Loudoun Water’s Central Water Supply Program
The Loudoun Water Board of Directors’ action was a culmination of years of effort that included long-range planning, alternatives analysis, negotiation between potential partners and outreach to community interests. Alternatives included increasing the amount of water purchased from Fairfax Water, and the purchase and upgrade of an existing water treatment plant owned and operated by the City of Fairfax.
Fairfax Water utilizes an integrated system to provide Loudoun Water up to 50 MGD of water from the Potomac River and the Occoquan Reservoir. This system provides a dependable source of water and was evaluated as an alternative to the proposed water storage option. However, significant costs are associated with the water volume necessary to meet Loudoun County’s needs and include the cost of upgrading Fairfax Water’s existing intake on the Potomac River, extending an additional 35 miles of finished water lines through both developed and natural areas of Loudoun and Fairfax Counties (instead of the 6-8 miles contemplated with the proposed Central Water Supply Program) and incurring ongoing operating costs of a system that requires the pumping of water between elevations that differ by as much as 340 feet.
The City of Fairfax obtains water from the Goose Creek Reservoir and existing agreements allocate up to 7 MGD to Loudoun Water as available. Droughts in recent years have diminished stream flow in Goose Creek, however, and Loudoun Water has only been able to reliably depend upon 3 MGD from this source.
Loudoun Water’s decision to build its own Potomac River water supply, to better locate its future water treatment plant near an existing/future customer base, and to utilize quarries for water storage was made in light of the factors cited above.
Components of the Potomac Water Supply Program Approved by Loudoun County
Loudoun Water’s Potomac Water Supply Program consists of individual components: a new intake and pump station at the Potomac River; a water treatment plant located near the Dulles Greenway at Goose Creek; and raw, non-potable water storage in a quarry owned by Luck Stone Corporation located near the W&OD Trail at Goose Creek.
Potomac Intake and Pump Station
The Potomac Water Supply Program includes a water intake to be located in the Potomac River and on a 23 acre riverfront property that Loudoun Water acquired in 1993. Raw, non-potable water will be pumped from the river and conveyed to the remaining components of the system. Loudoun County’s Revised General Plan recommends that Loudoun Water may provide its own water supply option along the Potomac River. Use of this parcel for an intake was shown on an approved concept plan associated with the River Creek rezoning (ZMAP 1989-0015), and the pump station that is part of the intake component is permitted as a by-right use per the Loudoun County Zoning Ordinance.
Water Banking: Raw Water Storage in Existing Quarries
Key to the Potomac Water Supply Program is a unique concept described as Water Banking; using retired quarries for water storage after they have been fully mined. Raw, non potable water is deposited in the quarries during times when Potomac River flows are normal to high, then withdrawn in lieu of continued withdrawals from the river during times of drought or excess turbidity. In this way sufficient water can be treated to serve the demands of Central System customers without impacts to the river or to the water supply needs of other jurisdictions.
Loudoun Water’s public/private partnership and business agreements with Luck Stone have been instrumental to implementing the Water Banking concept. Four quarries situated in proximity to each other, as well as Loudoun Water’s proposed water treatment plant, afford the opportunity to store up to eight billion gallons of water and minimize Loudoun Water’s withdrawals from the Potomac during less optimal times. In this manner, Loudoun Water will be able to use quarries for a beneficial public purpose.
Fred Jennings, Chairman, Loudoun Water Board of Directors describes the contribution that Luck Stone has made in offering their quarries for water storage: “The Potomac River is a resource we treasure not only for our water source, but for its intrinsic value to the region. That’s why the partnership we’ve formed with Luck Stone and their participation in the Plan is so important and demonstrates our shared values for this resource. By offering their quarries a second valuable life as a storage reservoir, the entire region benefits by ensuring the Potomac is used wisely”.
Loudoun County has approved of the use of Luck Stone’s quarry located north of the W&OD Trail and east of Goose Creek (“Quarry A”) for Water Banking. It is anticipated that approximately 1 billion gallons of water will be able to be stored in this quarry alone once mining operations are complete in the 2017-2020 timeframe.
Water Treatment Plant
Loudoun County has also approved the construction of a water treatment plant within the Central System, north of the Dulles Greenway to the west of Goose Creek. The facility will be constructed in two phases. Phase I will result in the construction of a 20 MGD facility by approximately 2016 to serve the short term water needs of the Central System. The fully expanded 40 MGD facility will provide for future needs to the 2035-2040 timeframe. Water from either the Potomac River or Water Banking site(s) will be processed into finished drinking water at the treatment facility. From there it will enter the Central Water Supply System via a finished water line that extends under Goose Creek to an existing water line along Belmont Ridge Road, Rt. 659, connecting to local water lines and to Loudoun Water’s Broadlands and Brambleton water tanks located approximately 1.6 and 4 miles to the south, respectively.
Current Loudoun Water Efforts to Secure a Water Withdrawal Permit from the State of Virginia
Loudoun Water continues to focus its efforts on securing permit approvals from State and Federal Agencies in order to withdraw water from the Potomac River. Several pre-application meetings have been held with public agencies to keep them informed of Loudoun Water’s activities. On December 28, 2010, Loudoun Water filed a Joint Permit Application with the Virginia Department of Environmental Quality, the Army Corps of Engineers, and the Virginia Marine Resources Commission. Loudoun Water hopes to receive necessary permits from all three agencies this year. The plan is to have Loudoun Water’s new water treatment plant operational in 2016. The first quarry will be ready for its new life as a reservoir in 2017.