonly discharges as a point source of pollution, such as a
storm sewer outfall or injection well.  However, urban runoff may also percolate to ground
water as a nonpoint discharge of contaminants.

One example of urban storm water containing nonpoint source pollutants that are possibly
contaminating ground water exists in Spokane, WA. Spokane's drinking water supply
comes from the Spokane-Rathdrum Aquifer, which is recharged in some vulnerable areas
by urban runoff.  An estimated 75% of urban  storm water in Spokane is disposed of in
Class V injection wells (Miller, 1990). Calcium chloride is used for de-icing roads in
Spokane and is found in urban runoff during the winter. During the winter, elevated levels
of chloride and calcium were found in ground water, and were attributed to recharge from
contaminated urban runoff in dry wells (Miller, 1985).

An example of ground-water contamination by urban storm water from point source
pollutants was discovered in Vancouver,  WA. In 1989, tetrachloroethylene or
perchloroethylene (PCE) from a dry cleaners contaminated the water table via dry wells. It
is theorized that 15 to 20 years ago, accidental or intentional dumping of PCE occurred.

Storm water that collected in a storm drain and infiltrated the ground through a dry well
helped disperse the PCE into the ground water. PCE is thought to be a "probable"
carcinogen by U.S. EPA and does not dissipate very rapidly (Westfall, 1989, sec. A, p.
1). One estimated cost of the ground-water cleanup in 1989 was approximately $2 million
(Ryll, 1989, sec. A, p.  1).

1.2.1   Hydrologic Cycle

Urban storm water represents only a portion of the hydrologic cycle in which water
circulates on the earth. A simplified explanation of the hydrologic cycle is illustrated in
Figure 1. Water reaches the land surface as precipitation. Precipitated water may runoff,
collect in surface waters, evaporate, infiltrate the ground to be either held or transpired by
plants, or percolate to the saturated zone. Once in an aquifer, water eventually moves
towards a discharge point, but can remain in the ground anywhere from several hours to
thousands of years.

1.2.2  Quantity of Urban  Storm Water

The quantity or volume of storm water runoff is related to the amount of precipitation and
degree of urbanization.  Therefore, storm water quantity is very variable and specific to an
individual storm event and site. Storm events are highly dynamic and the amount of
rainfall varies tremendously from storm to storm. Total rainfall volume depends on the
intensity and duration of the rain, which in turn depend on the geographic location and

Urbanization markedly alters natural drainage patterns. Pavement, buildings, and
compacted soils form impervious layers that do not allow rainfall to infiltrate the ground;
instead it collects and forms surface runoff (Novotny and Chesters, 1981, p. 7; Canning,
1988, pp. 1,5). Therefore, increased urbanization and the amount of impervious ground
cover increases the volume and the rate surface runoff (See Figure 1-2). Mar et al. also
discovered that the quantity of runoff can vary significantly on elevated and curbed
sections.of highways (1982, p. 18).

In contrast, overland water flow in forests is very limited because water is slowed and
trapped by the leaf duff and thick organic topsoils which allow it to filter into the ground
(Eckel, 1990). Grassland and cultivated agricultural areas generally yield less runoff than
urban areas, but more than forest land.

Increases in the quantity of urban storm water usually cause increased frequency and
volume of flooding, which can threaten human lives and property.  Also, the quality of
storm water or concentrations of pollutants in storm water is intimately tied to storm water
quantity which is discussed in the following section.

1.2.3  Quality of Urban Storm Water

The quality of storm water is also extremely variable, hard to generalize, and specific to
particular sites and storm events.  Concentrations of contaminants may range in several
orders of magnitude at any given site. Pollutant "mass loadings are very strongly
influenced by the amount of precipitation and runoff, and estimates of mass loads will be
biased by the size of monitored storm events."(U.S. EPA Nationwide Urban  Runoff
Program (NURP), 1983, p. 9-2). Novotny and Chesters state that "It is a known fact that
there is a close relationship of pollutant loadings from area! sources to the rain volume and
intensity, infiltration and storage characteristics of the watershed, and other hydrologic
parameters."(1981, p. 77). Other factors such as the frequency of storm events,  land use,

Figure 1
Hydrologic Cycle

             10% RUNOFF.


       30% RUNOFF
                                         , EVAPO
                                                55% RUNOFF
          Source: J.T. Tourbitr tod R. Wtstmacott, Witir Rtiourcu Pnttetian Ttchnology: A Hindbock of Mttturu to Prattet Hfitir
                Httevrtu in L*nd DtHlopaiuit, p. 3.

     Figure 1-2. Typical Changes in Runoff Volume Resulting from Paved Surfaces.
traffic density, and human and animal population densities affect the presence and
concentrations of pollutants found in urban storm water (Randall and Grizzard, 1983, p.
59). In performing regression analyses on the NURP data, Driver and Lystrom concluded
that "Total storm rainfall and total contributing drainage area are the most significant
variables in all of the storm-runoff-load relations. "(1986, p. 132). Other important
variables sited were land use, impervious cover, population density, rainfall duration, and
other storm event characteristics (Driver and Lystrom, 1986, p. 132).

Pollutant loadings in highly urbanized areas are also controlled by the amount and
composition of pollutants in the atmosphere and refuse accumulated on impervious
surfaces, which eventually end up in surface runoff. "Impervious areas accumulate
pollutants during dry periods, and then pollutants are washed off of the surfaces during
rainfall events, thus adding to the quantities washed out of the atmosphere." (Randall and
Grizzard, 1983, p. 63).  Urban storm water can contain pollutants with concentrations on
the same order of magnitude'or greater than municipal secondary wastewater effluent
(Novotny and Chesters, 1981, p. 11; NURP, 1983, p. 9-4). (See Table 2-1 of this report
for comparisons of concentrations.)  In  suburban and less urbanized areas soil erosion and
soil-adsorbed pollutants may play a greater role in the quality of storm water runoff
(Novotny and Chesters, 1981, p. 312).  The NURP Study found that the only statistically
significant difference in urban storm water quality was between urban and open/non-urban
land use categories (Athayde, Myers, and Tobin, 1986, p. 221).

1.3  Urban Storm Water Runoff and Ground-Water Quality

Urban storm water poses three types of problems: 1) flooding from the increased volume
and scouring; 2) sediment deposition; and 3) chemical and biological pollutants (Puget
Sound Water Quality Authority (PSWQA), 1986, p. 4-92). Unmanaged or uncontrolled
urban storm water poses a significant threat to the quality of receiving waters which include
rivers, lakes, streams, estuaries, wetlands, and ground water. The NURP study adopted a
useful three-level definition of when urban nonpoint source pollution becomes a problem:
1) impairment or denial of beneficial uses; 2) water quality criterion violation; and 3) local
public perception (1983, p. 3-5).

Ground-water contamination may occur from urban storm water recharge.  Contaminated
urban storm water recharge of ground water may be either natural or artificial. Natural
infiltration occurs when the landscape has not been altered by humans. Artificial recharge
results when urban storm water is trapped by control devices such as detention/retention
basins, grassy swales, injection wells, and reservoirs, and allowed to infiltrate the ground.

Surface water contaminated by urban storm water may also enter ground water. Whenever
surface water is at a higher hydraulic head than surrounding ground water, the surface
water will migrate toward the ground water. The rate of migration depends upon the
type(s) of earth materials between the surface water body and ground water.

From a public health standpoint, the most serious threat to ground water quality is to
drinking water sources. Ground water could be contaminated by heavy metals or organic
compounds in vulnerable areas where urban storm water recharges a drinking water
aquifer. Contaminated ground water that contributes to base flow of surface water could
also be a source of pollutants such as nutrients that cause eutrophication, and threaten
aquatic life. If contaminated ground water were used for irrigation in agriculture, toxicants
could enter the food supply or excessive amounts of salts could damage crops.

Urban storm water management techniques which reduce ground water recharge may
adversely impact drinking water supplies. Canning notes that "...the diminishment of
infiltration to the ground water reduces aquifer recharge which results in low summer
stream flows and water well levels."(1988, p. 5). This could be significant for
communities that depend heavily on ground water for drinking water if an aquifer could not
sufficiently recharge because of water lost to surface runoff and receiving waters.
Furthermore, water quality could suffer in coastal areas subject to saltwater intrusion if
ground water recharge rates decline.

Ground-water quality can be difficult and expensive to monitor. Once polluted, aquifers
are generally very difficult and expensive to clean up. In fact, technological or financial
constraints render some ground-water resources impossible or impractical to clean up.
Therefore, efforts should focus towards reducing the amount of contaminants entering
urban storm water, and then effectively managing storm water to prevent ground-water

1.4   Background

Up until the late 1960s and 1970s, nonpoint source pollution and the quality of urban storm
water runoff was not a widespread public concern. Historically, the focus of urban storm
water management has been to drain flood waters as quickly as possible (PSWQA, 1986,
p. 4-92; NURP, 1983, p. 1-1; Novptny and Chesters, 1981, p. 2).  This practice
sometimes causes degradation to wildlife habitat and  even increased flooding downstream.

The next focus of storm water management was to control runoff on-site, but was still
mainly concerned with the quantity of storm water (Canning, 1988, p. 1).

Currently, storm water quality issues are also being examined because of increased
knowledge about the possible harmful effects of contaminants found in urban storm water,
and subsequent federal regulatory involvement The 1972 amendments to the Federal
Water Pollution Control Act, (referred to as the Clean Water Act), prohibits the discharge
of any pollutant to navigable waters from a point source unless the discharge is authorized
by a National Discharge Pollution Elimination System (NPDES) permit Traditionally, the
NPDES program has concentrated on reducing pollutants in industrial and municipal
wastewater point source discharges, but now also includes nonpoint source pollution.
Urban storm water is unusual because it often discharges as a point source, but contains
contaminants derived from point and nonpoint sources.

The U.S.EPA NURP study collected and analyzed urban storm water quality data in 28
cities and evaluated available management controls. The study found that urban storm
water is extremely variable in quality, and can contain pollutants with concentrations on the
same order of magnitude of secondary wastewater effluent. The "National Water Quality
Inventory,  1986 Report to Congress" concluded that "pollution from diffuse sources as
runoff from agricultural and urban areas is cited by the States as the leading cause of water
quality impairment." (53 FR, 1988, p. 49417). In 1987, Congress reauthorized the Clean
Water Act and added Section 402, which requires EPA to develop regulations to issue
NPDES permits for urban storm water discharges, treating them as a point discharges.
EPA is expected to issue the final rule on storm water discharges by municipalities over
250,000 in population and industry in November 1990.

The effects of urban storm water runoff on surface water have been studied at length,
however, there has been little research published on the impacts of urban runoff on ground-
water quality. Nonetheless, available information on the quality and chemistry of urban
runoff may be useful to those responsible for protecting ground-water quality and
managing urban runoff. Urban runoff management practices are still evolving and have
ground-water implications, even if flood control and surface water quality are the focus of

                                 CHAPTER 2


2.1   Introduction

The quality and chemistry of urban storm water has been characterized in detail over the
past twenty years by many researchers with similar results and conclusions about the
constituents and their concentrations in urban storm water (Sartor and Boyd, 1972; Miller
and McKenzie, 1978; U.S. EPA, 1983; Pitt and Bissonette, 1983; Galvin and Moore,
1982; Wang, etal., 1983; Merrill, 1989). The urban storm water quality section of this
report will: 1) identify the types of parameters and ranges of contaminant concentrations
generally found in urban storm water, 2) discuss possible sources of pollutants, and their
toxic effects, with an emphasis on data collected in the Pacific Northwest region of the
United States.

2.1.1  How  Pollutants Are Reported

Pollutants and other parameters, such as pH and conductivity, can be broken down into
two broad categories: 1) standard or conventional and 2) toxicants.  In turn, these
categories can be broken down further into subgroups. Pollutants concentrations are
usually reported either as concentrations of pollutants in discrete samples or as loading
estimates of total inputs of pollutants to receiving environments.

Concentrations of pollutants are reported in milligrams per liter (mg/L) which equals parts
per million (ppm) or micrograms liter (ug/L) which equals parts per billion (ppb). The
concentrations and the amount of runoff are the basis on which  pollutant mass loadings in
the water column and sediments can be estimated (NURP, 1983, p. 9-2; Hvitved-
Jacobsen, 1985, p. 347).

Pollutant mass loadings can be used to characterize present loadings and future loadings
under expected changes in land use (Randall and Grizzard, 1983, p. 83). The estimation of
pollutant loadings are reported in many different units. Some examples are as kilograms
per hectare per year (kg/ha/y), pounds per acre (lbs./acre), lbs7acreAnches of rainfall, and
pounds per curb mile (lb./curb mi.). This lack of standard unit  usage makes comparison of
studies more difficult.

In recognition of the growing concern about the effects of urban storm water, the United
States Environmental Protection Agency's (U.S. EPA) Nationwide Urban Runoff Program
(NURP) from 1978-1983 set out to characterize the quality of urban storm water, its effects
on receiving waters, and the effectiveness of management controls of removing pollutants.
Data mainly on conventional pollutants was collected from sites in 28 cities with a variety
of climates, geologic settings, land use types, and population densities. The primary water
quality statistic the NURP study used to compare data  was the event mean concentration
0EMC), which is based on flow weighted composite samples for each storm event at each
site.  EMC equals the total constituent mass discharge  divided by the total runoff volume.
The major conventional constituents reported in the NURP study were total suspended
solids (TSS), biological oxygen demand  (BOD), chemical oxygen demand (COD), total
phosphorous (TP), soluble phosphorous (SP), total Kjedahl nitrogen (TKN), and nitrate-
nitrite (NO2-NOs).  The ranges of the site median EMC values are presented in Table 2-1
of this report.

2.1.2  Problems Comparing  Data

It is difficult to compare urban storm water quality data in a precise and quantitative manner
because of wide variation in storm events, sites, and methodologies. Inherent factors
controlling urban storm water quality include land use, geographic location, climate, and
water resource management controls of any given area. These inherent factors are
discussed in more detail in section 2.4 of this chapter.  The high methodological variability
in sampling, analytical techniques, units of measure, and different forms or species of
pollutants employed to describe urban storm water, make comparisons between studies
difficult (Galvin and Moore, 1982, p. 3-6; Canning, 1985, p. 69).

Site characteristics dictate what type of field sampling techniques will be used to sample
urban storm water, and often  are not fully described in final reports.  A crucial point to
consider is whether the sampling took place before or after the runoff reached receiving
waters, i.e. whether the data represents diluted or undiluted runoff.

Analytical techniques can also vary widely and laboratory quality assurance and control
data details, including detection limits, regarding this are rarely supplied in published
reports. When comparing data it is useful to know exactly what form or species of a
particular constituent was measured and whether it was in its solid or soluble form.  It is
also very useful to know what the detection limits of the instrumentation were and what
type of quality control was used in order to insure the validity of the data.

In comparing pollutant concentrations with water quality criteria or standards, percentages
of samples exceeding a certain level are often given. Care must be taken to discern whether
the percentage is derived from the total number of samples or the number of samples that
the pollutant was detected in.  Another important fact to consider is that water quality
standards are for receiving waters and urban storm water runoff data are usually reported as
undiluted concentrations. Galvin points out that comparison of water quality standards and
actual urban runoff data for metals is "very rough and even possibly misleading guide to
significance of the levels seen, since the runoff values are undiluted storm water and total
metal analysis, while the criteria are ambient water, supposedly bioavailable levels."
(Galvin, 1987, p.  11).

2.2  Conventional Parameters

Conventional parameters are those most commonly measured by communities and
researchers to characterize water quality. They have historically been used to describe
wastewater treatment effluent and-in water resource planning.  Conventional parameters can
be grouped  into five categories:  physical,  chemical, oxygen demand, nutrients,
and bacteria/viruses. Tables 2-1 and 2-2 compare data for conventional parameters
reported in the Nationwide Urban Runoff Program, three studies conducted in the Pacific
Northwest, secondary wastewater effluent, and National Drinking Water Regulations.

