The 1240 feet long dam is a concrete gravity section for the majority of its length with upstream and downstream embankments. At the right end of the dam adjacent to the spillway, the concrete section narrows to effectively become a 70 foot long concrete corewall for the surrounding earthen embankments. The top of the dam is approximately 51 feet above the old streambed at estimated elevation 174. Downstream embankments have a maximum slope inclination of 3 horizontal to 1 vertical. The spillway is a 70 foot wide concrete ogee weir flowing to the spillway channel cut into rock at the right end of the dam. Two 30 inch cast iron pipes pass through the dam; one at elevation 183 is a supply main, and the other at elevation 178, is the low level outlet. Based on the visual inspection at the site and past performance history, the dam appears to be in good condition. No evidence of structural instability was observed in either the concrete gravity section or the embankment - concrete corewall section of the dam. The downstream earthen embankment was observed to be in good condition, with only a minor surface slump in one area. There are some areas which do, however, require attention. Based upon our hydraulic computation, the spillway capacity is 2800 cubic feet per second (cfs), which is equivalent to approximately 25 percent of the Test Flood.

The dam consists of two sections. The portion of the dam from the spillway 185 feet to the left is an earthen embankment on the upstream side of a rubble masonry retaining wall. The remaining portion of the dam to the left of the retaining wall is an earthen embankment. According to the existing information, a rubble masonry corewall exists from the spillway 260 feet to the left. The spillway is reported as a 50-foot-wide concrete weir flowing to a steep channel cut into natural rock formations. A 16 inch diameter high level intake approximately 900 + or - feet to the right of the dam was used as a supply main. The supply main is operable, however the reservoir is not used as a water supply due to the turbidity and poor color quality of the water. A 12 inch, low level inlet passes through the dam, but is presently inoperable. Based upon visual inspections at the site and past performance history, the dam is judged to be inf air condition. No evidence of structural instability in the retaining wall or the embankment portions of the dam was observed. However, the masonry retaining wall is very irregular making it impossible to detect any misalignment or movement of the wall. There are areas requiring attention. Based upon our hydraulic computations, the spillway capacity is 850 cubic feet per second, which is equivalent to approximately 28 percent of the Test Flood. Peak inflow to the reservoir is 3,500 cubic feet per second; peak outflow (Test Flood) is 3,000 cubic feet per second with the dam overtopped 0.8 feet.

The dam is comprised of an earthen embankment on the upstream side of a near-vertical rubble stone masonry wall, which is approximately 340 feet in length and rises approximately 37 feet above the original streambed elevation of the Mill River. The upstream earthen embankment is approximately 20 feet wide at the dam crest and has an upstream slope with a maximum inclination of 3 horizontal to 1 vertical. The right portion of the spillway is a concrete compounded circular crest with a sloped downstream face. The left portion of the spillway is a side channel concrete ogee section. The area below the dam is developed with industrial buildings, a high school, and residential structures. Based upon the visual inspection at the site and past performance of the dam, the dam is judged to be in good condition. No evidence was observed of structural instability in the earthen embankment or the masonry wall. The condition of both the embankment and wall appears to be good. There are some areas requiring attention. Based upon our hydraulics computations, the spillway capacity is 9700 cubic feet per second, which is equivalent to approximately 21 percent of the Test Flood. Peak inflow to the reservoir is 48,600 cubic feet per second; peak outflow (Test Flood) is 46,500 cubic feet per second with the dam overtopped 4.4 feet.

The dam is an earth embankment founded on bedrock and measuring approximately 600 feet long, 22.5 feet high (26.5 structural height), and 12 feet wide at the top. The top of the dam is 4.5 feet above the principal spillway crest. The slopes and top of the embankment have a grass cover, with some riprap along the waterline. The principal spillway is a concrete drop inlet. There are two vertical 4 foot by 1 foot openings at the top of the riser structure, which allow water to flow into the chamber and out the 16 inch RCP. The low-level outlet, also part of this spillway structure, consists of a 15 inch ACCMP which extends for 30 feet from the riser chamber to the toe of the upstream slope. The emergency spillway is a grass lined channel extending around the right end of the dam. Based upon the visual inspection performed April 29, 1981, the project is assessed as being in good condition.

