United States
Environmental Protection
Agency
Water Planning Division
WH-554
Washington, DC 20460
            December 1983
Water
Results of the Nationwide
Urban Runoff Program

Executive Summary

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              RESULTS
              OF  THE
  NATIONWIDE URBAN RUNOFF PROGRAM
           December, 1983
          EXECUTIVE SUMMARY
       Water Planning Division
U.S. Environmental  Protection Agency
       Washington,  D.C.   20460
      National  Technical  Information  Service  (NTIS)
      Accession Number:   PB84-185545

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                         DISCLAIMER

This  report has  been  reviewed  by the  U.S.  Environmental
Protection  Agency and  approved  for release.   Approval  to
publish  does  not  signify  that  the   contents  necessarily
reflect any  policies  or decisions of the  U.S.  Environmental
Protection  Agency or  any  of  its offices,  grantees,  con-
tractors,  or subcontractors.

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                              ACKNOWLEDGEMENTS

The Nationwide Urban Runoff Program was  unusual  in its large scale, covering
a broad  spectrum of technical  and  planning issues at many  geographic loca-
tions.  Because the program placed such  emphasis  on tailoring the results to
support the planning process, it  involved  many participants  - some from EPA,
some  from  other  federal agencies, and many from state, regional,  and local
planning agencies and other consultants.

The program  was  developed,  implemented,  and  managed  by the Water Planning
Division, Office of  Water,  at EPA Headquarters,  Washington,  D.C.   Principal
contributors were:   Dennis N. Athayde, Program Manager; and Patrice M.  Bubar,
Norman A. Whalen, Stuart S.  Tuller,  and Phillip H. Graham,  all of whom served
as Project Officers.   Additional  contributions from EPA personnel  came from
Rod E. Frederick and Richard P.  Healy (Monitoring and Data  Support Division),
Richard Field  (Storm and  Combined Sewer  Section,  EPA Office  of  Research  and
Development), and many project staff in the various EPA Regional Offices.

As described elsewhere, much  of  the  field work,  water quality  analysis,  and
data  analysis  was  performed  by  the  U.S.  Geological  Survey  (USGS), under  a
Memorandum of  Agreement with  EPA.  Both  District Offices  and National Head-
quarters participated actively.   The  contributions of Messrs.  Ernest Cobb and
David Lystrom are especially acknowledged.

Members of  the project team  which  provided essential  strategic,  technical,
and management assistance to  the  EPA Water Planning Division through  a con-
tract  with Woodward-Clyde  Consultants  were:  Gail B. Boyd,  David Gaboury,
Peter Mangarella, and James  D. Sartor (Woodward-Clyde Consultants); Eugene D.
Driscoll (E. D. Driscoll and  Associates);  Philip  E.  Shelley  (EG&G Washington
Analytical Services Center,  Inc.); John  L. Mancini (Mancini  and  DiToro Con-
sultants) ;  Robert E.  Pitt  (private  consultant);  Alan Plummer  (Alan  Plummer
and Associates);  and  James P.   Heaney  and Wayne  C.  Huber  (University  of
Florida).

The   principal   writers  of  this   report  were   Dennis  N.  Athayde   (EPA),
Philip E.  Shelley  (EGSG  Washington   Analytical   Services   Center,   Inc.),
Eugene D.  Driscoll   (E. D. Driscoll   &  Associates),  and  David  Gaboury  and
Gail B. Boyd (Woodward-Clyde Consultants).
                                     111

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                              EXECUTIVE SUMMARY
BACKGROUND

The water  quality  effects of stormwater pollution  received little attention
prior  to  1960.    Stormwater concerns  were  primarily  related to  drainage
problems.   As  stormwater pollution  began  to  be   investigated,  the  work,
reported by  EPA and published  in professional journals, tended to  focus on
determining  (a) the type and amount of pollutants involved and/or  (b) methods
to  reduce  the loads.  However,  such  reports and articles  gave limited con-
sideration  to either  the level  of improvement  attainable or the need to
improve  quality  of the  receiving water body  associated with  the  study.  A
conclusion common  to all such  reports  was  that  not enough was known  about
stormwater,  and  recommendations  for  further  study and  more  data  were  the
norm.  A tangible  result of  the uncertain attitude  in this  area is  the fact
that stormwater  controls for water quality  have been implemented in  so  few
places throughout  the  nation.   Thus,  there  has  been a  critical need  to  ob-
jectively  examine  the situation.   This  need led to the development of  the
Nationwide Urban Runoff Program  (NURP).

The overall  goal of NURP was to  develop information that would help provide
local  decision makers,  States,  EPA,  and other interested  parties with  a
rational basis for determining  whether  or not urban runoff is causing water
quality  problems  and,  in  the   event that  it  is,  for postulating realistic
control  options  and developing water quality  management  plans,  consistent
with local needs,  that would lead to implementation of least cost  solutions.
It  is  also hoped  that this  information  base will  be used to  help  make  the
best possible policy decision  on Federal,  State,  and  local  involvement in
urban  stormwater runoff  and  its control.  Among the many objectives of NURP
was  the  assembly   of  an appropriate   data base   and  the  development  of
analytical methodologies that would allow us to examine such issues as:

     -  The quality characteristics of urban runoff, and similarities or
        differences at different urban locations;

        The extent to which urban runoff is a significant contributor to
        water quality problems  across  the nation; and

     -  The  performance  characteristics  and the overall  effectiveness
        and utility of management practices for the  control of pollutant
        loads from urban runoff.

Water quantity problems  are  relatively easy  to identify  and describe.   Water
quality problems,  on the other hand,  tend  _o be more elusive  because  their
definition often   involves  some  subjective  considerations, including  expe-
riential aspects and expectations of the populace.   They are not immediately
obvious and  are usually  less dramatic  than,   for example,  floods.   They also

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tend  to  vary  markedly  with  locality  and  geographic  regions  within  the
country.   Thus,  a  methodological  approach to  the determination  of  water
quality problems  is essential  if one  is  to consider  the relative  role  of
urban runoff as  a  contributor.  An  important  finding  of  the  work  conducted
during  NURP  was to learn  to avoid  the following  simplistic logic train:
(a) water quality problems are caused by pollutants, (b)  there are pollutants
in urban runoff, therefore, (c) urban runoff causes "problems".  The unspoken
implication is that  a  "problem"  by definition requires action, and  any type
of "problem" warrants equally  vigorous  action.   It  becomes clear  that a more
fundamental and  more precise  definition of a  water quality  "problem"  from
urban  runoff  is necessary.   For  this  purpose, NURP  adopted the  following
three-level definition:

        Impairment or denial of beneficial uses;

     -  Water quality criterion violation; and

        Local public perception.

The  foregoing  levels of  problem definition  provide an essential  framework
within which to discuss water  quality  problems  associated  with urban runoff.
However,  it is  important  to understand  that  when  one  is  dealing at  a local
level all  three elements  are  typically  present.  Thus,  it  is up to the local
decision makers, influenced by other levels of  support  and concern,  to care-
fully weigh each,  prior to making  a final  decision about  the existence and
extent of a problem and how it is to be defined.

The NURP  studies have greatly  increased our knowledge  of the characteristics
of urban  runoff,  its effects  upon designated  uses,  and  of  the  performance
efficiencies of selected  control  measures.   They have  also confirmed earlier
impressions that  some States  and local  communities  have  actually  begun  to
develop  and implement  stormwater  management  programs  incorporating  water
quality objectives.   However,  such  management  initiatives are,  at  present,
scattered  and  localized.   The  experience gained from  such efforts  is both
needed and sought after by many  other  States and localities.  Documentation,
evaluation, refinement  and transfer of  management  and  financing  mechanisms/
arrangements,  of simple and reliable problem assessment methodologies, and of
implementation guidance which can be  used  by planners and  officials at the
State and  local  level are urgently needed  as  is a forum  for  the  sharing  of
experiences by  those already  involved, both among  themselves  and with those
who are about to address nonpoint source issues.

