National Program for Inspection of Non-Federal Dams. Lower Glen (Greenfield) Reservoir Dam (MA 00048), Connecticut River Basin, Leyden, Massachusetts. Phase I Inspection Report

摘要

Lower Glen (Greenfield) Reservoir Dam is a 46-foot high stone masonry dam, spanning the lower portion of a 300-foot deep V-shaped valley. The dam has a crest approximately 95 feet long, a vertical downstream face, a service spillway and an auxiliary spillway. The upstream face of the dam is submerged, and since no construction data are available, the configuration of the upstream side of the dam is unknown. The dam was constructed around 1904 to provide a water supply reservoir for the Town of Greenfield. The reservoir has not been used for water supply purposes for more than 30 years; therefore, the dam now serves no useful purpose. The dam appears to be in poor overall condition. Several joints have opened due to structural movement of the dam as evidenced by a bulge on the downstream face of the dam located just to the east of the center dam pier at mid-height. A great deal of seepage was observed at the location of the bulge and toward the east side groin area. The test flood peak inflow to Lower Glen (Greenfield) Reservoir was computed to be 3,760 cfs. The test flood peak overflow is also 3,760 cfs, with a discharge 4.8 feet over the top of the dam. The service and auxiliary spillways have a combined discharge capacity of 740 cfs, or 20 percent of the routed test flood outflow, just prior to overtopping of the dam.