Quaddick Reservoir Dam is an earth embankment about 330 ft. long, with a maximum height of about 12 ft. TWo spillways, with a combined width of 78 ft., occupy a portion of this length. A dike is located in a saddle about 2,000 ft. east of the dam. The dam has a wet well intake structure with a 30 in. dia. outlet pipe controlled by a sluice gate. The drainage areas is about 24 sq. mi, and the maximum active storage to the top of the dam is 5,100 acre-ft. The dam and dike are judged to be in generally fair condition. The side walls of the west spillway appear to have been overtopped, resulting in some erosion of the embankment. The backfill along the east spillway has also settled. Most of the riprap protection downstream from both spillway chutes has been washed away. The masonry wall at the downstream end of the outlet pope is in poor condition. Brush and saplings have become established downstream of the west abutment area, in the east spillway discharge channel and on the upstream slope. There are several areas of local erosion on the crest, upstream and downstream slopes, and some rodent burrows on the downstream slope. Seepage was noted below the toe in the right abutment area and through the masonry outlet wall. The test flood would overtop the dam by about 1.3 ft. and the dike by about 2.8 ft. The combined spillways would pass about 30 percent of the test flood without overtopping the dam or dike provided that the stoplogs were not installed on the west spillway crest.

North Grosvenordale Pond Dam is a composite masonry and earth dam consisting of two downstream stepped, ashlar faced masonry overflow sections, a granite block and earth fill right abutment and an earth fill right abutment and and earthfill dike on the left abutment. The entire length of the dam is about 2,400 ft. It is a run-of-the-river dam which once served the industrial needs of the downstream mill. Outflows through the millrace are now used for fire protection of the mill. North Grosvenordale Pond is about 1.5 miles long and has a surface area at spillway level of about 60 acres. The drainage area above the dam is about 99 sq. mi. and the maximum storage to the top of the dam is estimated at about 840 acre-ft. The dam is judged to be in generally fair condition. At the time of the inspections, water was flowing over the right spillway, so that it was not possible to observe the condition of the downstream ashlar face, or to determine whether there is any erosion at the toe of the spillways. The crest of the left spillway is higher than the right spillway. The difference is less than 6 in. The sluiceway through the left spillway is inoperative. Some of the left spillway stones have been dislodged and displaces. Several joints in the training walls are in need of repointing. The bridges over the spillways are in a deteriorating condition. Tree and brush growth is abundant along the left abutment dike. The spillways are not adequate to pass the 1/2 PMP test flood of 25,400 cfs without overtopping the non-overflow sections of the dam. The test flood would overtop the dike by about 2.2 ft. The spillway can pass 4,950 cfs or about 20 percent of the test flood without overtopping the dike.