CONCLUSIONS

The  following summarizes  NURP's  conclusion  relating to  its  major objectives
and is based on the  results presented  in Chapters  6, 7,  and 8 of the report.
Conclusions reached by the individual NURP projects  are  also presented  to
further support the results of the national level analysis.

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URBAN RUNOFF CHARACTERISTICS

General

Field monitoring  was conducted to  characterize  urban runoff  flows  and pol-
lutant concentrations.  This  was  done for a variety of pollutants  at a sub-
stantial number of sites  distributed throughout  the  country.   The resultant
data  represent a  cross-section  of  regional  climatology,  land use  types,
slopes, and soil conditions and thereby  provide  a basis for identifying pat-
terns of similarities or differences and testing their significance.

Urban runoff  flows and concentrations  of contaminants are   quite variable.
Experience shows that substantial variations occur within a particular event
and from one  event to the next at  a  particular  site.   Due to the high vari-
ability of urban runoff, a large number  of  sites  and  storm events were moni-
tored, and a  statistical  approach was used to analyze  the data.  Procedures
are available for characterizing variable data without requiring knowledge of
or  existence  of  any  underlying  probability  distribution  (nonparametric
statistical procedures).  However,  where a  specific type  of probability dis-
tribution is  known to exist,  the information content and efficiency of sta-
tistical  analysis  is  enhanced.    Standard statistical  procedures  allowed
probability  distributions or frequency  of occurrence  to  be  examined  and
tested.  Since the underlying distributions were  determined to be adequately
represented by the lognormal distribution, the log  (base e) transforms of all
urban runoff data were used in developing the statistical characterizations.

The event  mean concentration  (EMC),  defined as  the  total  constituent mass
discharge divided by the total runoff volume,  was chosen as the primary water
quality  statistic.   Event mean  concentrations  were  based on  flow weighted
composite samples  for each event at  each site  in  the  accessible data base.
EMCs were  chosen   as  the  primary water  quality  characteristic  subjected  to
detailed analysis, even though it is  recognized  that  mass loading character-
istics of urban runoff  (e.g., pounds/acre for a  specified time interval)  is
ultimately the relevant  factor  in many  situations.   The  reason  is  that,
unlike EMCs,  mass loadings  are very  strongly  influenced  by the  amount  of
precipitation and runoff,  and estimates  of  typical annual mass loads will be
biased by the size of monitored  storm  events.   The most  reliable  basis  for
characterizing annual or  seasonal  mass  loads  is  on  the  basis of  EMC  and
site-specific rainfall/runoff characteristics.

Establishing  the  fundamental  distribution as lognormal and the availability
of  a  sufficiently large  population of  EMCs  to  provide  reliability  to  the
statistics derived has yielded a number of benefits, including the ability to
provide:

        Concise summaries  of highly variable data

     -  Meaningful comparisons of results  from different  sites,  events,
        etc.

        Statements concerning frequency  of  occurrence.  One can express
        how often  values will be  expected to exceed  various magnitudes
        of interest.

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        A more useful method  of reporting data than the  use  of ranges;
        one which is less subject to misinterpretation

     -  A framework for examining "transferability" of  data in a quanti-
        tative manner

Conclusions

1.  Heavy metals (especially copper, lead and zinc) are by  far  the  most  pre-
    valent priority pollutant constituents found in urban runoff. End-of-pipe
    concentrations  exceed  EPA  ambient  water quality  criteria  and  drinking
    water standards in many instances.  Some of the metals  are  present often
    enough and in high enough concentrations to be potential threats to bene-
    ficial uses.

    All  13 metals  on EPA's priority  pollutant list were detected  in urban
    runoff samples,  and all  but  three at  frequencies of  detection greater
    than 10 percent.  Most often detected among the metals were  copper,  lead,
    and zinc, all of which were found in at least  91 percent of  the  samples.

    Metal concentrations  in  end-of-pipe urban  runoff  samples  (i.e.,  before
    dilution by  receiving  water)  exceeded  EPA's  water quality  criteria  and
    drinking water  standards  numerous  times.   For example,  freshwater acute
    criteria were  exceeded by copper  concentrations  in  47 percent of  the
    samples and by  lead in 23 percent.  Freshwater chronic exceedances  were
    common for lead (94 percent),  copper (82 percent),  zinc (77  percent),  and
    cadmium  (48 percent).   Regarding  human toxicity,   the  most  significant
    pollutants were  lead and  nickel,  and for human carcinogenesis, arsenic
    and beryllium.   Lead  concentrations violated  drinking  water  criteria in
    73 percent of the samples.

    It should be stressed that the exceedances noted above do not necessarily
    imply that an  actual  violation  of standards will  exist in  the  receiving
    water body in question.   Rather, the  enumeration of  exceedances serves a
    screening function to identify those heavy metals whose presence in urban
    runoff warrants high priority for further evaluation.

    Based upon the much more  extensive  NURP data  set for  total  copper,  lead,
    and zinc, the site median EMC values for the median urban site are:   Cu =
    34 yg/1,  Pb = 144 yg/1, and Zn = 160 yg/1.   For the 90th percentile urban
    site the  values are:  Cu = 93  yg/1,  Pb =  350 yg/1,  and Zn =  500 yg/1.
    These values are suggested to be appropriate for planning level  screening
    analyses where data are not available.

    Some individual NURP project  sites (e.g.,  at DC1, MD1,  NH1)  found unus-
    ually high concentrations  of certain  heavy metals  (especially copper  and
    zinc) in urban runoff.   This was attributed by the  projects  to the effect
    of acid rain on materials used for gutters, culverts,  etc.

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2.   The  organic  priority  pollutants  were  detected  less  frequently  and  at
    lower concentrations than the heavy metals.

    Sixty-three  of  a  possible  106 organics  were  detected  in urban  runoff
    samples.   The  most  commonly  found  organic  was  the  plasticizer  bis
    (2-ethylhexl)   phthalate    (22 percent),   followed   by    the   pesticide
    a-hexachlorocyclohexane  (a-EHC)  (20 percent).  An  additional  11 organic
    pollutants  were  reported  at  frequencies  between  10  and  20 percent;
    3 pesticides, 3 phenols, 4 polycyclic aromatics, and a single halogenated
    aliphatic.

    Criteria  exceedar.ces  were  less  frequently observed  among the  organics
    than the  heavy  metals.  One  unusually  high  pentachlorophenol  concentra-
    tion of 115 ug/1  resulted  in  exceedances  of  the  freshwater acute  and
    organoleptic criteria.  This  observation  and  one for  chlordane  also  ex-
    ceeded  the  freshwater  acute  criteria.   Freshwater chronic  criteria  ex-
    ceedances  were   observed  for  pentachlorophenol,   bis  (2-ethylhexyl)
    phthalate, gamma-BHC, chlordane, and alpha-endosulfan.  All other organic
    exceedances  were  in  the human carcinogen category  and were  most serious
    for  alpha-hexachlorocyclohexane  (alpha-BHC),  gamma-hexachlorccyclohexane
    (gairana-BHC or Lindane) , chlordane,  phenanthrene, pyrene,  and chrysene.

    The  fact  that  the NURP priority pollutant monitoring  effort  was limited
    to two  samples at each  site leaves us unable to make many generalizations
    about those  organic pollutants  which occurred only  rarely.  We can spec-
    ulate that their  occurrences  tend to be very  site specific as opposed  to
    being a generally widespread  phenomena, but much more data  would  be  re-
    quired  to conclusively  prove  this point.-

3.  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  e'/ents  in many  surface waters,   even  those  providing  high
    degrees of dilution.

