Mike Mitchell U.S. EPA Region 4

Transcription

1 Mike Mitchell U.S. EPA Region 4

2 Urban stormwater is a leading source of water quality impairment Urban stormwater identified as source of impairment (2004 WQ Report) 22,559 miles of impaired rivers and streams 701,024 acres of impaired lakes 867 square miles of impaired estuaries Stormwater pollutants Sediments, nutrients, metals, temperature, trash, bacteria Cause beach closures and swimming illnesses Impact fisheries and shellfish harvesting Increase the costs of treating drinking water supplies Hydrologic impacts Increased stormwater volume can cause flooding, scouring and sewer overflows Reduce groundwater recharge 2

3 Stormwater is a growing water quality concern ~800,000 acres being developed every year, growing to ~1.2 million acres by 2040 Development increases the amount of impervious cover in the landscape Currently 100 million acres developed; 25% is impervious Discharge from 1 acre of impervious cover is 16x the discharge from a 1 acre of undeveloped land Small increase in impervious cover leads to big impacts in receiving waters Watersheds with <1-2% of impervious land area = biological impacts to surface waters Watersheds with >5-15% of impervious land area = surface water declines rapidly to degraded levels, loss of function; Loss in base flow in streams and groundwater recharge 3

4 Smarter Stormwater Management Traditional approach Convey stormwater quickly from site to MS4 system, detention pond or directly to waterbody. Manage peak flows for flood control, drainage and large scale downstream erosion. New approach Integrate green infrastructure in the design of the project View stormwater as a resource. Slow down the flow, allow to infiltrate. Reduces pollutant loads to waterbodies. Obtain multiple community benefits. 4

5 Green Infrastructure Approaches Infiltration - Evapotranspiration - Capture & Use Reduce impervious cover in parking & street designs Bioretention/rain gardens Permeable pavements Green roofs Cisterns & rain barrels Trees & expanded tree boxes Reforestation & restoration 5

6 Current MS4 Program Regulated Entities Medium and Large MS4s > 100,000 pop. Small MS4s in urbanized areas Map of current coverage (green) Primarily in urbanized area Accounts for much of the population Only 2% of the land area MS4 Permit Requirements Public Education & Outreach Public Participation Illicit Discharge Detection and Elimination Pollution Prevention/Good Housekeeping Active Construction Program Post construction program for new development and redevelopment sites 1 acre General requirement No performance standards required 6

7 Current Post Construction Requirements Under NPDES The Phase II Rule sets the goal that BMPs chosen should "attempt to maintain predevelopment runoff conditions." Identification of low impact development opportunities to reduce stormwater volume and velocity EISA 438 Guidance 7

8 Phase II Requirement for Post Construction 40 CFR (b)(5): 5) Post-construction stormwater management in new development and redevelopment. (i) You must develop, implement, and enforce a program to address stormwater runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale, that discharge into your small MS4. Your program must ensure that controls are in place that would prevent or minimize water quality impacts. (ii) You must: (A) Develop and implement strategies which include a combination of structural and/or non-structural best management practices (BMPs) appropriate for your community; (B) Use an ordinance or other regulatory mechanism to address post-construction runoff from new development and redevelopment projects to the extent allowable under State, Tribal or local law; and (C) Ensure adequate long-term operation and maintenance of BMPs. 8

9 Goals of Permit Language Recognize the environmental performance of different development strategies in postconstruction requirements Create model permit language that pushes the envelope Provide information/guidance from the state to the MS4 level 9

10 Underlying Principles NPDES Stormwater and Green Infrastructure Green Infrastructure to be the foundation for a state s NPDES stormwater management program Recognize that some development patterns have better environmental performance, e.g., redevelopment Use of an iterative approach to permitting, e.g., each permit cycle builds off gains made in the previous permit cycle 10

11 Expanding the Iterative Approach MEP standard Maximum Extent Practicable Technically feasible cost-effectiveness environmental benefit 11