                                            Table 2-1.
           Summary of Major Conventional Parameters of Urban Storm Water Runoff
           Compared to Water Quality Standards and Secondary Waste Water Effluent
Soluble P
Coliform Bacteria
100 (14-1247)
9 (2-23)
65 (23-146)
0.33 (0.02-2.83)
0.12 (0.005-0.39)
1.5 (0.3-9.9)
0.68 (0.20-5.17)
Summer: 63,000
Winter (4,600-
Bellevue, WA2
NURP 1983
50 (1-2740)
6.6 (<0.01-40)
60 (8-780)
0.15 (0.01-40)

1.1 (0.21-45)
0.21 (<0.01-4.5)
Portland, OR3 Spokane, WA4
USGS 1978 1983
(8-120) 89.0-2711.0
(0.01-1.1) 0.28-0.70

(0.25-5.4)b 1.65-2.31
(0.08-7.0) 0.78-0.83
Mean: 980 (5-27,000)
Min-Max: (1-66,000)
Metro Secondary
Waste Water Effluent



1 U.S. EPA. 1983. Nationwide Urban Runoff Program. Summary Data from 28 cities.
Site EMC for median urban site; ( ) = Min-Max of site.
EMC = Event median concentration = Total constituent mass discharge / Total runoff value.
2 Pitt and Bissonette. 1984. Bellevue.WA. NURP. Summary data from Table 25.
3 Miller and Mrttp.nzip. 1Q78 Summarv Hata from Tahlpc A anH S
(   ) = Min-Max of all samples.
a = Max only;  b = Total organic nitrogen
Miller. 1983. Spokane, WA. Summary data from flow weighted averages.
U.S. EPA National Drinking Water Regulations.
c = Secondary standard; d = Primary standard

                                                         Table 2-2.
                      Summary of Minor Conventional Parameters of Urban Storm Water Runoff
                                          Compared to Water Quality Standards
Beltevue, WA1
NURP  1983
Portland, OR2
USGS  1978
U.S. EPA Surface Water Q"fl'ty Criteria 1986
Fresh   Fresh   Marine Marine   Water & Fish
Acute  Chronic  Acute  Chronic  Ineestion
Temp. (C)
Conductivity (umhos/cm)
pH (pH units)
Alkalinity as CaCOs
Dissolved Oxygen
Ammonia as N
1 Pitt and Bissonette.
2 Millw anrt Mr.Kp.nzi
8.0 (2.6-14.8)
41 (12-1480)
6.7 (3.4-7.9)
12 (0-25)
24 X7-170)

0.14 (<0.01-7.2)

4.5 (0.8-380)
0.1 (0.1-0.4)
9.4 (2.6-61)
7.9 (2.3-34)
1.1 (0.3-20)
2.3 (0.9-210)
1.0 (0.6-11)

3 (0.1-15)

1984. Bellevue,WA. Nl
ift 1Q78 Summary Hata

                                                                                          Species dependent criteria-

       (    ) =  Min-Max of all samples.
       U.S. EPA National Secondary Drinking Water Regulations.
       a = National Primary Drinking Water Regulation  standard that  varies  with temperature.
                                      -Temperature and pH dependent criteria
                                                        0.019   0.011    0.013   0.0075

2.2.1   Physical

Solids found in urban storm water are composed mostly of relatively inert minerals such as
quart and feldspar, and are referred to interchangeably as sediments. The amount of solids
found in storm water is a function of how much exposed ground, construction activity, or
soil disturbance is occurring in a specific area. These solids can be divided into two classes
based on size and transport mechanism (Sartor and Boyd, 1972, p. 46). Settlable solids
are those sediments that are only partially suspended in the storm water and are dragged or
bounced along the surface of the street, parking lot, etc. These sediments tend to be in the
sand and silt particle size range and will settle out rapidly at low  current velocities.
Suspended sediments on the other hand remain suspended in the storm water until the
energy of the flow has been decreased enough to allow settling,  such as in a detention/
retention pond or grassy swale.  These particles tend to be the smaller silts and clays and
are more of a public health concern, because they can have pollutants attached to them
(adsorbed) such as phosphorous, heavy metals, and organic compounds. Randall and
Grizzard state that "The principal pollutant in storm water runoff, i.e. the pollutant present
in the largest amount, is nearly always suspended sediment." (1983, p. 60).

Solids are most commonly reported as total suspended solids (TSS) in mg/L.  The
Bellevue, WA NURP study reported a range of 1-2740 mg/L TSS (Pitt and Bissonette,
1984, p.75). Mar, et al. concluded in highway runoff study that pollutant loadings are
proportional to TSS (1982, p.18).

Dissolved solids are the minerals, metals, and other compounds in solution in water, and
usually are reported as total dissolved solids (TDS) in mg/L. This measurement gives a
rough indication of possible water quality deterioration such as "excessive hardness,
seawater intrusion, corrosive characteristics,  and other mineral concentrations." (Turney,
1984, p. 17). TDS is commonly thought of as a gross measurement of the major cations
and anions.

The acidity or alkalinity is reported in pH units.  pH is the negative logarithm of the
hydrogen ion concentration of a solution.  Neutral water has a pH of 7.0.  Urban storm
water tends to be slightly to moderately acidic. Hydrogen activity has a great affect on the
solubility of some metals and other constituents which, in turn, determines their biological
availability and toxicity levels.  pH can also determine the survival rate of pathogens
associated with animal and human excrement In general, increased acidity (lower pH),
increases the solubility of metals, and  decreases survival rates of pathogens.

Another measure of alkalinity is the equivalent concentration of calcium carbonate (CaCOs)
needed to neutralize a strong acid, (usually up to pH of 4.5), (Freeman, 1984, p. 37).
Highly alkaline waters may have an unpleasant taste and cause salt build up problems in
industrial processes.  "The alkalinity in irrigation water in excess of alkaline earth
concentrations may increase the pH of the soil solution, leach organic material and decrease
permeability  of the soil, and impair plant growth." (Freeman, 1984, p. 37). Calcium
carbonate in water acts as a buffer which maintains an elevated pH, which decreases most
metals' solubility. This fact is significant in areas such as the Pacific Northwest, where
there is little or no naturally occurring calcium carbonate (limestone) contributing to the
buffering capacity of ground waters. Metals in these areas are probably likely to be more
soluble and therefore more bioavailable. Davies also notes that increases in alkalinity and
hardness generally decrease the toxicity of metals to aquatic organisms (1986, p. 61).

"Hardness is related to the ability of soap to produce a lather in water, soft water reacts
favorably with soap to produce an abundant lather with no residue, and hard water
produces less lather and leaves a soapy residue. Hardness is caused primarily by the
presence of calcium and magnesium in water, however, iron, manganese, and strontium
also may contribute to water hardness. "(Turney, 1986, p.  14). Calcium, magnesium, and
iron are widely found in soils and rocks in the Earth's crust. "Hardness of waters in
contact with limestone commonly exceed 200 mg/L." (Freeman, 1984, p. 39).

Conductivity or specific conductance measures the ability of water to carry an electrical
current and is sometimes used as gross estimate of total dissolved solids (Freeman, 1989,
p. 39). It is typically reported as micro-ohms per centimeter (umhos/cm) and ranged from
12-1480 umhos/cm in the Bellevue NURP and 32-284 umhos/cm in the USGS Portland,
OR study.

Temperature is almost always reported in degrees Centigrade. Temperature controls the
level of dissolved oxygen in water and is more of a concern when surface water is the
receiving water for urban storm water. Increased temperature raises the pH, by releasing
the CO2 out of solution, which generally decreases the availability or level of toxicity of
metals.  Davies, however notes that increases in temperature can increase metal toxicity as a
result of increasing an organism's metabolism (1986, p. 61).

2.2.2   Chemical

The elements included in this category are commonly referred to as the major cations and
anions.  These elements occur in more than trace amounts and are not considered toxic or
harmful in small quantities. A few of these elements are included in the secondary drinking
water standards and are considered more of an aesthetic problem.  Table 3 compares
concentrations of some of these elements found in urban storm water to water quality
standards and criteria.

Major anions
Chloride, flouride, and sulfate are anions that are commonly measured in urban storm
water and other water quality determinations. These anions are minor constituents in the
Earth's crust and pose problems in industrial processes if occurring in excessive amounts
(Freeman, 1984, p. 37). Excessive chloride and sulfate may give drinking water an
objectionable taste. A common source of chloride in urban storm water is rock salt that is
used for de-icing roads in the winfer.

Major cations
Calcium, magnesium, sodium, potassium, iron, and silica are major cations that are
abundant and widely distributed in the Earth's crust and natural waters.  All of the major
cations may precipitate out of solution, forming deposits or scale in pipes and boilers.
These cations are generally undesirable in industrial processes.

Sodium in excessive amounts can be harmful to humans with cardiac, renal, and circulatory
diseases, and to women with toxemias of pregnancy.  With regard to agriculture, large
amounts of sodium are toxic to plants, may decrease soil permeability, and increase the pH
of the soil solution. Calcium and magnesium are the main constituents that commonly
contribute to the total hardness of water. Magnesium, present in drinking water in large
concentrations, can act as a cathartic or diuretic. Excessive amounts of iron in domestic

water supplies "may adversely affect the taste of water and beverages and stain laundered
clothes and plumbing fixtures. "(Freeman, 1984, p. 36).

2.2.3  Oxygen Demand

Dissolved oxygen (DO) in water is commonly used to characterize receiving waters' ability
to sustain aquatic life. Generally, increases in oxygen consuming pollutants, temperature,
and salinity decrease the amount of dissolved oxygen in water. DO levels naturally vary
greatly among ground waters. Decreased levels of DO could indicate possible
contamination problems if a ground water normally had high levels of DO.

Oxygen demanding or consuming pollutants are organic materials that decrease dissolved
oxygen in receiving waters. Substantial loads of oxygen consuming materials can cause
fish kills, foul odors, discoloration, and algae growth (Sartor and Boyd, 1972, p. 50).
Biological oxygen demand (BOD) and chemical oxygen demand (COD) are both analytical
techniques and discrete measures of these organic pollutants that include animal and human
excrement, oil and grease, and pesticides. BOD and COD are usually reported in mg/L.

BOD measures pollutants that consume oxygen through bacterial degradation processes
over a measured period of time, such as aerobic bacteria decomposition of organic material.
BOD5 is the BOD for five days and ultimate BOD is all the oxygen a substance could
possibly consume.  Chemical oxygen demand measures pollutants that consume oxygen
through both bacterial and chemical degradation processes (Canning, 1988, p. 65-66). The
ranges of BOD5 found in the 1983 NURP study were comparable to those concentrations
found in secondary wastewater discharge (p. 9-4).

2.2.4  Nutrients

Nutrients of primary interest found in urban storm water are the  various forms of nitrogen
and phosphorous. These compounds encourage the growth of algae in surface water, and
in large amounts can drastically decrease dissolved oxygen to very low levels that can
induce massive  fish kills and the eutrophication of surface waters.  The major sources of
nutrients in urban storm water include yard fertilizers, animal wastes, eroded soil, organic
debris, and atmospheric fallout (Canning, 1988, p. 68). Prych and Ebbert concluded that
one third of total nitrogen in storm water is from rainfall (1986,  p. 1).

Nitrogen concentrations are most commonly reported either as total nitrogen or as nitrate-
nitrite. Nitrates and ammonium nitrogen are of primary interest with respect to
bioavailability and eutrophication. Since nitrogen is readily transformed to either of these
forms, a measure of total nitrogen reflects nitrogen nutrient availability (Sartor and Boyd,
1972, p.59). Total nitrogen is usually reported as either total Kjedahl nitrogen (TKN) or
total nitrogen (TN). TKN is a specific analytical technique used to measure organic
nitrogen plus ammonia. Ammonia is also a common measure of nitrogen

Nitrate-nitrite (NO2-NO3) is commonly thought of as a measure  nitrate, because the nitrite
concentrations are generally small in comparison to nitrate (Turney, 1984, p. 19).
Concentrations of 0.3 mg/L or more are generally thought to promote algal blooms. Nitrate
is extremely soluble in water and almost always found in its dissolved form (Canning,
1988, p. 68).  With respect to ground water and drinking water,  excessive levels of nitrate
(> 10 mg/L) can cause a blood disease methemoglobinemia in infants ("blue babies") which
deprives them of oxygen (Sartor and Boyd, 1972, p. 60).

Phosphorous also exists in several forms and is most often reported as total phosphorous
(TP) and soluble phosphorous. A recent Metro study on phosphorous in Lake
Sammamish, WA reported phosphorous concentrations as bioavailable phosphorous
(BAP). Orthophosphate (PO4> occurs both as particulates adsorbed onto sediments and in
dissolved form. Phosphate is thought to be the growth-limiting nutrient in freshwater and
algal blooms are likely to occur if concentrations exceed 0.01 mg/L (Canning, 1988, p.

2.2.5   Bacteria/Viruses

Fecal coliform
Fecal coliform bacteria is a relatively harmless group of bacteria found in the intestines of
warm blooded animals, including humans, and is usually reported in colonies/lOOmL.
Fecal coliform, in particular Esherichia coli (E. cob'), is used as an indicator organism of
pathogenic or disease-causing bacteria and viruses that are associated with human or animal
excrement (Canning, 1988, p. 63; Turney, 1984, p. 20). Fecal streptococci are used as an
indicator of human waste contamination usually from combined sewer overflows and septic
systems.  Ratios of total fecal coliform to fecal streptococci of 2:1 or more, generally
indicate contamination by sewage; ratios of 1:1 or less indicate an animal source  of wastes
(Novotny and Chesters, 1981, p. 407-408).

Bacteria and viruses can remain suspended in water or can adsorb onto sediments which
can increase their rates of survival. With regard to  ground-water contamination,  Yates and
Yates noted  that microorganisms have been found to migrate considerable distances in the
subsurface.  "Viruses, in particular, due to their small size (20 to 200 nm) and long
survival times can migrate very large distances in soil and ground water, as much as 1600
m have been reported for certain viruses in karst terrain (Gerba, 1984b) and up to 400 m in
sandy soil (Keswick and Gerba, 1980)." (Yates and Yates, 1989, p. 202).

The main source of bacteria and viruses in urban storm water is pet animal and bird
excrement washed off of street surfaces and yards. The ranges of fecal coliform found in
undiluted storm water by the 1983 NURP study were 4600-281,000 colonies/100 mL in
summer and 120-330,000 colonies/mL in winter. The primary drinking water standard for
coliform is 1 colony/100 mL monthly average with individual measurements allowed to
exceed this.

2.2.6   Studies

The U.S. EPA NURP study focused more on the short term effects of conventional
pollutants on receiving waters, rather than cumulative effects, and concluded that nutrients
and oxygen  demanding pollutants do not pose a significant problem in most instances.
This is probably an inaccurate interpretation because it ignores the long term accumulation
of these pollutants. However, it did conclude that "coliform bacteria are present  at high
levels in urban runoff and can be expected to exceed EPA water quality criteria during and
immediately after storm events in many surface waters, even  those providing high degrees
of dilution." (p. 9-3). TSS was also noted to be fairly high in comparison to wastewater
treatment effluent and could have detrimental physical effects to aquatic life and build up
toxic sediments (p. 9-5).

The Bellevue, WA NURP study reportedthat approximately two-thirds of the total solids
and phosphorous loads, and one-third of the TKN, TN, and organic carbon loads were in
suspended rather than dissolved forms (Pitt and Bissonette, 1984, p. 74).


Miller and McKenzie concluded in the Portland, OR study that "In general, constituent
concentrations of storm-water runoff exceed domestic sewerage-treatment standards for
settlable solids, suspended sediments, and fecal colifoim", but that "BOD concentrations
were not high enough to indicate that treatment would be necessary." (1978, p. 43).

2.3   Toxicants

In recent years more attention has been given to describing toxicants in urban storm water
because of the increasing awareness of their possible deleterious impact on public health
and the environment Advances in technology have also made it possible to measure
toxicants in urban storm water at trace levels. However, toxicant levels remain difficult and
expensive to quantify because concentrations often occur at the detection levels of complex
analytical instrumentation. 'Toxicant" is a general term for inorganic and organic chemicals
that are either carcinogenic, mutagenic, teratogenic, or otherwise harmful to organisms and
humans in both lethal and sub-lethal concentrations.

Toxicants are generally classified into two broad categories of metals and organics. It is
commonly recognized that many of these pollutants are for the most part not soluble, but
instead exist in solid or colloidal forms or adsorbed onto sediments (usually silts and
clays), which eventually accumulate in receiving waters. The long term accumulation and
effects rather than the short term effects of these pollutants (especially metals), in receiving
waters and sediments may be a more serious hazard to human and aquatic life (Galvin,
1987, p.  14).

In an expanded companion study to the NURP study, the NURP Priority Pollutant
Monitoring Program (PPMP), urban storm water was analyzed for 127 out of 129 priority
pollutants identified by EPA in 1980. 14 inorganic and 63 organic of these pollutants were
detected and of these lead, selenium, and 2 pesticides (alpha-hexachlorocyclohexane
(alpha-BHC) and gamma-hexachlorocyclohexane (gamma-BHC) were thought to represent
a potential risk to humans in undiluted runoff (1983, p. vi). (See Appendix A for the
summary of the NURP PPMP findings.)

2.3.1  Metals

Metals found in urban storm water are a major concern because of their high prevalence and
potential toxicity. The term "heavy metals" is used loosely and can be confusing because it
sometimes includes both very common elements such as iron and zinc, and trace elements
such as lead and arsenic.  Metals are represented in several water quality regulations and
classifications according to their varying degrees of toxicity and environmental impacts.
These classifications include the National Primary and Secondary Drinking Water
Regulations, U.S. EPA Priority Pollutant classification, U.S. EPA Water Quality Criteria
for freshwater and marine aquatic life, and various  state water quality standards. It is
worth pointing out again that criteria are also for receiving waters and not undiluted runoff.
These standards are listed in Table 2-3, along with  summary data from various toxicants

From a ground-water perspective, the National Drinking Water Regulations are the most
pertinent  The primary maximum contaminant levels are concerned with the "contaminants
that may have a significant direct impact on the health of the consumer and are enforceable
by EPA."(Freeman, 1984, p. 40).  Most of the EPA priority pollutant metals are
represented in this list The secondary maximum contaminant levels "deal with
contaminants that may not have a significant direct  impact on the health of the consumer,


but their presence in excessive quantities may affect the aesthetic qualities and discourage
the use of a drinking-water supply by the public."(Freeman, 1984, p. 40). (See Figures 2-
1,2-2, and 2-3 for comparisons of metals concentrations found in urban storm water
runoff and the National Drinking Water Regulations.)

