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Master Plan Design

Award-Winning Master Plan Design – Hunting Run Dam and Motts Run Water Supply, Treatment, and Transmission.
  • Aerial view of Spotsylvania County’s Motts Run Water Treatment Plant - Gannett Fleming

    Spotsylvania County’s Motts Run Water Treatment Plant.

  • Face of Hunting Run Dam, a 2,200-foot-long, 90-foot-high, composite roller-compacted concrete and earthen pump storage water supply dam and reservoir - Gannett Fleming

    Hunting Run Dam, a 2,200-foot-long, 90-foot-high, composite roller-compacted concrete and earthen pump storage water supply dam and reservoir.

  • Motts Run Water Treatment Plant and Dam, including new grass-lined emergency spillway - Gannett Fleming

    Aerial view of Motts Run Water Treatment Plant and Dam, including new grass-lined emergency spillway.

Spotsylvania County Utilities Department

Spotsylvania County, Virginia

Our Role
Comprehensive Planning, Site and Route Selection, Surveys, Subsurface Exploration, Permitting and Regulatory Assistance, Water and Sewer Master Plan, Environmental Assessment and Study, Road Reconstruction, Roller-Compacted Concrete Dam Design, Water Treatment Plant Design and Rehabilitation, Raw Water Intake, Pump Station Design, Regulatory Agency Coordination, Transmission Mains, Construction Management, Inspection Services.

Construction Cost
9 years
  • Provides reliable drinking water supply for rapidly growing community
  • First ballasted flocculation system in operation in Virginia
  • Partnering approach enabled successful resolution of construction issues.

This comprehensive water supply planning project was initiated by the county of Spotsylvania (County), Virginia, in response to rapid economic development of the area. The County had outgrown its existing water system and the adjacent city of Fredericksburg (City) was also facing major upgrades to its water treatment plant (WTP) to meet increasing demands. 

Working together, the two entities decided to combine for a comprehensive water system expansion and upgrade. These projects were constructed to provide additional treatment capacity and raw water supply and to enable the County and City to support future growth. The joint project allowed the City to forego a major upgrade to its aging Cossey WTP and allowed removal of its low-head dam on the Rappahannock River.

What We Did

Gannett Fleming provided comprehensive water system planning, design, and construction management and inspection services for all components of the projects, including the 12-mgd Motts Run WTP and transmission mains, the Ni River WTP chemical building, Hunting Run Dam and reservoir, two river intakes and pump stations, and modifications to Motts Run Dam to convert it to a pumped storage facility.

A critical requirement of the project was to monitor, using cost-effective techniques, the diverse, new facilities from centrally manned locations. We designed a wide-area communications network and data interfaces, which brought together telemetry from the new dam and other remote water supply sites for viewing and storage on the Motts Run WTP distributed control system. This allowed plant operators to monitor and control remote facilities from one central location, resulting in a significant improvement to operational personnel efficiency.

Key Features

  • Facility design complements the region’s rich architectural heritage
  • First Virginia WTP to use Actiflo system
  • Use of IntelliGrout®, an innovative, electronic monitoring and recordation of grouting production
  • Improved existing dam spillway and embankment to prevent flooding
  • Reservoir covers 420 acres, contains 3.1 billion gallons of water, and provides an additional 8 mgd of water supply to the County.

Sustainability Features & Outcomes

  • Preserved Motts Run Reservoir’s dual purpose as a drinking water source and a recreational area
  • Coordination with the Virginia Department of Game and Inland Fisheries and the Virginia Marine Resources Commission regarding the restoration of shad to the Rappahannock River
  • Wetland mitigation was conducted to replace impacted areas
  • River intakes use wedgewire screens equipped with automatic airburst backwash. The screens are designed to protect migratory fish, eggs, and fingerlings in accordance with the requirements of the U.S. Army Corps of Engineers and the Virginia Department of Game and Inland Fisheries.

Awards & Recognition

  • Hunting Run Dam, Project of the Year, 2003, Construction Management Association of America (CMAA), Mid-Atlantic Chapter
  • Spotsylvania Water Supply, Honor Award, 2004, American Council of Engineering Companies of Virginia (ACEC/VA), in the category of multiple services in the planning, design, and construction of an enlarged, improved water supply system
  • Hunting Run Dam, Public Project Recognition, 2002, Construction Management Association of America, Mid-Atlantic Chapter, in the Less than $50 Million Dams and Waterways category
  • Motts Run Water Treatment Plan, E. Boyd Graves Award, 2000, Historic Fredericksburg Foundation, Inc., for Excellence in Historic Preservation.

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