12 Post-Construction Planning An effective post-construction plan will: Include a pre-and post-development hydrologic analysis Identify low impact development opportunities Identify pollutants of concern Identify pollution prevention measures Identify controls that provide treatment and reduce stormwater volume and velocity Provide for long-term operation and maintenance of controls Provide for plan review, inspection, and enforcement 12

13 2009 NRC Report: Urban Stormwater Management in the U.S. Current approach 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 ensure compliance A more 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. 13

14 Key Elements of the Proposed Rule 1. Establish performance standards for discharges from newly developed and redeveloped sites. 2. Require certain regulated MS4s to develop a program to address discharges from existing sites (retrofits). 3. Extend protection of MS4 Program. 14

15 Element 1: Performance Standards Why What Who When How Where Why: New and redevelopment presents an opportunity for stormwater management practices at sites to be designed in a way that protects water quality. Retention of small storms onsite mimics natural hydrology and results in a reduction in pollutants leaving the site, erosion of the receiving waterbody, local flooding and many other benefits. The standard will promote cost effective methods to protect water quality.

16 Element 1: Performance Standards Why What Who When How Where What: - Performance standard could require that newly developed and redeveloped sites of a certain size must retain stormwater discharges resulting from small storms. - Small storms could be defined as a percentile storm event. - Rule could allow site-specific hydrologic analysis, however a minimum standard may be necessary to reduce pollutant loading. Rainfall Frequency Spectrum for Minneapolis, MN. Center for Watershed Protection, 2008

17 Element 1: Performance Standards Why What Who When How Where How: The standard could be met by reducing impervious cover and/or installation of stormwater controls which infiltrate, evapotranspire and harvest and use the rain water. Proper operation and maintenance must be ensured. Standard could accommodate site constraints: volume that cannot be retained on site could be managed through treatment, off-site mitigation in the same subwatershed or payment in lieu. Site constraints could include water rights laws. Pervious Paver Parking Stalls, Redlands, CA. Photo courtesy of Jeff Endicott.

18 Current Volumetric Retention Standards for Discharges from New Development EPA rule could allow much flexibility for states with existing standards. How should EPA evaluate state standards that are as protective as a national standard? State or Locality (date enacted) Size Threshold Standard California 1 acre LID BMPs designed to retain runoff from 24-hour 85 th percentile storm event Montana (2009) 1 acre Infiltrate, evapotranspire, or capture for reuse runoff from first 0.5 of rain Wisconsin (2010) 1 acre Infiltrate runoff to achieve 60% -90% of predevelopment volume based on impervious cover level West Virginia (2009) 1 acre Keep and manage on site 1 rainfall from 24-hour storm preceded by 48 hours of no rain Denver, CO 1 acre Manage excess urban runoff volume (approximately 1 inch for Denver) 18

19 Element 1: Performance Standards Why What Who When How Where Where: The standard could be applied to newly developed and redeveloped sites nationwide or only those sites discharging to regulated MS4s. Applying the standard nationwide would create a level playing field for developers among municipalities and protect downstream communities from upstream development. District of Columbia Metro Area Urbanized Area Map US Census 2000 (red hatched)

20 Element 1: Performance Standards Why What Who When How Where Who: All types of construction projects including residential, commercial, industrial, and institutional. Owner of a construction project which meets the site size threshold. Current site size threshold in the MS4 program is projects which disturb one acre or more; or less than one acre if the project is part of a greater plan of development. Responsibility for proper operation and maintenance transfers to new owners of a property. When: Stormwater discharges after construction is complete. Cost effective ways to meet the standard Incorporate controls in the site design by preserving vegetation, reducing impervious cover Integrate green infrastructure practices into landscape or other areas which would manage the specified volume in the standard. Begin Site Design File Notice of Intent Active Construction File Notice of Termination Standard applies to discharges from the site Project Timeline

21 Element 1: Performance Standards Discharges from Redeveloped Sites Recommend lower standard for redevelopment Recognize site constraints To encourage redevelopment to revitalize urban communities Considering additional incentives for smart growth and brownfields development LA Infiltration Planters. Photo courtesy of Bill DePoto. 21

