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EPA’s Stormwater Rulemaking: How Potential Changes in the NPDES Stormwater Regulations Could Impact the Design of Stormwater Controls
Rachel HerbertUSEPA/OW/OWM/WPD
forAASHTO Subcommittee on Design Meeting
Purpose of Today’s Discussion
Construction & Development Effluent Limitation Guidelines
www.epa.gov/guide/construction
New Stormwater Regulationswww.epa.gov/npdes/stormwater/rulemaking
Overview of Construction & Development Effluent Limitation Guideline (C&D ELG)General Overview of RequirementsErosion & Sedimentation RequirementsSampling RequirementsOther Requirements
General C&D ELG RequirementsEPA promulgated new regulations for construction and
development (C&D) sites on December 1, 2009. New rule requires all construction sites subject to permits to implement erosion and sediment controls and pollution prevention measures
Phase-in requirement for sites to sample stormwater discharges and comply with a numeric effluent limitation (NEL) of 280 nephelometric turbidity units (NTU).Beginning August 1, 2011 sites disturbing 20+ acres at onceBeginning February 2, 2014 sites disturbing 10 acres at once
Requirements must be incorporated into state permits (general or individual) whenever permits are re-issued
EPA intends to issue a new CGP in June 2011
Erosion and Sedimentation RequirementsControl stormwater volume and velocity within
the site to minimize soil erosion;Control stormwater discharges to minimize
erosion at outlets and downstream channel and streambank erosion;
Minimize the amount of soil exposed during construction activity;
Minimize the disturbance of steep slopes;Design, install and maintain erosion and sediment controls considering factors
such as precipitation and soil characteristics;Provide and maintain natural buffers around surface waters, direct stormwater
to vegetated areas to increase sediment removal and maximize stormwater infiltration, unless infeasible; and
Minimize soil compaction and, unless infeasible, preserve topsoil.
Sampling Requirements280 NTU Limitation does not apply on days with
precipitation exceeds the local 2-year, 24-hour storm event
Monitoring frequency is up to the permitting authority, but EPA recommends at least 3 grab samples per day at each discharge point
EPA has not specified any analytical methods, but envisions that use of a properly calibrated field turbidity meter is adequate
For linear projects, permitting authority can consider representative sampling instead of sampling at each discharge point
Even if permitting authority allows representative sampling, all discharge points are still subject to compliance with effluent limitation
Permitting authority will specify data reporting requirements
Other RequirementsSoil Stabilization & Dewatering Requirements
Initiate stabilization of disturbed areas immediately whenever any clearing, grading, excavating or other earth
disturbing activities have permanently ceased, when earth disturbing activities have temporarily ceased
and will not resume for a period exceeding 14 calendar days.
Where vegetative stabilization is infeasible, alternative stabilization measures must be employed.
Pollution Prevention Requirements
Prohibited Discharges
Overview of New RulemakingBackground on the Federal
Stormwater ProgramStormwater ChallengesThe National Research Council (NRC)
ReportEPA has initiated a rulemaking to
improve its stormwater program.Stormwater Rulemaking SchedulePreliminary Considerations for
Rulemaking
Federal Stormwater Regulations
Phase I Phase II
Year Finalized 1990 1999
Regulated Entities
Medium & large MS4s Small MS4s in an “urbanized area” (UA)
10 categories of industrial operations
Additional designated MS4s outside of UAs
Active construction sites of 5 acres or more
Active construction sites disturbing between 1 and 5 acres
Federal Stormwater Regulations (cont’d)Phase I Phase II
MS4 Stormwater Management Program (SWMP) Requirements
MS4 must develop and implement a SWMP to:
• find and eliminate illicit discharges
• control discharges from its system by addressing discharges from active construction sites, new development and redevelopment, and industrial activities
MS4 must develop and implement a SWMP that includes 6 minimum measures:
• Public education & outreach• Public participation/ involvement• Illicit discharge detection & elimination• Construction site runoff control• Post-Construction site runoff control• Pollution prevention/ good housekeeping
Federal Stormwater Regulations (cont’d)
Phase I Phase II
Stormwater Pollution Prevention Plan (SWPPP) Requirements
Construction & industrial stormwater dischargers must develop and implement a SWPPP
N/A
Stormwater Challenges
• Urban stormwater is the primary source of water quality impairment:13% of all rivers and streams18% of all lakes32% of all estuaries
Much progress has been made; however, significant challenges remain to protect waterbodies from impact of stormwater discharges
The National Research Council (NRC) ReportIn 2006 EPA commissioned the National Research Council (NRC) to study
EPA’s stormwater program
In October 2008 NRC released Urban Stormwater Management in the United States, available at: www.epa.gov/npdes/stormwater
Key FindingsCurrent approach is unlikely to produce an accurate picture of the
problem and unlikely to adequately control stormwater’s contribution to waterbody impairment
Requirements leave a great deal of discretion to dischargers to set their own standards and ensure compliance, which results in inconsistency across the nation
Poor accountability and uncertain effectiveness
Key Recommendations in the NRC Report“A straightforward way to regulate stormwater
contributions to waterbody impairment would be to use flow or a surrogate, like impervious cover, as a measure of stormwater loading ….”