    Fecal coliform  counts in urban runoff  are typically  in  the  tens to hun-
    dreds  of  thousand per  100  ml during  warm  weather conditions,  with  the
    median  for  all sites  being around   21,000/100 ml.  During cold  weather,
    fecal coliform counts are more typically in the 1,000/100 ml range, which
    is  the  median  for all  sites.  Thus,  violations of  fecal ccliform stand-
    ards were  reported by  a  number of  NURP  projects.   High  fecal  colifcrm
    counts  may  not cause  actual  use  impairments,  in some instances,  due  to
    the  location of the urban runoff discharges relative to swimming areas or
    shellfish beds  and  the degree of  dilution/dispersal and  rate of die off.
    The  same is  true  of total coliform counts, which were found to exceed EPA
    water quality criteria in undiluted urban runoff at virtually every site
    every time it rained.

    The  substantial  seasonal  differences noted above do  not correspond with
    comparable variations  in  urban  activities.  The NURP  analyses as well  as
    current literature  suggest  that  fecal  coliform  may  not  be  the  most
    appropriate  indicator  organism  for  identifying  potential health  risks
    when the source is stormwater runoff.

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4.  Nutrients are generally present  inurban  runoff,but with a few individ-
    ual site exceptions,concentrations do not  appear to be high _in compari-
    son with other possible discharges to receiving water bodies.

    NURP data for total phosphorus, soluble phosphorus, total kjeldahl nitro-
    gen, and nitrate plus  nitrite as nitrogen  were carefully examined.   Me-
    dian site EMC median concentrations in urban  runoff were TP = 0.33 mg/1,
    SP = 0.12 mg/1, TKN =  1,5 mg/1,  and NO2+3 - N = 0.68 mg/1.   On an annual
    load basis,  comparison with typical monitoring data,  literature values,
    and design objectives  for discharges from a well  run secondary treatment
    plant  suggests  that mean  annual nutrient  loads   from urban  runoff  are
    around an order of magnitude less than those from a POTW.

5.  Oxygen demanding substances are present in urban runoff at concentrations
    approximating  those  in_ se_condary treatment  plant  discharges.   If  dis-
    sqlyed oxygen problems__are_ present  in  receiving waters of interest,  con-
    sideration of urban runoff  controls as well  as advanced waste treatment
    appears to be warranted.

    Urban  runoff median site  EMC median concentrations of  9 mg/1  BODS  and
    65 mg/1 COD are reflected in the NURP data, with 90th percentile site EMC
    median values being 15 mg/1 BODS and  140  mg/1 COD,   These concentrations
    suggest that, on an annual  load basis,  urban runoff is comparable in mag-
    nitude to secondary treatment plant discharges,

    It  can be  argued  that  urban runoff  is  typically  well oxygenated  and
    provides  increased stream  flow  and,  hence,  in view of  relatively  long
    travel  times  to   the  critical  point,  that   dissolved  oxygen  problems
    attributable solely to urban runoff should  not be  widespread occurrences.
    No NURP project specifically identified a low DO condition resulting from
    urban  runoff.   Nonetheless,  there  will  be  some  situations  where  con-
    sideration of urban runoff  controls for oxygen demanding  substances in an
    overall water quality management  strategy would seem appropriate.

6.  Total  suspended solids  concentrations  in  urban runoff are^ fairly high in
    comparison  withtreatment  plant  discharges.  Urban  runoff  control  is
    stronglyindicated_where water qualityproblems associated  with TSS,  in-
    cluding build-up of contaminated  sediments, exist.

    There  are  no formal water  quality criteria  for  TSS  relating  to either
    human  health or aquatic life.   The  nature  of the  suspended  solids  in
    urban  runoff is different from those in treatment plant discharges, being
    higher  in  mineral  and  man-made  products  (e.g.,  tire  and street surface
    wear  particles)  and somewhat  lower in organic particulates.   Also,  the
    solids  in  urban  runoff are  more  likely  to have  other  contaminants
    adsorbed  onto  them.  Thus,  they cannot  be simply  considered as benign,
    nor  do they  only  pose  an  aesthetic  issue.   NURP  did  not  examine  the
    problem  of contaminated  sediment build-up due to urban runoff,  but it
    undeniably exists, at  least at some locations.

    The  suspended  solids  in urban runoff can also exert deleterious physical
    effects  by sedimenting over egg deposition sites,  smothering  juveniles,
    and  altering benthic communities.

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    On an annual load basis,  suspended solids contributions from urban runoff
    are around an order of magnitude or more  greater  than those from second-
    ary treatment plants.   Control of urban  runoff,  as  opposed  to advanced
    waste treatment, should be considered where  TSS-associated water quality
    problems exist.

7.   A  summary  characterization of  urban runoff  has been  developed  and  is
    believed to be  appropriate  for use in estimating urban  runoff pollutant
    discharges  from sites wheremonitoringdata  are  scant  or  lacking,  at
    least for planning level purposes.

    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 explain-
    ing 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.   The finding that  EMC values  are essen-
    tially not  correlated with  storm runoff volumes  facilitates the transfer
    of urban runoff  characteristics to unmonitored  sites.   Although there
    tend  to be  exceptions to  any  generalization,  the  suggested summary urban
    runoff characteristics given  in  Table 6-17 of  the report are recommended
    for planning level purposes as the best estimates, lacking local informa-
    tion to the contrary.

RECEIVING WATER EFFECTS

General

The  effects of  urban runoff  on  receiving  water quality  are  highly site-
specific.  They depend on the type,  size,  and hydrology of  the water body;
the urban runoff quantity and quality  characteristics;  the  designated bene-
ficial use;  and  the concentration  levels  of the specific  pollutants  that
affect that use.

The  conclusions which follow  are based on  screening  analyses  performed  by
NUKP,  observations  and  conclusions  drawn by  individual NUKP projects  that
examined  receiving  water  effects in differing levels of detail and rigor, and
NURP's three  levels of problem  definition.   Conclusions are organized on the
basis  of  water body type:  rivers  and streams,  lakes,  estuaries and embay-
ments,   and   groundwater  aquifers.   Site-specific  exceptions  should  be
expected,  but  the  statements presented  are believed to  provide an accurate
perspective  on  the  general tendency of urban runoff to contribute signifi-
cantly to water quality problems.

Rivers and Streams

1.  Frequent  exceedances  of  heavy metals ambient  water quality criteria for
    freshwater  aquatic life are produced by urban  runoff.

    The  Denver NURP project  found that in-stream concentrations  of copper,
    lead,  zinc, and cadmium  exceeded State  ambient  water  quality standards
    for the  South Platte  River during essentially  all storm events.

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    NURP screening  analyses suggest  that frequent  exceedances  of both  EPA
    24-hour and  maximum water quality  criteria for  heavy  metals  should  be
    expected on a relatively general basis.

2,  Although_ a  significant number  of probl_em  situations  could result  from
    heavy  metals i_n__urba_n runoff,  levels  of  freshwater  aquatic  life  use
    impairment suggested by the  magnitude and frequency of  ambient criteria
    exceedances were not observed.

    Based upon the magnitude and frequency of freshwater aquatic life  ambient
    criteria  exceedances,  one would expect  to observe  impairment of  this
    beneficial use  in  most streams  that receive  urban runoff  discharges.
    However, those  NURP project studies  which examined  this  issue did  not
    report significant use impairment problems associated with  urban runoff.

    The  Bellevue,  Washington  NURP  project concluded  that  toxic effects  of
    urban runoff pollutants did not appear to be a significant  factor.

    The  Tampa,   Florida  NURP  project conducted  biological studies  of  the
    impact  of  stormwater  runoff   upon  the  biological  community  of  the
    Hillsborough River.  They  conducted  animal bioassay experiments  on five
    sensitive species in two  samples of  urban runoff  from  the  Arctic  Street
    drainage basin.   Thirty-two bioassay experiments were completed including
    22 acute tests  and  10 chronic  tests.  Neither  sample of  stormwater  was
    acutely  toxic   to  test organisms.   Long-term  chronic  experiments  were
    undertaken with two species and resulted in no significant  effects attri-
    butable to stormwater exposure.

    NURP screening  analyses suggest  that the potential  of urban  runoff  to
    seriously impair this beneficial use will be strongly influenced by local
    conditions and  the  frequency of  occurrence  of concentration  levels which
    produce  toxic  effects under the intermittent,  short duration  exposures
    typically produced by urban runoff.

