National Program for Inspection of Non-Federal Dams. Potash Pond Dam (CT 00193), Thames River Basin, Windham, Connecticut. Phase I Inspection Report.
CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV
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Potash Pond dam is a stone-faced earth embankment dam constructed around 1880 with an impoundment capacity of 75 acre-feet at the spillway crest elevation of 190.0 NGVD. The dam has a maximum height of 18 feet and is approximately 200 feet in length including the spillway with an average crest width of 14 feet and and upstream slope of 31. The spillway is a stone masonry, uncontrolled, vertical fall, broad crested weir, with a 4 inch concrete cap, 55 feet in length. The assessment of the facility is based on the visual inspection since engineering, operational and maintenance data are not available. The dam is judged to be in FAIR condition with several items that require attention to insure the long-term performance of the structure. They include apparent movements in the area of the penstock as indicated by crest settlement, deflection of the stone wall on the crest and seepage at the toe inoperable outlet works missing and dislodged masonry blocks on the upstream face of the dam missing mortar between the stone masonry of the spillway training walls the lack of a scheduled inspection or maintenance program and trees and brush growing on top of the left abutment of the dam. Calculations indicate that the routed test flood outflow of 2,200 CFS would overtop the dam by about 1.6 feet therefore, the spillway capacity is considered inadequate. Assuming the pool elevation at the top of the dam, the spillway can pass a flow of 840 CFS, which represents only 38 percent of the routed test flood outflow.
- Hydrology, Limnology and Potamology
- Civil Engineering