Norwich Combined Sewer Overflow Plan - May 2015

Municipality where proposed project might be located: Norwich

Project Location: The Greenville, Eastside, Thamesville, Laurel Hill and Downtown areas of Norwich

Project Description: Norwich is a combined sewer overflow (CSO) community, where both sanitary sewage and stormwater are carried in a single pipe.  During rainfall events of sufficient intensity and duration, the capacity of the collection system is overwhelmed and excess flows discharge to nearby rivers via built-in overflows in the collection system. The overflows were designed to prevent the combined sewer flows from backing up into basements and surcharging onto the streets. 

The collection system will undergo a separation which will involve the construction of a new sewer parallel to the existing combined sewer, thereby segregating the sources. After completion of a separation, one dedicated stormwater sewer will transport runoff directly to the local receiving waters, while the other sewer will be dedicated to carrying wastewater to the wastewater treatment plant for treatment prior to discharge into the river.

The CSO Long Term Control Plan recommends complete separation of all remaining combined sewer areas in Norwich, with the separation projects to be implemented in a phased approach, over a 20 year period. The highest priority areas would be done first, with the option to reevaluate the final phase of separation as the project progresses, based on environmental improvements, changes in regulations and new technological solutions that may emerge. 

The proposed sewer separation project will be conducted according to a “Five-Phase Implementation Plan.”  The separation plan is structured to give the highest environmental benefits at the beginning of the program.  At the end of the first phase, in year 4 of the “Five-Phase Implementation Plan,” the Greenville area separation will be completed, which is projected to eliminate half of the CSO discharge volume.  At the end of the third phase, in year 8, over 98% of the CSO discharge volume will be eliminated.  In year 15 of the program, after the first four separation phases are completed, over 99% of the CSO discharge volume (on an annual basis for the typical year) will be removed.  At that point Norwich will evaluate the progress made to date and the cost-effectiveness of implementing the final phase, phase 5, of the separation work.

Project Maps: Click here to view a table outlining the Five-Phase Implementation Plan
                        Click here to view a figure depicting the Five-Phase Implementation Plan

Additional information about the project can be viewed in person at:

            Department of Energy and Environmental Protection
            Bureau of Water Protection & Land Reuse (2nd floor)
            79 Elm Street
            Hartford, CT  06106

Written comments from the public are welcomed and will be accepted until the close of business on: June 5, 2015

Any person can ask the sponsoring agency to hold a Public Scoping Meeting by sending such a request to the address below.  If a meeting is requested by 25 or more individuals, or by an association that represents 25 or more members, the sponsoring agency shall schedule a Public Scoping Meeting.  Such requests must be made by May 15, 2015.

Written comments and/or requests for a Public Scoping Meeting should be sent to:

If you have questions about the public meeting, or other questions about the scoping for this project, contact Ms. Marusin, as directed above.

The Connecticut Department of Energy and Environmental Protection is an Affirmative Action/Equal Opportunity Employer that is committed to complying with the requirements of the Americans with Disabilities Act.  Any person with a disability who may need a communication aid or service may contact the agency's ADA Coordinator at 860-424-3194 or at deep.hrmed@ct.gov.  Any person with limited proficiency in English, who may need information in another language, may contact the agency's Title VI Coordinator at 860-424-3035 or at deep.aaoffice@ct.gov.  ADA or Title VI discrimination complaints may be filed with DEEP’s EEO Manager at (860) 424-3035 or at deep.aaoffice@ct.gov.