The City of New Haven has a CSO (Combined Storm/Sewer Overflow) system which it operates and maintains. In an effort to reduce overflows into the Long Island Sound, the Greater New Haven Water Pollution Control Authority is responsible for implementing a Combined Sewer Overflow Long-Term Control Plan (CSO-LTCP) in an effort to eliminate overflows to the Long Island Sound. The CSO-LTCP includes the continued separation of the storm and sanitary sewers in the City as well as a capture and treat program to minimize overflows.
The City of New Haven does not have a stormwater management ordinance at this point in time; however, New Haven was an elected municipality to participate in Public Act No. 07-154. This legislative act provided grant funding for the conduct of a stormwater authority pilot program including the legal authority to establish such a Stormwater Authority. Many recommendations emerged as a result of this study, including implementing post-construction stormwater management requirements and a stormwater utility structure.
Most of the current stormwater management activities are administered by various departments within the City with prime participants being the City’s Departments of Engineering and Public Works. These activities include planning and construction of capital improvements, regulatory compliance and managing maintenance operations for storm sewers, catch basins, pipes, culverts, and drainage channels.
On June 29, 2007, Connecticut Governor M. Jodi Rell signed legislation granting municipal entities the authority to create a separate stormwater authority/agency in their respective municipality.
The Public Act No. 07-154 provided grant funding for the conduct of a stormwater authority pilot program including the legal authority to establish such a Stormwater Authority. Three municipalities, New Haven, New London, and Norwalk elected to participate in the pilot program.
The purpose of the SMP is to establish, implement and enforce a stormwater management program to reduce the discharge of pollutants from the City’s urbanized areas (e.g., roadways, facilities etc.) to protect water quality and to satisfy the appropriate requirements of the Clean Water Act. It should be noted that interstate highways which fall within the City’s boundaries are to be covered under the State of Connecticut Department of Transportation’s SMP regardless of location. Individual facilities such as airports, maintenance garages, ports, salt sheds and other miscellaneous facilities are or will be covered under general permits (industrial) with the CTDEP.
1.2. Overview of Current Program
The City’s storm sewer system was originally built as a combined sewer system, conveying both stormwater and sanitary sewage to the New Haven East Shore Treatment Plant. Currently, it is estimated that more than half of the stormwater flow is serviced by separated stormwater sewers and the remainder by combined storm and sanitary sewers.
The City maintains responsibility for the stormwater system; however, the City is no longer responsible for the sewage system or treatment plant.
In an effort to better coordinate sewage treatment within the local region, the Greater New Haven Water Pollution Control Authority (GNHWPCA) was established in July 2005 to serve as a Regional Sewer Authority (RSA), providing sewer services to the communities of New Haven, East Haven, Hamden and Woodbridge. The City’s East Shore Treatment Plant was transferred from the New Haven Water Pollution Control Authority to the newly created GNHWPCA, where it would receive all combined flows from the participating communities. With a design capacity of 40 MGD and current average daily flow of about 35 MGD, the East Shore Treatment Plant is now the second largest wastewater treatment plant in Connecticut.
The GNHWPCA is responsible for implementing a Combined Sewer Overflow Long-Term Control Plan (CSO-LTCP) in an effort to eliminate overflows to the Long Island Sound. The CSO-LTCP includes the continued separation of the storm and sanitary sewers in the City as well as a capture and treat program to minimize overflows. The current estimated cost of implementing the CSO-LTCP is approximately $400 million. In an effort to ensure that costs are commensurate with benefits, the City has entered into a cost-sharing agreement with the GNHWPCA whereby the costs for implementation of the CSO-LTCP are shared 40/60 between the City and GNHWPCA respectively.
1.2.1. City Responsibilities and Limitations
It is the mission of the City of New Haven Public Works Department to provide mechanical and custodial maintenance of City’s entire infrastructure, including buildings, grounds, parks and roads. Most of the current stormwater management activities are administered by various departments within the City with prime participants being the City’s Departments of Engineering and Public Works. These activities include planning and construction of capital improvements, regulatory compliance and managing maintenance operations for storm sewers, catch basins, pipes, culverts, and drainage channels. However, some of the activities are also performed by the GNHWPCA such as implementation of the CSO-LTCP.
1.3. Overview of Stormwater Management Regulations
The United States Environmental Protection Agency (EPA) considers pollution from all nonpoint sources, including urban stormwater pollution, to be the most important source of contamination for the nation's waters. EPA ranks urban runoff and storm sewer discharges together as the second most prevalent source of water quality impairment in the nation's estuaries.
A federal regulation, commonly known as Stormwater Phase II, requires permits for stormwater discharges from Municipal Separate Storm Sewer Systems (MS4s) in urbanized areas and for construction activities disturbing at least one acre of land. The CTDEP has been delegated authority from the federal government to implement federal regulations that pertain to water resources protection.
Details of the regulatory approach for New Haven are presented in Section 3 of this report.
1.4. Stormwater Management Plan Approach
The City has developed and implemented a Stormwater Management Plan (SMP) to meet the NPDES Phase II stormwater regulations. The Phase II regulations require operators of MS4s located in urbanized areas to obtain a NPDES permit for their stormwater discharges. The CTDEP is the agency responsible for enforcing the EPA’s requirements through the General Permit for Discharge of Stormwater from Small MS4s in the State of Connecticut.
The central focus of the NPDES Phase II permit is the development of a SMP, which describes the goals of reducing the discharge of pollutants from the MS4 to the maximum extent practicable and protecting water quality. The NPDES Phase II permit outlines six (6) minimum control measures (MCM) that must be addressed by Stormwater Management Programs. In the City’s 2004 Stormwater Management Plan, the City defined Best Management Practices (BMPs) for each of the six MCM. In addition, an implementation schedule and measurable goals were developed throughout the 5-year permitting period to achieve the BMPs. A copy of the City’s Stormwater Management Plan was provided in the Joint Report and is also included herewith in Appendix A.
Under the NPDES Phase II permit, the City is required to submit reports annually addressing the progress of each defined BMP in addition to the goals for the upcoming year. The Annual Reports are a valuable benchmark in determining the progress and effectiveness of the SMP in reducing the discharge of pollutants. The City has completed Year 5 of the 5-year permit term, and has submitted reports for 2004 through 2009. Elements of this report will be included in future reports. An approach for updating the SMP is provided in Section 3 of this report.
3.4.5. Post-Construction Stormwater Management in New Development and Redevelopment
There are two significant impacts that can occur from post-construction runoff, which includes an increase in the type and quantity of pollutants in stormwater runoff and the increase in the quantity of water delivered to the receiving water body during storms. The type and quantity of pollutants increase in post-construction areas because as the water runs over surfaces altered by development it picks up sediment and pollutants and conveys it to the receiving water. The quantity of water increases due to an increase in impervious areas, which limits the amount of stormwater percolating into the soil and vegetation. The impervious area collects stormwater, quickly sending large quantities of runoff to nearby streams and rivers. The volume and speed of conveyance creates stream bank scouring and downstream flooding.
The City has proposed to review land use regulations to meet MS4 requirements, to develop a post-construction ordinance, and to develop and implement a post-construction BMP strategy.
Currently, the City has reviewed the land use regulations. However, as the City is fully developed at this time, the City has deferred the development of any further BMPs until a later date. The City has also identified treatment at outfalls as a long-term requirement to meet future discharge requirements into the Quinnipiac and Long Island Sound.