National Program For Inspection Of Non Federal Dams Country Club Ma 00756 Connecticut River Basin Northampton Massachusetts Phase I Inspection Report

The dam is basically comprised of 2 stone masonry vertical faced spillways. The main spillway has a length of 69 ft. and a structural height of 32 ft. The secondary spillway has a length of 30 ft. and a height of about 9 ft. The visual inspection did not disclose any findings that indicate an immediate unsafe condition. The size classification is small with a hazard potential of significant. Due to the lack of drawdown capabilities, the dam is considered in fair condition. (Author).

Lower Roberts Meadow Reservoir Dam is an earthfill embankment with a maximum height of 22.7 feet and a greatly curved crest, 550 feet long and 10 feet wide. A concrete and stone masonry spillway about 50 feet long, 14 feet high, and a freeboard of 9.3 feet is located near the northeast end of the embankment. Concrete and stone masonry training walls flank the spillay. A concrete low level intake structure with a manully controled slide gate is located about 180 feet west of the spillway. Phase I inspection and evaluation of the Lower Roberts Meadow Reservoir Dam does not indicate conditions which would constitute an immediate hazard to human life or property. Based on engineering judgment and the performance of the earth embankment and the outlet works, the project is considered to be in good condition. The project has a number of deficiencies which, if not remedied, have the potential for developing into hazardous conditions. It is estimated that 23% of the PMF over the combined drainage area could be processed by the combined Middle and Lower Reservoir storage and spillway capacities without overtooping the Lower Dam.

The dam is a 1200 ft. long, 23 ft. high earth embankment dam. The visual inspection of the dam did not disclose any immediate stability problems. It is recommended that the seepage condition below the toe of the dam be investigated and an adequate collection and monitoring system be designed.

Vistron Dam, also known as Pro Brush Dam is a stone masonry gravity dam across the NMill River. The dam has a hydraulic height of 24 feet, 195 feet long, 8 feet wide at the crest with downstream face battered at approximately 1H: 12V. The spillway section of the dam is 140 feet long. The dam is founded on bedrock which is exposed at the southwesterly abutment and along the base of the dam. The dam is presently in good condition with no major problems. The main deficiency noted is the presence of trees growing near the top and out of the side of the dry laid stone retaining wall at the northeasterly abutment. Considering a 20,000 cfs inflow, from the 52 square mile drainage area, and assuming no downstream controls, the dam would be overtopped by approximately 4 feet. Spillway capacity at the top dam is 10,500 cfs which is approximately 4 feet. Spillway capacity at the top of dam is 10,500 cfs which is approximately 52 percent of the 1/2 PMF.

This dam is a 940 foot long earth embankment dam with a concrete spillway. It is recommended that the areas of erosion both on the upstream and downstream faces where the abutments and embankment interface be repaired. Surface water in these areas should be redirected to prevent future erosion. The riprap on the upstream face should be extended to the dam's crest. The water exiting from the toe and core wall drains should be directed to a control channel and weir where the flow can be periodically measured. The 20-in capped pipe running beneath the dam to the downstream toe should be uncapped and extended to the lower reservoir. This will prevent the potential of a pressurized pipe (should the outlet gate be left open) from bursting and undermining the dam. Although the spillway can not discharge the test flood without overtopping the dam, the spillway capacity is comparatively large. Because of the hydrologic and safety relationships between this dam and the lower reservoir, it is necessary that future hydrologic studies concerning spillway capacities at either project should simultaneously encompass studies for both projects.

West Parish Filter No. 3 Dam is an earthen embankment structure 37.5 feet high and 800 feet long. A side-channel spillway is located at the right abutment. It has a concrete overflow section which is 23.4 feet long. Outlet piping passes beneath the embankment and connects directly to the water treatment plant which serves the City of Springfield, Mass. The dam is situated on a very small (0.07 sq. mi) drainage area, and serves as offstream storage and as a sedimentation basin for water which is piped from other dams. Based on the visual inspection, the dam is judged to be in fair condition. The following deficiencies were observed at the dam: a soft, wet area near the downstream toe; a row of evergreen trees along the downstream toe with some roots penetrating the embankment; rodent holes on the downstream slope; wheel tracks on the crest of the dam; misaligned riprap and loose rock and trees overhanging the spillway; low areas on the top of the dam; and no means of controlling flow at the upstream end of the outlet conduit. The spillway capacity is about 335 percent of the routed test flood outflow of 142 cfs. During the test flood, the freeboard would be 1.9 feet.

The stone masonry gravity dam has a hydraulic height of 23 ft., and a length of 190 ft. The dam is presently in fair condition; however, there are deficiencies which if not corrected could jeopardize the safety and integrity of the structure. The major concern is undermining of the base of the dam which has left a section of the downstream face unsupported. It is small in size with a hazard potential of high. A registered professional should be hired to design repairs to pressure leaks which appear in the face of the dam. (Author).

The dam is generally comprised of a 401-foot long, 10 to 28 foot high main spillway, a head gate building, an overflow canal spillway and a canal leading to two 8 foot diameter penstocks used in electrical power generation. There are two inoperable gates located in the main dam. The dam is normally operated with two feet of flashboards above the spillway crest. The visual inspection did not disclose any findings that indicate an immediate unsafe condition. The 1 /2 PMF test flood used will produce an inflow/outflow of 70,830 cfs. The dam is a run-of-the-river type and the spillway crest would be overtopped by about 14 feet. The spillway has a capacity of 29,500 cfs (42 percent of 1/2 PMF outlfow) at elevation 166.6, top of non-overflow section. The non-overflow section is overtopped by about six feet. This flow would not overtop the upstream training walls which are at elevation 174.0. The overall condition of the dam is considered fair due to the lack of adequate draw down capacity. Remedial measures consist of removing vegetation from the downstream face of the dam, further observation of seepage at the right abutment, repair the wooden crest cover, and develop a formal warning system to warn downstream areas in case of an emergency.