The toxicity of a metal depends on its form or state, which dictates it's mobility and
availability for uptake and accumulation in organisms (Sartor and Boyd,  1972, p. 68). A
metal's form or state includes its valence (electrical charge), and whether it exists in
solution or is tied up in a complex organic or inorganic solid compound. Many metals are
adsorbed to particles through a complex electro-chemical bonding that is controlled by the
pH of the water and sediments (Canning, 1988, p. 69).  Low pH, oxidation-reduction
potential (Eh), and DO favor metal solubility (NURP PPMP, 1983, p. 83).  "The dissolved
metal fraction is most directly related to toxicity, however, water quality criteria and
standards are based on total fractions because they provide an indication of the amount of
metal available for dissolution." (NURP PPMP, 1983, p.  63).

Galvin and Moore found that metals are "almost completely associated with storm water
particles," except for copper and zinc, which showed significant dissolved concentrations
(1984, p. 3-3). A serious concern is that physical disturbances such as dredging and flood
scouring can resuspend contaminated sediments that may re-release pollutants into the
water column.

The NURP PPMP Special Metals Project tried to differentiate between three different
fractions or forms of metals.  Dissolved or "soluble" metals were defined as those metals
that passed through a 0.45 micron membrane filter. This fraction is sometimes referred to
as the ionic fraction which is considered to be the most available for uptake by organisms.
Total recoverable or "extractable" metals are those metals in an unfiltered sample following
treatment with hot dilute mineral acid. Total metals are those metals in an unfiltered sample
following vigorous digestion with concentrated nitric acid.

Lead, zinc,  and copper are the metals most often reported because of higher frequencies
and concentrations in urban storm water. In the NURP PPMP, lead and zinc were detected
in 94% of the samples and copper was detected in 91% of the samples in the NURP PPMP
study. All three metals were detected in 100% of the Metro toxicant study samples. The
NURP PPMP reported that "Levels of cadmium, copper, lead, and zinc in undiluted runoff
exceeded EPA 1980 acute criteria for protection of aquatic life by a factor of 2 to 8.
Consequently these pollutants could cause harm to aquatic life, depending upon receiving
stream dilution, storm duration, and whether the metal was in the more toxic soluble form."
(NURP PPMP, 1983, p.  vi).

Lead is probably the most notable heavy metal because of its high toxicity and
bioaccumulation in humans and other organisms.  The NURP PPMP reported total lead
concentrations in undiluted urban storm water runoff ranged from 6-460 ug/L with an EMC
of 144 ug/L, which exceeded the 50 ug/L drinking water standard in 73% of the samples
(1983, p. 6-47). Concentrations ranged from 60-460 ug/L with an EMC of 210 in the
Metro Toxicant study (1984, p. 3-8), also exceeding the 50 ug/L drinking water standard
(See Figure 2-1). In 1989, Merrill reported an EMC of 57 ug/L in Seattle storm water,
which supports the notion that the concentration of lead in urban storm water has
significantly decreased, reflecting the phasing out of leaded fuels.

Lead was reported to almost exclusively exist in its solid form by Galvin and Moore (1984,
p. 3-3) and the NURP PPMP (1983, p. vi). Sartor and Boyd also found that lead had a
strong tendency to be associated with fine particles, with almost 90% of the total lead found


with particles smaller than 246 microns (1972, p. 75). "The sources of lead include
gasoline products, by-products of their combustion, and exterior paints and stains."
(Marsalek, 1986, p. 53).

Zinc is the most prevalent heavy metal in street surface contaminants (Sartor and Boyd,
1972, p. 68) and occurs in the highest concentrations by far.  Concentrations ranged from
10-2400 ug/L with an EMC of 160 ug/L in the NURP PPMP (1983, p. 6-47) (See Figure
2-3), and approximately 40% of the total zinc was in soluble form (p. vi). Sartor and Boyd
discovered that zinc was not associated with any particular size range of sediments (1972,
p. 74). "The most significant sources of zinc in urban runoff include atmospheric fallout,
corrosion processes (particularly galvanized metal sewers), tires, pavement wear,
automobile exhausts, exterior paint, road salt and possibly some terrestrial sources."
(Marsalek, 1986, p. 53). Most zinc compounds are not particularly toxic in low-to-
moderate concentrations to humans and are considered more toxic to aquatic organisms.

Copper is the other highly prevalent metal found in urban storm water. Total copper
concentrations ranged from 1-100 ug/L with and EMC of 34 ug/L in the NURP PPMP
study (See Figure2-3). Like zinc, 40 %  of the total copper was in soluble form (1983, p.
vi). Copper is not particularly toxic to humans and other higher organisms, but can be to
lower ones. It also does not have the cumulative effect that other heavy metals exhibit
Copper compounds in low concentrations are sometimes used to control algae and aquatic
weeds (Sartor and Boyd, 1972, p. 74), and are frequently associated with fish kills and
degraded aquatic habitat (Canning, 1988, p. 71). "The sources of copper include corrosion
of copper plumbing, electroplating wastes, some algicides, brake linings,  and asphalt
pavement wear." (Marsalek, 1986, p. 53).

Other Trace Metals
Other trace metals found less frequently in urban storm water include antimony, arsenic,
beryllium, cadmium, chromium, nickel, and selenium. (See Table 2-3 for specific ranges
of concentrations and detection frequencies and Figures 2-1 and 2-2 for comparisons of
metals concentrations to the drinking water standards.) In the NURP PPMP study
selenium concentrations ranged from 2-77 ug/L and exceeded the 10 ug/L drinking water
standard  in 10% of the samples it was detected in. Nickel concentrations ranged from 1-
182 ug/L and exceeded the human health criterion of 13.4 ug/L in 21% of the samples.
Nickel is not a significant health risk in water when ingested, but "Ni compounds are
suspected of acting synergistically with some carcinogens to increase mutagenic effects"
(Sunderman, 1981, in  NURP PPMP, 1983, p. 44).  Arsenic concentrations frequently
exceed EPA human carcinogenic criterion (10 to the minus 5 risk level) of 0.022 ug/L.
Only one sample, however, exceeded the 50 ug/L EPA drinking water standard. 12% of
samples that beryllium was detected in exceeded the carcinogenic criterion. Mercury
ranged from 0.6-1.2 ug/L and did not exceed the drinking water standard.

The NURP PPMP study concluded that dilution in receiving waters and wastewater
treatment would probably decrease these concentrations, but these levels could be
hazardous in the following worst case scenarios: 1) if runoff was most of the total
receiving water flow in a dilution of less than  1 to 10; 2) if these concentrations occur
above drinking water intakes; 3) lead and selenium removal by wastewater treatment is
minimal  (1983, p. 44).

                                         Table  2-3.

Summary of Metals Found in  Urban Storm Water  Runoff Compared to Water  Quality Standards.

                                                                U.S. FJA Water Quality Criteria 1986
PARAMETER EPA NURP1 Metro Toxicant2 Seattle, WA3 Fresh Fresh
titfJL) PPMP1983 Bellevue. WA 1982 1989 NDWR4 Acute Chronic
Antimony 2.6-23 9,000* 1,600*
Arsenic 1-50.5 13 (3-37, 50a
Arsenic (Pent) 850* 48*
Arsenic (Tri) 360 190
Barium l,000a

( ) =
** _
+ =
1-49 130* 5.3*
0.1-14 0.7 (0.2-1.9) 0.8 10a 3.9+ 1.1 +
1-90 7% (2-19) 6.2 50*
(Hex) 16 11
(Tri) 1.700+ 210+
34 (1-100) 20 (4-46) l,000b 18+ 12+
2-300 22 5.2
144 (6-460) 210 (60-460) 57 50a 82+ 3.2+
0.6-1.2 2a 204 0.012
1-182 1,400+ 160+
2-77 10a 260 35
0.2-0.8 0.6 50a 4.1+ 0.12
1-14 1,400* 40*
160 (10-2,400) 120 (28-250) 117 5,000b 120+ 110+
U.S. EPA. 1983. Nationwide Urban Runoff Program. Priority Pollutant Monitoring Program.
Calvin and Moore. 1982. Metro Toxicant Program. Bellevue, WA. NURP. Tables 7 and 8, pp.3-8, 3-9.
Merrill. 1989. Table 1, p. 9.
U.S. EPA National Drinking Water Regulations.
a = Primary standard; b = Secondary standard
Insufficient data to develop criteria. Value presented is the Lowest Observable Effect Level (L.O.E.L.)
Human health criteria for carcinogens reported for three risk levels. Value presented is the 10~6 level.
Hardness dependent criteria (100 mg/L).
Marine Marine
Acute Chronic
2,139* 13*
69 36

43 9.3

1,100 50
2.9 2.9
1 1
14 5.6
2.1 0.025
410 54
95 86

Water & Fish
0.0022 **



Figure 2-1.  Comparison of Ranges of Metals Concentrations Found in Urban Storm
            Water to the National Primary Drinking Water Regulations (NPDWR).
                                                                        NURP PPMP
                                                                        Galvin and Moore

                      1 -
                                                                        NURP PPMP
 Sources: NURP PPMP. 1983. Summary data from Table 6-19, p. 6-47.
        Galvin and Moore. 1982. Tables 7 and 8, pp. 3-8 and 3-9. Metro Toxicant Program. Bellevue, WA.
        Merrill. 1989. Table 1, p. 9. Seattle, WA.

Figure 2-2.  Comparison of Ranges of Metals Concentrations Found in Urban Storm
           Water to the National Primary Drinking Water Regulations (NPDWR).
                     40 -
                                                    Galvin and Moore
                                                                       NURP PPMP
                                                                         Galvin and Moore
                                                                     *   Merrill
                                                B  Galvin and Moore
                                                *   Merrill
Sources: Summary data from NURP PPMP. 1983. Summary data from Table 6-19, p. 6-47.
       Galvin and Moore. 1982. Tables 7 and 8, pp. 3-8 and 3-9. Metro Toxicant Program. Bellevue, WA.
       Merrill. 1989. Table 1, p. 9. Seattle, WA.

Figure 2-3. Comparison of Ranges of Metals Concentrations Found in Urban Storm
           Water to the National Secondary Drinking Water Regulations (NSDWR).
                                                                       NURP PPMP
                                                                     B  Galvin and Moore
                                                                     *   Merrill
                                                                       NURP PPMP
                                                                     B  Galvin and Moore
                                                                     *   Merrill
Sources: NURP PPMP. 1983. Summary data from Table 6-19, p. 6-47.
       Galvin and Moore. 1982. Tables 7 and 8, pp. 3-8 and 3-9. Metro Toxicant Program. Bellevue, WA.
       Merrill. 1989. Table 1, p. 9. Seattle, WA.

2.3.2   Organics

Oil and Grease and Total Organic Carbon
The two most common and crudest measurements of organic materials in urban storm
water runoff are oil and grease and total organic carbon (TOC) (Galvin, 1987, p. 14).
However, not all the organic materials in oil and grease and TOC measurements are
considered toxicants.  Oil and grease concentrations ranged from <1 to 10 mg/L and
dissolved organic carbon concentrations ranged from 0.2 to 120 mg/L in the Bellevue, WA
NURP study. Specific groups of organic materials that are commonly measured include
polycyclic aromatic hydrocarbons (PAHs), pesticides, and polychlorinated biphenals
(PCBs).  These groups are composed of very specific compounds, each with their own
chemical signature that can be detected by complex analytical instruments.  See Appendix A
for specific ranges of concentrations of these organic compounds found in the NURP
PPMP study.
Polycyclic aromatic hydrocarbons are "products of incomplete combustion and are found in
everything from cigarette, coal and wood stove smoke to gasoline and diesel exhaust.
They are major components in air-suspended participates (e.g.,soot) and are common in
street dust, tightly bound up in fine particles." (Galvin, 1987, pp.  19, 21). PAH's are
commonly found in highway runoff and can be traced to combustion byproducts
(Marsalek, 1986, p. 53).

Refractory organics
Refractory organics are chemicals that are man-made and highly resistant to chemical and
biological degradation. These chemicals include pesticides, herbicides, PCBs, cleaning
solvents, and photofinishing chemicals.  The long term accumulation of these pollutants
from constant low level inputs (especially from atmospheric fallout), is more of a problem
with respect to acute or sub-lethal toxicity. (Canning, 1988,p. 69).

Organic pesticides are a major public health and environmental concern because of their
widespread presence and high persistence in the environment  Most pesticides and
herbicides in urban runoff are washed from landscaping foliage, lawns,  and gardens, with
the majority adsorbed onto sediments. (Canning, 1988, p. 69).  "The two most prevalent
pesticides, alpha-BHC and gamma-BHC, are used commonly in soil treatment to eliminate
nematodes and other pests." (Marsalek, 1986, p.  53).

PCBs are chlorinated organic compounds that  are extremely stable and persistent in the
environment, similar to organochlorine pesticides. These compounds are not very mobile
in soils and tend to adsorb onto soil particles (Novotny and Chesters, 1981, p. 243).
"Because PCBs are soluble in lipid tissue, these components have been found to
accumulate in the fat of living organisms including man."(Novotny, 1981,p. 15). The
major sources of PCBs are leaks from fire-resistant transformers, insulating condensers,
hydraulic systems, spills and losses in manufacturing of PCBs, vaporization or leaching
from PCB-containing formulations, and disposal of waste PCBs (Novotny and Chesters,
1981, p. 15; Marsalek, 1986, p. 53).

The NURP PPMP study detected 63  of the possible 106 organic priority pollutants at lower
concentrations than the inorganic pollutants and at frequencies of 22% or less. This study
concluded that:

    The organic priority pollutants found most frequently pose little risk to humans at
    detected levels, except possibly for alpha-hexachlorocyclohexane (alpha-BHC) and
    chlordane.  These pesticides and the three polycyclic aromatic hydrocarbons (PAHs),
    chrysene, phenanthrene, and pyrene were found in 5 to 20 percent of the urban runoff
    samples at concentrations exceeding the EPA criteria for the protection of human health
    from carcinogenesis for 10 to the minus 5 risk level...At the 10 to the minus 7 risk
    level, gamma-hexachlorocyclohexane (lindane) also exceeded the carcinogenic activity
    carcinogenic criteria in at least 10 percent of the samples.(1983, p. 43).

The study sited pesticides, fossil fuel combustion, plastic products, and automobile-related
activities.as the main sources of the priority pollutant organics (1983, p. 40). (See
Appendix A for list of organic priority pollutants.)

The Metro Toxicant study detected 19 of 111 organics at detection frequencies of 20% or
less. The "most frequently detected were lindane (tentative), alpha-BHC (tentative),
pentachlorophenol, fluoranthene, phenanthrene, and pyrene." (Calvin and Moore, 1982, p.
3-20).  Merrill found low and high molecular weight polycyclic hydrocarbons, phthalate
esters, and 2-methyl naphthalene ranging in concentrations from 0.1 to 25 ug/L in greater
than 33 percent of samples of Seattle storm water in 1989 (p. 8).

2.4  Factors Affecting Urban Storm Water  Quality

Sartor and Boyd hypothesized that "The principal factors affecting the loading intensity at
any given site include the following: surrounding land-use, the elapsed time since streets
were last cleaned (either intentionally or by rainfall), local traffic volume and character,
street surface type and condition, public works practices, season of the year, etc." (1972,
p. 6).  However, several studies have concluded that concentrations of urban storm water
pollutants do not appear to vary significantly with land use, except perhaps some cases
where metals concentrations in highway runoff seem to be higher (Galvin and Moore,
1982, p. 3-3; NURP, 1983, p. 9-5). The NURP study concluded the following:

         As a result of extensive examination, it was concluded that geographic location,
         land use category (residential, commercial, industrial park, or mixed), or other
         factors (e.g., slope, population density, precipitation characteristics) appear to be
         of little utility in consistently explaining overall site-to-site variability in urban
         runoff EMCs or predicting the characteristics of urban runoff discharges from
         unmonitored  sites. Uncertainty in site urban runoff characteristics caused by
         high event-to-event variability at most sites eclipsed any site-to-site variability
         that might have been present. (1983, p. 9-5).

2.4.1   Urban Land  Use

Although general land use types by themselves are not particularly valuable in explaining
specific variations in urban storm water quality, it is useful to understand the activities
taking place in them that generate pollutants found in urban storm water runoff. For the
purposes of this report the  sources of urban storm water pollutants will be discussed
according to individual  activities or sites occurring in one or more of these land use

Urban land use types are generally grouped into four categories: residential, commercial,
industrial, public/government

Residential land use encompasses both single-family housing and multi-family housing.
Sources of storm water pollutants from residential land use include:  streets, driveways,
yards and landscaping, woodburning, automobile maintenance, disposal of household
chemicals, and pets.

Shopping centers, parking lots, highly urbanized downtown areas, warehousing, storage,
office parks, gasoline service stations, and small businesses represent some commercial
land uses that generate pollutants found in urban storm water.

Industry can discharge pollutants during the production, storage, and transportation of raw
materials, products, and wastes used in manufacturing.

Public activities which generate urban runoff pollutants include: 1) transportation systems
(rail, highways, roads); 2) public facilities (parks, boat launches); 3) port facilities (air
terminals, off-loading facilities); 4) internal government facilities (automobile maintenance
and fuel stations); and 5) landfills (PSWQA, 1986, p. 4-98). The most widespread and
studied of these has been highways.

