National Program for Inspection of Non-Federal Dams. Ashland Pond Dam (CT 00437), Thames River Basin, Griswold, Connecticut. Phase 1 Inspection Report

摘要

Ashland Pond Dam is an earth dam reportedly constructed in the late 1700's. The dam has a maximum height of 25 feet and is approximately 450 feet in length. The spillway is located at the left side of the dam embankment. This stone masonry spillway has a crest length of about 110 feet and has no provision for flashboards. An abandoned penstock to the adjacent mill complex and gate structure is located near the right end of the dam. An abandoned headrace and gate structure is located at the left abutment of the dam. Due to its age, Ashland Pond Dam was neither designed nor constructed by present state-of-the-art procedures. Based upon the visual inspection at the site and the lack of engineering, operational and maintenance data, there are areas of concern which must be corrected to assure the long-term performance of this dam. The dam is considered to be in FAIR condition. Deficiencies include large tress growing on the dam embankment, indication of potential overtopping and limited discharge capacity of the spillway, inoperable outlet structures resulting in no drawdown capability, and the minimal cross section of the right embankment which requires strengthening. The maximum spillway discharge of 5,535 CFS represents only 13 percent of the test flood outflow.