GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 1
Green roofs retain stormwater on site while providing
many other benefits such as heat island mitigation.
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                                                                United States
                                                                Environmental Protection
                                                                Agency


                                                                EPA832F12012

         General  Accountability

    Considerations  for Green

                          Infrastructure


            This factsheet is the first in a series of six on integrating green
                infrastructure concepts into permitting, enforcement, and
                                water quality standards actions.
Introduction
Terminology and Articulating Standards Page 3
Metrics and Performance Evaluation   Page 3
Appropriate Schedules
Reporting Requirements
                                                           Enforceable Mechanisms for

                                                           Operations and Maintenance
                                                           Modification Provisions

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

This factsheet is the first 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.
Introduction

Accountability considerations are important in all actions
involving permits or enforcement orders, regardless of the
approaches used to achieve and maintain compliance with
established standards. Different accountability mechanisms
may be appropriate for permits and enforcement actions
with green infrastructure components, however, because
green infrastructure approaches function differently from
more traditional grey infrastructure approaches.
This fact sheet discusses six accountability mechanisms
that may be applied to permits or enforcement actions that
include green infrastructure. Permitting and enforcement
authorities can work with regulated entities to determine
the mix of accountability mechanisms most appropriate for
specific situations.

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GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 1
  1) Terminology and Articulating Standards
 Terms such as "green infrastructure," "low impact
 development (LID)," and "conservation design" can apply
 to a wide array of designs that achieve a wide range
 of outcomes. For example, design manuals may apply
 the label "LID" or "green infrastructure" to retention,
 extended detention, and/or extended filtration devices,
 even though the outcomes associated with these devices
 are quite different. Because conceptual terms such as
 "LID" and "green infrastructure" may be applied to a
 range of practices resulting in a range of environmental
 outcomes, these terms in and of themselves are inadequate
 in articulating standards. For example, a standard
 requiring permittees to "implement LID practices at new
 development sites in your jurisdiction" would be a difficult
 standard to implement and enforce. A more effective
 approach would be to define the standard as the desired
 result and allow for various green infrastructure or green-
 grey combinations to achieve this result. For example, a
 requirement that would be less ambiguous and easier to
 implement and enforce might read as follows:

    "The permittee must implement and enforce via
    ordinance and/or other enforceable mechanism(s)
    the following requirement for new and
    redevelopment: Site design standards for all new
    and redevelopment that require, in combination
    or alone, management measures that keep and
    manage on site the first one inch of rainfall from
    a 24-hour storm preceded by 48 hours of no
    measurable precipitation. This first one inch of
    rainfall must be 100% managed with no discharge to
    surface waters."
In certain contexts, standards based on environmental
outcomes may be supplemented with standards based on
implementation goals. This is especially important where
a long-term schedule of compliance is included. In such
cases, enforceable medium- and long-term targets can
be expressed  in terms of environmental outcomes (e.g.,
number of CSO overflows), while enforceable interim
targets can be defined in terms of implementation goals
related to the desired environmental outcome (e.g.,
number of acres retrofitted to retain a certain volume
of stormwater). Water quality improvements on the
sewershed scale may not be measurable until a certain
amount of green infrastructure has been installed;
therefore, the  inclusion of interim targets is essential
to evaluate progress over time and allow for adaptive
management as  needed.
Stormwater wetlands can effectively absorb stormwater while also
providing natural habitatforwildlife. Photo courtesy of Philadelphia
Water Department
 2) Metrics and Performance Evaluation

 Quantifiable metrics are an essential part of a permit or
 compliance order regardless of the types of practices that
 will be implemented to meet performance requirements
 and protect water quality. The need for such metrics
 is no different for green infrastructure than for grey
 infrastructure control  measures, but the  actual metrics that
 may work best for green infrastructure measures may vary.