    While the application of the screening analysis  to the Bellevue and Tampa
    situations supports the absence of a problem situation in these cases,  it
    also suggests that  a significant number of problem  situations  should  be
    expected.  Therefore, although not the general,  ubiquitous  problem situa-
    tion that criteria  exceedances  would suggest,  there  are  site-specific
    situations in which urban runoff could be  expected  to  cause significant
    impairment of freshwater aquatic life uses.

    Because  of  the  inconsistency  between criteria  exceedances  and observed
    use  impairments  due  to  urban  runoff,   adaptation  of  current  ambient
    quality  criteria to  better  reflect use impacts  where pollutant exposures
    are  intermittent  and of short duration  appears  to be a useful area  for
    further investigation.

3.  Copper,  lead and zinc appear to pose a significant threat to aquatic life
    uses in  some areas  of the country.   Copper is  suggested to be the most
    si gni ficant  of  the  three.

    Regional differences in surface water hardness,  which has a strong influ-
    ence on  toxicity,  in conjunction with regional variations in stream flow

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    and rainfall  result  in significant differences in  susceptibility to ad-
    verse impacts around the nation.

    The southern  and southeastern regions of  the country are  the  most sus-
    ceptible to aquatic  life effects  due  to  heavy metals, with the northeast
    also a sensitive area, although somewhat less so.

    Copper is the major  toxic  metal in urban runoff,  with lead and zinc also
    prevalent but a  problem in more  restricted  cases.   Copper discharges in
    urban  runoff  are, in  all but  the most  favorable  cases,  a  significant
    threat to aquatic life uses in  the southeast and  southern regions of the
    country.  In  the northeast,  problems would  be  expected only  in rather
    unfavorable conditions  (large urban area contribution and high  site con-
    centrations) .   In the remainder of the country (and for the other metals)
    problems would only  be expected under quite  unfavorable  site  conditions.
    These statements are based on total metal concentrations.

4.  Organic priority pollutants in urban  runoff  do not  appear to  pose a gen-
    eral threat to freshwater aquatic life.

    This conclusion is based on limited data on  the  frequency with  which or-
    ganics are found in urban runoff discharges and measured end-of-pipe con-
    centrations relative to published toxic  criteria.   One unusually  high
    pentachlorophenol concentration of  115 yg/1  resulted  in  the only exceed-
    ance  of  the  organoleptic  criteria.   This  observation  and  one  for
    chlordane   exceeded   the   freshwater   acute  criteria.    Freshwater
    chronic  criteria  exceedances   were  observed   for   pentochlorophenol,
    bis    (2-ethylhexyl)   phlhalate,    y-hexachlorocyclohexane   (lindane),
    a-endosulfan,  and chlordane.

5.  The physical aspects of  urban runoff, e.g.,  erosion  and  scour,  can be a
    significant cause of  habitat  disruption  and  can  affect the  type  of
    fishery present.   However, this  area was  studied  only  incidentally  by
    several of  the projects  under the  NURP  program and more  concentrated
    study is necessary.

    The Metropolitan  Washington  Council of Governments  (MWCOG) NURP project
    did an analysis of fish diversity in the Seneca Creek Watershed, 20 miles
    northwest of Washington, D.C.  In this study, specific changes in fishery
    diversity were   identified due  to  urbanization in  some  of  the  sub-
    watersheds.   Specifically,  the number of fish species present are reduced
    and the  types of  species  present  changed dramatically,  e.g.,  environ-
    mentally sensitive species were replaced with more tolerant species.  For
    example, the  Blacknose Dace  replaced the Mottled  Sculpin.  MWCOG con-
    cluded that the changes in fish diversity  were due  to habitat deteriora-
    tion caused by the physical aspects of urban runoff.

    The Bellevue,  Washington  NURP  project  concluded  that  habitat  changes
    (streambed scour  and sedimentation)  had a more  significant  effect than
    pollutant concentrations,  for the changes produced by urbanization.

6.  Several projects identified possible problems in the sediments because of
    the build-up  of priority  pollutants contributed wholly or  in part  by
    urban runoff.   However, the NURP  studies in  this  area were few  in number

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    and limited in scope, and the findings must be considered only indicative
    of the need for further study, particularly as to long-term impacts.

    The Denver  NURP project  found significant  quantities  of  copper,  lead,
    zinc,  and  cadmium in  river  sediments.  The  Denver Regional Council  of
    Governments is concerned that during periods of continuous low flow,  lead
    may reach levels capable of adversely affecting fish.

    The Milwaukee NURP project reported the observation of elevated levels of
    heavy metals,  particularly lead,  in  the  sediments of a  river  receiving
    urban runoff.

7.  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 most rivers and streams.

    Violations   of  the  fecal coliform standard  were reported by a  number of
    NURP projects.   In some  instances,  high fecal  coliform counts may  not
    cause actual  use impairments  due to  the  location of  the urban  runoff
    discharge relative to  swimming  areas  and the degree of  dilution  or  dis-
    persal and rate of die off.

    Coliform bacteria are generally accepted to  be  a  useful  indicator of the
    possible presence of human pathogens  when the source  of  contamination is
    sanitary sewage.  However, no such relationship has been  demonstrated for
    urban runoff.   Therefore,  the  use of coliforms as  an  indicator of human
    health risk when the  sole  source  of contamination  is urban runoff,  war-
    rants further investigation.

8.  Domestic water  supply  systems with intakes  located on streams  in close
    proximity to urban runoff discharges are encouraged to check for priority
    pollutants  which have  been detected in urban runoff,  particularly those
    in the organic category.

    Sixty-three of a possible 106 organics were detected in urban runoff sam-
    ples.    The  most   commonly   found  organic  was   the   plasticizer   bis
    (2-ethylhexl)   phthalate   (22 percent),   followed  by   the    pesticide
    a-hexachlorocyclohexane  (a-BHC)  (20 percent).  An  additional  11 organic
    pollutants   were  reported at   frequencies  between  10  and  20 percent;
    3 pesticides, 3 phenols, 4 polycyclic aromatics, and a single halogenated
    aliphatic.

Lakes

1.  Nutrients  in  urban  runoff may  accelerate  eutrophication problems  and
    severely limit  recreational  uses,  especially in  lakes.   However,  NURP's
    lake projects   indicate  that  the  degree  of beneficial  use  impairment
    varies widely,  as does the significance of the urban runoff component.

    The Lake Quinsigamond NURP project  in Massachusetts identified  eutrophi-
    cation as a major problem in the lake, with  urban  runoff  being  a prime
    contributor of the critical nutrient phosphorus.  Point source discharges
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    to the lake have  been  eliminated almost entirely.  However,  in  spite of
    the abatement  of  point sources, survey  data indicate that the  lake  has
    shown little improvement  over  the  abatement period.  In  particular,  the
    trophic  status of  the  lake has  shown  no change,  i.e., it  is  still
    classified as  late  mesotrophic-early  eutrophic.   Substantial growth is
    projected in the basin, and  there  is  concern that Lake  Quinsigamond will
    become more eutrophic.  A proposed water quality  management plan for the
    lake includes the objective of reducing urban runoff pollutant loads.

    The Lake George NUKP project in New York State also identified increasing
    eutrophication as a potential problem  if current  development  trends con-
    tinue.  Lake George  is not classified as eutrophic, but  from 1974 to 1978
    algae production in  the lake increased logarithmically.   Lake  George is a
    very long  lake,  and the  limnological  differences between the north  and
    south  basins   provide  evidence  of human  impact.  The  more  developed,
    southern portion of the  lake exhibits lower transparencies,  lower  hypo-
    limnetic dissolved  oxygen concentrations,  higher phosphorus and  chlor-
    ophyll a_ concentrations,  and a trend toward seasonal blooms of blue-green
    algae.  These differences in water  quality indicators  are associated with
    higher levels  of  cultural activities  (e.g.,  increased  sources of  phos-
    phorus)  in the southern  portion of  the  lake's watershed, and  continued
    development will tend to  accentuate the differences.

