National Program for Inspection of Non-Federal Dams, Brockton Reservoir Dam (MA 00786), Taunton River Basin, Avon, Massachusetts. Phase 1 Inspection Report

摘要

Brockton Reservoir Dam is a 94 year old earth embankment approximately 1,800 feet long with a top width of 16 feet and a maximum height of about 10 feet. Both the upstream and downstream side slopes are 2H:1V. The concrete spillway with a 25-foot long broad crested weir, which has been fitted with steel flashboards, is located at the left abutment. The dam appears to be in fair condition. Small trees growing from the upstream slope may displace riprap in addition to the riprap already displaced, thus exposing additional embankment to hydraulic erosion. The marshy area near the right abutment immediately downstream of the dam may be an indication of seepage through the dam, foundation or abutment. The dam does not have a low level outlet which could be used to drawdown the reservoir during emergencies. The routed test flood outflow of 2,300 cfs overtops the dam by 0.4 feet. The spillway capacity without overtopping the dam with the flashboards in place is 495 cfs and without the flashboards in place the capacity is 978 cfs or about 22 percent and 43 percent, respectively, of the routed test flood outflow.