The Hultman Aqueduct, built 1938-40, had its origins in the “Special Report of the Metropolitan District Water Supply Commission and the Department of Public Health Relative to Improvements in Distribution and to Adequate Protection of Pollution of Sources of Water Supply within the Metropolitan Water District,” published in 1937. The Hultman was constructed to bypass Sudbury Reservoir, the watershed for which had become increasingly subject to pollution; and to bring clean water from Wachusett Reservoir directly to the Metropolitan Water District. The original plan for the “new pressure aqueduct” called for its extension all the way to Chestnut Hill Reservoir and for construction of a “tunnel loop” within the immediate Boston area. The segment from Southborough to Weston was completed in 1940. With the nation’s entry in World War II, however, the “city tunnel” section to Chestnut Hill was delayed, Federal authorization having been denied on grounds that it was not essential to the war effort, despite intensive lobbying by the state legislature. Construction resumed in 1947, and the city tunnel extension was completed in 1950. Subsequently, the tunnel extension to Malden (1962) and Dorchester (1974) extended the pressure system into the heart of Metropolitan Boston. The Cosgrove Tunnel extended the system west to the Wachusett Reservoir upon its completion in 1965.