2.4.2   Sources  of Pollutants

Refuse and fine paniculate matter that accumulate on impervious surfaces such as streets,
highways, parking lots, yards, and roofs are major sources of pollutants in urban storm
water. This material has a variety of sources that include atmospheric deposition, litter,
road traffic, animal fecal waste, dead leaves, grass, and animals (Novotny,1981,p.313).
(See Table 2-4 for a summary of urban storm water pollutant sources.) Most street refuse
is very coarse litter, however most pollutants are associated with the finer fraction
(Novotny and Chesters, 1981, p. 324; Galvin and Moore, 1982, pp. 3-42, 3-62).

Atmospheric Deposition
Dust particles from soil and urban litter, is always present in the air.  Most dust particles are
fairly large and are deposited near their source. Industrial emissions, motor vehicle traffic,
and motor vehicle exhaust probably contribute the majority of air-born pollutants found in
urban storm water. "Fly ash from industrial coal burning operations and disintegration of
urban litter is another significant source of atmospheric deposition, especially in or near
urban and industrial centers." (Novotny and Chesters, 1981, pp. 152,  154). The NURP
PPMP study concluded that "Predominant sources of the priority pollutants are thought to
be gasoline and other fossil fuel combustion, metal alloy corrosion and other automobile-
related activities."  (1983, p. 40).

Motor Vehicles
Sartor and Boyd sited the following motor vehicle sources of street surface contaminants:
1) leakage of fuel, lubricants, hydraulic fluids, and coolants; 2) fine particulates worn off
of tires and clutch and brake linings;  3) paniculate exhaust emissions; 4) dirt, rust, and
decomposing coatings which drop off of fender linings and under carriages; 5) vehicle
components broken by vibration or impact (glass, plastic, metals, etc.) (1972, p. 28).
"Each year more than one billion pounds of tire matter is worn off in the United States."
(Randall and Grizzard, 1984, p. 61).  This tire matter contains such pollutants as zinc, oil,
and oxygen-demanding organic polymers. Automobile exhaust contains lead,
hydrocarbons, phosphorous, and nitrous oxides that are deposited dry or washed out of the
air by rainfall.  Automobile parts wear contributes copper and chromium to street surfaces.


                                                                              Table  2-4.

                                                           Sources  of Urban  Storm  Water Pollutants.
Urban Sources
Water Quality Impacts on Receiving Waters
         &  Oxygen
Soil erosion
Automobile wear
Automobile exhausts
Industrial emissions

De-icing salts
Decomposing plants and animals
Soil erosion
Combined sewer overflows
Pet and bird fecal matter
Industrial emissions
Atmospheric deposition

Automobile exhausts
Automobile wear
Industrial discharges
Atmospheric deposition
Soil erosion
Combined sewer overflows
Automobile exhausts
Automobile wear
Industrial discharges
Atmospheric deposition
Fire-resistant transformers
Insulating condensers
Hydraulic systems
Disposal of waste PCBs
Transformer oil reprocessing

Pest and weed control
Soil erosion
Combined sewer overflows
Pet and bird fecal matter
Carries organic and inorganic toxicants.
Decreases drinking water quality.
Degrades habitat and decreases the viability and variability of aquatic species
Decrease in value for recreational and commercial activities.

Decreases drinking water quality.
Degrades habitat and decreases the viability and variability of aquatic species
Damages crops.

Nitrates can cause infant health problems.
Eutrophication of lakes and estuaries.
Bioaccumulation and biomagnification.
Decreases drinking water quality.
Accumulates in bottom sediments, posing risks to bottom-feeding organisms and their
Disrupts aquatic food chains.
Can affect reproduction rates and life spans of aquatic species.

Bioaccumulation and biomagnification.
Toxic to marine life.

Bioaccumulation and biomagnification.
Persistance in the environment is generally greater than that for most chlorinated pesticides.
Predominant fate is adorbtion onto sediments.
Bioaccumulation and biomagnification.
Some are carcinogenic, mutagenic, or teratogenic.
Persistance in the environment is generally greater than that for most chlorinated pesticides.
Human health hazard via consumption of contaminated fish and water.
Degrades habitat and decreases the viability and variability of aquatic species

Associated pathogens and disease-bearing organisms.
Human health hazard.
Reduced recreational usage.
Decreased drinking water quality.
          Sources: Puget Sound Water Quality Authority, 1989; U.S. EPA, 1984; Randall and Grizzard, 1984; Novomy and Chesters, 1981.

Highways and Streets
Like other urbanized areas, highways interrupt natural drainage patterns and have distinct
linear form.  Highway and street surfaces contribute significant amounts of pollutants to
urban storm water. "The nature, conditions, and gradient, of the contributing surface is of
major significance in controlling pollutant delivery to the sewer system."(Ellis, 1986, p. 6).
Other factors that affect pollutant loadings on road surfaces are the speed and the frequency
of the traffic flow.

"Street surface characteristics were found to have an effect on the contaminant loadings
observed at a given site"; asphalt surfaces and those in fair-to-poor conditions contributed
significantly higher loadings (Sartor and Boyd, 1972, p. 9). The weathering of asphalt and
pavement contributes solids that contain lead, chromium, copper, nickel, zinc, grease, and
petroleum to urban storm water (PSWQA, 1986, p. 4-98). Mar et al., discovered that
levels of solids and metals in highway runoff were similar and nutrient concentrations were
lower compared to those concentrations found in other urban runoff and treated sewage
(1982, p. 19).  This study also found that most of the pollutants were insoluble and bound
to particles.  In particular, the majority of metals in highway runoff are in unavailable forms
and can be immobilized in soils and vegetation (Mar, et al.,1982, pp. 19,23).  High
density and heavy stop-and-go traffic will generate the greatest amount of pollutants from
highways (PSWQA, 1986, p. 4-98).

Higher speed travel significantly impacts atmospheric deposition of pollutants generated by
automobile exhaust. Traffic-generated winds are very effective in removing pollutants
from highways and "the steady-state volume of solids on a highway is controlled by the
width of the distress land, the height of the curbing, and the speed of the traffic."(Mar et
al., 1982, p. 12).  Wang, et al. concluded that "A significant fraction of the solids
generated by the highways is blown and deposited within 15 meters of the roadway and is
incorporated in the vegetation and top soil. The remainder is widely dispersed at low
concentrations. Metals associated with the soils can be leached by runoff waters with pH
lower than 5; otherwise metals appear to be immobile."(Mar, et al., 1982, p. 23).

Yards and other urban vegetated areas contribute suspended solids, nutrients, pesticides,
fecal coliform, and oxygen-consuming pollutants to urban storm water. Lawn fertilizers
are a major source of nitrogen and phosphorous.  Lawn and garden products such as
pesticides, insecticides, and herbicides contribute refractory organic chemicals to urban
storm water, which persist in the environment for long periods of time. Domestic animals
and birds in the urban environment are sources of pathogens associated with fecal matter.
Leaves, grass clippings, other organic lawn wastes, and animal fecal matter are major
contributors of phosphorous and other oxygen demanding materials.

Construction Sites
Construction sites in any land use setting are a major contributor of sediments to urban
storm water. Unlike other urban activities, construction activities are short-lived events.
Soil disturbance and subsequent erosion by precipitation, wind, or gravity, generate
sediments that are pollutants themselves and also serve as transport mechanisms for
pollutants generated elsewhere.

Spills. Leaks, and Dumping
Accidental or intentional point source discharges also contribute pollutants to urban storm
water that are more likely to cause acute environmental problems when combined with
cumulative nonpoint source effects. Possible point sources may include spills or leaks
from households, small businesses, large industries, trucks, and railroad cars.

Household chemicals entering urban storm water include:  1) automobile oils, coolants, and
other fluids; 2) household cleaning wastes; 3) lawn and garden chemicals; and 4) paints and
solvents. Typical entryways into urban storm water are directly through disposal into
storm drains and sewers or dumping on the ground or street.

Small businesses that use products containing hazardous chemicals, (such as dry cleaners
and gasoline service stations), are potential sources of pollutants in urban storm water. The
example of PCE contaminated ground water attributed to a dry cleaning business described
in the introduction of this report, serves as an illustration. Gasoline service stations and
automobile repair shops are sources of petroleum products that, if spilled, eventually wash
into storm sewers or dry wells.

Industrial discharges
Industrial discharges can result from spills, storage leaks, or atmospheric releases.  Metal
smelters are notorious for emitting toxic metals such as lead and arsenic into the atmosphere
and into storm water runoff from slag piles. Other examples are petroleum refineries and
gasifiers that discharge hydrocarbons through atmospheric emissions, leaking storage
tanks, etc.

Combined sewer overflows
Combined sewers in older urban areas are those systems that collect and treat both storm
water and sanitary sewerage. Combined sewers represent a significant source of pollutants
because in most instances the "pipes and the treatment plants are not designed to handle all
of the storm water from large storms. During heavy rainfall, the sewage system discharges
some of the excess flow of raw sewage and storm water through combined sewer
overflows (CSOs) into nearby water bodies such as lakes, rivers, or Puget Sound."
(PSWQA, 1986, p. ii.). The main pollutant concerns seem to be:  1) high fecal coliform
and associated pathogen concentrations and 2) possible accumulation of toxicants in
receiving water sediments and their effects on aquatic organisms around CSO outfalls.

2.4.3   Geographic Location

Rainfall intensity, duration, and frequency explains a large majority of the variation in
urban storm water quality, and at times will overshadow any variations in land use. "The
rate at which rainfall washes loose paniculate matter from street surfaces depends upon
three primary factors:  rainfall intensity, street surface characteristics, and particle size."
(Sartor and Boyd, 1978, p. 9).

In developing regression relationships, Driver & Lystrom hypothesized that "total storm
rainfall and the size of the drainage area are the most significant variables affecting storm-
runoff-load relations." (1986, p.  132). Miller and McKenzie also concluded that total
rainfall frequently explained most of the variation of the dependent variable in multiple
regression analysis performed on their storm water data (1978, p. 1). Ellis also notes that
the quantity of storm water or "the flow factor plays a dominant role in urban runoff
pollution dynamics, as it is the driving force in the mobilisation, transport, and deposition
of pollutants." (1986, p. 6). Pin and Bissonette found wide variations in major ion
concentrations in Bellevue storm water and speculated that "these variations are most likely
caused by the large variations in storm flows represented in these samples." (1984, p. 71).

Antecedent conditions, particularly the time between storm events is a variable controlling
the amount of pollutants found in urban storm water. The longer the time between storm
events, the more pollutants are allowed to build up on impervious surfaces such as streets.
This may be significant, because housekeeping practices such as intensive street sweeping


could be effective in reducing pollutant deposition during dry periods when rainfall is

"First flush" Phenomenon
Surface runoff that occurs right after a storm begins, often contains higher concentrations
of pollutants than what is found later during the same storm event or closely following
storms (Canning, 1988, p. 9). This phenomena is commonly know as the "first flush"
which concentrates pollutant loads in the first part of runoff waters. This results in a small
portion of the total runoff volume containing a large fraction of the total pollutant load
(Randall and Grizzard, 1983, p. 68). Randall and Grizzard noted that "extractable metals
exhibited the greatest propensity toward the first flush effect, followed by total nitrogen and
total phosphorous." (1983, p. 69).  Prych and Ebbert concluded that when "discharge is
high, concentrations of constituents in suspended form tend to be higher and those in
dissolved  forms tend to be lower than when discharge is low." (1986,  p. 2).

Some researchers, however, speculate that in regions like western Washington, which
experience low intensity and long duration rainfall, there is a "less  noticeable first flush
effect" except perhaps during the winter rainy  seasons when storms are more intense
(Canning, 1988, p. 10).  "A large initial flush of runoff to wash accumulated solids from
the drainage system is uncommon. Instead, the runoff volume slowly increases and any
accumulated solids are gradually carried from the system." (Mar,  1982, p. 15).

The topography or slope of the landscape directly affects the quantity of urban storm water,
and in turn the quality of storm water.  An increase in slope increases the amount and the
rate of flow of surface runoff. In terms of storm water quality, an  increase in slope
translates into a greater capacity of runoff to loosen and transport pollutants.  Also, the
degree of urbanization and amount of impervious ground cover determines the amount of
surface runoff, as discussed in chapter 1.  The amount and flow rate of runoff, along with
pervious ground cover characteristics also controls how fast the runoff is able to infiltrate
the ground.

Permeability (the rate of water movement through the soil column under saturated
conditions) and infiltration (the rate at which water percolates from the  surface storage into
the soil zone) are determined by ground cover and soil characteristics (Novotny and
Chesters,1981, p. 82). In addition, the ability of soils to retain, modify, decompose, or
sorb pollutants are dependent on chemical and  physical soil parameters  that are extremely

Chemical  soil parameters include mineral composition, organic content, clay mineral
content, pH, exchangeable cation and anion content and capacity, and total concentration of
salts. Particle size, texture, compaction, and cultivation represent some of the major
physical soil parameters (Novotny and Chesters, 1981, pp. 82-83). Soil moisture and
vegetation also affect permeability rates.

Soils with high clay content are not very permeable, but have a high pollutant retention
capability, as do soils high in organic matter. Pollutants such as phosphorous, most toxic
metals, and pesticides are largely immobile in these type of soils because they are adsorbed
onto soil particles with available cation/anion exchange sites.  These pollutants are not
likely to be leached from these soils unless very acidic water percolates through or all the
available cation/anion exchange sites are filled up. Nitrates and chloride, which are
extremely soluble, are not likely to be retained by these soils.

Sandy soils on the other hand are more permeable, but do not have a great capacity to retain
pollutants. This is a cause for concern because pollutants which permeate the topsoil might
migrate down to ground water and possibly contaminate drinking water (Novotny and
Chesters, 1981, pp. 82-83).

                                 CHAPTER  3


Increasing numbers of people in the United States are obtaining their drinking water from
ground water, both through public water supplies and from private wells. Urban areas and
associated impervious ground cover often expand over crucial aquifer recharge zones,
possibly affecting the quantity and quality of ground water.

The normal recharge of ground water is often altered because of impervious ground cover
that disrupts natural drainage patterns and channels runoff away from recharge areas to
other receiving waters.  Aquifers may become depleted because stormwater runoff is not
allowed to infiltrate the surface and eventually percolate down. Depleted aquifers in turn
are not able to naturally discharge to surface  waters  such as smaller lakes and streams that
depend primarily on ground water for their sources of water. Conversely, human-made
structures such as retention basins are sometimes used deliberately to recharge ground

3.1  Ground-Water Recharge from Urban Storm Water

The quality of ground water could be degraded by either natural or artificial recharge from
polluted storm water. Undiluted storm water may naturally infiltrate topsoils and percolate
down to an aquifer. Diluted storm water in surface  waters may also seep through cracks
and pores in the bottom of lakes and streams. Artificial recharge may occur in a variety of
settings, including settling basins  (detention or retention), biofiltration strips, dry wells, or
cracks in the pavement or sidewalk. These artificial pathways are discussed in more detail
in chapter 4 of this report. For a general discussion of hydrology and ground-water
protection, see "Ground Water Resource Protection: A Handbook for Local Planners and
Decision Makers in Washington State" published by the Washington State Department of
Ecology and King County Resource Planning.

3.2  Studies

There has been very little quantitative research done linking urban storm water pollutants
and ground-water contamination.  Ground-water monitoring is both very complex and
expensive; therefore, local governments have been reluctant to implement ground-water
monitoring because they often lack the necessary financial and personnel resources. Local
governments are slowly starting to move towards monitoring urban storm water and its
effects on ground water because of increasing risks to drinking water supplies and the
advent of federally mandated storm water permitting.

3.2.1  Nationwide  Urban Runoff Program  (NURP,  1983)

The NURP study concluded that ground water was not imminently threatened by deliberate
recharge from urban stormwater at the two sites where it was investigated (Long Island,
New York and Fresno, California). The Long Island, NY and Fresno, CA NURP projects
studied recharge basins, ranging from newly installed basins,  to basins exceeding 20 years
in age. The primary focus of these studies was to find out whether urban storm water
pollutants were migrating into ground water. The following were the general findings from
these two studies (NURP, 1983, p. 7-24):

         Heavy metals, coliform bacteria, pesticides, and many of the organic priority
         pollutants were intercepted in soils during infiltration and prevented from
         reaching ground water aquifers.

         Chlorides were  not attenuated by soils.

         Pollutants accumulate in the upper soil layers in higher concentrations near the
         surface and none were found several meters below the surface. All soil types
         tested retained pollutants, both clays and sands. Pollutant concentrations were
         found to be a function of the length of time a basin has been in service.

         "The limit of the ability of the soil to retaining the pollutants of interest is
         unknown... However given the long service periods of a number of the recharge
         basins studied, this does not appear to represent an imminent concern."

         Ground-water surfaces were at least 20 feet in depth at both study sites, so these
         findings may not be appropriate for sites with shallow ground water.

         "No significant differences in interception/retention of pollutants is apparent for
         basins with bare versus vegetated recharge surfaces. However, vegetation does
         apparently help  to maintain infiltration rates normal for the soil type."

         Priority pollutants accumulated in soils in basins used for both recharge and
         recreation may present health risks or require special maintenance and warrant
         further investigation.