“Efforts to reduce stormwater flow will automatically achieve reductions in pollutant loading. Moreover, flow is itself responsible for additional erosion and sedimentation that adversely impacts surface water quality.”
“Stormwater control measures that harvest, infiltrate, and evapotranspirate stormwater are critical to reducing the volume and pollutant loading of small storms.”
US Department of Transportation Headquarters
Washington, DC
Turkeyville, MI Rest Area 722
Stormwater Rulemaking SchedulePrimary impetus: to protect waterbodies
from the stormwater impact of urbanization
Completed Activities:
October 30, 2009: Federal Register (FR) Notice announcing EPA’s intent to distribute questionnaires (Information Collection Request (ICR) seeking data to inform the rulemaking from three groups:Owners, operators, developers, and contractors of developed sitesOwners of Municipal Separate Storm Sewer Systems (MS4s)States and territories
January – March 2010: Listening Sessions input on preliminary rulemaking considerations (FR Notice published Dec. 28, 2009)
May 2010: EPA published a final FR ICR Notice
Stormwater Rulemaking Schedule (Cont’d)
Upcoming Activities:
Summer 2010: EPA expects to distribute the questionnaires
Late 2011: EPA expects to propose a rule to be published in the FR for public comment
Late 2012: EPA expects to take final action
Preliminary Considerations for Rulemaking
1. Expand the universe of regulated discharges beyond urbanized area
2. Establish substantive post-construction requirements for new and redevelopment
3. Develop a single set of consistent requirements for all MS4s, in place of existing “Phase I” and “Phase II” rules
4. Address stormwater discharges from existing development through retrofitting
5. Consider additional requirements to further reduce stormwater impacts in the Chesapeake Bay
NOTE: No decisions have been made on any of the items discussed from this slide forward.
1. Expand the universe of regulated discharges beyond urbanized area:Depiction of Current MS4 Roadway Regulation
Area B (not a regulated MS4)
Area C(regulated MS4)
Area A(regulated MS4)
Regulated MS4 areaKey
NOTE: Disturbances of ≥ 1 acre are required to comply with NPDES construction requirements, even If outside the urbanized area.
1. Expand the universe of regulated discharges beyond urbanized area • What is the best way to expand the universe of regulated discharges
beyond Urbanized Area?
• Is there an appropriate boundary for permit coverage if not based on the current definition of Urbanized Area?
• What criteria could be used to identify areas?
• Should States decide the areas to include?
2. Establish substantive post-construction requirements for new and redevelopmentDevelop a standard that promotes sustainable practices that
mimic natural processes to infiltrate and recharge, evapotranspire, and/or harvest and reuse precipitation.
Should there be a national requirement for on-site stormwater controls such that post development hydrology must mimic pre-development hydrology on a site-specific basis?
Options for meeting the requirement could be: on-site retention of specific sized storm, limits on amount of effective impervious area, use of site-specific calculators to determine predevelopment hydrology, and/or use of regional standards to reflect local circumstances.
Options if standard could not be met: off-site mitigation, payment in lieu, others?
Should the standards be different for new development vs. redevelopment?
3. Develop a single set of consistent requirements for all regulated MS4sMany Phase I & II MS4s address issues that are similar, but the regulatory requirements are different.
Should DOTs have different requirements than traditional MS4s?
What requirements should EPA apply to DOTs? Should EPA apply all of the 6 minimum measures to DOTs? Are there other measures that would achieve better water quality, like more emphasis on source control?
Phase I MS4s are required to implement a program to control discharges from industrial facilities. Should this requirement be extended to all MS4s?
4. Addressing stormwater discharges from existing development
Stormwater discharges from developed areas are significant contributors to water quality impairments; some MS4
permits require retrofit practices that infiltrate or retain stormwater.
Should EPA consider retrofit requirements, such as:Development of a retrofit plan? Implementation of a retrofit plan?Should any requirements apply only to large
MS4s?Should any requirements apply only to water
quality impaired waters?
5. Consider additional requirements to further reduce stormwater impacts in the Chesapeake Bay
What additional requirements should EPA consider to protect the Chesapeake Bay?Buffer requirements?Additional requirements on active construction?Further extending area of coverage?
Should these provisions be applied to other sensitive areas?
