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City of Evansville Clean Water Act Settlement

(WASHINGTON - January 10, 2011) The city of Evansville, Indiana., has agreed to make extensive improvements to its sewer systems that will significantly reduce the city's longstanding sewage overflows into the Ohio River in a comprehensive Clean Water Act settlement with federal and state governments, the Justice Department, the U.S. Environmental Protection Agency (EPA), and the state of Indiana announced today. The agreement would resolve allegations made in a lawsuit filed by the United States and Indiana in September 2009 against Evansville for alleged violations of its Clean Water Act discharge permits.

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Overview of Sewer Authority and Facility Location

The City of Evansville is located in southwestern Indiana and has a service population of approximately 163,000. The City owns and operates a combined sanitary sewer (CSO) system, including two wastewater treatment plants (WWTP). Effluent is discharged to the Pigeon Creek and Ohio River. The City has 22 CSO outfalls which activate about 53 times a year, as well as numerous sanitary sewer overflows (SSOs).

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  • Combined sewer overflows (SSOs) resulting in the discharge of pollutants without a permit and, thus, violating Section 301 of the Clean Water Act (CWA), 33 U.S.C. § 1311.
  • Sanitary sewer overflows (SSOs) resulting in the discharge of pollutants without a permit violates Section 301 of the Clean Water Act (CWA), 33 U.S.C. § 1311.
  • Sewage release into the homes, streets, and yards of Evansville's residents poses an imminent and substantial endangerment to human health. Section 504 of the CWA, 33 U.S.C. § 1364.
  • Failure to comply with conditions of a permit issued pursuant to CWA Section 402, 33 U.S.C. § 1342.

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Injunctive Relief

Evansville has agreed to improve its WWTPs and sewage collection system. Under the consent decree, Evansville must assess its sewer system, implement immediately known system improvements, develop and implement a detailed management, operations and maintenance program, formulate a corrective action plan to address the problems, and implement the remedial measures in a timely manner.

In addition, Evansville must develop and submit for approval an Integrated Overflow Control Plan (IOCP). The IOCP is a combination of a long term control plan (LTCP) to develop CSO control measures, and remedial measures to eliminate SSOs. All remedial measures, including any necessary capital improvements, shall be fully implemented no later than May, 2032. This date may be extended by the Parties, for up to five years, if Evansville can demonstrate that the cost of the wastewater improvements will exceed 2.5% of the medium household income.

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Pollutants Reductions

  • Total Suspended Solids - 136,985 lbs/year
  • Biological Oxygen Demand - 182,646 lbs/yeat
  • Chemical Oxygen Demand - 3,622,881 lbs/year

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Health and Environmental Effects

  • Total Suspended Solids (TSS) - TSS indicates the measure of suspended solids in wastewater, effluent or water bodies. High levels of TSS in a water body can diminish the amount of light that penetrates the water column and reduce photosynthesis and the production of oxygen.
  • Biological Oxygen Demand (BOD) - BOD is an indirect measure of the biologically degradable material present in organic wastes. High BOD means there is an abundance of biologically degradable material that will consume oxygen from the water during the degradation process. It may take away oxygen that is needed for aquatic organisms to survive.
  • Chemical Oxygen Demand (CBOD) - CBOD is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemical.

Civil Penalty

The City of Evansville will pay a civil penalty of $490,000 derived according to the Clean Water Act Settlement Penalty Policy.

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State Partner

The State of Indiana is a co-plaintiff.

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For more information, contact:

Alan Morrissey
Water Enforcement Division
1200 Pennsylvania Ave., NW
Washington, DC 20460
(202) 564-4026
Alan Morrissey (

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