National Program for Inspection of Non-Federal Dams. Stillwater Pond Dam (CT 00098), Housatonic River Basin, Torrington, Connecticut. Phase I Inspection Report.
CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV
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The dam is an earth embankment approximately 15 feet wide at the crest, 443 feet long and 35 above the streambed of West Branch, Naugatuck River. The spillway is a 193 foot long compound concrete weir. Three outlet pipes 30 inch diameter, 6 inch diameter and 16 inch diameter run from the bottom of the outlet structure through the downstream training wall. The operating mechanisms for these outlets are in the gatehouse approximately on the centerline of the dam. Based upon the visual inspection and past performance of the dam, the dam is judged to be in fair condition. No evidence of instability was observed in any component of the dam. There is extensive spalling of the downstream face of the spillway spalling of the top face of the upstream training wall brush, tree growth and tree stumps on the slopes and crest of the embankment and disrepair of the gatehouse and security fencing. Based upon the size Intermediate and hazard classification High of the dam in accordance with Corps of Engineers Guidelines, the test flood will be equivalent to the Probable Maximum Flood PMF. Peak inflow to the reservoir is 20,400 cfs peak outflow is 19,800 cfs with the dam overtopped by 0.5 feet. Based upon our hydraulics computations, the spillway capacity is 16,000 cubic feet per second cfs, which is equivalent to 81 of the routed test flood outflow.
- Hydrology, Limnology and Potamology
- Civil Engineering