National Program For Inspection Of Non Federal Dams Washington Mountain Lake Dike Ma 00319 Housatonic River Basin Washington Massachusetts Phase I Inspection Report

The dike, an earth embankment, was found to be in good condition. The dike is intermediate in size and its hazard potential is high. Because of this, the test flood for the dam is the Probable Maximum Flood.

The dam is an earth embarkment 1145 ft. long and 44 ft. high at the downstream toe with a drop inlet service spillway structure and a 30 inch outlet conduit. The size of the dam is intermediate and the hazard potential is high. The dam was found to be in fair condtion. The drainage area of the dam is 1.3 square miles and is made up of primarily of rolling hill woodland.

The entire dam is about 850 feet long and has two angle points along its face. The center portion of the dam is of stone masonry construction flanked by earthen embankments on each side. The dam is intermediate in size and its hazard classification is high. The test flood for this dam is the Probable Maximum Flood. The dam was found to be in poor condition. Failure of the dam will result in serious damage to 3 homes.

The dam is a 41 foot high, 1550 foot long embankment dam containing a concrete and masonry spillway and a gate structure. The dam appears to be in generally fair condition. It has a classification size of intermediate and a hazard potential of significant. There are various recommendations and remedial measures that should be implemented by the owner.

The dam is a concrete gravity dam 750 ft. long and about 105 ft. high. The dam is in poor condition. It is large in size and has a high hazard potential. Failure of the dam will pose a serious threat to two houses and two water supply structures, as well as access to the road to the dam.

Ashley Reservoir Dam is an earth embankment dam approximately 250 feet long and 33 feet high. The embankment has a top width of 12 feet with 2 1/2 H to 1V upstream slopes and 2H to 1V downstream slope. There is a 5-foot wide berm with a 3-foot wide stone gutter on the downstream slope. Between the berm and the downstream toe, the slope flattens to 2 1/2 H to 1V. There is a 70-foot long concrete overflow spillway. The spillway crest is 5 feet lower than the top of dam. Based on the visual inspection, the overall condition of the dam is fair. Spillway capacity with water at the elevation of the existing low points in the top of dam is 1700 cfs which is 57% of the test flood outflow.

Long Pond Dam is located on Long Pond Brook about two (2.0) miles above Green River, a tributary of the Housatonic River in Great Barrington, Massachusetts. The dam is an earth embankment about 240 feet long with a vertical concrete core wall and a height of 15.4 feet, and maximum storage capacity at top of dam of about 700 acre feet. A concrete spillway with a crest length of 9.6 feet and a road bridge overhead is located in the right abutment; an 8-inch cast iron pipe drain near the center of the dam; one 10-inch cast iron water supply intake left of the dam center, and a second 14-inch cast iron water supply intake passes the left abutment. Water treatment facilities are located downstream of the left end of the dam. The pipe outlets are controlled by gate valves. The dam is in FAIR condition. The embankment is stable with no visible leakage. The dam top is not a uniform elevation and a few protective stones on the upstream face have fallen into the reservoir. Trees and shrubs are growing in the downstream slope of the dam. The spillway is in fair condition, but a stop log has been used to raise reservoir level for water works purposes and the approach channel retaining wall is tilting into the channel. The spillway and dam are adequate for 100 year frequency (1% probability) storm runoff though there would be little freeboard protection against wave action. A storm runoff of half probable maximum flood would raise the reservoir to about 0.9 feet above the top of the dam, assuming that the dam remained.