3.2.2  Long Island, NY NURP  (1982)

The Long Island area has glacially derived soils similar to those in parts of the Puget Sound
area. These soils are mostly classified as either loamy soils or sandy soils (p. 39). Five
artificial recharge basins were studied and a total of 46 storm events were sampled in the
Long Island, NY NURP study. This study had the following general conclusions:

         The limited results of this study indicate that the continued use of recharge basins
         is justified and warranted. CoUform and fecal streptococcal bacteria were found
         in runoff but not in the groundwater beneath  the recharge basins. The
         concentrations of other pollutants, which were generally relatively low in runoff,
         were even lower in the groundwater beneath  the basins.  It appears that
         infiltration through the soil is an effective mechanism for the attenuation of some
         of the heavy metals and organic compounds... It also appears that, contrary to
         the widely held view, the removal of vegetation from the basin floor is not
         necessary, and that the vegetation may actually facilitate  the infiltration of storm
         waters (L.I.NURP, 1982, p. xxiii).

Most inorganic constituent concentrations detected were relatively  low in urban storm water
samples and within permissible levels for drinking water. However, median lead
concentrations in storm water draining from a  major highway consistently exceeded
drinking water standards and chloride concentrations were generally higher during the
winter months (p. 115). Researchers concluded that "Conform and fecal streptococcal
indicator bacteria are removed from stormwater as it infiltrates through the soil." (p. 116).
No conclusions about possible contamination  of ground water by organic priority
pollutants in normal surface runoff were made, but it was noted that illegal discharges of
organic chemicals that runoff may carry into storm drains or recharge basins could be
significant (p. 116).


3.2.3  Fresno, CA  NURP  (1984)

The Fresno, CA NURP study had similar conclusions as the Long Island, NY NURP:

         Soils results showed that the soils in the recharge basins provide a high degree of
         removal of storm runoff contaminants, thereby protecting groundwater quality.
         Although there is some evidence of downward movement of some contaminants
         in the soil, no contamination of the soil water or groundwater has occurred in any
         of the five basins studied (p. 1-3). Lead concentrations in the soil water and
         groundwater underlying the recharge basins were very comparable to
         background levels found in the regional ground water.  This shows that the soil
         layer is an excellent mechanism for removing the lead from the percolating runoff
         water (Fresno, CA NURP, 1984, p. 1-4).

3.2.4  Spokane, WA (1985)

Spokane, located in eastern Washington, has a large number of dry wells (approximately
6,000) that are used to dispose of storm water runoff, which may in turn be contaminating
ground water. A study by the city of Spokane in the early 1980s monitored ground water
quality in a monitoring well adjacent to three of these dry wells.

Miller and others found that aquifer water levels along with calcium and chloride
concentrations demonstrated a one to two week lag time between precipitation events.
Contaminants in general seemed to be "stratified" in ground-water samples. These
generalizations applied to very gravelly soils with a total depth to water of about 20 meters
(65 ft.), (1985, pp. 60, 61).  It was also discovered that:

         Calcium concentrations are generally lower in storm water runoff than in
         groundwater. This is not true however for winter runoff events occurring
         following extensive use of de-icing  salts. The use of calcium chloride results in
         both elevated chloride and calcium.  This feature can potentially indicate the effect
         of a specific  storm on groundwater  and, for at least one event during this study,
         does (Miller, 1985, p. 60).

3.3  Contamination Risks to Ground Water

With respect to ground-water quality, the major concern is the possible contamination of
drinking water supplies from recharge by polluted urban storm water. Ground-water
supplies seem to be at risk in both the short and long term.

The short term profound risks appear to stem  more from point source discharges such as
leaks or spills of undiluted pollutants into storm drains. These  short term risks are
extremely unpredictable and present acute toxicity or "shock effects" to ground water.
Once introduced into ground water these pollutants are diluted slower than in surface
waters and are harder to clean up.

The long term effects of "normal" or diluted urban storm water runoff composed primarily
of pollutants washed off of impervious surfaces is unkown at this point. Heavy metals and
organic chemicals that are adsorbed onto sediments accumulate in the upper layers of soils,
where their fate is uncertain. Researchers have demonstrated that soils have a great
capacity to immobilize and retain a large number of the pollutants found in urban
stormwater. The major unanswered question  is how long will these contaminants remain


relatively immobile in soils and whether they will eventually migrate down to aquifers.
Two possible transport mechanisms for re-release into the environment could be erosion or
leaching by acidic water infiltrating and percolating these soils.

                                 CHAPTER  4


4.1  Introduction

The ultimate goal of urban storm water quality management is to prevent the pollution of
receiving waters and sediments. This goal can be achieved through numerous structural
and non-structural methods. A comprehensive local storm water management plan is
comprised of the following components : 1) information, 2) monitoring, 3) ordinances, 4)
spill response, 5) engineering design, operations, and maintenance, 6) funding and
staffing, 7) agreements with neighboring jurisdictions, 8) education and public
involvement, and 9) enforcement (Hubbard and Calvin, 1989). The three basic tools of
storm water management are storm water utilities, ordinances, and drainage manuals.
Storm water utilities are also called surface water or drainage utilities. Their purpose is to
finance, develop and implement storm water drainage ordinances and management plans,
and educate the public.  Storm water ordinances specifically address such things as non-
storm water discharges, permits, spill control, erosion and sedimentation plans, storm
water standards for new development and retrofitting existing development, privately-
owned systems, and sensitive areas such as wetlands or wildlife habitat (Hubbard and
Galvin, 1989, p. 27-29). Storm water or drainage technical manuals provide the
engineering details for choosing and designing the appropriate water quality and quantity
controls for a given site.

As the chemistry of urban storm water runoff is unique to a given site, so are the quality
controls used to reduce the pollutants contained in storm water. The type of storm water
quality controls used depend on: 1) whether quantity control is also a goal; 2) size of the
drainage basin; 3) rainfall characteristics; 4) what maximum size storm is chosen to control;
and 5) geology and hydrology of the area. This report will give a brief overview of these
approaches, and describe basic principles, and consider their possible effects on ground-
water quality. Details on the specific engineering aspects of these designs can be found in
the Washington State Department of Ecology (WDOE) Stormwater Management Manual
for the Puget Sound Basin - Draft: Controlling Urban Runoff: A Practical Manual for
Planning and Designing Urban BMPs by Thomas Schueler, Biofiltration Systems for
Storm Runoff by Richard Horner, and Urban Runoff Quality: Effects and Management
Options by Douglas Canning.

Up until recently, urban storm water control techniques have focused on the quantity rather
than the quality aspects of storm water management. Improvements in quality were only
incidental to controlling the volume of runoff, as in the case of some detention/retention
ponds. Conversely, some quantity control methods actually decrease the quality of storm
water when the primary goal is to channel runoff away as quickly as possible.  This
increases the volume and velocity of storm water and its ability to carry pollutants.

The three basic approaches to improving urban storm water quality are: 1) preventing
pollutants from entering runoff through "housekeeping" practices; 2) reducing the volume
of runoff by decreasing the amount of impervious surfaces; and 3) treating contaminated
runoff before it reaches receiving waters. Storm water treatment is the most widely
practiced, but is usually incidental to flood control.  Storm water is detained in some
manner, which allows pollutants to settle out or become immobilized by natural processes
(PSWQA, 1986, p. 4-100). However, Canning points out that "The problem of pollution
is not solved by this approach; the site of the problem is merely displaced unless die

pollutants can be retrieved. Retrieval is often possible then necessitating proper disposal of
the material." (1988, pp. 13-14).

Other factors to consider besides pollutant removal in considering storm water quality
management controls or best management practices (BMPs) include:  1) quantity control; 2)
construction and maintenance costs; 3) destruction or creation of wildlife habitat; 4)
potential safety hazards; 5) aesthetic value; and 6) recreational benefits (Schueler, 1987, p.

Urban storm water quality management can be classified as either structural or non-
structural. Structural controls are natural or human-made physical features and structures
that are used to prevent pollutants from entering or remove pollutants from storm water.
These controls can be on-site or regional and include detention/retention ponds, grassy
swales, or infiltration structures.  Non-structural controls are activities, policies, and
regulations that attempt to improve the quality of urban storm water and mitigate its effects
on the environment
4.2  Structural Controls

4.2.1   Detention/Retention

Detention and retention ponds or basins are the two basic types of traditional facilities used
to impound water for flood control and/or remove pollutants from storm water. The strict
definition of a detention pond is one that only temporarily detains storm water and then later
re-releases it as surface runoff, with little or no water infiltrating the ground (WDOE, 1990,
p. ni-4-1; Canning, 1988, p. 17). Retention ponds are generally classified as those which
retain storm water that is only released through infiltration and evaporation processes
(URS, 1988, p. 3-15). There are many gray areas in between these two types and
sometimes the term "detention/retention" pond is used because infiltration, evaporation, and
temporary detention processes take place in most ponds.(URS, 1988, p. 3-15).
Detention/retention facilities are discussed below and retention facilities that are strictly
infiltration devices are discussed in the following section.

Detention ponds have historically been used to control flooding, and whatever water quality
improvements occurred due to settling of contaminants were incidental. Dual purpose
detention basins provide both quantity and quality control. Quantity control is achieved by
briefly detaining large storms to prevent flooding. Quality control is achieved through the
prolonged detention of small storms for at least 18 to 24 hours, to allow settling of
suspended solids is necessary for water quality control (Canning, 1988, p. 18). "Detention
basins are widely used in the Puget Sound area where low permeability subsoils preclude
the use of retention-infiltration basins." (Canning,  1988, p. 17).

Detention ponds can remove storm water pollutants through sedimentation of particulates or
biological uptake of dissolved pollutants. The detention pond design will determine the
degree to which each process operates and its efficiency in removing pollutants.(WDOE,
1990, p. ffl-4-1). WDOE classifies detention facilities either as "wet" ponds that maintain
a permanent pool of water or "dry" ponds that drain after a relatively short period of time.
These facilities can also be either above ground or underground.

The NURP study found that pollutant removal ranged from "insignificant to quite poor" for
dry basins investigated. Wet basin performance ranged from poor to excellent because of
differences in the size of the basin relative to the drainage basin and local storm
characteristics. Detention basins in which the "runoff from an individual storm displaces


all or part of the prior volume, and the residual is retained until the next storm event" were
shown to have high pollutant removal capabilities (NURP, 1983, p. 8-3).

Surface "wet" ponds are thought to be the most effective in improving storm water quality
because they maintain a permanent pool of water which promotes particulate removal and
biological uptake of pollutants. Particulate removal is improved in both above ground and
underground ponds by: 1) decreasing the energy of storm water as it enters the basin; 2)
preventing scour and resuspension of material on the bottom; and 3) allowing exchange of
incoming storm water with previously captured water, thus providing additional time
between storms to settle pollutants (WDOE, 1990, p. 4-2). However, biological
assimilation of dissolved pollutants is only promoted in above ground wet ponds. In above
ground ponds, aquatic plants and algae can take up soluble pollutants such as nutrients and
some metals, and bacteria are allowed to decompose some of the organic pollutants (URS,
1988, p. 33-16).

Canning notes that:  "The principal faults with current detention basin design are (1) an
often inadequate outlet structure and detention period for effective sedimentation, (2) the
stirring up and resuspension of sediments by inflowing storm water, and (3) inadequate
maintenance." (1988, p. 17). Scouring and resuspension of contaminated sediments,
which could then re-release pollutants to receiving waters, is a major concern in designing
detention basins. Regularly scheduled removal of sediments is necessary for detention
basins to remain as effective water quality control facilities (PSWQA, 1986, p. 4-103).
Another concern is the disposal of contaminated sediments which accumulate in these
basins and possible leaching of pollutants into ground water from landfills.

Extended detention wet ponds were ranked first in treatment efficiency of storm water by
detention facilities in the WDQE Puget Sound Stormwater Management Manual - Draft.
Schueler notes that:

         Extending the detention time of dry or wet ponds is an effective, low cost means
         of removing particulate pollutants and controlling increases in downstream back
         erosion. If stormwater is detained for 24 hours or more,  as much as 90%
         removal of particulate pollutants is possible.  However, extended detention only
         slightly reduces levels of soluble phosphorous and nitrogen found in urban
         runoff. Removal of these pollutants can be enhanced if the normally inundated
         area of the pond is managed as a shallow marsh or a permanent pool.(1987, p.

Schueler recommends a two stage detention pond design with an upper and lower stage.
The upper stage is designed for flood control for larger infrequent storms and remains dry
most of the time. This can prevent the resuspension of contaminated sediments by initially
reducing the energy of the water entering the lower stage. The lower stage is designed for
water quality control and allows the fine particles and pollutants to settle out This stage
maintains a permanent pool and could be an artificial wetland in which plants could help
stabilize sediments uptake soluble pollutants (1987,  p. 3.16)

Routine maintenance of detention facilities may include mowing, inspections, debris and
litter removal, erosion control, and nuisance control (odors,mosquitos,weeds,litter). Non-
routine maintenance of detention facilities may include structural repairs and replacement,
and sediment removal (Schueler, 1987, pp. 3.21-3.23).

4.2.2   Infiltration

Infiltration facilities are structures that directly infiltrate storm water into the ground. These
facilities include large off-site retention basins, small on-site units such as infiltration pits
and trenches, percolating catch basins, dry wells, and porous pavement (NURP, 1983, p.
8-15).  Most infiltration structures except for porous pavement also provide storage volume
and flood control capabilities (NURP, 1983, p. 8-15). The two basic principles behind
improving stormwater quality through infiltration are 1) attenuation (immobilization) of
pollutants by soils and 2) dilution of stormwater with large amounts of uncontaminated
ground water.

Pollutants such as soluble heavy metals, phosphorous, and pathogens can be attenuated by
soils. Attenuation processes are very complex and include adsorption, precipitation,
trapping, straining, and bacterial degradation or transformation. Attenuation rates for
individual pollutants depend on their solubility and biochemistry, and the physical and
chemical properties of the soils and ground water (Schueler, 1987, p. 5.13).

Infiltration devices are a viable water quality control option in medium textured soils with
moderate permeability where the water table is well below the soil surface (URS, 1988, p.
3-18; Schueler, 1987, p. 6.2). However, infiltration facilities are generally not designed to
trap coarse sediments mat can sometimes clog the soil pores on the pond floor, thus
preventing infiltration.  "Fine soils are subject to clogging, while coarse soils can pass
pollutants to groundwater.  Excessively rapid percolation through coarse soils allows
insufficient time and soil surface contact for effective pollutant removal. Therefore,
whether a rate is too rapid depends on whether an aquifer lies relatively near the
surface."(URS, 1988, p. 3-18).

Clogging is a major drawback of infiltration devices which results in significantly reduced
or no infiltration. Infiltration structures are most vulnerable to clogging during their own
construction because of soil disturbance and erosion. Pre-settling basins or biofiltration
can sometimes be used to trap coarser sediments and prevent clogging. The NURP study
noted that:

         Pollutant removals are reduced in direct proportion to the runoff volume which is
         intercepted and recharged.  Load reductions will be further enhanced if quality
         improvements occur in the portion of the runoff which is not captured. The
         combination of soil infiltration rate and percolating area provided determines the
         "treatment rate" of a specific recharge device... Overall performance will be
         related to the size of the recharge device relative to the urban catchment it serves
         and the permeability (infiltration rate) of the soil (1983, p. 8-15).

Of all the storm water quality control methods, infiltration probably has the greatest
potential to contaminate ground water with pollutants found in urban storm water,
especially in soils with high permeability. Careful site-specific considerations should be
made when determining whether infiltration methods are appropriate for a given area.
Other site conditions  that could preclude the use of infiltration methods include steep
slopes, shallow depth to ground water, and close proximity to water supply wells (NURP,
1983, p. 8-14).  "SEEPAGE", a qualitative system to evaluate sites for infiltration facilities
has been developed by the Soil Conservation Service and is included in the WDOE
Stormwater Management Manual for the Puget Sound Basin - Draft.

Infiltration basins
Infiltration basins are generally large off-site retention basins that can serve two purposes.
With respect to water quantity, retention basins can control flooding and also store runoff
for later infiltration into the ground; ground waters in turn recharge rivers and streams.
Schueler notes that "Infiltration basins divert a significant fraction of the annual runoff
volume back into the soil.  This enhanced recharge can maintain flow levels in small
headwater streams during critical dry weather periods."(1987, p. 6.7). The other purpose
is related to water quality.  Retention basins are effective in removing both fine
contaminated sediments and soluble pollutants found in urban runoff through soil
adsorption processes (Schueler, 1987, p. 6.1).

Infiltration trenches
Infiltration trenches are usually on-site and are basically smaller versions of infiltration
basins.  These structures can also facilitate removal of soluble and paniculate pollutants,
and can provide ground water recharge and flood control depending on their size and
infiltration capacity.  (Schueler, 1987, p. 5.1)

Porous pavement
Porous pavement is asphalt or concrete pavement that has sufficient voids or pore space to
allow water to infiltrate into the ground. Schueler describes porous pavement as having a
"high capability to remove both soluble and fine paniculate pollutants in urban runoff, and
also provides ground-water recharge, low flow augmentation, and stream bank erosion
control. Its use is generally restricted to low volume parking areas...The major drawback
associated with porous pavement is that if is becomes clogged it is difficult and costly to
rehabilitate. The risk of premature clogging of the pavement is fairly high, and can be
prevented only if sediment is kept off of the pavement before, during, and after
construction." (Schueler, 1987, pp. 7-1, 7-2).

