National Program for Inspection of Non-Federal Dams, Lower Housatonic River Basin, Shelton, Connecticut, Trap Falls Reservoir Dam (CT 00091). Phase I Inspection Report.
CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV
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The dam is a concrete gravity structure with concrete buttresses adjacent to the downstream face of the dam spaced at approximately 18 feet on center. An earthen embankment slopes down from the exposed concrete section at a maximum inclination of 2 horizontal to 1 vertical on the downstream side of the dam. The structure is approximately 1080 feet long and has a maximum height of approximately 48 feet above the old streambed. Outlets consist of a 30 inch cast iron low level line at elevation 172, a 30 inch cast iron transmission main and an 8 inch cast iron service main. The spillway is a 137 foot wide nappe-shaped concrete weir with concrete sidewalls. The area downstream of the dam consists of residential and industrial developments, Connecticut Route 8, and further downstream, urban areas of Stratford. Based upon visual inspections at the site and past performance history, the dam appears to be in good condition. No evidence of structural instability was observed in the concrete section, buttresses or the earthen embankment. However, there are some areas which require attention. Based upon our hydraulic computations, the spillway capacity is 4300 cubic feet per second, which is in excess of 100 percent of the Test Flood. Peak inflow to the reservoir is 2600 cubic feet per second peak outflow Test Flood is 1400 cubic feet per second with the dam maintaining a minimum freeboard of 1.8 feet. It is recommended that the left wingwall adjacent to the spillway be monitored to ascertain whether movement which has occurred to date is continuing.
- Hydrology, Limnology and Potamology
- Civil Engineering