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Mayors Convene to Review EPA Enforcement on Combined, Sanitary Sewer Overflows

By Rich Anderson
March 8, 2010

The Mayors Water Council met in Washington (DC) on February 24 to review and discuss enforcement and legal actions taken by the US EPA with local government in several principal cities. In 2004, EPA reported to Congress that 746 communities with combined sewer and stormwater systems experienced overflows (Combined Sewer Overflows - CSOs) resulting in an estimated 850 billion gallons of untreated wastewater and stormwater releases. The EPA estimates three to ten billion gallons a year of untreated releases come from Sanitary Sewer Overflows (SSOs). The overflows pose a potential for damage to water quality, ecosystems, and public health. EPA has exercised its authority under the Clean Water Act to reduce overflows to meet water quality standards, and has taken legal action against many cities to develop enforceable plans to do so. Akron (OH) Mayor Donald L. Plusquellic has praised EPA’s history of achieving national clean water goals; but more recently Akron, and many other cities, are facing CSO/SSO enforcement actions that appear to be overly costly, overly prescriptive and beyond the financial capability of local government to implement.

Michael Musgrave, Director of Program Development with MWH, a well-recognized engineering consulting firm, presented comparative information on Consent Decrees (CDs) in four jurisdictions, two of which included Atlanta and Indianapolis. Musgrave, who has extensive program management experience, pointed out that the EPA does not apply a consistent approach in addressing the Combined Sewer Overflow (CSO) issues in the various EPA Regions. The result is a less than optimal engineering solutions for cities, taxpayers and the environment. On the other hand, Musgrave provided a “best practice” example of a more collaborative approach where the EPA and state water regulators have recognized overly prescriptive infrastructure solutions are not in the public’s best interest, and that working more like “partners” than “prosecutors” can yield better solutions that achieve the goal of elimination of overflows. Ultimately, the participating mayors discussed ways to promote the best engineering approaches at the lowest cost resulting in the greatest environmental benefits.


Musgrave stated that Atlanta completed their CSO CD program at a cost of $759 million on a seven-year schedule. The overflow issue now is focused on an SSO program where a critical element is setting the design parameters of the plan for an appropriate storm event. In the case of Atlanta, a two-year storm event is the design criteria for the program. US municipal CDs include different design criteria that may vary by EPA region or by city. The lower wet weather event storm definition can have significant financial ramification to the city’s infrastructure development costs.

From Atlanta’s SSO Consent Decree, another example of a costly EPA requirement that provided questionable environmental benefit was discussed in the area of sewer surcharges. The case in point involves the CD requirement for zero surcharge incidents. A surcharge is sanitary sewer engineering language for effluent normally flowing in an underground conveyance system (pipe) that, when a storm event occurs, exceeds the design capacity of the conveyance system. In normal engineering practice, the excess capacity between the design capacity and the flow capacity is treated as available storage. At no time does sewage in the scenario escape the system. MWH estimates that allowing surcharge that does not result in an overflow could have saved multi-million dollars in the capital investment program.

Region 3

Another opportunity to lower costs and optimize environmental solutions was provided in Region 3. A major northeast city was used as an example where their CD includes completion of their control measures projects on various dates between 2008 and 2010. The design solution was valued at just over $136 million to prevent a 15 million gallon (MG) overflow situation (phase 1 involves 12 MG, two additional phases would reduce 1.5 MG each). The city, however, is geographically located downstream in the same watershed that includes the surrounding county. The county is also subject to a CSO CD enforcement action. It has been noted that the county’s CD includes dates for completion of their projects between 2010 and 2016. Musgrave pointed out that had the EPA considered the timing of the city and county implementation of overflow control measure dates, the city could save millions of dollars on the cost and achieved 100 percent of the environmental benefits.


Musgrave described the situation in Indianapolis as follows:

The city agreed to a CD in 2006 that was amended in 2008. It involves a program with an estimated value of $3.5 billion including its Capital Improvement Program that extends to 2025 for completion. The CD requires capture rate of 97 percent with two overflows annually for the Fall Creek waterway and 95 percent with four overflows for the rest of the affected streams. Indianapolis Mayor Greg Ballard has emphasized the importance of sustainable investments and clean water. He also emphasized the importance of quality of life including keeping sewer rates low to the citizens. Given the extreme cost of the capital investment required in the CD, the city proposed a new amendment that could achieve considerable savings for the same or better environmental benefit. Referred to as an Enhancement Plan, the plan accelerates portions of the plan by capturing an additional seven billion gallons of sewage through 2025 and it addresses 54 CSOs four years earlier than current plan. The Enhancement Plan achieves all of the CD performance criteria. The amendment was submitted in May 2009, but has not yet been accepted by EPA. It is still in the discussion phase. It may be a preferred model in the world of CDs for performance based requirements versus prescriptive design requirements that achieve compliance criteria but are less costly.

Region 9

MWH also provided an example of good collaboration between a Municipal Utility District and the regulators. Unlike the previous three city examples, this case study provided a progressive example of how an EPA region and state water regulators have agreed to work with local government to find an environmentally superior solution with a “right'sized” financial investment. Musgrave stated that Utility District is currently required to achieve primary treatment levels for the wet weather SSO. More recently, the district has been required to apply secondary treatment to the SSO; a very costly requirement.

Rather than pursue an overly prescriptive course of action, the EPA has agreed to a Stipulated Order in the CD to allow three to five years of review and an iterative process of defining optimal engineering solutions to formalize recommendations to determine the best final engineering solutions. During this time, the Utility District will focus on private house laterals immediately in an attempt to reduce a significant volume of water that would require secondary treatment. This approach is logical and allows time to fully understand the issues before requiring an overly costly solution.

Key Considerations to Improve Consent Decrees

Musgrave summarized some characteristics of CSO and SSO consent negotiations that might be helpful in improving the process by reducing costs and still achieving compliance with the elimination of overflows:

  • Time is needed to better define solutions.

  • Prescriptive design language can limit your ability for better engineering and lower costs; more emphasis should be placed on performance and achievement.

  • For SSOs wet weather design parameters can have major cost impacts, and especially the design event is defined in years, (e.g. two-year event vs. five-year event, etc.).

  • Holistic views of watersheds, drainage basins and water quality as well as the timing of capital investments can take advantage of reduced flows in the upstream portions of a watershed can lower costs.

  • Given current economic conditions, affordability criteria should be re-evaluated; and the 1994 EPA Guidance should be reviewed even if it is not as clear on this point as it should be.

  • In instances with separated systems, blending should continue to be allowed, mixing primary and secondary effluent.

  • The Cities recognized that efficient infrastructure investment has another benefit-it creates jobs.