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Wet Weather Issues

EPA's Stormwater Phase II Advisory Subcommittee Discussions

Background: EPA is continuing a stormwater Phase II national policy dialogue with stakeholders through federal advisory committee meetings. AMSA has been actively involved in the Subcommittee which is expected to eventually guide EPA in proposed stormwater phase II rulemaking activities.

Status: EPA's proposed Phase II stormwater rule is currently under review by the White House's Office of Management and Budget (OMB). EPA was granted an 3-month extension to publish the proposed Stormwater Phase II rule which is now scheduled for publication by November 25, 1997. The final rule deadline has not been extended and remains as a court-ordered deadline of March 1999. The next meeting of EPA's Advisory Committee is scheduled for October 6-7, 1997. CONTACT: Mark Hoeke, AMSA 202/833-9106, or George Utting, EPA 202/260-9530.

Sanitary Sewer Overflow (SSO) Policy Framework

Background: EPA is continuing a SSO policy dialogue with stakeholders through federal advisory committee meetings. AMSA has been actively involved in the Subcommittee discussions, which are expected to eventually guide EPA in policy-making activities regarding a sanitary sewer overflow policy or regulatory framework.

Status: Efforts at EPA are continuing to resolve internal headquarters and regional differences on proposed SSO policies developed by EPA's SSO Advisory Committee. In a recent transmittal to EPA, AMSA and other municipal interests of the EPA SSO Advisory Committee expressed strong sentiments for a national SSO policy which includes relief from liability for those SSOs which have been defined as "unavoidable." One of the major sticking points in headquarters and regional staff discussions, is the issue of boilerplate "affirmative defense" permit language which is intended to give permittees liability relief for those SSO events which are beyond the reasonable control of the operator. Regional EPA enforcement officials strongly believe that a national policy should not compromise EPA's latitude to enforce against any and all SSOs, and believe that "regulatory reasonableness" can be attained through enforcement discretion and through nonregulatory, nonbinding guidance that defines the boundaries of the SSO program. In its August 12 comments, AMSA and other operators expressly oppose any approach that does not faithfully parallel the discussions within the Federal Advisory Committee, which have supported a regulatory change to 40 CFR Part 122 to include boilerplate affirmative defense language. The group asserts that "not providing for an affirmative defense sets up an unattainable and unreasonable expectation among the public and regulatory staff that SSOs can be eliminated" and that "operators need a clear and technically valid shield from ill-informed and invalid enforcement and third-party actions." Results of the internal EPA discussions, and whether EPA will address operator concerns regarding affirmative defense will soon be known, as EPA plans to release its "blueprint" for the national policy to the Regions and states. The "blueprint" will include an outline for an interim permitting approach on SSOs and proposed regulatory changes. Subsequently, more detailed policy language will be issued to Regions, states, and stakeholder groups for review prior to the next meeting of EPA's Federal Advisory Committee, which is now expected to be held sometime in late 1997. CONTACT: Kevin Weiss, EPA 202/260-9524, or Mark Hoeke, AMSA 202/833-9106.

Sanitary Sewer Overflow (SSO) Policy Cost Analysis

Background: In June 1997, EPA released a draft cost/benefit analysis for different scenarios of proposed SSO policy and regulatory revisions. EPA solicited comment on the draft document which includes a discussion of sanitary sewer operating characteristics, a discussion of causes and abatement of SSOs, a description of the cost model and model inputs, and resulting output of model runs. The National Office solicited member comments on the draft cost analysis via a June 18, 1997 Regulatory Alert RA 97-14. The document describes model inputs, and discusses cost model development of various SSO mitigation alternatives, including flow equalization storage, increased wet weather capacity, sanitary sewer system rehabilitation, as well as unit cost estimates for operation and maintenance. Seventeen case studies were used to calibrate the cost models. In addition to providing input on EPA's cost model methodology and assumptions used, members are encouraged to provide additional data to help calibrate EPA's final model.