     Quantifiable metrics are an essential part of a
     permit or compliance order regardless of the types
     of practices that  will be implemented to meet per-
     formance requirements and protect water quality.
Metrics are standard measures to assess performance
relative to a specific goal. Metrics and indicators are used
for all types of technologies to gauge implementation and
effectiveness. Tracking and reporting based on metrics is
appropriate for most permits and enforcement actions. It
may be advisable in many situations to have metrics that
gauge both implementation and effectiveness. See Box 1 for
examples of both implementation and effectiveness metrics.
In addition to metrics based on stormwater volumes, it
may be necessary to establish metrics based on pollutant
loadings.  For example, meeting a waste load allocation
(WLA) established in a total maximum daily load (TMDL)

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Many cities have implementation targets for urban tree canopy. Trees in the urban environment provide many
environmental benefits, including stormwater management, air quality management, and urban heat island mitigation.

             Boxl
             Implementation metrics might include:
             • Number, square footage, and capacity of green roofs in place
             • Number and capacity of rain gardens and other infiltration practices
             • Acreage of impervious surfaces in the service area where rainwater drains to a green infrastructure control measure
             • Gallons kept out of the sewer system during 2- or 10-year storm events through the use of green infrastructure
             • Reductions to Effective Impervious Area (EIA)
             • Quantification of flow volume reductions, e.g., flows into or from the sewer system in various size storm events, on an
               annual basis, or in a typical year
             Effectiveness (receiving water  response)  metrics might include:
             • Pre- and post-implementation water resources monitoring and assessment
             • Assessment of erosion rates in receiving waters
             • Attainment of water quality standards for specific pollutants
             • Percent stormwater volume capture in combined sewer area
             • Percent reduction in CSO volume as a result of green infrastructure

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GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 1
 requires specific reductions in pollutant loads. Note
 that continuous flow monitoring is generally advisable
 for monitoring wet weather discharges. Grab samples
 will, in many cases, vary depending on at what point in
 the storm cycle the sample was collected, and may not
 be representative of the pollutant concentrations in the
 stormwater throughout the duration of the storm event.
 It may also be appropriate in some cases to have metrics
 for individual controls, or a sample set of controls.  These
 metrics could be used in combination with system-wide
 measurements. Metrics for specific controls could include
 volume reductions or reductions in pollutant loadings.
 Percent pollutant removal is not a good measure of
 performance of stormwater controls because it is very
 dependent on the characteristics of the stormwater
 entering the practice, and also may not account for the
 volume reductions achieved through the management
 practice. Event Mean Concentrations (EMCs) may be
 appropriate for assessing the performance of a sample set
 of green infrastructure practices.
 It is important to carefully select a set of metrics and
 incorporate them into evaluation requirements to ensure
 that desired  outcomes are being approached and/
 or achieved. The ultimate desired outcomes are those
 centered on environmental protection and improvement,
 and metrics  should be focused on those outcomes. In the
 shorter term, it may be appropriate to establish interim
 performance criteria. For example, interim criteria may
 specify that discharges  be reduced by a certain volume
 orthat pollutant loadings be demonstrably reduced.
 Evaluations may appropriately include field monitoring,
 modeling, or a combination of methods.

     It is important to carefully select a set of
     metrics and incorporate them into evaluation
     requirements to ensure that desired outcomes
     are being approached and/or achieved.