    The Lake George NURP project estimated that urban  runoff  from  developed
    areas currently accounts  for only  13.6 percent of  the annual phosphorus
    loadings to Lake  George  as  a whole.   In contrast, developed areas con-
    tribute 28.9 percent of  the annual phosphorus  load to  the   NURP   study
    areas at  the  south end  of  the  Lake.   Since  there are  no point  source
    discharges, this phosphorus loading is due solely  to urban runoff.   These
    data  illustrate  the  significant  impact of urbanization on  phosphorus
    loads.

    The NURP screening analysis  suggests  that lakes  for which the  contribu-
    tions of  urban  runoff are  significant  in  relation to other  nonpoint
    sources (even in the absence of point source discharges)  are  indicated to
    be highly susceptible  to  eutrophication and that urban runoff  control  may
    be warranted in such situations.

2.   Coliform bacteria discharges in urban  runoff have a significant  negative
    impact on the recreational uses of  lakes.

    As was the case with rivers  and streams,  coliform bacteria in urban run-
    off can cause  violations  of criteria for the  recreational use of  lakes.
    When unusually high  fecal coliform counts are  observed,  they  may be par-
    tially  attributable  to  sanitary  sewage  contamination,  in  which  case
    significant health risks  may be involved.

    The Lake Quinsigamond NURP project in  Massachusetts found  that bacterial
    pollution was  widespread  throughout  the drainage  basin.   In all  cases
    where samples  were taken,  fecal  coliforms were  in  excess  of 10,000  counts
    per 100 ml, with  conditions worse  in the  Belmont street storm drains.
    This project concluded  that the  very  high fecal coliform   counts  in  their
                                     11

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    stormwater are at least partially  due  to  sewage contamination apparently
    entering the stormwater system throughout the local catchment.

    The sources of  sewage contamination are  leaking  septic  tanks,  infiltra-
    tion from sanitary sewers into storm sewers, and leakage at manholes.   In
    the northern  basin,  the  high fecal  coliform  counts  are attributed  to
    known sewage contamination sources on Poor Farm Brook.   The data from the
    project suggest that it would be unwise to permit body contact recreation
    in the northern basin of the lake during or immediately following signif-
    icant storm events.   The project  concluded  that disinfection at selected
    storm drains should be considered in the future, especially if the sewage
    contamination cannot be eliminated.

    The Mystic River NURP project  in  Massachusetts  found various areas where
    fecal coliform  counts were  extremely  high  in  urban  stormwater.   Fecal
    coliform levels of  up to one  million  with  an  average  of 178,000/100 ml
    were recorded  in  Sweetwater Brook, a  tributary to Mystic River,  during
    wet weather.  These high fecal coliform  levels  were  specifically attrib-
    uted  to surcharging  in  their sanitary  sewers,  which  caused  sanitary
    sewage  to  overflow into  their storm  drains via  the combined  manholes
    present in this cathcment.   Fecal coliform levels above the class B fecal
    coliform standard of 200 per 100 ml were found in approximately one-third
    of the samples tested in the upper and  lower forebays of the  Upper Mystic
    Lake and occasionally near the lake's  outlet.   In  addition,  Sandy Beach,
    a public  swimming area on  Upper Mystic  Lake,  exceeded the  State  fecal
    coliform criteria in July of 1982, and  warnings that swimming may be haz-
    ardous to public health were posted for several days.  It is  important to
    note that  sewage  contamination of surface waters  is a major problem in
    the watershed.  The project concluded  that urban runoff  contributes  to
    the bacteria  load during wet  weather  but,  comparatively, is much  less
    significant than the sanitary sources.

Estuaries and Embayments

1.  Adverse effects of urban runoff in marine waters will  be a highly speci-
    fic local  situation.  Though  estuaries and embayments were  studied  to a
    very  limited  extent  in NURP, they  are not  believed  to be  generally
    threatened by urban runoff,  though specific  instances where use  is  im-
    paired  or  denied  can be  of significant  local  and even  regional  impor-
    tance.   Coliform  bacteria  present  in  urban  runoff  is  the  primary
    pollutant of concern, causing  direct impacts  on shellfish harvesting and
    beach closures.

    The significant impact  of  urban  runoff on shellfish harvesting  has been
    well documented by the Long Island, New York NURP project.  In this proj-
    ect, stormwater runoff  was identified as the major source  of  bacterial
    loading to marine waters and,  thus,  the indirect cause of the  denial of
    certification by the New York  State Department  of  Conservation  for about
    one-fourth of  the  shellfishing  area.   Much  of this  area is along  the
    south shore, where  the  annual  commercial shellfish harvest  is  valued at
    approximately $17.5 million.

    The Myrtle Beach, South Carolina NURP  project  found  that stormwater dis-
    charges from the City of Myrtle Beach directly onto the beach showed high
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    bacterial counts for short durations  immediately  after  storm events.   In
    many instances these counts violated EPA water quality criteria for aqua-
    tic life and contact recreation.  The high bacteria counts, however, were
    associated with standing pools  formed at  the  end  of collectors for brief
    periods following the cessation of  rainfall and before  the runoff perco-
    lated into the  sand.   Consequently, the threat to  public  health was  not
    considered great enough to warrant closure of the  beach.

Groundwater Aquifers

1.  Groundwater aquifers that receive deliberate  recharge of urban runoff do
    not appear to be imminently  threatened  by this practice at the two loca-
    tions where it was investigated.

    Two NURP projects  (Long Island  and  Fresno) are situated over sole source
    acquifers.  They have been practicing recharge with urban  runoff for  two
    decades or more at some sites, and extensively investigated the impact of
    this practice on the quality  of their groundwater.   They both found that
    soil processes  are  efficient in retaining urban  runoff pollutants quite
    close to  the  land surface,  and concluded that no  change  in the  use of
    recharge basins is warranted.

    Despite the fact that some of these basins have been in service for rela-
    tively long periods of time  and pollutant breakthrough  of  the upper soil
    layers has not  occurred,  the ability of  the  soil to continue  to retain
    pollutants is unknown.   Further attention to this  issue is  recommended.

CONTROL EFFECTIVENESS

General

A limited number of techniques  for the control of urban runoff  quality were
evaluated by  the  NURP program.   The  set is considerably smaller  than prev-
iously published lists of potential management practices.   Since the control
approaches  that  were  investigated were  selected at the  local level,  the
choices may be taken as an initial  indication of  local perceptions regarding
practicality and feasibility from the standpoint of implementation.

Conclusions

1.  There is a strong preference  for  detention devices,  street sweeping,  and
    recharge devices  as reflected  by the  control measures selected  at  the
    local level for detailed investigation.   Interest  was also  shown in grass
    swales and wetlands.

    Six NURP projects  monitored the performance  of  a total of  14 detention
    devices.   Five  separate  projects  conducted  in-depth  studies  of  the
    effectiveness of street sweeping on the control of urban runoff quality.
    A total  of 17  separate study catchments  were involved in  this  effort.
    Three NURP projects examined  either the potential of recharge devices to
    reduce discharges of urban runoff  to surface  waters or the  potential of
    the practice to contaminate  groundwaters.  A  total  of  12  separate sites
    were covered by this effort.
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    Grass swales were studied by  two  NURP projects.   Two swales  in  existing
    residential areas,  and one experimental swale constructed to serve  a com-
    mercial parking lot were studied.

    A number of  NURP projects indicated  interest  in wetlands  for  improving
    urban runoff quality at early stages of the  program.  Only  one  allocated
    monitoring activity to this control measure,  however.

    Various other management practices were identified as  having local  inter-
    est  by  individual  NURP  projects,  but none of  them was  allocated  the
    necessary resources to be pursued to a point which  allowed  an evaluation
    of their  ability  to  control pollution  from  urban runoff.   Management
    practices  in  this  category  included  urban housekeeping  (e.g.,  litter
    programs,  catch  basin cleaning, pet  ordinances)  and public  information
    programs.