Injection wells
Underground injection wells, also known as dry  wells, are also a form of infiltration used
to dispose of storm water runoff on-site. Schueler classifies dry wells as "underground
infiltration trenches". Dry wells are probably the most likely to contaminate ground water
because they "provide little pretreatment and act as a direct conduit for stormwater to enter
the unsaturated zone and the aquifer, bypassing soil column attenuative
processes..."(Goldstein, 1987).

Dry wells are used in all types of land use areas.  Spills and leaks of undiluted hazardous
chemicals that eventually find their way to dry wells are the most serious threat posed to
ground water.  The contamination of ground water by PCE given in the introduction is an
example of this hazard. The potential impact of "normal" urban storm water on ground
water via dry wells is still relatively unknown.  The WDOE "Guidelines for Stormwater
Disposal Via Dry Wells" recommends the following:

         Dry wells are not generally an acceptable method of disposing of stormwater.
         Grassy swales, percolation areas, and wet and dry ponds provide better treatment
         and protection to ground  water. Use dry wells only where alternatives, such as
         retention basins or storm sewers, are not practical or feasible (1989, p. 4).

If dry wells are used,  it is generally  recommended that some sort of pre-treatment occur
before stormwater enters the well. This may consist of biofiltration, a pre-settling basin, or
oil-water separator.

Detention/retention versus infiltration
The Puget Sound Water Quality Authority provides an excellent discussion of the tradeoff
between detention and retention (infiltration) facilities in its 1986 Nonpoint Source
Pollution issue paper. A portion of this discussion is quoted below.

         The choice between detention and retention basins involves tradeoffs between
         risking contamination of ground water, adding pollutants to surface waters, and
         preventing damage to fish habitat Retention basins reduce contamination of
         surface waters (because contaminants remain in the basin or enter the ground
         water instead of flowing with stormwater into streams), reduce the volume of
         streams during and after flooding, and "save" the water as ground water for later
         recharge of streams during dry seasons. Retention, therefore, provides greater
         protection to both spawning and rearing habitat for salmon. Unfortunately,
         retention basins can potentially cause contamination of ground water as dissolved
         contaminants from stormwater filter down. Detention basins, on the other hand,
         do not contaminate ground water. However, they do not reduce the total volume
         of stormwater to streams nor do they help to prevent streams from drying out
         during the summer (p. 4-102).

4.2.3   Biofiltration

Biofiltration can be defined as "processes in which a wastewater stream receives treatment
through interaction with vegetation and the soil surface. "(Horner, 1988, p. i). The basic
principle of biofiltration  is that vegetation acts as a physical and chemical filter to
immobilize pollutants and prevent them from entering receiving waters. Biofiltration
processes include  sedimentation, infiltration, adsorption, and biological uptake of
pollutants (WDOE, 1990, p. ni-6-1). There are three basic types of biofiltration: 1)
grassed swales, 2) filter strips, and 3) wetlands.

Grassy swales
A grassy swale is a vegetated channel similar to a storm drain channel (WDOE, 1990, p.
ni-6-2-). "Grassed swales function primarily by sedimentation of suspended solids and
pollutants. The velocity of water flowing through a grassed swale is reduced sufficiently to
promote sedimentation.  Additionally, as the runoff infiltrates porous ground, pollutants are
also filtered out by the root mat and upper soil horizon.  Some dissolved pollutants may
also be adsorbed onto the surface of the vegetation, the root mat, or soil particles."
(Canning, 1988, p. 23).  To be effective, the flow of stormwater should not exceed the
height of the vegetation in the grassed swale (WDOE, 1990, p. ni-6-2).

In Washington Department of Transportation sponsored highway studies, University of
Washington researchers found grassy swales to be the most cost effective means of
removing solids and associated pollutants from highway runoff, but were not as effective
removing soluble metals.(Canning, 1988, p. 21). In that particular study Wang et al.
concluded that "a slightly sloped channel of hydraulically sufficient cross-sectional area and
60 m in length is capable of removing 60-80 percent of the Pb, Zn, and Cu, in highway
runoff." (1982, p. 28).

The NURP study concluded that grassy swales moderately improved urban runoff quality.
The authors cited slope, vegetation type and maintenance, control of flow velocity and
residence time, and enhancement of infiltration as factors to consider in the design of
grassed swales (1983, p. 9-14). A major concern of biofiltration systems is maintaining
vegetation. If swales have standing water for prolonged periods of time or excessive
sedimentation occurs, vegetation will die off and its benefits cease.

Filter strips
Filter strips are smaller versions of grassed swales. The main difference between the two
is that filter strips are used when runoff is a sheet flow, grassy swales or channels are used
when runoff volume is sufficient to form channels (Horner, 1990). "Filter strips provide a
vegetated buffer around streams, lakes, and wetlands" and "also protects the water body
from litter, bank erosion, and other impacts of intense use. Close-growing, fine grasses
provide the best pollutant removal action, but woody vegetation offers other buffering
advantages."(URS, 1988, p. 3-17).

In a 1988 review of biofiltration systems in the region Homer noted that:

         A minority had poor vegetation coverage, and some exhibited persistent pooling
         of water, perhaps due to the prevalent shallow slopes, as well as high water
         tables. Saturation can kill grasses and be an aesthetic drawback near homes and
         businesses. Little siltation was evident, except at construction sites, although
         few biofilters are preceded by settling devices. Therefore, maintenance could be
         limited in most cases to mowing.(Homer, 1988, p.ii).

Wetlands include bogs, shallow  marshes, shrub/scrub wetlands, and forested wetlands,
and are classified as either natural or artificial. Some of their functions include flood
storage and desynchronization, sediment trapping, and nutrient retention and removal
(Canning, 1988, p. 27). Canning describes their primary water quality function as being

         The principal water quality improvement mechanism is sedimentation. As storm
         water enters a wetland, flow velocities are diminished by obstructing vegetation
         and shallow depths. To the extent that flow velocity is diminished, suspended
         solids settle to the bottom of the wetland.  Since many of the contaminants are
         adsorbed to sediments, sedimentation clears the runoff not only of the solids but
         also of some heavy metals, phosphorous, refractory organics, petroleum
         hydrocarbons, and bacteria and viruses (1988, p. 33).

"The use of natural wetlands for  storm water control is highly controversial because of the
possible cumulative effects of pollutants in storm water on wetland vegetation and wildlife.
These effects are still not clear from the literature. "(PSWQA, 1986, p. 4-101). Stockdale
points out that:

         It should be kept in mind that wetlands are not final  sinks for nutrients, heavy
         mental and other substances that are discharged to them. Wetlands improve
         water quality by transforming, removing, storing and releasing those substances,
         at modified rates and times. (1986, p. 17).

As with other urban storm water quality controls using infiltration processes, caution must
be taken in areas with highly permeable soils and shallow ground water to avoid possible
ground-water contamination.

Artificial wetlands
Artificial wetlands can be thought of as modified retention/detention ponds because they
have many similar design principles .(URS, 1988, p. 3-17). Location and vegetation are
two key considerations in designing artificial wetlands for storm water quality control.
Location considerations include proper elevation relative to the ground water table, soils,
geology, and ground-water hydrology (Canning, 1988, p. 36). A design should have a
pre-settiing basin, maintain a permanent pool with a minimum of open water, and


preferably use native and dense-growing species of vegetation (Canning, 1988, pp. 36,
38).  (See Canning and the Puget Sound Stormwater Management Design Manual for
specific details on artificial wetland design).

4.2.4  Oil-water Separators

Traditional oil-water separators work on the principle that oil floats on water and typically
use a "T" outlet which traps the oil.  However, oil-water separators are effective only if
they are regularly maintained by removing the oil and grease between each storm event. If
this is not done die oil becomes resuspended or re-emulsified and then discharged during
subsequent storms. Another problem with oil-water separators is that very intense storms
may flood and not allow the oil enough time to separate (PSWQA, 1986, p. 4-100).

Another type of oil-water separator is a coalescing plate separator, which "uses packs of
corrugated plates to coalesce small oil and grease droplets into larger droplets which can be
skimmed off the top." (PSWQA, 1986, p. 4-100). These separators can also be effective if
properly functioning and maintained.

Normal urban storm water has relatively low concentrations of oil and grease which
available devices cannot remove to any significant degree. Horner and Wonacott studied a
detention pond/coalescing plate separator system at Boeing Computer Services, a light
industrial site.  They discovered that the coalescing plate oil/water separator was not
utilized because oil and grease concentrations in the storm water were very low to begin
with and the detention pond removed the vast majority of pollutants found (1985, p. iv).
Land treatment of detention pond effluent such as through a grassy swale could be used to
remove these small amounts.

Areas that are vulnerable to spills or leaks from vehicles would justify using oil and grease
separators. These include areas where there is a large amount of heavy industrial traffic
(e.g., trucking bases) or in areas prone to spills.  Vehicles tend to leak most when their
seals contract upon cooling. Therefore, large parking lots with considerable in-and-out
traffic can be significant source, while high-speed highways operating normally may not be
(URS, 1988, p. 3-19).

4.2.5  Prevention  of Erosion on  Construction  Sites

Construction sites are a major source of sediments that enter urban storm water and often
carry adsorbed pollutants. The theory behind erosion control is to minimize bare areas,
especially on steep slopes, through vegetation and also to prevent sediment in runoff from
leaving the site by straw bales and other filtering devices.

4.3  Non-Structural  Controls

4.3.1   Housekeeping

Prevention and removal of pollutants from impervious surfaces such as streets, before they
enter urban storm water is die main principle behind housekeeping practices. General
"housekeeping" practices such as spill prevention, cleaning practices, and regular
inspection of storage areas can greatly reduce the amount of pollutants entering urban storm
water form all land use areas.  Street sweeping, however has generally been ineffective in
removing contaminants and improving storm water quality, because it does not remove the
finer particles which have pollutants adsorbed onto them (NURP, 1983; Sartor and Boyd,
1972; Pitt and Bissonette, 1984; Galvin and Moore, 1983).


4.3.2   Primary or Secondary Treatment of Urban Storm Water

Primary or secondary treatment of urban storm water in wastewater treatment facilities is
technically possible, but the variability and sometimes large volumes of runoff make this
option economically infeasible (URS, 1988, p. 3-19). Low volume storms or the first few
hours of a storm could be routed to be treated.  "However, generally the volume of storm
water exceeds the capacity of the sewer lines resulting in an overflow of storm water
exceeds the capacity of the sewer lines resulting in an overflow event of combined storm
and sanitary sewage. "(PSWQA, 1986, p. 4-105).

4.3.3   Investigative Monitoring and  Site  Visits

Investigative monitoring and site visits are also a means to reduce point source pollutants in
urban storm water.  "This technique is a method for an enforcement agency to identify the
source of a pollutants in storm water in order to require control.  Storm drains are sampled
and when more than typical amounts of pollutants are found, the pollutant is tracked up the
line until, by process of elimination, the source is identified. Sampling sediments in storm
drains is effective because, unlike water samples, sediment samples integrate pollutant
inputs over time." (PSWQA, 1986, p. 4-104).

                                 CHAPTER 5

                      POLICIES AND REGULATIONS
5J.  Introduction
In 1972 and 1977 Congress amended the Federal Water Pollution and Control Act, also
known as the Clean Water Act (CWA). The CWA prohibits the discharge of any pollutant
to navigable surface waters from a point source unless the discharge is authorized by a
National Pollution Discharge Elimination System Permit (NPDES), but does not
specifically address discharges to ground water. There is no federal program that
addresses ground water protection in a comprehensive manner. The NPDES program has
focused predominantly on reducing pollutants from point source discharges, such as
industrial and municipal wastewater, in order to improve surface water quality (53 FR,
1988, p. 49417).

Although EPA was given the legal authority to implement this Act, the primary
responsibility for water pollution control has fallen on the states and local governments.
Section 208 of the CWA required states to develop comprehensive water quality plans to
protect its surface water bodies from both point and nonpoint sources of pollution.  In
terms of storm water discharges, the Safe Drinking Water Act indirectly addresses possible
ground water contamination through the National Drinking Water Standards, the
Underground Injection Control Program, Sole Source Aquifer Program, and the Wellhead
Protection Program.

EPA issued its first storm water regulations on May 22,1973 in 38 FR 13530.  These
regulations exempted most storm water discharges from permitting except for storm water
from industrial and commercial activities identified as being a significant contributors of
pollution (53 FR, 1988, p. 49419). Reluctance to regulate storm water was probably due
to the great difficulty in how to defining and regulating storm water. EPA's reasoning
behind this decision was that: 1)  storm water discharges were not suited to the NPDES
permitting program and traditional end-of-pipe wastewater treatment because of the inherent
variable quantity and quality of storm water, 2) it was thought that storm water could be
better managed at the local level through source controls; 3) requiring individual permits for
the hundreds of thousands storm water outfalls "would create an overwhelming
administrative burden and would  divert resources away from control of industrial process
wastewater and municipal sewage."(53 FR, 1988, p. 49419).

Over the last eighteen years there has been much debate over which storm water discharges
should be regulated and how they should be regulated. The rules have been alternately
broadened and narrowed after a series of court challenges from both environmentalists and
industry.  However, in general the movement has been slowly towards increasing
regulation of urban storm water. EPA has had the difficult task of balancing "the
environmental concerns associated with such discharges with the practical limitations of
individual NPDES permits and the reality of limited resources."(53 FR, 1988, p. 49419).

5.2  Water Quality Act  of 1987

5.2.1   Section  402

To further clarify its intent to improve the nation's water quality, Congress reauthorized
and amended the Clean Water Act by passing the Water Quality Act of 1987 (WQA).
Sections 402,401, and 503 of the WQA specifically address the issue of storm water.  In
Section 402(p)(l),(2), and (4) Congress laid out the following regulatory timetable for
industrial and municipal storm water discharges:

                           Cities over      Cities        Cities
                             250,000      100,000 to      under
                           & Industry      250.000      100.000

EPA Regulations              2/4/89         2/4/91        10/92

Applications                  2/4/90         2/4/92          ?

Permitting                    2/4/91         2/4/93          ?

Compliance                  2/4/94         2/4/96          ?

The WQA also gives the Administrator considerable discretion to regulate any discharge
that "contributes to the violation of a water quality standard or is a significant contributor of
pollutants to the water of the United States."(WQA, Section 402(p)(2)(E), 1987).

Section 402(p)(3)(A) on industrial discharges requires that "permits for discharges
associated with industrial activity must meet all of the applicable provisions of section 402
and section 301 including technology and water quality based standards for discharges
from municipal storm sewers."(53 FR, 1988, p. 49424).

Large- and medium-sized municipalities
Section 402(p)(3)(B) on municipal storm water discharges provides that permits:

       (i)   May be issued on a system- or jurisdiction-wide basis.

       (ii)   Shall include a requirement to effectively prohibit non-storm discharges into
            the storm sewers.
       (Hi.) Shall require control to reduce the discharge of pollutants to the maximum
            extent practicable, including management practices, control techniques and
            system, design and engineering methods, and such other provisions as the
            Administrator or the State determines appropriate for the control of such

Part (i) of this section is very significant because it gives EPA the discretion to issue
system-wide permits for municipalities that have hundreds or even thousands of storm
water discharges.  "This should reduce significantly the monitoring, data, and information
requirements for permit application,  but permit application requirements will still be
substantial." (Tucker, 1989, p. 114). This system-wide approach will probably alleviate
only some of the administrative burden at all levels of government, but it will take time  to
figure out how to issue system-wide permits efficiently and realistically.

Part (ii) totally prohibits non-storm water discharges which includes combined sewers and
illegal hookups to storm sewers. These connections are difficult to find and very costly to
correct In older urban areas with combined sewers this could be very significant problem
to correct.

Part (iii) is written very vaguely, and the term "maximum extent practicable" has caused
much concern, because it is left open to interpretation. This vagueness could work in a
positive or a negative way. It could provide the flexibility needed for local governments
and industry to be innovative in managing storm water or provide a loophole for inaction
and noncompliance. EPA and State permit writers will have to decide what constitutes
"maximum extent practicable" for each site. Interpretation of this term will likely be tested
in the judicial system.

Small municipalities
Section 402(p)(5) requires EPA to perform two studies on storm water discharges,
potential impacts, and management controls from municipalities under 100,000 in
population. Based on those studies, section 402(p)(6) requires EPA in consultation with
States and local officials to issue regulations and deadlines for issuing permits for those
discharges by no later than October 1,1992.

5.2.2  Sections 401 and  503

Section 401 excludes "discharges of storm water runoff from mining operations or oil and
gas exploration, production, processing, or transmission facilities if the storm water
discharge  is not contaminated by contact with, or does not come into contact with any
overburden, raw material, intermediate product, finished product, byproduct, or water
product located on the site of such operations. "(53 FR, 1988, p. 49424). Section 503
excludes agricultural storm water discharges from the definition of point sources.