Black Pond Dam is a stone masonry and earth embankment structure approximately 100 feet long and 26 feet high with a 25-foot wide paved road (Birdsey Avenue) on the crest. A majority of the downstream embankment consists of a vertical stone masonry face. The 14-foot wide spillway is a 14-foot by 3-foot concrete culvert under the road at approximately the center of the dam. There is a mortared stone gate inlet structure that controls a 20-inch cast iron water main that passes through the base of the dam. The water main connects into the City's distribution network, and is used only for emergencies. There is no low-level discharge. The pond is presently used for recreation. The drainage area is 1.2 square miles and the reservoir has approximately 353 acre-feet of storage capacity. The assessment of the dam is based on the visual inspection, past operational performance and hydraulic/hydrologic computations. The dam is judged to be in fair condition with several areas that require attention. These areas include seepage through the dam, missing mortar in the downstream face, trees on the embankments as well as along the toe of the dam and the lack of a low-level discharge pipe. The test flood for this dam is 1/2 the PMF and is calculated to be 560 cfs. The spillway capacity at the top of the dam is 250 or 45 percent of the test flood outflow. The test flood outflow will overtop the dam by 1.1 feet.

The project, built about 1891 has a total length of 545 feet consisting of a 340-foot masonry core with earth fill on the upstream and downstream sides, a 115 foot long earth embankment at the right end of the dam, and sections of concrete corewall at each end. A 71-foot broad-crested masonry spillway is located at the central portion of the dam. The top of the dam (elevation 312.0) is 7 feet wide and 16.5 feet above the Harbor Brook streambed. The maximum storage capacity with the pond level to the top of the dam is approximately 216 acre-feet of water. A gatehouse, located upstream and adjacent to the right end of the spillway, contains two valves which regulate a 20-inch blowoff and a 12-inch supply main which once led to the Bradley and Hubbard Corp. In accordance with the Army Corps of Engineers's Guidelines, Bradley Hubbard Reservoir Dam is classified as a high hazard, small size dam. The test flood range is from one-half to full Probable Maximum Flood (PMF). The selected test flood for Bradley Hubbard Reservoir Dam is equivalent to the PMF. Peak inflow to the reservoir at the test flood is 1500 cubic feet per second (cfs); peak outflow is 1325 cfs with the dam overtopped by 0.9 feet. The spillway capacity with the reservoir level to the top of the dam is 223 cfs, which is equivalent to 17% of the routed test flood outflow.

Cheshire Reservoir Dam is an embankment dam 168 feet long having a maximum height of 18 feet, with a centrally located concrete and stone fill spillway section. The spillway is semi-circular in plan and 74 feet long. The overflow cascades over a series of 16-inch-high steps that discharge to Mixville Brook. The spillway is flanked at each end by concrete training walls. An earth embankment section is on each side of the spillway connecting to high ground at either side. The embankment side slopes are 1 vertical on 2 horizontal. The embankments are grass covered gravel and clay. A 24-in diameter blow-off pipe passes through the dam embankment and outlets at the right spillway training wall. Based on the visual inspection, the Cheshire Reservoir Dam appears to be in fair condition. The grassed slopes are well maintained. The vertical and horizontal alignment of the dam is good. Some erosion and slumping was noted adjacent to both training walls of the centrally located spillway. Several animal holes were noted on both downstream slopes (right and left of spillway). No upstream slope protection was noted along the right side of dam. A wet and spongy area was observed near the downstream toe along the left side of the dam. No piping or boils were noted. The concrete spillway is in poor condition. The surface has areas of extensive spalling, efflorescence, and erosion. The training walls have deteriorated and aggregate is visible. The gatehouse is in good condition. The test flood would overtop the dam by about 1.1 feet. The spillway is adequate to pass about 47 percent of the spillway test flood outflow without overtopping the dam.