2.   Detention basins are capable of providing very effective  removal of pol-
    lutants in urban runoff.   Both the  design  concept and  the size of  the
    basin in relation  to  the  urban  area served have a'critical influence on
    performance capability.

    Wet  basins  (designs  which maintain  a permanent  water  pool)  have  the
    greatest performance capabilities.  Observed pollutant  reductions  varied
    from excellent to very poor in the basins  which were monitored.   However,
    when basins  are  adequately  sized,  particulate   removals  in  excess  of
    90 percent (TSS,  lead) can be obtained. Pollutants with significant sol-
    uble fractions in  urban runoff show lower  reductions;  on  the  order of
    65 percent for total  P  and approximately 50 percent  for BOD, COD,  TKN,
    Copper, and Zinc.   Results  indicate that  biological processes which  are
    operative in the permanent pool produce significant  reductions  (50 per-
    cent or more)  in   soluble  nutrients,  nitrate and  soluble  phosphorus.
    These performance characteristics  are indicated by both  the  NURP analysis
    results and conclusions reached  by individual projects.

    Dry  basins,  (conventional stormwater  management  basins), which are  de-
    signed to attenuate peak runoff rates  and hence only  very briefly  detain
    portions of flow from the larger storms, are indicated by NURP data to be
    essentially ineffective for reducing pollutant  loads.

    Dual-purpose basins (conventional dry  basins with  modified  outlet  struc-
    tures which significantly extend detention time)  are suggested by limited
    NURP data  to  provide  effective reductions  in  urban runoff  loads.   Per-
    formance may approach that of wet  ponds;  however, the  additional  proc-
    esses which reduce  soluble  nutrient forms do not appear  to be  operative
    in these basins.   This  design concept is  particularly  promising because
    it represents  a  cost  effective approach  to  combining flood  control  and
    runoff  quality  control  and  because  of  the  potential  for  converting
    existing conventional  stormwater management  ponds.

    Approximate costs of wet pond designs are  estimated to be in the order of
    $500 to  $1500  per  acre of  urban  area  served,  for on-site applications
    serving relatively  small  urban areas,  and   about  $100  to  $250  per  acre
    of urban area for off-site  applications  serving  relatively large urban
                                     14

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    areas.  The costs reflect present value  amounts  which include both capi-
    tal and operating  costs.   The difference is  due to an economy  of scale
    associated with  large  basin volumes.  The range  reflects  differences in
    size required to produce particulate removals  in the  order of 50 percent
    or 90 percent.  Annual costs per acre of urban area served are estimated
    at $60 to $175, and $10 to $25 respectively.

3.  Recharge Devices are capable of providing very effective control of urban
    runoff pollutant discharges to surface  waters.  Although continued atten-
    tion  is warranted,  present evidence does not indicate that  significant
    groundwater contamination will result from this practice.

    Both individual project results and NURP screening analyses indicate that
    adequately sized recharge devices are capable of providing high levels of
    reduction in  direct discharges of urban runoff to surface waters.   The
    level of  performance  will depend on both the size of  the unit  and  the
    soil permeability.

    Application will be restricted to  areas where conditions  are favorable.
    Soil  type,  depth to  groundwater,  land  slopes,   and  proximity of  water
    supply  wells  will  all influence  the  appropriateness  of this  control
    technique.

    Surface accumulations which result  from the  high efficiency  of  soils to
    retain pollutants,  suggest  further  attention in  applications  where  dual
    purpose recharge areas  also serve as  recreational fields  or playground
    areas.

4.  Street sweeping is generally ineffective as a technique  for improving the
    quality of urban runoff.

    Five NURP projects evaluated street  sweeping  as  a management  practice to
    control pollutants  in urban  runoff.   Four  of these projects  concluded
    that  street  sweeping was  not effective for  this  purpose.  The  fifth,
    which had  pronounced  wet and  dry seasons,  believed  that  sweeping  just
    prior to the rainy season could produce  some  benefit  in terms of reduced
    pollution in urban runoff.

    A large data  base  on the  quality  of urban  runoff from street  sweeping
    test sites was obtained.  At 10 study sites  selected  for  detailed analy-
    sis, a total of 381 storm events were monitored under control  conditions,
    and an  additional  277  events  during periods  when  street  sweeping opera-
    tions were in effect.   Analysis of these data  indicated that  no signifi-
    cant reductions in pollutant concentrations in urban runoff were produced
    by street  sweeping.

    There may  be special cases in  which  street cleaning applied at restricted
    locations  or  times  of year  could  provide improvements  in urban  runoff
    quality.  Some examples that have been  suggested, though not demonstrated
    by the  NURP program,  include  periods following  snow  melt or  leaf  fall,
    or urban  neighborhoods where  the general level  of cleanliness  could be
    significantly improved.
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5.  Grass swales can  provide  moderate improvements in urban  runoff quality.
    Design  conditions  are important.   Additional study  could  significantly
    enhance the performance capabilities of swales.

    Concentration  reductions  of  about  50 percent  for  heavy  metals,  and
    25 percent  for  COD, nitrate,  and ammonia  were  observed in  one of  the
    swales  studied.   However the  swale  was  ineffective  in  reducing concen-
    trations  of organic  nitrogen, phosphorus,  or bacterial species.   Two
    other swales  studied failed to  demonstrate any quality  improvements  in
    the urban runoff passing through them.

    Evaluations by  the  NURP projects involved  concluded, however,  that this
    was an  attractive control technique whose performance could  be improved
    substantially by application of appropriate design considerations.  Addi-
    tional study to develop such information was recommended.

    Design  considerations cited  included slope, vegetation  type  and mainte-
    nance,  control  of flow velocity  and residence time, and enhancement  of
    infiltration.   The  latter factor  could  produce load reductions greater
    than those  inferred from concentration changes and effect  reductions  in
    those pollutant species  which are  not  attenuated by  flow  through  the
    swale.

6.  Wetlands are considered to be  a  promising  technique  for  control of urban
    runoff quality.  However, neither  performance  characteristics nor design
    characteristics in relation to performance were developed by NURP.

    Although a  number of projects  indicated interest,  only one  assigned NURP
    monitoring  activity to a  wetland.   This was a natural wetland, and flows
    passing though  it were uncontrolled.  Results suggest its potential  to
    improve  quality,  but  the investigation  was  not  adequate  to  associate
    necessary design factors to performance capability.  Additional attention
    to this control technique would be  useful,  and  should  include factors
    such  as  the  need  for  maintenance  harvesting  to  prevent  constituent
    recycling.

ISSUES

A  number  of  issues with respect  to managing  and controlling urban runoff
emerge from the conclusions  summarized  above.   In  some instances  they repre-
sent  the  need  for additional  data/information  or  for  further  study.   In
others they point to the need for  follow-up activity by  EPA,  State, or local
officials to  assemble and  disseminate what is  already known  regarding  water
quality problems caused by urban runoff and solutions.

Sediments

The nature and  scope of the potential  long-term threat posed by nutrient and
toxic pollutant accumulation in the  sediments of urban lakes  and streams
requires  further  study.  A  related  issue  is  the safe  and  environmentally
sound disposal  of  sediments  collected in detention basins  used  to control
urban runoff.
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 Priority  Pollutants

 NURP  clearly demonstrated that many priority pollutants  can be  found  in  urban
 runoff  and  noted  that  a  serious human health risk  could  exist when water sup-
 ply  intakes are in close proximity to urban stormwater  discharges.   However,
 questions related to the sources, fate, and transport mechanisms of  priority
 pollutants  borne by  urban  runoff and  their frequencies  of  occurrence  will
 require further study.

