City Reaffirms Its Commitment To Reducing South Mill Pond Discharges

June 19, 2017

In documents filed with the Environmental Protection Agency (EPA) on Friday, June 16, 2017, the City of Portsmouth reaffirmed its commitment to achieve further reductions in combined sewer overflow (CSO) discharges including those discharges to the South Mill Pond. In April 2017, the EPA commented on the City’s Post-Construction Monitoring Plan/Report (PCMP/R); on Friday, the City responded to those comments and submitted a Supplemental Compliance Plan. Those responses and the Supplemental Compliance Plan can be found at under the title of Reverse Chronological List of Documents.

City Engineer Terry Desmarais explained that “the Peirce Island Wastewater Treatment Facility upgrade was one component of the City’s obligations under the Consent Decree with the EPA and the State of New Hampshire. The City was also required under the Consent Decree to make upgrades in the collection system to reduced combined sewer overflows. The City has already spent over $50 million in the last 15 years to make upgrades in the collection system by completing sewer separation projects in the downtown area. This infrastructure investment to date has not only reduced CSO events as required by the Consent Decree, but also reduced flooding and backups into buildings. The Supplemental Compliance Schedule submitted to the EPA on Friday describes the City’s next steps to further improve the City’s infrastructure and operations to better meet water quality requirements.”

The City’s next steps described in the Supplemental Compliance Schedule include undertaking additional water data gathering and analysis and updating the Long Term Control Plan. The Long Term Control Plan is the mechanism to determine the programs and projects to undertake next. The Deputy City Attorney elaborated: “This build and measure approach is part of the existing Consent Decree structure and allows for not only the best engineering solutions but also for continuing public engagement regarding next actions to improve water quality. Water quality data gathering will begin in January 2018 with work commencing on an updated long term control plan in November 2019. In the interim, the City will continue to incorporate sewer separation work into City Council approved projects and proceed with programs that reduce inflow and infiltration into the system.”

In order to respond to some of the frequently asked questions concerning the City’s combined sewer overflows the City will soon be publishing a webpage to provide further information. This will be provided as a link on


For More Information:

Terry Desmarais, Jr.
City Engineer
(603) 766-1421


Read original Press Release here

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