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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