 For many types of metrics, tracking or monitoring data will
 need to be compared to standards or thresholds (e.g., the
 number and  capacity of green infrastructure measures
 installed might be compared to the number and capacity
 planned). Standards or thresholds should be precise
 enough to allow for such comparisons. There should also
 be clear expectations for corrective action when observed
 values and progress do  not meet established standards or
 thresholds. In some contexts, it is perfectly reasonable to
include a period for refinement of methods and thresholds.
However, there should also be a clear understanding of
the point at which data are considered representative and
actionable. It is important that information be relatively
unambiguous and interpretable. This will  allow for effective
compliance monitoring and enforcement, if necessary, of
the permit or order provisions. In addition, for long-term
compliance schedules, performance data should be fed
back into an adaptive management framework so that
performance can be continuously improved overtime.
An example of language from a CSO enforcement action
dealing with metrics and performance evaluation:
   "The Sewer District shall develop and submit to EPA
   a Green Infrastructure Plan. The  Plan shall propose
   a process for locating, designing, constructing,
   operating, and evaluating a set or sets of green
   infrastructure control measures to capture a
   minimum of [XX] million gallons of wet weather
   flows in a typical year that would otherwise be
   discharged bythe District as CSOs. This [XX] MG
   volume of capture shall be in addition to the capture
   pertypical yearthatwould be achieved by all of the
   other grey infrastructure control  measures required
   underthe Consent Decree in the absence of the
   Green Infrastructure control measures.  ...
   The Plan shall describe how the Sewer District
   will adjust the hydrologic model parameters
   directly related to the Green Infrastructure control
   measures (prior to and during model recalibration)
   as necessary to accommodate changes in model
   parameterization caused by shifts in runoff
   hydrology from the Green Infrastructure control
   measures. The District shall then use the model in
   two forms (the first encompassing all CSO control
   measures including the Green Infrastructure
   control measures proposed, and a second model
   identical to the first, but without the Green
   Infrastructure control measures), to simulate the
   system's typical year performance. The District
   shall use the difference in performance  between
   the two simulations to gauge compliance with the
   requirement that Green Infrastructure measures
   control a minimum additional CSO volume of [XX]
   MG pertypical year."

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3) Appropriate Schedules
As in other contexts and with other control technologies,
it is important to establish schedules that are measurable
and realistic. Compliance schedules must conform to Clean
Water Act (CWA) requirements and EPA regulations (see 40
CFR § 122.47), as summarized in EPA guidance.

   Compliance schedules may include:
   •   Dates/deadlines for updating ordinances;
   •   Dates for implementing pilot projects;
   •   Milestones for broad, systematic installation of
       green infrastructure measures;
   •   Benchmarks and/or standards to quantify
       green infrastructure performance and dates
       for achieving benchmarks/standards (e.g.,
       implement measures with a cumulative storage
       capacity of [XX] gallons by [XX] date).
Additional information on the inclusion of compliance
schedules in NPDES permits can be found in the Office of
Wastewater Management Memo of May 10, 2007:
Compliance Schedules for Water Quality-Based Effluent
Limitations in NPDES Permits (available at: http://water.
epa.gov/lawsregs/guidance/wetlands/upload/
signed-hanlon-memo.pdf). The memo outlines the
situations in which it may be appropriate to develop
compliance schedules extending beyond a typical 5-year
permit term. For more information on compliance schedules
with large construction projects and significant
expenditures that may require more than one permit cycle,
see 40 C.F.R. §§ 122.44 and 122.47, and EPA's CSO policy
(found at: http://cfpub.epa.gov/npdes/cso/cpolicy.
cfm?program_id=5).
                                                             It is important to establish schedules that are
                                                             measurable and realistic.
4)  Reporting Requirements

When implementing grey infrastructure approaches,
permittees will typically report on progress in meeting
schedules and milestones, and in many cases will monitor
and report on discharge characteristics. The same applies
to green infrastructure elements. See examples of reporting
activities in Box 2 below.
Along with standard reporting provisions in the permit,
administrative order, or judicial order, post-construction
monitoring and reporting  should be implemented to ensure
the permittee has come into compliance with the CWA
and is required for CSO discharges. However, receiving
water monitoring and reporting should not wait until after
all green infrastructure projects have been constructed.
Rather, monitoring and reporting requirements must be
sufficient to measure the in-stream benefits of green
infrastructure as they begin to accrue and during the life of
a long-term implementation plan.
Box 2

Examples of Reporting and Tracking Activities
• Report on policy and administrative accomplishments, e.g., adoption of new ordinances, standards, site plan review
  procedures, and operation and maintenance protocols. These are short-term elements that would typically be
  expected to be completed in the first 2-5 years of the  program.
• Report on implementation activities and accomplishments (e.g., number of green roofs or number of rain gardens).
• Report on the cumulative storage capacity of and/or cumulative runoff volume managed by installed green
  infrastructure  practices, and/or the extent of the service area where rainwater drains to a green infrastructure
  control measure.
• Measure and report on flows to, through, or from the sewer system in different-sized rain events to  quantify the flows
  that are kept out of the system  by green infrastructure practices.
• Monitor and report on a sampling of green infrastructure practices, where they adhere to standard  community
  designs, to gauge performance.
• Using performance data from a sampling of green infrastructure installations, periodically model and report on
  annual discharges from the sewer system (e.g., CSO volume or pollutant loadings).
• Track and report on operation and maintenance (O&M) activities for all green infrastructure installations.

