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Occoquan River Crossing Project

Webpage updated 5/26/2023 

Service Authority Project Manager 

Debbie J. Maxwell, P.E., CCM

Project Description

Fairfax Water will install two parallel 42-inch water mains underneath the Occoquan River and make other improvements in order to increase drinking water transmission capacity, maintain system reliability and enhance availability for existing and future Service Authority customers in eastern Prince William County. The project is a collaboration among three providers of drinking water: Fairfax Water, the Service Authority and Virginia American Water. The project also entails connecting Fairfax Water’s Griffith Water Treatment Plant to the new 42-inch water mains at the Occoquan River, installing a new water pump at the Griffith Plant and establishing interconnections between existing water mains at Tanyard Hill Road and at the Horner Road Commuter Parking Lot in Prince William County.

Current Project Activities

Fairfax Water is preparing for construction of the tunnel which will house new water mains and cross beneath the Occoquan River near the Town of Occoquan. Below the water table, controlled blasting will be performed using explosives to demolish bedrock for tunnel and water main installations. Blasting activities, conducted by certified and licensed personnel, are anticipated to occur mid-April through September 2023. Blasting is permitted at the project site Monday through Friday, 8 a.m. to 6 p.m., and Saturday, 9 a.m. to 5 p.m.. Over this 6-month period, a single, one-second blast will be detonated during the allowable timeframe every other day. See attached document for more information and safety details associated with the blasting process.