GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 6
                                                                       United States
                                                                       Environmental Protection
                                                                       Agency


                                                                       EPA832F12017
         Water Quality  Standards


           This factsheet is the sixth in a series of six on integrating green
                 infrastructure concepts into permitting, enforcement, and
                                  water quality standards actions.
Introduction
Antidegradation
Use Attainability Analysis

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                                                                Introduction
Integrating Green Infrastructure Concepts into
Permitting, Enforcement, and Water Quality
Standards Actions

This factsheet is the sixth in a series

of six factsheets in the U.S. EPA Green

Infrastructure Permitting and Enforcement

Series (http://water.epa.gov/infrastructure/

greeninfrastructure/gi_regulatory.

cfm#permittingseriesA This series

describes how EPA and state permitting and

enforcement professionals can incorporate

green infrastructure practices and approaches

into National Pollutant Discharge Elimination

System (NPDES) wet weather programs,

including stormwater permits, Total

Maximum Daily Loads (TMDLs), combined

sewer overflow (CSO) long-term control

plans (LTCPs), and enforcement actions.

This series builds upon EPA's continued

investment in green infrastructure and low

impact development. Existing EPA authority,

guidance, and agreements enable EPA

Regions and state agencies to  work with

permittees to include green infrastructure

measures as part of control programs.
For additional resources on green infrastructure
go to the EPA Green Infrastructure Web
page: http://water.epa.gov/infrastructure/
greeninfrastructure/index.cfm.

Key green infrastructure guidance issued
to date can be found at: http://water.epa.
gov/infrastructu re/green infrastructure/
gLpolicy.cfm.
Pursuant to Section 303 of the Clean Water Act (CWA), States
and authorized Tribes establish water quality standards for
the waters of their jurisdiction. Water quality standards in-
clude designated uses (e.g., swimming, wading, public water
supply, habitatfor aquatic species), water quality criteria
(numeric and narrative expressions of the water quality
characteristics needed to protect designated uses), and an
antidegradation policy and implementation procedures.
The purpose of this factsheet is to describe how green
infrastructure approaches can be considered as part of an
Antidegradation Review or Use Attainability Analysis.

Antidegradation

Antidegradation provisions are intended to protect existing
uses and high quality waters, including outstanding national
resource waters (sometimes referred to as Tier 3 waters)
and water bodies where water quality is better than the
criteria specified to protect designated uses (sometimes
referred to as Tier 2 waters).

    Antidegradation provisions are intended to protect
    existing uses and high quality waters.

In developing  permit requirements for point source
discharges, permit writers need to include requirements
to ensure the discharges achieve water quality standards,
including antidegradation provisions. For Tier 2 waters, if
a permittee proposes a new or increased discharge, an
Antidegradation Review or Antidegradation Demonstration
must be completed.
An Antidegradation Review typically considers:
  Athorough alternatives analysis, examining whether
   reasonable non-degrading or less-degrading alternatives
   exist (i.e., whether allowing the lowering of water quality
   is "necessary");
  Social/economic importance of the new or increased
   discharge;
  Implementation of highest statutory and regulatory
   requirements for other point sources;
  Cost-effective and reasonable best management
   practices for nonpoint sources; and
  Public participation and intergovernmental coordination.

In many cases an antidegradation alternatives analysis for
a new or increased point source discharge may focus on
treatment technologies for the waste stream. The permittee
and/or State or Tribe may arrive  at a conclusion there is not
an available/feasible treatment technology that could be
used to better control the discharge (i.e., to avoid a new or
increased discharge). However, there is a much wider

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GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 6
 range of controls that permittees. States, and/or Tribes may
 want to consider in the alternatives analysis:
    Pollution prevention measures;
    Product substitution (e.g. substitution of less toxic
     substances);
    Reduction in scale of the project;
    Water recycling or reuse;
    Innovative treatment technologies (e.g., land application
     of wastewater);
    Seasonal or controlled discharge options to avoid
     critical water quality periods;
  Alternative discharge locations; and
  Green infrastructure controls on wet weather discharges.

