Mansfield Hollow Dam
by Pete Zizka





Most people in the Willimantic area today were probably not around to see the devastating flood and hurricane of 1938 except in pictures and stories. One prominent series of photos shows a washed out railroad crossing on Bridge Street while another shows Cardinal Square which, along with lower Bricktop Road, was hard hit by the overflowing Natchaug River. That area had been flooded just as badly in 1936. U.S. Senator Augustine Lonergan (D-CT) and Second District Congressman William Fitzgerald subsequently became champions for the region by spearheading a movement to have the Geodetic Survey map the flood plain areas and, “With a view to providing flood protection to Willimantic and environs, Army Engineers will review their report on the Natchaug River”. Senator Lonergan the ensured that the Senate Commerce Committee would endorse this project. By 1940, the Corps of Engineers had developed a plan which included three reservoirs/dams in Connecticut but ultimately, only the Mansfield project was approved. By 1945, rumors abounded in Mansfield about the location of the dam and the size of the lake that it would create. The Mansfield First Selectman, concerned that so little information was available, write to Governor Baldwin, requesting that Mrs. Chase Going Woodhouse, the U.S. representative, meet with concerned residents, “to explain the purpose of the proposed dam and the probable results”. In October, 1945, during a three hour hearing in Hartford, citizens whose property would be affected assailed the project while citizens downstream from that area appealed for protection from disastrous floods such as they had experienced. In December, 1945, Governor Baldwin agreed to the construction of the Mansfield Hollow Dam and Reservoir. In February, 1947, the final specifications for the dam were completed and the project was put out for bid. Due to ongoing opposition, however, in June, 1949 a re-survey of the project was undertaken to see if a modification to the project was warranted or if the project was even necessary. But in July, the construction of the dam began and affected landowners received notices that their property was being taken. From 1949-1953 the government continued to acquire land for the project. Hearings were held to, “assay the value of land condemned by the federal government”.  In order to construct the project, the government took 180 acres of woodland, 310 acres of pastureland, 80 acres of residential land and 5 acres of commercial land. Because one of the dikes interfered with Windham Airport, a runway had to be extended. Parts of two highways, RT6 and RT89, had to be relocated. Water backed up by the dam flooded "Turnip Meadows", a swamp located at the confluence of the Fenton, Mount Hope, and Natchaug rivers and created a lake of 450 acres. The total cost of the project was $7.6 million but the dam proved its worth during several hurricanes and several years of large snow melt. The Army Corps of Engineers website offers some interesting facts about the project. “The dam consists of earth fill with stone slope protection. It has a length of 14,050 feet and a height of 68 feet. The project also consists of six earth fill dikes with stone slope protection that total 2,656 feet in length and have a maximum height of 53 feet. A concrete spillway spans the main channel of the Natchaug River with a concrete weir 690 feet long. The flood storage area of the project, which is normally empty and is only utilized to store floodwaters, totals 1,880 acres.. Mansfield Hollow Lake can store up to 8.3. billion gallons of water for flood control purposes. Total potential flood control storage at Mansfield Hollow Lake amounts to 16.1 billion gallons of flood water.( Today’s photo, taken during the dam’s construction is used courtesy of the Mansfield Historical Society


                                                Click on photo for larger version

<<HOME>>                    <<back to Historical Articles index>>