22 How have developers responded to post construction standards in GA? What percentage of developers changed their site design to reduce impervious cover (ex. narrower streets, cluster design, short setbacks) to meet the standard in Georgia? What percentage of developers implement stormwater controls (ex. bioinfiltration, green roofs, pervious pavement) to meet the standard in Georgia? What is the correct combination of reduced impervious cover and structural controls to assume? Have municipalities in Georgia changed codes and ordinances to allow developers to implement narrower streets or smaller parking lots? Studies show increase in property value in residential development with narrower streets and LID. Are these results typical? Are there locations in Georgia we can study? How has smaller parking lots or LID impacted commercial properties? Are there locations in Georgia that we can study? 22

23 Element 2: Municipal Program to Manage Discharges from Existing Sites (Retrofits) Address existing degradation from existing sites and help restore urban waters Proposed approach could require certain regulated municipalities to: Identify long term goals, highest priority projects and milestones Integrate green infrastructure into projects cities are already doing Implemented through an iterative approach as part of stormwater management plan Could Apply to: Regulated MS4s serving 100,000 population or greater Regulated MS4s serving 50,000 population or greater Could allow exemptions where MS4 discharges do not cause or contribute to violations of water quality standards 23

24 Retrofit Projects Vacant Land Program BEFORE AFTER Curb Extension Green Roofs Downspout Disconnection 24

25 Element 3: Extending the Protection of the MS4 Program Helps ensure standards are properly implemented which could reduce need for expensive retrofits later Builds on existing framework of local oversight Implements 6 minimum measures which help prevent contamination Options 1. Urbanized clusters as defined by Census (density of 1,000 people/mi 2 ) Reaches unregulated densely populated areas Could specify a population threshold 2. Small watershed (HUC 12) which overlap with urbanized area Reaches areas of high growth Promotes watershed approaches Could specify a population threshold 25

26 Element 3: Extending the Protection of the MS4 Program to All Principal Arterial Roads Federal Highway Administration Category: roads which connect urbanized areas with more than 50,000 people and urban areas 61% of principal arterials are currently regulated Rulemaking could extend the MS4 program to the remaining 39% of principal arterials 12 states currently apply the MS4 program to all state-owned roads Arizona, California, DC, Illinois, Michigan, Nevada, New Jersey, New Mexico, North Carolina, Oregon, South Carolina, Tennessee, Utah

27 Industrial Program Replace the SIC code system with the NAICS system to modernize the identification of industrial discharges covered by NPDES stormwater regulations. Government-owned maintenance yards 1990 rule included the SIC Code covering maintenance yards Government-owned maintenance yards are listed under a administrative SIC code, which unintentionally excluded them from regulation Rule could propose including these facilities as an industrial discharger 27

28 Rulemaking Website 28

29 Current Status Rulemaking Update EPA and the Chesapeake Bay Foundation are currently in negotiation to determine a new schedule for proposal of the stormwater rulemaking and for taking final action. EPA is continuing work on developing the proposed stormwater rule. The rulemaking schedule has been delayed to provide EPA additional time to develop its benefits and cost analyses. Important to note : There has not been a major change in the rulemaking considerations: performance standard for new/redevelopment, MS4 expansion, retrofits, principal arterials and maintenance yards. It is important for EPA to continue to get feedback on these ideas until proposal. 29

30 Other EPA Activities MS4 Program Developing summaries of current stormwater program activities that MS4s are performing Construction Program EPA finalized its Construction General Permit (CGP) in February 2012 Updates will be made to existing documents and tools Construction & Development Effluent Limitation Guideline federal register notice requesting additional data and information 30

31 Other EPA Activities (Cont d) Industrial Program Begin updating the EPA s Multi-Sector General Permit (MSGP) for industrial stormwater discharges (the current permit expires 9/29/13) Green Infrastructure Continuing to work on community partner efforts Available Grants Sustainable Communities Partnership Urban Waters (Proposals due 1/23/12) 31

32 Questions & Answers 32