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GREEN INFRASTRUCTURE PERMITTING AND ENFORCEMENT SERIES: FACTSMEET 1
  5) Enforceable Mechanisms for Operations and  Maintenance
  Operation and maintenance (O&M) are critical to ensure
  the continuing effectiveness of any suite of controls,
  including green infrastructure. For green and grey
  infrastructure components, O&M plans and schedules
  should be established, and accountability measures should
  be included to assure that necessary O&M is carried out.
  In some cases, the green infrastructure may be located on
  private property. It is necessary to establish a provision(s)
  to assure responsibility and accountability for the O&M.
  This typically includes:
  •   Requirements in codes and ordinances for private prop-
     erty owners to  inspect and maintain practices, with pro-
     visions for fines or cost recovery should this not occur;
  •   Maintenance agreements with similar elements;
  •   An inspection program, which could include private
     property owner responsibility for 3rd party inspection
     with subsequent reporting to the municipality; and/or
     a municipal inspection program that prioritizes certain
     practices for periodic inspections;
  •   Development of a municipally-operated tracking system
     to document locations and types of practices, the party
     responsible fortheir maintenance, maintenance reports,
     and maintenance needs, as appropriate.

  Most green infrastructure programs will also make
  significant investment in publicly owned and operated
  systems. In these cases, O&M planning must include:
  •   The development of protocols and schedules for
     different types of green infrastructure practices (e.g.,
     the frequency with which curb extension bioretention
     cells need to be inspected, and their maintenance
     needs, such as weeding or plant replacement);
  •   Identification of which municipal department(s) will
     conduct or oversee O&M;
  •   Development of a tracking system to ensure all elements
     of the O&M program are fulfilled and documented;
•  Establishment of a reliable source of funding for
   ongoing O&M.

O&M requirements often vary among sites or projects.
Therefore, it is importantthatthe permit or enforcement
document make clear what will constitute non-compliance.
Maintenance  needs may vary notably depending on
soils, seasonal or annual climate conditions, land use,
and other factors. After initial vegetation establishment,
many practices need little or no  maintenance to function
properly. Alternatively, due to a site-specific event, a given
practice may need additional attention to establish or
restore proper function.
Example language that could be  used in a permit or
enforcement action:
   "Maintenance. The Sewer District will establish
   a database to manage information on all green
   infrastructure practices (e.g., green roofs, rain
   gardens, constructed wetlands) put in place
   pursuant to this Order/Consent Decree. The
   Sewer District will enter into the database
   GPS coordinates for the practices and as-built
   information. For each practice, the Sewer District
   will also identify maintenance activities for
   the practice and schedules for maintenance.
   The Sewer District will use the database to
   schedule/track maintenance activities and assure
   maintenance is performed.  Documentation such
   as inspection reports or records relating to
   maintenance conducted shall be maintained in the
   database or linked to from the database."
  6) Modification Provisions

  Permits and enforcement orders typically include
  modification provisions to deal with performance
  issues or unexpected occurrences. Such modification
  provisions should be included in permits or enforcement
  orders focused on grey infrastructure solutions, green
  infrastructure solutions, or a combination. In permits, this
  may be accomplished through use of the standard NPDES
  modification provision in 40 CFR 122.62. Enforcement orders
also should include an evaluation and revision process.
That is, if the compliance requirements are not met,
after sufficient compliance testing has been performed
and despite performance of the required projects, the
government should retain authority underthe decree or
orderto require additional compliance measures.

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

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