The main objective of the project is to adhere to CT DEEP requirements for dam safety and protect properties downstream from flood events (see inundation maps) while still providing an essential water supply for First District Water customers. There will be no increase in the amount of water available in the dam and approximately 0.11 acres of total impacts to wetlands at the site including temporary impacts.

The project activities include the following:

• Raise the top of non-spillway portion of the dam by 4 feet with a cast-in-place concrete cap, and re-grade at dam abutments to mitigate overtopping during the ½ PMF (probable maximum flood)
• Repointing the downstream face of the dam and grout the stone masonry
• Constructing the earthen embankment along the east side of Grupes Reservoir and re-grade the existing high ground and access road to mitigate overtopping/flooding during the ½ PMF
• Construction of parapet / retaining walls along east side of Grupes Reservoir to mitigate overtopping/flooding during the ½ PMF 
• Installation of post-tensioned anchors to increase the sliding resistance and overturning stability during seismic events
• Modifications to the gatehouse, low-level outlets, and gates to facilitate releases to the stream and water system 
• Demolish the former chlorination building and other obsolete water distribution piping downstream of the dam
• Installation of new 24-inch water main along east service road, connect to existing distribution system via a stream crossing
• Installation of articulated concrete block at auxiliary spillway invert, remove trees and boulders that could potentially obstruct discharge channel during storms

Design elements of the project incorporate mitigation of wetland, wildlife and fish habitat impacts resulting from construction. The construction activity has been designed to avoid environmental alteration or disturbance where possible.

There are no identified endangered species in the vicinity of Grupes Reservoir Dam. No permanent alterations of wetlands or watercourses are anticipated as a result of the dam safety improvement at the Grupes Reservoir Dam.

                     The Grupes Reservoir is an integral part of the District’s water supply and critical to its continued operation.

Any questions on the project, please contact the First Taxing District Water Department at info@firstdistrictwater.org or (203) 847-7387.