Considering stormwater discharges and green
infrastructure opportunities may reveal opportunities
to reduce wet weather-related pollutant loadings that
could potentially counterbalance some of the increases
in the point source loadings. Where the biological health
of a water body could be affected, green infrastructure
solutions can help protect the hydrology and habitat of
the receiving water and lessen the impacts of a new or
increased discharge.
      Rain barrels, pervious pavers, and vegetated areas designed to retain stormwater are all components of green infrastructure.
  Use Attainability Analysis
 Whether a water body meets water quality standards can
  be affected by a wide variety of factors, including point and
  nonpoint source loadings, background conditions, geomor-
  phologic factors, and land use. A designated use of a water
  body that is not being attained may be changed if the State
  or Tribe can demonstrate that attaining a use is notfeasible.
  EPA's regulations under the Clean Water Act (40 CFR
  131.10(g)) identify six reasons or factors for changing a
  current use designation, which are summarized below:
  1.  Naturally occurring pollutant concentrations prevent
    attainment of the use.
  2.  Natural, ephemeral, intermittent or low flow conditions
    or water levels prevent attainment of the use.
 3.  Human-caused conditions or sources of pollution
    prevent attainment and cannot be remedied or would
    cause more environmental damage to correctthan
    leaving in  place.
 4.  Dams, diversions, and other hydrologic modifications
    prevent attainment and it is not feasible to restore the
    water or operate the  modification in a way that would
    result in attainment.
  5.  Natural physical  features prevent attainment of aquatic
    life uses.
6.  Controls more stringent than required effluent limita-
   tions or new source performance standards would be
   necessary to attain the use and would result in substan-
   tial and widespread social and economic hardship.
A use attainability analysis (UAA) is a structured scientific
assessment of the aquatic life and/or recreational (aka,
"fishable and swimmable") beneficial uses of a water
body given application of required effluent limits for
point sources and implementation of cost-effective and
reasonable management practices for nonpoint sources.
(See 40 CFR 131.3(g))
Where a State or Tribe is considering whether or not a use
is feasible to attain based on factor 6, it may be appropriate
to first consider whether there are  alternative measures
that could be taken to counterbalance point source
loadings. For example, there may be situations where
restoring natural green infrastructure and creating new
green infrastructure to trap pollutants and manage wet
weather flows may allow designated uses to be attained
and alleviate the pressure for downgrading a designated
use. Also, green infrastructure practices, such as
stormwater parks in distressed urban neighborhoods, may
provide notable  social  and/or economic benefits.

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The benefits of green infrastructure include not only water quality
protection, but also a range of social and economic benefits associated
with the integration of vegetation into the built environment.
             Green Infrastructure Permitting and Enforcement Series
             This series on integrating green infrastructure concepts into
             permitting, enforcement, and water quality standards actions
             contains six factsheets plus four supplemental materials
             that can be found at http://water.epa.gov/infrastructure/
             greeninfrastructure/gi_regulatory.cfm#permittingseries.

             Factsheets
             1. Potential Challenges and Accountability Considerations
             2. Combined Sewer Overflows
             3. Sanitary Sewer Overflows
             4. Stormwater
             5. Total Maximum Daily Loads
             6. Water Quality Standards

             Supplemental Materials
             1. Consent Decrees that Include Green Infrastructure Provisions
             2. Consent Decree Language Addressing Green for Grey
               Substitutions
             3. Green Infrastructure Models and Calculators
             4. Green Infrastructure in Total Maximum Daily Loads (TMDLs)

&EPA
       United States
       Environmental Protection
       Agency
       For additional resources on green infrastructure,
       go to the EPA Green Infrastructure Web page:
       http://www.epa.gov/greeninfrastructure/.

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