Blue Hills Design Build Covered Storage Project
GEI was a key member of the design-build team restoring the Blue Hills Reservoir use as a part of the Massachusetts Water Resources Authority (MWRA) drinking water supply system. The Blue Hills reservoir was an open reservoir for storage of drinking water and served the southern portion of the MWRA system from the early 1950s to 1970, when its use was discontinued due to deterioration of water quality. The MWRA has built and continues to build covered storage tanks to replace small open reservoirs near cities and towns. Covered storage lessens the risk of contamination of water once it has been treated and is required by the Massachusetts State Department of Environmental Protection (DEP) rules.
Key Challenges
The Blue Hills project involved the construction of two 10-million-gallon drinking water storage tanks and associated structures within the existing reservoir. A new dam to restore a portion of the open reservoir was also constructed. The reservoir is part of an aquatic and wetland habitat that meets permitting requirements for wetlands mitigation. GEI’s work included design of the foundation support and subsurface drainage system for the tank; complete design of the dam, including hydrologic, hydraulic, structural, and geotechnical analyses; preparation of construction drawings and specifications for the geotechnical and dam construction; dam permitting; approval of fill soils; observation and approval of fill placement and tank foundation subgrades, the prepared bedrock surface below the dam core wall, foundation grouting for the dam, and fill placement for the dam; and final inspection and approval of the completed dam