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Lake Mooney Reservoir
Future Water Supply SystemRocky Pen Run
A key component of the county's water supply system is the Lake Mooney Reservoir. This project has been in the planning and permitting phases for the past fifteen years.

Lake Mooney Reservoir was created by the construction of a dam approximately 2,000 feet upstream of the mouth of Rocky Pen Run, north of the Rappahannock River in Stafford County, Virginia. At a normal pool elevation of 230 feet mean sea level (msl), the reservoir surface area will be 503 acres, and will hold 5.3 billion gallons of water. Roller compacted concrete (RCC) construction has been proposed for the dam, which is planned to be 130 feet in height and 1,200 feet in length.

Water Withdrawal
The Lake Mooney Reservoir will be operated as an off-stream water storage reservoir, with water pumped from the Rappahannock River during periods of high water flow. River withdrawals are limited to those time periods when the water flow is above permitted minimums. Water will be withdrawn from the reservoir and treated at a new adjacent water treatment facility.

A 40 million gallon per day (mgd) Rappahannock River Pump Station will be located on the north shore of the river, approximately 4,500 feet downstream of the mouth of Horsepen Run and 10,000 feet upstream of the mouth of Rocky Pen Run. This pump station will draw water from the river, and pump it to an outfall on the reservoir shoreline through a 42-inch diameter, 2,600 foot-long pipeline.

Connecting to Existing Water System
Another pumping station will withdraw water from the reservoir and transfer it through a 36-inch pipeline to the treatment facility. The completion of the 30 mgd capacity raw water pump station would be located on the east side of Rocky Pen Run Valley below the dam site, and the treatment plant site located at the south end of Route 656. The ultimate capacity of the treatment plant would be approximately 25 mgd, in order to treat the projected maximum water demand.  From the treatment plant site, a 42-inch diameter finished water pipeline would extend to U.S. Route 17, where it would connect to the county's existing water distribution system.