National Program for Inspection of Non-Federal Dams. Nagog Pond Dam (MA 00129), Merrimack River Basin, Acton, Massachusetts. Phase I Inspection Report.

The dam is a concrete gravity section keyed into bed-rock. The top of the dam is approximately 168 ft. long and 15 ft. high. The dam is in good condition, based on a visual examination of the structure. Although some deficiencies were noted, there was no evidence of settlement, lateral movement or other signs of structural failure or other conditions which would warrant urgent remedial treatment. Based on size and hazard classification in accordance with Corps of Engineers guidelines, the test flood for this dam is the 100-year flood. With the water level at top of dam, the spillway has a capacity of 60 cfs. Hydraulic analyses indicate the test flood outflow of 22 cfs 17.7 csm can be passed with a freeboard of 0.76 ft. remaining.