Status: On August 14, AMSA and the National League of Cities (NLC) jointly submitted concerns regarding EPA's draft cost analysis for the proposed national SSO Policy. In a detailed technical analysis, AMSA and NLC felt that the draft cost analysis significantly underestimates the incremental costs resulting from the implementation of a National SSO Policy as presented, mostly due to an inappropriate selection of current baseline and compliance end-point controls. Baselines of a two-year storm and five-year storm rainfall event scenarios were used to take into account compliance levels and outcomes by NPDES authorities in absence of a National policy. A ten-year storm was selected as the result of an aggressive national SSO abatement policy. AMSA argues that many communities experience SSO rates that are up to 50 or more times greater than baseline, and that it would be more appropriate for EPA to select current conditions as baseline, and select target performance levels of two- or five-year storms when developing the cost model. However, AMSA also points out that if alternatives, such as the watershed approach, were seriously implemented and allowed in a national SSO policy, costs of a national SSO abatement could be significantly lower, when compared to strict performance targets. In the comments, AMSA and NLC also had concerns regarding the cost model methodology, calibration, and data, as well as application of the cost/benefit model to individual systems, and lack of emphasis on operation and maintenance costs. EPA plans to revise and reissue the draft cost analysis sometime this fall. CONTACT: Kevin Weiss, EPA 202/260-9524, or Mark Hoeke, AMSA 202/833-9106.

EPA's Urban Wet Weather Flows Advisory Committee Activities

Background: The UWWFAC, chartered in May 1995, is responsible for "developing recommendations to address cross-cutting issues associated with the human health and environmental impacts of urban wet weather discharges (including storm water, combined sewer overflows, and sanitary sewer overflows) in an innovative and cost-effective manner." The UWWFAC is composed of EPA, state regulatory, environmental, municipal government, industrial, business development, and local wastewater agency interest groups. AMSA has been actively involved in the Committee, and its workgroups.

Status: The UWWF advisory committee held its latest and potentially last plenary meeting on July 28-29, 1997. The Committee is expected to continue its work through small workgroups. Below is a summary of current Committee activities. CONTACTS: Mark Hoeke, AMSA 202/833-9106 or Will Hall, EPA 202/260-1458.

Table 2 - UWWFAC Activities



Committee Activities


EPA Action Taken or Expected
Watersheds: Watershed Policy

Water Quality Standards: Wet Weather Standards Recommendations

Watersheds: Monitoring Recommendations

Stormwater: Phase I Reapplication Requirements

Stormwater: Interim Policy on BMPs in Lieu of Numeric Standards

Stormwater: No Exposure Incentive

Stormwater: Expanded General Permit Notice of Intent

Stormwater: Database on BMP Effectiveness

Stormwater: Definition of Maximum Extent Practicable

Stormwater: Phase I Enforcement

Stormwater: Background Sources

Policy (Fall 1997)

Guidance (Fall 1997)

Proposed Rule on WQS

Policy Issued (5/17/96) [RA96-15]
Policy Issued (8/1/96) [RA96-18]

Proposed Rule (Fall 1997)

Proposed Rule (Fall 1997)

Database Availability (1/31/98)

Guidance to be Issued (1/31/98)

Guidance or Policy (9/30/97)

Guidance or Policy (9/30/97)


  • Watershed Policy: The Committee has been working for the past two years to develop a document titled, "A Watershed Alternative for the Management of Wet Weather Flows." The document is intended to express EPA's support for a process of pursuing a watershed approach as an alternative to the traditional NPDES permitting approach for meeting water quality standards through control of individual wet weather point sources, and builds upon EPA's previous watershed-related efforts. Consensus on the watershed alternative was not reached as municipal groups urged EPA to adopt language supporting "proportionate share responsibility" within the document. A small workgroup meeting will be held on Sept. 17 in Washington, D.C. to pursue consensus on the document.

  • Watershed Monitoring Recommendations: These recommendations will supplement the Watershed Alternative document by providing guidance on the development of watershed-based monitoring strategies.

  • Wet Weather Standards Recommendations: Some committee members are uncomfortable with applying national water quality criteria, derived from bioassays based on steady-state exposures, to wet weather conditions, which are characterized by discontinuous exposures. A number of other issues have been raised regarding objectives, the applicability of standards, and how standards should be implemented in wet weather NPDES permits. At the July 28-29, 1997 meeting, the Committee discussed whether EPA should transmit a letter to Regions and States "reminding" them of the CSO policy implementation language that stipulates "development of the long-term plan should be coordinated with the review and appropriate revision of WQS...." EPA has agreed to develop a letter which discusses a broad suite of CSO implementation issues, including review and revision of water quality standards.