 Rainfall  pH Effects

 The  relationship  between pH and  heavy  metal values in  urban  runoff has not
 been  established  and needs further study.   Several  NURP projects (mostly in
 the northeastern  states) attributed high heavy metals concentrations  in  urban
 runoff  to the effects  of acid rain.  Although it is quite plausible that acid
 rain  increases  the level of pollutants  in urban runoff and may  transform them
 to more toxic and more easily assimilated forms, further study  is required to
 support this speculation.

 Industrial  Runoff

 No truly  industrial  sites  (as opposed  to industrial parks)  were included in
 any  of  the NURP  projects.   A very  limited body  of data  suggests,   however,
 that  runoff from industrial sites may  have significantly  higher contaminant
 levels  than runoff from  other  urban  land use sites,  and this issue should be
 investigated further.

 Central Business  Districts

 Data  on the characteristics of urban runoff from  central  business districts
 are  quite  limited as  opposed to  other land use  categories  investigated by
 NURP.   The  data do suggest, however, that  some sites may produce pollutant
 concentrations  in runoff that  are significantly  higher  than those from  other
 sites in  a  given  urban area.  When combined with their typically high degrees
 of imperviousness, the pollutant  loads from central business districts can be
 quite high  indeed.   The opportunities  for  control in central  business dis-
 tricts  are  quite  limited, however.

 Physical  Effects

 Several projects  concluded that  the  physical impacts  of  urban  runoff upon
 receiving waters  have  received  too little attention and,  in some cases, are
more  important  determinants  of beneficial use attainment  than  chemical pol-
 lutants.  This contention requires much more detailed documentation.

 Synergy

NURP did  not evaluate  the synergistic effects that might result from pollut-
ant concentrations experienced  in stormwater runoff, in association  with pH
and temperature ranges that occur  in the  receiving waters.  This type of in-
vestigation might reveal  that control  of a specific parameter,  such as pH,
would adequately  reduce an adverse synergistic effect caused by the  presence
of other  pollutants  in combination and  be  the most  cost effective solution.
Further investigations should include this issue.
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Opportunities for Control

Based upon the results of NURP's  evaluation  of the performance of urban run-
off controls, opportunities  for  significant  control of urban  runoff  quality
are much  greater for  newly  developing areas.   Institutional  considerations
and availability of space are  the key factors.  Guidance on this  issue  in a
form useful  to States  and urban planning authorities  should be prepared and
issued.

Wet Weather Water Quality Standards

The NURP  experience  suggests that EPA should  evaluate the possible  need to
develop "wet weather" standards,  criteria, or modifications to ambient crite-
ria to reflect differences in  impact  due  to  the intermittent,  short duration
exposures  characteristic   of   urban  runoff   and  other  nonpoint   source
discharges.

Coliform Bacteria

The appropriateness  of using  coliform bacteria  as indicator  organisms  for
human health risk where the  source is exclusively urban runoff warrants fur-
ther investigation.

Wetlands

The use of wetlands as a control measure  is  of great  interest  in many areas,
but the  necessary information on design performance  relationships required
before cost  effective  applications can be considered  has  not  been adequately
documented.   The environmental   impacts  of  such  use upon  wetlands  is  a
critical issue which, at present, has been addressed marginally, if at all.

Swales

The use  of grass swales was suggested by two NURP projects  to  represent a
very  promising   control  opportunity.   However,  their performance is  very
dependent upon design  features about which  information is  lacking.  Further
work to address  this deficiency and appropriate maintenance practices appears
warranted.

Illicit Connections

A number of  the NURP projects  identified  what  appeared to be  illicit connec-
tions of  sanitary discharges to  stormwater  sewer  systems,  resulting  in high
bacterial counts and dangers to  public health.   The  costs  and complications
of locating  and  eliminating  such connections may  pose  a  substantial  problem
in urban areas,  but the opportunities for dramatic improvement in the quality
of urban stormwater discharges   certainly  exist  where this  can  be  accom-
plished.  Although not emphasized in the NURP effort, other than  to assure
that the selected monitoring sites were  free from sanitary sewage contamina-
tion,  this BMP is clearly a desirable one to pursue.
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Erosion Controls

NURP  did not  consider  conventional erosion  control  measures because  the
information base  concerning them  was  considered to  be adequate.   They  are
effective, and their use should be encouraged.

Combined Sewer Overflows

In order to address urban runoff from separate storm sewers, NURP avoided any
sites  where  combined  sewers  existed.   However,  in  view  of  their  relative
levels  of  contamination, priority should be  given  to control of  combined
sewer overflows.

Implementation Guidance

The NURP studies have  greatly  increased our  knowledge of the characteristics
of urban  runoff,  its  effects  upon designated uses,  and of  the performance
efficiencies of selected control measures.   They  have also  confirmed earlier
impressions that  some States  and  local communities  have  actually  begun  to
develop  and implement stormwater  management  programs incorporating  water
quality objectives.   However,  such  management  initiatives are, at  present,
scattered and  localized.  The experience  gained from  such efforts  is  both
needed and sought after  by many other States and localities.   Documentation,
evaluation,  refinement and  transfer of management  and  financing mechanisms/
arrangements,  of simple and reliable problem assessment methodologies, and of
implementation guidance  which  can  be used by planners and officials  at  the
State  and local  level are urgently needed as is a forum for  the  sharing  of
experiences by those  already  involved,  both among  themselves  and  with those
who are about to address nonpoint source issues.
                                     19

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                                  APPENDIX
                    THE NATIONWIDE URBAN RUNOFF PROGRAM
Program Design

NURP was not intended to be a research program, per  se,  and  was not designed
as such.   Rather,  the program  was intended to be a support  function  which
would  provide  information and methodologies  for  water  quality  planning
efforts.  Therefore, wherever possible,  the projects selected were ones  where
the work undertaken would  complete the urban runoff  elements of formal  water
quality management  plans  and the  results  were  likely to be incorporated  in
future plan updates and lead to implementation of  management recommendations.
Conduct of the  program  provided direction and assistance to 28 separate  and
distinct planning projects, whose  locations are shown in Figure 1 and listed
in Table 1, but the results will be  of value  to many other  planning efforts.
NURP also acted as  a  clearinghouse and,  in that capacity, provided a common
communication link to and among the 28 projects.

The NURP  effort began with a  careful review of what was known  about  urban
runoff  mechanisms,  problems,  and  controls,  and then built  upon  this  base.
The twin  objectives  of  the program  were  to provide credible  information  on
which  Federal,  State,  and local  decision makers could base future  urban
runoff management decisions and to support both planning and implementation
efforts at the 28 project locations.

An early step in implementing the NURP program involved  identifying a limited
number of locations where  intensive  data gathering and  study  could be  done.
Candidate locations were assessed relative to three basic selection criteria:

     -  Meeting program objectives;

        Developing implementation plans for those  areas;  and

        Demonstrating transferability, so  that solutions and knowledge
        gained in the study area could be  applied  in  other  areas, with-
        out need for intensive,  duplicative data gathering efforts.

The program design used for NURP included providing a full range of technical
and management assistance to each project as the needs arose.  Several forums
for the communication of experience and sharing of data  were provided through
semi-annual meetings involving participants from all projects.  The roles  and
responsibilities of the various State, local, and  regional  agencies and par-
ticipating Federal  agencies were  clearly  defined and  communicated at  the
outset.   These  were  reviewed  and revised  where   warranted  as the projects
progressed.
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Figure 1.  Locations of the 28 NURP Projects
      TABLE 1.  NURP PROJECT LOCATIONS
EPA
Region
I



11




III


IV




NURP
Code
MAI

MA2
NH1
MY1

NY2
NY3

DC1

MD1
FL1
NCI
SCI
TNI

Project Name/Location
Lake Quinsigamond
(Boston Area)
Upper Mystic (Boston Area)
Durham, New Hampshire
Long Island (Nassau and
Suffolk Counties)
Lake George
Irondequoit Bay (Rochester
Area)
WASHCOG (Washington, D.C.
Metropolitan Area)
Baltimore, Maryland
Tampa, Florida
Winston-Salem, North Carolina
Myrtle Beach, South Carolina
Knoxville, Tennessee

EPA
Region
V





VI

VII
VIII


IX


X

NURP
Code
IL1
IL2
Mil
MI2
MI3
WI1
AR1
TX1
KS1
C01
SD1
UT1
CA1

CA2
OR1
WAI
Project Name/Location
Champaign-Urbana, Illinois
Lake Ellyn (Chicago Area)
Lansing, Michigan
SEMCOG (Detroit Area)
Ann Arbor, Michigan
Milwaukee, Wisconsin
Little Rock, Arkansas
Austin, Texas
Kansas City
Denver, Colorado
Rapid Citv, South Dakota
Salt Lake" City, Utah
Coyote Creek
(San Francisco Area)
Fresno, California
Springfield-Eugene, Oregon
Bellevue (Seattle Area)
                      21

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The 28 NURP projects  were  managed by designated State, county,  city,  or re-
gional  governmental  associations.   The  U.S.  Geological  Survey   (USGS)  was
involved with EPA  as  a cooperator, through an  inter-agency  agreement,  on 11
of the  NURP  projects.  The Tennessee Valley  Authority was  also  involved in
one project.

