National Program for Inspection of Non-Federal Dams. Hanover Reservoir Dam (CT 00470), Thames River Basin, Sprague, Connecticut. Phase I Inspection Report

摘要

The dam, built around 1900, is an earth embankment approximately 26.5 feet in height and 750 feet in length including a 147 foot long masonry spillway. With the reservoir level to the top of the dam, the reservoir impounds approximately 400 acre-feet of water. The top of the embankment is 6.6 feet above the spillway crest and approximately 30 feet wide with a paved road on it. The broad crested masonry spillway is located at the left end of the dam and there is a 3 span steel bridge over the spillway approach channel. The outlet works, which have been abandoned, consist of a 54 inch diameter low-level outlet and a penstock. Based upon the visual inspection at the site and past performance, the project is judged to be in poor condition. There is substantial seepage emanating from 3 locations at the toe of the downstream slope, which requires monitoring. Items which require maintenance are the dense vegetation and debris on the dam, the irregular shape of the embankment, erosion of the upstream slope, deterioration of the masonry spillway training walls and erosions of the concrete bridge piers. The questionable condition of the outlet works requires further investigation. The spillway capacity, with the reservoir level to the top of the dam, is 5,600 cfs, which is equivalent to 52% of the routed test flood outflow.