National Program for Inspection of Non-Federal Dams. Bird Pond Dam (MA 00804), Neponset River Basin, Walpole, Massachusetts. Phase 1 Inspection Report

摘要

Bird Pond Dam is an 18.5 ft. high, 291 ft. long composite rubble masonry, concrete and earth embankment to consisting of a 39 ft. long central spillway, a 132 ft. long earth embankment the right of the spillway and a 120 ft. long earth embankment to the left of the spillway. The test flood outflow (15,000 cfs.) would overtop the dam by about 5.7 ft. with stop-logs in place and 5.3 with stoplogs removed. With the stoplogs in place the spillway can pass about 500 cfs of about 3 percent of the test flood outflow without overtopping the dam. With the stoplogs removed and the spillway sluice gates open the spillway can pass about 2,070 cfs or about 14 percent of the test flood outflow without overtopping the dam. The dam is judged to be in generally fair condition because of the seepage through the left spillway training wall and because the low level outlet has not been operated in many years and is presumed to be inoperative. There is brush and tree growth on the left embankment. Mortar is missing from the joints of the rubble masonry training walls of the spillway. The concrete spillway service service bridge is deteriorated. Minor erosion has taken place on the downstream slope of the left embankment. There may also be some seepage from the right spillway training wall which at the time of the inspection could not be determined because of the high flow conditions.