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An association representing municipal wastewater treatment agencies and two other groups have asked the Environmental Protection Agency to withdraw a memorandum that recommends changes in EPA's stormwater program, including the use of numeric water quality-based effluent limits in permits for stormwater discharges.
Because the memo addresses “a critically important issue” for municipalities, it should be withdrawn and a decision made on how to proceed after EPA proposes its planned stormwater rule, Nathan Gardner-Andrews, general counsel of the National Association of Clean Water Agencies (NACWA), told BNA May 24.
In requesting withdrawal, the groups--NACWA, the American Public Works Association, and the National Association of Flood & Stormwater Management Agencies--expressed strong concerns about the substance and timing of the November 2010 internal memo, which was sent to EPA regional water directors (41 ER 2690, 12/3/10)).
In an e-mail to BNA May 24, EPA said it “is currently reviewing the comments for our November 12 Stormwater Memorandum and is unable to provide additional details until that review is complete. The Agency plans to make a decision by August 15, 2011, to either retain the memorandum without change, to reissue it with revisions, or to withdraw it.”
EPA's November 2010 memorandum, Establishing Total Maximum Daily Load (TMDL) Waste Load Allocations (WLAs) for Storm Water and [National Pollutant Discharge Elimination System] Permit Requirements Based on Those (WLAs), significantly revises a stormwater memorandum issued by the agency in 2002.
In 2002, EPA said it expected most water quality-based effluent limitations for National Pollutant Discharge Elimination System (NPDES)-regulated municipal and small construction stormwater discharges to be in the form of best practices and that “numeric limitations will be used only in rare instances.”
EPA separately is developing a major rule on stormwater from post-construction and redevelopment that is expected to set numeric limits for pollution and include requirements for green infrastructure. The rule is expected to be proposed in September and finalized in late 2012.
In a letter sent to EPA on May 12, NACWA, along with the American Public Works Association and the National Association of Flood & Stormwater Management Agencies, questioned EPA's accuracy in asserting that more than 30 states are using some type of numeric effluent limits on stormwater discharges, Gardner-Andrews said. The trade groups also raised the issue during an April meeting with agency staff, he said.
In their letter, the groups asked EPA to provide a list of those states, information on these permitting approaches, and whether those states have strict numeric limits or benchmarks.
The letter questioned EPA's assertion in its March request for comments that it had found “the use of numeric effluent limitations no longer is a novel or unique approach in stormwater permitting” (42 ER 644, 3/25/11).
“We have serious questions about the accuracy of this assertion, and whether the agency is failing to take into account the fundamental legal and practical distinctions that must be drawn between the use of numeric 'effluent limitations' on the one hand, and numeric 'benchmarks,' 'triggers,' or 'measurable goals' on the other,” the letter said.
Because of these questions, “we cannot provide meaningful comment” on the premise of the memorandum, the letter said.
State water pollution control officials also expressed concerns about the memorandum in comments submitted May 16, but while they seek revisions, they are not calling for its withdrawal.
In comments submitted May 16, the Association of State and Interstate Water Pollution Control Administrators (ASIWPCA) said establishing numeric limits for stormwater discharges can sometimes require a complex, costly analysis--an approach that “may not be possible in many watersheds.”
While there is some variation among states regarding the approaches they use for limiting stormwater runoff and other stormwater issues, “there is complete consensus that states be allowed to maximize the flexibility when making their determinations,” ASIWPCA said.
“EPA's memorandum presents implementation challenges for many states. For example, most TMDLs do not include site-specific stormwater Best Management Practices. Likewise, numeric stormwater effluent limitations are not always feasible, and may in fact be unnecessary to meet water quality goals,” the letter said.
In its November memorandum, EPA said that since 2002, states and EPA have obtained considerable experience in developing total maximum daily loads and waste-load allocations that address stormwater sources. “Where feasible,” the NPDES permitting authority should exercise its discretion to translate waste-load allocations into numeric effluent limitations in stormwater permits to meet water quality standards, the memo said.
A TMDL is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that load among the various sources of that pollutant.
Alexandra Dunn, ASIWPCA executive director and general counsel, told BNA May 24 that ASIWPCA has not calculated the number of states that have numeric effluent limits for municipal separate storm sewer systems (MS4s), industrial wastewater, and construction stormwater. While more than 30 states might have such limits, Dunn said she suspects the majority of these represent new programs and efforts “that really have not been proven over time.” She said establishing limits would require more precise, accurate data than many states have.
Although significant advances have been made in quantifying pollutants in stormwater, ASIWPCA said the vast majority of TMDLs developed and adopted by states contain estimated rather than precise stormwater loading calculations.
The association said a revised memorandum should include EPA plans to develop opportunities and resources for states, sewer authorities, and municipalities to develop alternative watershed remediation plans where impairment is wholly driven by nonpoint sources.
In addition, ASIWPCA recommended that EPA connect by reference the revised memorandum to the ongoing stormwater rulemaking. Earlier this year, state and municipal officials weighed in on the planned proposed rule in letters to EPA (42 ER 233, 2/4/11).
By Linda Roeder
The letter to EPA from the National Association of Clean Water Agencies, the American Public Works Association, and the National Association of Flood & Stormwater Management Agencies is available at http://op.bna.com/env.nsf/r?Open=smiy-8h72jr .
The comment letter to EPA from the Association of State and Interstate Water Pollution Control Administrators is available http://op.bna.com/env.nsf/r?Open=smiy-8h7txq .
EPA's November 12, 2010, memo recommending numeric limits for stormwater pollutants is available at http://op.bna.com/env.nsf/r?Open=jsun-8bhqay .
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