BACKGROUND

In the late 1980s and 1990s, the U.S. EPA, through the Clean Water Act, called for eliminating sanitary sewer overflows (SSOs) and reducing combined sewer overflows (CSOs) into local waterways. This action affected every wastewater utility in the country, including MSD.

 

Increased scrutiny in the late 1990s from the U.S. Department of Justice (DOJ) and U.S. EPA brought the issue to the forefront as they began enforcing the ruling in large cities and leveling heavy civil penalties on those out of compliance.

 

In 1999, MSD, which had already begun eliminating SSOs and reducing CSOs, entered into negotiations with the EPA, DOJ, and the State of Ohio to establish a formal remediation program. These negotiations resulted in two Consent Decrees and a Wet Weather Improvement Plan (WWIP), which are collectively known as our Wet Weather Program.

 

CONSENT DECREES

MSD is under two Consent Decrees:

 

• Global Consent Decree (2004) On June 9, 2004, the the City of Cincinnati and Hamilton County entered into a Global Consent Decree with the U.S. EPA, Ohio EPA, and the Ohio River Valley Water Sanitation Commission (ORSANCO). This global decree covered Combined Sewer Overflows (CSOs), Wastewater Treatment Plants, and Implementation of Capacity Assurance Program Plan for Sanitary Sewer Overflows. The decree was lodged with the United States District Court for the Southern District of Ohio, Western Division.
  • Global Consent Decree (2004)
  • Exhibits
• Interim Partial Consent Decree (2002) On February 15, 2002, the City of Cincinnati and Hamilton County entered into an Interim Partial Consent Decree on Sanitary Sewer Overflows (SSOs) with the U.S. EPA, Ohio EPA, and the Ohio River Valley Water Sanitation Commission (ORSANCO). The decree was lodged with the United States District Court for the Southern District of Ohio, Western Division.
  • Interim Partial Consent Decree (2002)
  • Exhibits

 

WET WEATHER IMPROVEMENT PLAN (WWIP)

In August 2010, the U.S. EPA approved MSD's Wet Weather Improvement Plan (WWIP), a >$3.1 billion (in 2006 dollars) roadmap for reducing CSOs, eliminating SSOs, and addressing sewer backups.

 

• Original Wet Weather Improvement Plan (2010)

 

 

 

The WWIP is being conducted in phases:

 

• Phase 1 (2009-2021): Phase 1, which is now complete, cost approximately $1.1 billion (in 2006 dollars) and included 133 projects, as well as special programs (known as allowances) to reduce or eliminate sewer overflows and address sewer backups. The largest-scale project was the Lower Mill Creek Partial Remedy, which reduces overflows into the Mill Creek by nearly 2 billion gallons a year, primarily through the Lick Run Greenway. In total, Phase 1 has eliminated nearly 8 billion gallons annually of sewer overflows from across MSD's service area. View the list of projects competed during Phase 1 
• Bridge Plan (2018-2023): - As an interim phase between Phase 1 and Phase 2A, MSD is working on 20 wet weather projects known as the Bridge Plan. 18 projects have been completed as of March 2024. The two remaining projects are in construction, with completion anticipated in spring 2024. Updates on the Bridge Plan can be found in the Consent Decree Quarterly Reports on the Progress page. View progress on the bridge plan 
• Phase 2A (2023-2024): A Phase 2A schedule was approved by the U.S. EPA and other regulators on August 29, 2023. It includes construction of three projects by the end of 2024, including the Mill Creek WWTP Diversion Chamber (which is already completed), CSO 402-406 Regulator Improvements, and the Little Miami Standby Power project. It also includes design of two projects, including a new influent pump station at Mill Creek to serve a future Enhanced High-Rate Treatment (EHRT) facility (design is under way) and planning for improvements to the East Branch Muddy Creek Interceptor and associated pump stations. VIEW THE APPROVED PHASE 2A SCHEDULE
• Phase 2B: A proposed Phase 2B plan was submitted by Hamilton County to the Regulators on June 28, 2024 View the proposed Phase 2B plan