One of the oldest dams in New England, the Blackwater Dam in Webster, NH, is located approximately 8.6 mi above the confluence of the Blackwater and Contoocook Rivers. It is part of a network of five flood-control dams in the Merrimack River Basin that work together to control flood waters during heavy rains and storms until rivers begin to drop and the stored water can be slowly and safely released. The reservoir has a storage capacity of 15 billion gal. of water.
The U.S. Army Corps of Engineers (USACE), who oversees the property, engaged The Aulson Company to complete major concrete repairs and waterproofing to restore the dam and pedestrian walkway to peak condition after 60 years of deterioration. The USACE had made previous attempts at restoration but was not satisfied with the results.
The Restoration Challenge
When the Blackwater Dam was built in 1941, the technology used to mitigate expansion and contraction was to install horizontal and vertical joints. No weepholes were provided in the original design to allow drainage back to the channel, so