5.2.3  Current EPA Ruling on Urban Storm Water

The final EPA rule on regulating storm water discharges from municipalities over 250,000
in population and industry is expected in November 1990.  Some of the issues involved in
the current ruling are: 1) what type of sampling and data collection should be required in
the permitting process; 2)  whether to issue group permits for industrial facilities of the same
type, and if so, how it would be done; 3) whether industrial facilities or municipalities
should be  responsible for providing storm water quality control for industrial discharges
into a municipal storm sewer system; 4) allowing a system- or jurisdiction-wide approach
for municipalities, where one permit instead of individual permits would be issued; 5)
flexibility  in permitting municipal storm water management programs which reflect site-
specific characteristics and impacts associated with these discharges (Gallup and Weiss,
1989, pp.  104-105).

5.3  Safe Drinking Water Act

The main  goal of the SDWA of 1974 was to ensure public health by improving the quality
of the nation's drinking water. Congress directed EPA to establish minimum national
drinking water standards which set limits on the concentrations of chemicals sometimes
found in drinking water.  These standards apply to water supplies with at least 15
connections or serving 25 or more people. Suppliers must also inform the public if their
drinking water does not meet these standards and what precautions to take. Enforcement of
the SDWA is carried out either by the States or by EPA on request by the States or when
the States  are slow to act.


The four major components of the SDWA are the 1) National Drinking Water Standards
(1974), 2) Underground Injection Control Program (1974), 3) Sole Source Aquifer
Program (1974), 4) Wellhead Protection Program (1986). The 1986 Amendments to the
SDWA further clarified Congressional intent to improve drinking water by specifically:  1)
prohibiting the use of lead-containing materials in drinking water supply systems; 2)
accelerating the regulation of drinking water pollutants by setting a specific schedule with
deadlines for EPA to develop and enforce drinking water standards; 3) expanding and/or
improving federal water quality programs.

5.3.1  National Drinking Water Regulations

Congress first required EPA to establish national drinking water standards through the
SDWA of 1974 to ensure the quality of the nation's drinking water at the tap. The 1986
amendments to the SDWA require EPA to strengthen these standards, which apply to both
surface water and ground-water sources of drinking water. The National Drinking Water
Regulations consist of primary and secondary standards that reflect both human health and
aesthetic concerns with regard to  public water supplies.

The purpose of the primary drinking water standards is to protect public health. The
concentrations of chemical constituents in these standards are levels in drinking water that
EPA has determined as being safe for human consumption. Under the authority of the
SDWA, EPA is required to issue a Maximum Contaminant Level Goal (MCLG) and an
Maximum Contaminant Level (MCL) for various chemical constituents found in drinking

A maximum contaminant level goal (MCLG) is a nonenforceable health goal. EPA issues
maximum contaminant level goals for substances only included in the primary drinking
water standards. MCLGs are set  at a level at which "no known or anticipated adverse
effects on the health of persons occur and which allow an adequate margin of
safety."(GAO, 1988, p. 52). MCLGs are usually set at a risk level of one-in-one-million
risk of cancer to humans. A maximum contaminant level (MCL) is an enforceable primary
drinking water standard. MCLs are set as close as possible to  MCLGs as feasible and
achievable through available technology.

The secondary drinking water standards are not concerned with public health, but are
designed to protect public welfare. Their purpose is to "provide guidelines regarding the
taste, odor, color, and other aesthetic aspects of drinking water which do not present a
health risk." (EPA, 1989, p. 18).

5.3.2  Underground Injection Control Program

Created in 1974, the Underground Injection Control (UIC) Program focuses on preventing
the underground injection of waste that could cause ground water contamination and
subsequent violations of national drinking water standards. The UIC program requires
EPA to establish minimum requirements for state regulation and permitting of deep well
injection of wastes or "subsurface emplacement of fluids into underground wells".

The simple definition of "injection well" is a hole in the ground that is deeper than it is
wide. EPA classifies injection wells into five broad categories based on the type of injected
material and the location of the injected material in relation to an aquifer (Barrett, 1987,
p. 13). These five categories are also subdivided into more specific types of injection wells.
Congress exempted oil, natural gas production and associated petroleum development

brines from extensive regulation, only requiring states to prove that the brines would not
endanger drinking water (Gordon, 1984, p. 97).

5.3.3  Sole Source Aquifer Program

The purpose of the Sole Source Aquifer Program is to protect aquifers which serve as the
primary drinking water supply for a large portion of the population of a given area.
Current EPA policy requires that some person or organization petition EPA to designate an
aquifer as a sole or principal source of drinking water. Once an area has been designated as
a sole source aquifer, EPA has the authority to review and approve any federally funded
projects that could threaten ground-water quality within the sole source aquifer area
(Barrett, 1987, p. 13). This program is very limited in scope because it does not include
federal projects themselves or any projects without federal financial assistance.  However,
local attention given to designated sole source aquifer areas may in a indirect may serve to
help state and local governments develop laws and ordinances protecting ground water and
the impetus to implement existing laws.(Gordon, 1984, p. 97).

5.3.4  Wellhead  Protection Program

The goal of the Wellhead Protection Program is to prevent the contamination of public
water supply wells through the protection of recharge areas surrounding ground-water
wells. This program makes the link between land use and human activities near wellhead
areas and ground-water quality, and provides another mechanism for ground-water

5.4  Other Federal Statutes - FIFRA. TOSCA. RCRA. CERCLA

Other federal statutes that indirectly protect ground-water resources include the Federal
Insecticide, Fungicide, Rodenticide Act (FIFRA), Toxic Substances Control Act (TOSCA),
Resource and Conservation and Recovery Act (RCRA), and Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) or "Superfund".

Both FIFRA and TOSCA regulate toxic chemicals that could harm human health and the
environment.  FIFRA "establishes procedures for governing the registration, classification,
sale, use, research, monitoring , and disposal of pesticides"(Barrett, 1987, p. 15).  TOSCA
gives EPA authority to "review new chemical substances and mixtures prior to
manufacture, develop rules for industry testing of chemicals, assess risks, and control
existing toxic chemicals."(Barrett, 1987, p. 15).  In terms of ground water, a benefit of
regulating these chemicals in a pru'dent manner is the prevention of underground drinking
water supply contamination.

A primary goal of the Hazardous Waste Management Program under RCRA is to protect
ground-water resources from potential contamination of existing hazardous waste facilities.
RCRA requires generators of hazardous wastes to track it from generation to disposal and
regulates hazardous waste storage and disposal facilities (Barrett, 1987, p. 14).

The CERCLA or Superfund program in contrast is response oriented and designed to
mitigate the past and current releases of hazardous substances at hazardous waste sites.  In
nominating sites for the National Priority List for Superfund eligibility, the Washington
State Department of Ecology and EPA rank them according to the: 1) potential for
contaminating drinking water supplies or other pathways that can affect human health and
2) potential for destruction of sensitive ecosystems (Barrett, 1987, p. 14). "To  date,

federal response actions under CERCLA have principally addressed ground water
contamination problems."(Barrett, 1987, p. 15).

                                 CHAPTER 6

6.1  Introduction

Currently, there is no comprehensive federal legislation or program which protects ground-
water quality from all potential or existing sources of contamination,(including urban storm
water runoff), or that establishes national ground-water standards (Barrett, 1987, p. 15).
The Safe Drinking Water Act and other narrowly focused federal legislation, along with
state and local laws and ordinances, provide a legislative patchwork that attempts to protect
the nation's ground-water quality.  To fill the void, some states are using the National
Drinking Water Regulations as ground-water quality standards for lack of federal ground-
water standards. Other federal programs, such as the Sole Source Aquifer Program are
severely limited in their scope and effectiveness in protecting ground-water quality.

6.2  Assessment  of  the  Water Quality Act of 1987

"The long term goal of EPA appears to be to force the development of comprehensive
storm water management plans at the local level that will in time reduce the discharge of
pollutants into and from storm waters." (Tucker, 1989, p. 120).  Currently, a few local
jurisdictions are moving ahead in developing storm water or surface water utilities in
anticipation of EPA's final rule on storm water discharges. The City of Bellevue in
Washington state was the first city in the country to develop a storm water utility,
ordinances, and water quality drainage plan. This may be an instance of local government
taking initiative in the absence of national or state guidance, which may significantly
influence national policy in the future.

Only urban storm water discharges to surface water will require NPDES permits under the
WQA of 1987. However, the issuance of these NPDES permits may have a indirect
positive effect on the quality of urban storm water discharges to  ground water.
Management controls used to improve the quality of urban storm water in order to prevent
surface water contamination may also have a byproduct effect of preventing ground-water

The WQA of 1987 excludes the regulation of mining, and petroleum industry storm water
runoff that does not come into contact with any materials produced at the operations site. It
is very unrealistic to think that storm water emanating from mining operations or petroleum
refineries does not contain significant amounts of toxicants. Some of these activities,
especially refining processes certainly take place in or near urban areas. Why should storm
water from these industries be excluded? Even if they are located in rural or semi-rural
settings, contaminated  storm water could pollute surface water that reaches urban areas or
recharge an aquifer with pollutants possibly migrating underground to public drinking
water supply wells.

All levels of government will have a tough time implementing this massive program that
will require additional staffing and funding. Small municipalities will probably be
especially hit hard because of lack of trained staff and no established drainage plans.  The
capital and operating expenses necessary to comply with these regulations will cost an
enormous amount of money. Who will pay for it? The federal government is currently
having serious budgetary problems and is not in a position to provide as much financial aid
to local  governments as in the past. Tucker points out that "The financial burden of the


municipal storm sewer permitting program will fall primarily on local governments, i.e.,
cities, counties, flood control districts, etc. The permitting program is not voluntary and
there are no grants or federal funding support to assist with meeting permit
requirements."(1989, p. 112).

6.3  Assessment of the Safe Drinking  Water Act

Although EPA does not explicitly support the adoption of national ground-water standards,
the agency is implicitly supporting the use of the national drinking water standards as
ground-water standards through its ground-water protection programs.(GAO, 1988, p. 3).
A 1988 General Accounting Office (GAO) report found that both EPA and some states are
encouraging the use of drinking water standards as ground-water standards.

GAO found four EPA programs that encourage the use of drinking water standards as
ground-water standards at the local level. To prevent ground-water contamination, the Sole
Source Aquifer program implicitly encourages states and municipalities to designate
aquifers used  as a primary source of drinking water sources. Section 1424 (e) allows EPA
to make such designations, but the Agency only responds to petitions, and does not
explicitly encourage the submission of petitions. The EPA Office of Pesticide Programs
also takes a preventative stance in that actions should be taken before concentrations of
pesticides in ground water reach the drinking water standard MCLs. Both the RCRA and
Superfund programs rely  heavily on MCLs in the drinking water standards to instigate
remediation actions at hazardous waste sites (GAO, 1988, p. 3). The GAO report states

      An assumption common to all of these policies is that MCLs play a key role in
      helping to determine the need and scope of regulatory actions, and when coupled
      with appropriate control techniques and programs, their use will result in an
      acceptable level of groundwater protection.(1988, p. 3).

Gordon points out the major flaw behind this reasoning is that "...a drinking water supply
could be severely contaminated by toxic substances for which there are no MCLs and still
meet the federal requirements for safe drinking water."(Gordon,  1984, p. 89).

In the absence of national ground-water quality standards, 26 states have numeric ground-
water standards that rely heavily on the EPA national drinking water MCLs. Both the
substances chosen and their allowable levels found in these  states' ground-water standards
were based on the drinking water standards.(GAO, 1988, p. 4-6). The states are
essentially implementing a policy of limited degradation of ground water up to the legally
enforceable MCLs set in the drinking water standards. GAO found that ground-water
quality at 92 percent of the locations studied met all the drinking water standard MCLs and
that 71 percent met the MCLGs for all substances measured.(1988, pp. 1,38).

Should there be national ground-water standards?  If so, should the goal of ground-water
standards be nondegradation or limited degradation up to the point of the drinking water
standards? Another option could be a policy of antidegradation similar to the urban storm
water discharge requirements in Section 402(p)(3)(B)(iii) of the CWA of 1987. This
policy would require that  the best management practives be used to reduce ground-water
pollution to the maximum extent practicable.

In addition to drinking water, ground water is used for irrigation and livestock. Ground
water also affects the habitat of aquatic life because it flows into surface water. Allowing
limited degradation through application of the drinking water standards for ground-water


protection could jeopardize other uses that require standards higher than those for drinking
water. EPA MCLs for drinking water were at least as stringent as levels recommended for
livestock and irrigation, but MCLs for 17 substances were less stringent than levels set for
aquatic life (GAO, 1988, p.9).  GAO concluded that the adoption of drinking water
standards as ground water standards "would allow the potential for degradation of a
considerable amount of groundwater (to the level of contamination allowed by drinking
water standards)."(GAO,  1988, pp. 1, 38).

Most states lack a comprehensive ground-water protection strategy, and instead have
disjointed statutes that are implemented by several states agencies. These regulations
generally fall into four broad categories: 1) regulation of contaminants; 2) classification of
aquifers; 3) ground-water quality standards; and 4) control of land use in aquifer-recharge
zones.(Gordon, 1984, p.48). Variability in regional ground-water quality and
contamination sources, along with the absence of comprehensive federal ground-water
regulations account for the great diversity in state ground-water regulations. At the local
level, jurisdiction over ground water is also often split between different departments, such
as the public works and engineering department, health department, and water utility.
Development pressures and the fact that aquifers often extend over governmental
boundaries also add to the difficulties in protecting ground water (Gordon, 1984, p. 49).

6.4   Recommendations

In order for local governments to succeed in managing storm water and protecting ground-
water quality, guidance must come from EPA and the states to show local governments
how to develop comprehensive storm water management plans and ordinances. Instead,
EPA and the states seem to be waiting to see what happens at the local level before
proceeding further, especially in the area of ground-water protection.

A clear and enforceable comprehensive federal policy protecting ground-water quality from
ail sources of contamination, (including urban storm water), is needed to provide direction
to state and local government. This policy could take the form of the nondegradation or
antidegradation of existing ground-water quality of any given aquifer.  Another option
would be to develop a specific set of national ground-water quality standards similar to the
National Drinking Water Standards. A regional approach could also help local
governments cope with implementing both storm water management and ground-water
protection.  Development of regional ground-water management authorities with the
authority to both  plan and enforce rules because of the regional nature of ground water and
the multiplicity of governmental interests (Gordon, 1984, p. 49).

Sharing information between all levels of government could expedite the development of
storm water management plans and avoid duplication of work. Aggressively developing
information networks could play a key role in providing much needed information to local
jurisdictions where the actual implementation of water quality control takes place. An
example of this the Municipality of Metropolitan Seattle's current development of an
computer database of annotative bibliography of publications related to urban storm water
quality and management

Urban storm water quality and its management  is an extremely complex and variable issue.
It will take a collective and innovative effort at all levels of government and by the public to
practically and effectively control urban storm water and mitigate its effects on the


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TABLE 6.   (Continued)
37. PCB-1016 (Aroclor 1016)
38. PCB-1221 (Aroclor 1221)
39. PCB-1232 (Aroclor 1232)
40. PCB-1242 (Aroclor 124.4)
41. PCB-1248 (Aroclor 1248)
42. PCB-1254 (Aroclot 1254)
43. PCB-1260 (Aroclor 1260)
44. 2-Chloronaphthalene
45. Methane, brono- (methyl bromide)
46. Methane, chloro- (methyl chloride)
47. Methane, dichloro- (methylene chloride)
48. Methane, chlorodibromo-
49. Methane, dichlorobromo-
50. Methane, tribromo- (bromotorm)
51. Methane, trichloro- (chlorotocm)
52. Methane, tetrachloro- (carbon tetrachloride)
53. Methane, trichlorof luoro-e
54. Methane, dichlorodif luoro- (Preon-12)e
55. Ethane, chloro-
56. Ethane, 1,1-dichloro-
57. Ethane, 1,2-dichloro-
58. Ethane, 1,1,1-tnchloro-
59. Ethane, 1,1,2-tnchloro-
60. Ethane, 1,1,2,2-tetrachloro-
61. Ethane, hexachloro-
62. Ethene, chloro- (vinyl chloride)
63. Ethene, 1,1-dichloro-
64. Ethene, 1,2-trans-dichloro-
65. Ethene, trlchloro-
66. Ethene, tetrachloro-
67. Propane, 1,2-dichloro-
68. Propene, 1,3-dichloro-
69. Butadiene, hexachloro-
70. Cyclopentadiene, hexachloro-
71. Ether, bis(chloromethyl)e
72. Ether, bis(2-chloroethyl)
73. Ether, bis(2-chloroisopropyl)
74. Ether, 2-chloroethyl vinyl
75. Ether, 4-bromophenyl phenyl
76. Ether, 4-chlorophenyl phenyl
77. Bi9(2-chloroethoxy) methane
Frequency ot
Cities where detected** detection ()

Not detected
Not detected
Not detected
Not detected
Not uetecteu
Not detected
Not del. i-l

Not detected
Not detected
4, 17, 22
4, 28
Not detected
Not detected
Not detected
Not detected
2, 4,8, 24, 2U
Not detected
Standard methods inappropriate

Not detected
Not detected
Not detected
Not detected
Not detected
Not detected
Not detected





Kanye ot oecectea
concentrations ( U3/1/


5-14. 5A




TABLE 6.  (Continued)





