National Program for Inspection of Non-Federal Dams. Williams Mill Pond Dam (MA 00121), Blackstone River Basin, Worcester, Massachusetts. Phase I Inspection Report

摘要

Williams Mill Pond Dam is a 360-foot long, 14-foot high earthfill dam. The original dam at this site, which was constructed around 1888, was partly rebuilt after being washed out in 1923. There is no other information available on the construction of this dam. The stone masonry spillway has a sharp-crested concrete weir and a stepped stone cascade. The 47-foot long spillway crest has been breached in a 20.2-foot section near the right training wall. The crest is at Elevation (EL) 505.4 in the breached section and 508.0 in the unbreached section. There is no apparent outlet at this dam. The dam is in poor condition. The following are visible signs of distress that could indicate a potential hazard at the site: breached section of the spillway; lack of a low level outlet; erosion at several locations along the embankment and down the left bank of the discharge channel; possible seepage through the left embankment; dense growth of trees and brush on both slopes and on the spillway crest; loose and displaced stone blocks on the spillway, the side walls, and the apron of the cascade; erosion and unidentified flow from beneath the concrete retaining wall; and accumulation of branches and debris in the downstream channel. An outflow test flood of 4,170 cfs (one-fourth the estimated probable maximum flood) will overtop the dam by a maximum of 1.8 feet. The spillway can discharge 45 percent of the outflow test flood.