  • No Exposure Incentive: The Committee has developed criteria for determining whether an industrial facility has "no exposure" to stormwater under the Phase I stormwater program. These facilities which are defined as having "no exposure" would reduce NPDES permit requirements to a one-time, or annual certification of "no exposure". Industrial interests on the Committee had major concerns with the latest EPA draft. EPA hopes to propose a change to the Phase I regulations in Fall 1997.

  • Expanded General Permit Notice of Intent (NOI) Form: The Committee has developed an expanded industrial NOI form which allows the public to obtain more information on an industrial facility's potential impact on stormwater runoff. EPA expects to have expanded NOI form ready in September 1997, when existing general permits expire.

  • Database of Best Management Practices (BMP) Effectiveness: The Committee is currently tracking progress of a cooperative EPA/ASCE project on the effectiveness of BMPs. Existing literature on stormwater BMPs and performance data are being compiled and compared. Also, software is being developed which will assist future BMP effectiveness research by defining the parameters which need to be assessed when evaluating BMP performance. A beta version of the software should be available in the late Fall 1997.

  • Definition of Maximum Extent Practicable (MEP): The Committee is developing a process by which the term "MEP" can be clarified or defined so that Phase I requirements for MS4s are clear and consistent. EPA expects that it can issue guidance on the definition in January 1998, and has indicated its desire to develop performance standards to quantify MEP in January 1999 (see discussion of performance standards in Phase II Stormwater Committee). During the January 1997 meeting, the Committee discussed several outcomes of the Committee's MEP workgroup. Significant areas of agreement were reached on several issues, including: 1) MEP is viewed as the technology standard (rather than a technology-based standard); 2) MEP should be viewed as a "process" and not so much as an endpoint (i.e., numeric effluent limitations); 3) MEP is one way to get to water quality attainment, which is the ultimate goal; 4) MEP is a minimum performance requirement for municipalities under CWA ยง402(p); 5) EPA should put out guidance along these lines, to help permit writers and permittees, and, 6) the MEP process should be applicable to Phase II communities. Continued work on MEP is scheduled for Fall 1997.

  • Background Sources: The Committee is discussing issues concerning background sources of pollution (i.e., air deposition and run-on) that may contribute to point source stormwater discharges and/or contribute to point source discharge violations. The Committee may eventually recommend a permitting policy to EPA.

    AMSA to Conduct CSO Permit Negotiation Workshop

    AMSA will sponsor a one and a half day workshop this fall designed to assist publicly owned treatment works (POTWs) with the negotiation of combined sewer overflow (CSO) permits. The AMSA CSO Permit Negotiation Workshop, to be held Sept. 25-26, 1997, in Cincinnati, Ohio, will allow AMSA members to share information and experiences regarding the CSO permitting process. The workshop will allow POTWs that have completed permitting negotiations to assist other agencies with the varying interpretations of the policy through case study examples and general tips. The workshop agenda is currently under development by AMSA staff and members of the Association's Wet Weather Issues Committee. The workshop is scheduled to begin with an overview of CSO policy, with an emphasis on what the "CSO policy is and what it is not." The overview will be followed by an update on the status of national implementation, with an examination of permits that have been issued, enforcement activities, compliance with the nine minimum controls and performance plans. An overview of the permitting process will focus on the planning, scope and implementation of long-term control plans with an emphasis on meeting both technology and water quality-based requirements. Sessions on monitoring will characterize CSO impacts and the efficacy of CSO controls, and look at long-term compliance with water quality standards. Other sessions will provide an in-depth examination of compliance with water quality standards, negotiated permitted bypasses, implementation of nine minimum controls and enforcement. An advanced notice of the workshop, and accompanying draft agenda was forwarded to the membership via Member Update, MU 97-14. CONTACT: Mark Hoeke, AMSA 202/833-9106.