National Program for Inspection of Non-Federal Dams. Number 5 Reservoir (MA 00693), Quinebaug River Basin, Southbridge, Massachusetts. Phase I Inspection Report.
CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV
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Reservoir no.5 Dam is an 1130 foot long, 33-foot high earth embankment dam with a concrete masonry core. The outlet works include three 16-inch screened inlets at varying elevations used to provide raw water for a 20-inch water supply outlet, and a 36-inch outlet which discharges at the toe of the downstream slope. The emergency spillway is a 150-foot long concrete broad-created weir. Flashboards 1.5 feet high can be installed at the spillway, The spillway is located immediately upstream of the right abutment and discharges to a poorly defined natural channel. The following deficiencies were observed at the site seepage issuing from the toe of the downstream slope at five 5 separate locations and minor depressions of the earth embankment behind the rubble wall on the upstream dam face. Generally, the dam is in fair condition. Hydraulic analyses indicate that the emergency spillway, without flashboards, can discharge 3640 cfs and the total routed test flood outflow is 1100 cfs. Thus, the spillway can discharge 330 percent of the routed test flood. The estimated test flood stage is about 2.5 feet below the top of the dam.
- Hydrology, Limnology and Potamology
- Civil Engineering