78. Benzene
79. Benzene, chloro-
80. Benzene, 1,2-dichloro-
81. Benzene, 1,3-dichloro-
82. Benzene, 1,4-dichloro-
83. Benzene, 1,2,4-tnchloro-
84. Benzene, hexachloro-
85. Benzene, ethyl-
Hi. Benzene, nitr'o-
87. Toluene
88. Toluene, 2,4-dinitro-
89. Toluene, 2,6-d\nltco
90. Phenol
91. Phenol, 2-chloro-
92. Phenol, 2,4-dichloro-
93. Phenol, 2,4,6-tr ichloro-
94. Phenol, pentachloro-
95. Phenol, 2-nitro-
96. Phenol, 4-nitro-
97. Phenol, 2,4-dinitro-
98. Phenol, 2,4-dimethyl-
99. m-Ccesol, p-chloro-
100. o-Cresol, 4,6-dinitro-
101. Phthalate, dimethyl
102. Phthalate, diethyl
103. Phthalate, dl-n-butyl
104. Phthalate, di-n-octyl
105. Phthalate, bis (2-ethylhexyl)
106. Phthalate, butyl benzyl
107. Acenaphthene
108. Acenaphthylene
109. Anthracene
110. Benzo (a) anthracene
111. Benzo (b) luocanthene
Frequency ot
Cities where detected" detection ()

Not detected
Not detected
Not detected
Not detected
Not !' t i-ctfij
4,8,1 /,/U,2b,2tt
Not detected
Not detected
Not detected

Not detected
Nut detected
Not detected
Not detected

3, 4, 17,20,21

Not detected
Not detected








k4m)e ot ue tec tea
concentrations ( uj/i)





IT- 3 7



1-1 On

                    TABLE 6.   (Continued)
                                                                              Frequency  of
                                                   Cities where detected"     detection  (%)
                                              Range of detected
                                            concentrations (
Benzo(k) f luoranthene
Benzo(g,h, i)perylene
Oibenzo (a >h) anthracene
Indenod ,2,3-c,d)pyrene
.4.8,12,17, 21, 26, 27,211
2,0, 17,20,21,26,27,28
4, 3,o, 12, U, 21. 26.2-7, ^8
1-1 OH
0.3'1'- 21

123.  Nitrosaaine, dimethyl.  (DMN)
124.  Nitrosamine, diphenyl
125.  Nitrosanine, di-n-propyl
126.  Benzidine
127.  Bensidine, 3,3'-dichloro-
128.  Hydrazine, 1,2-diphenyl-
129.  Accylonitrile
Standard methods inappropr.ate
Standard methods inappropriate
Not detected
Standard methods inappropriate
Not detected
Standard methods inappropriate
Holding times exceeded
                   * Based on 121 sample results received as  of  9/30/83,  adjusted for  quality  control  review.

                   b Cities ron which data are available:
                          1.  Durban, NH                          20.   Little  Rock,  AK
                          2.  Lake Quinsigamond, HA               21.   Kansas  City,  Ka
                          3.  Mystic Klver, MA                    22.   Denver, CO
                          4.  Long Island, NY                     23.   Salt  Lake City, UT
                          7.  Washington, DC                      24.   Rapid City, SU
                          8.  Baltimore, HD                       26.   Fresno, CA
                         12.  Knoxville, TN                       27.   Hellevue,  MA
                         17.  Glen Ellyn, IL                      28.   Eugene, OR
                         19.  Austin, TX
                     Numbering of cities conforms to NURP convention.

                   c Percentages rounded to nearest whole number.

                     Some reported concentrations are qualified  by STORET quality control remark codes,  to wit:  A  -  Value reported is the
                     mean of two or more determinations;  G   Value reported  is the maximum of  two or more determinations;  L   Actual  value is
                     known to be greater than value given; M  - Presence of material  verified but not quantified; T    Value reported is less
                     than criteria of detection.  One value in this column indicates one  positive observation or that all  observations were
                    No longer included as a priority pollutant.

                               APPENDIX B

Athayde, Dennis N., Carl F. Myers, Patrick Tobin. 1986. "EPA's Perspective of Urban
    Nonpoint Sources" In Urban Runoff Quality - Impact and Quality Enhancement
    Technology, ed. Ben Urbonas and Larry A. Roesner. New York: American Society
    of Civil Engineers.

Barrett, Tony. 1987. State of Washington Ground Water Quality Management Strategy:
    You Drink What You Pour Out. Olympia, Washington: Washington State Department
    of Ecology.

Canning, Douglas J. 1988. Urban Runoff Water Quality: Effects and Management Options
    (Shoreline Technical Advisory Paper No.4\ Olympia, Washington: Shorelands and
    Coastal Zone Management Program, Washington Department of Ecology.

Davies, Patrick H. 1986. "Toxicity and Chemistry of Metals in Urban Runoff." In Urban
    Runoff Quality - Impact and Quality Enhancement Technology, ed. Ben Urbonas and
    Larry A. Roesner. New York: American Society of Civil Engineers.

Driver, Nancy E. and David J. Lystrom. 1986. "Estimation of Urban Storm-Runoff
    Loads." In Urban Runoff Quality - Impact and Quality Enhancement Technology, ed.
    Ben Urbonas and Larry A. Roesner. New York: American Society of Civil Engineers.

Eckel, Bill. 1990. Water Quality Project Manager, Surface Water Management Division,
    Department of Public Works, King County, Seattle, Washington. Interviewed by
    Jayne Nussbaum, June 6, 1990.

Ellis, J. Bryan. 1986. "Pollutant Aspects of Urban Runoff." In Urban Runoff Pollution.
    NATO Advanced Science Series, ed. Harry C. Torno, Jiri Marsalek, and Michel
    Desbordes. New York: Springer-Verlag.

Gallup, James D. and Kevin Weiss. 1988. "Federal Requirements for Storm Water
    Management Programs." In Design of Urban Runoff Quality Controls, ed. Larry A.
    Roesner, Ben Urbonas, and Michael B. Sonnen.  New York: American Society of
    Civil Engineers.

Galvin, David G. and Richard K. Moore. 1984. "Toxicants in Urban Runoff." Seattle:
    Municipality of Metropolitan Seattle.

Galvin, David G. 1987. "Toxicants in Urban Runoff."Paper presented at a conference on
    "Northwest Nonpoint Source Pollution," at the University of Washington on March
    25,1987: pp. 176-210. Proceedings of the Northwest Nonpoint Source Conference,
    ed. R.Seabloom and G.Plews. Olympia, Washington: Washington Department of
    Social and Health Services.

Goldstein, Larry. 1987. Residential Areas Stormwater Drainage Wells. (January).
    Olympia, Washington: Water Quality Program, Washington State Department of

Gordon, Wendy. 1984. Citizen's Handbook on Groundwater Protection. New York:
    Natural Resources Defense Council.


Hall and Associates, Ruth Dight, and Applied Geotechnology, Inc. 1986. Ground Water
    Resource Protection: A Handbook for Local Planners and Decision Makers in
    Washington State. King County Resource Planning and Washington State Department
    of Ecology.

Homer, Richard R. 1988. Biofiltration Systems for Storm Runoff Water Quality Control.
    (December). Olympia, Washington: Washington State Department of Ecology.

Homer, Richard R. and Steven Wonacott 1985. "Performance Evaluation of a Detention
    Basin and Coalescing Plate Oil Separator for Treating Urban Stormwater Runoff-
    Report to the State Washington Water Research Center and U.S.Geological Survey."
    (June). Department of Civil Engineering, University of Washington. Seattle.

Horner, Richard R. 1990. Department of Civil Engineering, University of Washington,
    Seattle, Washington. Interviewed by Jayne Nussbaum.

Hubbard, Tom and David Galvin. 1989. "Stormwater Quality Management in the Seattle-
    King County Region: An Issue Paper." (August). Seattle: Municipality of Metropolitan

Hvitved-Jacobsen, Thorkild. 1986. "Conventional Pollutant Impacts on Receiving
    Waters." In Urban Runoff Pollution. NATO Advanced Science Series, ed. Harry
    C.Torno, Jiri Marsalek, and Michel Desbordes. New York: Springer-Verlag.

Jones, Jonathan E. 1986. "Urban Runoff Impacts on Receiving Waters." In Urban Runoff
    Quality - Impact and Quality Enhancement Technology, ed. Ben Urbonas and Larry A.
    Roesner. New York: American Society of Civil Engineers.

Mar, Brian W, et al. 1982. Summary-Washington State Highway Runoff Water Quality
    Study. 1977-1982. Seattle: Department of Civil Engineering, Environmental
    Engineering and Science, University of Washington.

Marsalek, Jiri. 1986.  "Toxic Contaminants  in Urban Runoff: A Case Study." In Urban
    Runoff Pollution. NATO Advanced Science Series, ed. Harry C. Torno, Jiri
    Marsalek, and Michel Desbordes. New York: Springer-Verlag.

Merrill, M. Steve. 1989. "City of Seattle Storm Water Monitoring Analysis of
    Measurements." (May 16). Brown and Caldwell.

Miller, Stan. 1990. Program Manager, Water Quality Management Program, Spokane
    County Public Works, Spokane, Washington. Interviewed by Jayne Nussbaum,
    June 8,  1990.

Miller, Stan. 1985. "The Impact of Stormwater Runoff on Groundwater Quality and
    Potential Mitigation." Paper presented at a conference on the "Protection and
    Management of Aquifers with an emphasis on the Spokane-Rathdrum Aquifer," in
    Pullman, Washington on October 10,1984.

Miller, T. L. and S. W. McKenzie. 1978. Analysis of Urban Storm-Water-Quality from
    Seven Basins Near Portland. Oregon.  Washington, D.C.: U.S. Geological Survey.

Novotny, Vladimir and Gordon Chesters. 1981. Handbook of Nonpoint Source Pollution.
    New York: Van Nostrand Reinhold Co.

Pitt, Robert and Pam Bissonette. 1984. Nationwide Urban Runoff Program. Bellevue
    Urban Runoff Program. Washington. Summary Report.Washington. D.C.: U.S.
    Environmental Protection Agency.

Prych, Edmund A. and J. C. Ebbert 1986. Quantity and Quality of Storm Runoff from
    Three Urban Catchments in Bellevue. Washington. Report no. 86-4000. Lakewood,
    Colorado: U.S. Geological Survey.

Puget Sound Water Quality Authority. 1986. "Nonpoint Source Pollution Issue Paper."
    (May). Seattle.

Puget Sound Water Quality Authority. 1986. "Combined Sewer Overflows." (April).

Randall, Clifford W. and Thomas Grizzard. 1983. "Runoff Pollution." In Stormwater
    Management in Urbanizing Areas. Englewood Cliffs, New Jersey: Prentice-Hall, Inc.

Ryll, Thomas. 1989. "Consultant Turns Detective in Quest for Chemical  Source."
    Columbian. sec.A, p. 1. (June 9). Vancouver, Washington.

Sartor, James D. and Gail B. Boyd. 1972 .Water Pollution Aspects of Street Surface
    Contaminants. EPA-600-12-77-047. Washington, D.C.: U.S. Environmental
    Protection Agency.

Schueler, Thomas R. 1987. Controlling Urban Runoff: A Practical Manual for Planning
    and Designing Urban BMPs. (July). Washington, D.C.: Washington Metropolitan
    Water Resources Planning Board.

Stockdale, Eric C. 1986. The Use of Wetlands for Stormwater Management and Nonpoint
    Pollution Control: A Review of the Literature. (October). Olympia, Washington:
    Washington State Department of Ecology and King County Department of Planning.

Terstriep, Michael L., Douglas C. Noel, G. Michael Benden. 1986. "Sources of Urban
    Pollutants: Do We Know Enough?" In Urban Runoff Quality - Impact and Quality
    Enhancement Technology, ed. Ben Urbonas and Larry A. Roesner. New York:
    American Society of Civil Engineers.

Tucker, L. Scott.  1988. "A View from the 'Bottom': Challenges and Prospects." In Design
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    B. Sonnen. New York: American Society of Civil Engineers.

Turney, G. L. 1986. Quality of Ground Water in the Puget Sound Region. Washington.
    WRI Report  no. 86-4154. Lakewood, Colorado: U.S. Geological Survey.

URS Consultants et al.1988. "City of Puyallup Stormwater Management  Program - Final
    Report." (September).

U.S. Environmental Protection Agency. 1988. "National Pollutant Discharge Elimination
    Permit Application Regulations for Storm Water Discharges; Proposed  Rule." Federal
    Register, vol. 53, no. 235, (December 7).

U.S. Environmental Protection Agency. 1986. Quality criteria for Water:  1986. EPA
    440/5-86-001. Washington, D.C.: U.S. EPA, Office of Water Regulations and


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    Washington, D.C.

U.S. Environmental Protection Agency. 1983. Results of the Nationwide Urban Runoff
    Program. Volume I. Final Report. NTIS Report no. PB 84-185552. Washington,

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    Pollutant Monitoring Project: Summary of Findings. NTIS Report no. PB 84-175686.
    Washington, D.C.

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    Program Project: Final Report 1984. Brown and Caldwell.

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    Urban Runoff Program. Long Island Regional Planning Board. NTIS Report no.

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    Water Standards by the States-Report to the Chairman, Subcommittee on Hazardous
    Wastes and Toxic Substances, Committee on Environment and Public Works, U.S.
    Senate." GAO/PEMD-89-1. (December).

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    "Transport, Deposition, and Control of Heavy Metals in Highway Runoff-Report to
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    Engineering, University of Washington. Seattle.

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    Puget Sound Basin - Technical Review Draft. (June). Olympia, Washington.

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    Dry Wells. (August). Olympia, Washington.

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    Planning. 1986. Ground Water Resource Protection: A Handbook for Local Planners
    and Decision Makers in Washington State. Olympia, Washington.

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    Columbian, sec. A, p. 1. (June 13). Vancouver, Washington.

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    Minimize Virus Contamination of Drinking Water." Ground Water, vol. 27, no. 2,

                               APPENDIX C

                           LIST OF CONTACTS
U.S. Environmental  Protection Agency
Region 10
1200 6th Ave.
Seattle, WA 98101
      Jonathan Williams
      Elbert Moore
      Sally Marquis
      Steve Bubnick
      Toby Hegdahl
      Martha Sabol

U.S.  Geological Survy
      Chuck Swift
      Rick Dinicolo

Washington State Department of Ecology
Water Quality Program
Mail Stop PV-11
Olympia, WA 98504-8711
      Stormwater Unit
             Peter Birch
             Helen Pressley
             Jerry Anderson
      Ground Water Unit
             Bert Bowen
             Ginny Stearn
             Elizabeth Phinney
      Office of Financial Management
             Bill Miller(206)459-6971


Heather Saunders
Greg Grunenfelder
Tom Holz

Earl Rowell
Gil Mallory
Tom Waltz
Jane Hedges

Eric Stockdale
Resource Planning Section
707 Smith Tower
506 Second Ave.
Seattle, WA 98104




                         Bill Eckel                       (206)296-6519
                         River and Water Resource Section
                         730 Dexter Morton Bldg.
                         710 Second Ave.
                         Seattle, WA 98104

                         Steve Wells                      (206)296-8625

Other Local Jurisdictions

       Municipality of Metropolitan Seattle
       821 Second Ave.
       Seattle, WA 98104-1598
             DaveGalvin                                  (206)684-1216
             Vickey Ridge-Cooney                         (206)684-1217
             Anita Diaz                                    (206)684-1232
             Louise Kulzer

       Puget Sound Water Quality Authority
             VaUana Piccolo                                (206)464-7320

       City  of Bellevue
       Storm and Surface Water Utility
       301 116th Ave. SE  Suite 230
       P.O. Box 90012
       Bellevue, WA 98009-9012
             Dave Renstrom                                (206)455-7818

       City  of Renton
       Public Works  - Stormwater Utility
       200 Mill Ave  S.
       Renton, WA 98055
             Kim Scattered                                (206)277-6193
             Randall Parsons

             Joann  Richter - Public Works

             Paul Bucich - Sewer Utility         v            (206)591-5588
             Steve Shonafeld - Public Works                 (206)591-5588

       City  of Puyallup                                  (206)841-4321
       Public Works Dept
       218 West Pioneer
       Puyallup.WA 98371
             TomHeinke                                  (206)841-5491

      Water Quality Management Program
      County Public Works
      N. 811 Jefferson St.
      Spokane, WA 99260-0180
             Stan Miller                                    (509)456-6024

      Department of Engineering
             Gary Nielsen                                  (509)456-3600
             Brenda Sims

      Seattle - King Co. Health DepL
      211 Smith Tower
      Seattle, WA
             Caroline Boatsman                             (206)296-4739
             BUI Lasby

      Office of Long Range Planning
             Richard Marks                                (206)684-8056

      Drainage and Wastewater Utility
             Cindy Thrush                                 (206)684-7586

      Molly Adolfson                                      (206)778-4273

      Derek Sanderson                                     (509)674-5215

      Steve Merrill
      Brown and Caldwell

      Richard Horner                                      (206)543-7923
      Environmental Engineering and Sciences
      Department of Civil Engineering
      University of Washington  FX-10
      Seattle, WA 98195

      Jennifer R.B. Fulton                                  (206)823-6919
      Beak Consultants
      12931NE 126th PI
      Kirkland, WA 98034