Project Selection

Projects were  selected from  among the 93 Areawide  Agencies that had  iden-
tified urban runoff as one of  their  significant problems.   The  intention was
to build upon what these  agencies had already  accomplished  in  their earlier
programs.  Also, projects that would be a part  of  this program  were  screened
to be  sure that they represented a broad  range of  certain characteristics
(e.g., hydrologic  regimes,  land uses,  populations,  drainage system types).
Actual  selection  of  projects  was  a joint  effort among  the  States,  local
governments,   and  Regional  EPA offices.   The  five  major  criteria  used  to
screen candidate projects were as follows:

     1.  Problem Identified.    Had  a problem  relative  to  urban  runoff
         actually  been  identified?   Could  that  problem  be  directly
         related to separate storm sewer  discharges?   What  pollutant or
         pollutants were thought  to  be causing  the problem? Using  the
         NURP problem identification categories, what was  the "problem"
         (i.e.,   denying  a  beneficial  use,  violating  a  State  water
         quality standard,  or public concern)?

     2.  Type of Receiving Water.  The  effects  of stormwater runoff on
         receiving water quality  were  the NURP  program's  ultimate con-
         cern.   Because  flowing  streams,   tidal  rivers,   estuaries,
         oceans, impoundments,  and lakes  all have different hydrologic
         and  water quality  responses,  the  types of receiving  waters
         associated with each  candidate project had  to be  examined to
         ensure that an appropriately representative  mix was included in
         the overall NURP program.

     3.  Hydrologic Characteristics.   The pattern  of  rainfall  in  the
         study  area  is  perhaps  the single  most important factor  in
         studying urban runoff  phenomena, because  it  provides the means
         of conveyance of pollutants from their source to  the receiving
         water.   For this reason, projects in locations having different
         hydrologic regimes were chosen for the program.

     4.  Urban Characteristics.    Characteristics  such  as   population
         density,   age of  community,  and  land  use  were  considered  as
         possible  indicators  of   the  waste  loads and  ultimately  the
         rainfall-runoff water quality relationship.   The type of sewer-
         age system was  another factor considered (e.g., whether it is
         combined,  separate, or mixed;  how severe the infiltration  and
         inflow problems may  be) .   Such  factors have different effects
         on the quantity and quality of storm  runoff, and  were  balanced
         as well as possible in selecting projects.
                                     22

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     5.  Beneficial Use of Receiving Water.  Because this factor greatly
         affects the type  of  control  measure that would be appropriate,
         attempts  were  made   to  include  a wide  range  in  selecting
         projects.

Although these were the primary criteria used to identify potential projects,
other  factors  also  had  to  be  considered  (e.g., the applicant  agencies'
willingness to participate, the  State's  acceptance  of  the  project,  the expe-
rience  of  the proposed project  teams).    Because the NURP  program  used
planning grants  (not research funds)  a  major consideration was  the antici-
pated  working relationships with  local  public agencies and  the  applicants'
ability to raise local matching funds.

Program Assistance

Technical expertise and  resources  available  for  urban  runoff  planning varied
among  the  various projects participating  in  NURP.  Therefore,  the program
strategy called  for providing a broad  spectrum  of technical  assistance  to
each project  as needed and  for intercommunication of experiences  and sharing
of data in a timely manner.

Assistance was also provided to the applicants in developing their final work
plans.   This   was  done  to ensure that  there  would   be  consistency  among
methods, especially  in the collection of data.   If there were  to be differ-
ences in data  from city  to city, they must  be due  to  the  characteristics  of
each city and not a result of how the data were obtained.

Assistance with instrumentation  was  provided during the program  in  the form
of information  on  available equipment, installation,  calibration,  etc.   Be-
cause one of the more important elements of  a  data  collection program is the
"goodness" or  quality  of the  data themselves, questionable data  would be  of
little use.  Accordingly, a quality assurance and quality control  element was
required in the plans for each project.

Periodic visits were  made to  each project  site  to ensure that the  partici-
pants were provided  opportunities  to discuss any problems, technical or ad-
ministrative.   The visiting team typically  included an EPA Regional Office
representative, an  EPA  Headquarters  representative,  and  one  or two  expe-
rienced consultants.  All  interested  parties,  including representatives from
State or local governments, were  requested to attend those  visits.

As the projects moved farther into their planned  activities and the  time for
data analysis approached, each project was  required to  describe  how they were
going to analyze their data.  No  single method was recommended for each proj-
ect,  because  it was  believed that  a broad  diversity of available methods
would be suitable, if used properly.  Guidance on proper use was  provided  as
a part of  technical  assistance through project visits  and  special  workshops
for this purpose.

Communication

It was  intended that  the  entire group  of NURP  participants  function  as  a
single team.   Accordingly, a communication   program  was developed.   National
                                     23

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meetings were  conducted semi-annually  so  that key personnel  from the  indi-
vidual projects  would have an  opportunity to discuss  their experiences and
findings.

Reports were required of  each project quarterly.   EPA Headquarters also pro-
vided composite  quarterly  reports  summarizing the status of each project and
discussing problems encountered and solutions  found.

OUTPUTS TRANSFERABLE TO STATE AND LOCAL GOVERNMENTS

The program has  yielded a  great deal  of information which will be useful for
a broad spectrum of planning  activities for many years.  Furthermore, it has
fostered valuable cooperative  relationships  among planning  and regulatory
agencies.  The  most tangible  products of  the program are  this  report, the
reports of  various grantees  (available under separate  cover),  and  several
technical reports which  focus on  specialized aspects  of  the  program, its
techniques,  and  its findings.  In  addition,  a considerable number  of  indi-
vidual articles  drawing on information developed  under the, NURP program have
already appeared in  the technical literature  and address specific technical
or planning aspects of urban runoff.

At the time of publication of this Final Report,  the main technical effort of
the NURP program is  complete; the field studies  and  the analysis of most of
the resultant data are  complete enough that the findings reported herein can
be taken with  confidence.   However, there  is  still some work in progress to
make certain details  of the program available  for  future use.  The products
of this on-going work include:

        A detailed  database which has been compiled  to make technical
        information from  the  28 projects  available for  review and use
        (DECEMBER 1985);

     -  A technical  report which  focuses  on  the  program's  studies and
        findings relative  to detention and  recharge devices   (MAY  1984) ;

     -  A technical report on urban  runoff effects on the water quality
        of rivers and streams  (MARCH 1984); and

        A technical report on the  effectiveness of street sweeping as a
        potential "best management practice" for  water pollution control
        (MAY 1984).

This report supersedes  the earlier NURP publication,  "Preliminary Results of
the  Nationwide  Urban  Runoff  Program," March 1982.   Information presented
there has been expanded, updated, and  in some  cases revised.
                                     24
                                                ĽU.S. ooTZRmair PRIKTIKO omcs t 198* 0-421-082/519

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