To reinforce its water distribution system and comply with an Environmental Protection Agency (EPA) Master Agreement, the City of Flint added a backup water supply system. More than 30,000 linear feet of 36-inch-diameter water transmission main was constructed from the City’s Water Treatment Plant (WTP) to the Genesee County Drain Commissioner’s (GCDC) North Water Loop. Wade Trim provided design and construction engineering services for Flint’s Secondary Water Supply project. Since completion, the secondary water supply has been used in response to issues within the distribution system to avoid a lengthy boil water emergency that resulted due to a transmission main break from the City’s water supplier.

The water transmission main route was designed to minimize construction impacts and reduce cost. Originally planned through Michigan Department of Transportation right-of-way on Dort Highway and a heavy industrial area, an alternate transmission main route along Consumers Energy properties was selected. This avoided high-conflict areas parallel to Dort Highway and its intersection with Frances Road. In addition, jack-and-bore construction under County roadways, Dort Highway, and the CSX railroad minimized disruption.

Water system monitoring capabilities were expanded. A master meter vault was added at both ends of the transmission main that includes meters, valves, instrumentation, and SCADA for monitoring by all stakeholders. Additional design elements included isolation and vacuum-air release valves, blow-off hydrants, and drain crossings. Because the secondary water supply project added new transmission main connections to the City’s WTP, connection vaults were added. Control valves, meters, piping, and connection points at the WTP were modified or replaced as needed.