By Tara Bahrampour
Washington Post Staff Writer
Thursday, January 29, 2009
A plan announced this week by Loudoun Water to use stone quarries to store untreated Potomac River water came after the utility spent years looking at how it could supply enough water to the eastern part of the county in the coming decades.
Under the proposal, which needs approval from regulators, the agency eventually would store 8 billion gallons of water in four quarries after Luck Stone, the company that owns them, is finished mining them. The first quarry would be converted in 2017 after construction of a water treatment plant nearby, said utility officials, who did not have an estimate of when the others would become available.
Loudoun Water serves about 55,000 customers in eastern Loudoun. As early as 2001, officials at the agency discussed "water banking," or storing water for use during times of scarcity, said Loudoun Water spokeswoman Samantha Villegas, adding that the drought of 2007 provided additional impetus to look into storage options.
The utility can purchase up to 50 million gallons of water a day from Fairfax County and up to 7 million a day from Fairfax City under agreements with those jurisdictions. But based on Loudoun's projected growth, the utility estimates it will need to supply 40 million more gallons a day by 2035.
Loudoun officials had considered increasing the amount coming from Fairfax County, a plan that would have eliminated the need to build a new Loudoun treatment plant. But they eventually concluded that the cost of transporting the water would outweigh the savings, Villegas said.
Under the new plan, Loudoun Water would begin drawing 20 million gallons a day from the Potomac in 2017 by putting its own intake in the river on property it owns. By 2035, that amount would double. It also would continue to receive 50 million gallons a day from Fairfax Water.
The utility would buy a $6.7 million parcel near Luck Stone's operation just southeast of Leesburg and share use of the property with the stone company. Luck Stone will seek permits to dig an additional quarry there. As the company finishes mining each of its quarries, it will allow Loudoun Water to use them. The utility plans to construct a $280 million treatment plant on its portion.
The quarries would give Loudoun Water more flexibility in meeting water demand, Villegas said. The utility would bank water during times of plenty and have enough to guarantee a 120-day supply during times of drought. The stored water also would be available to neighboring counties.
That last element helped sell the idea to environmental groups and the Interstate Commission on the Potomac River Basin, Villegas said. "We consulted them a lot as to what the impact would be . . . and for the most part we received lots of support."
Storing the water should help the county avoid "scenarios like 2007, where people were losing their landscapes," she said, adding that "without the quarry, I think this would have been a difficult quest." Villegas said trails eventually might be built around the reservoirs for recreational use.
The quarry proposal comes a year after the utility announced an $89 million, 10-year upgrade of the pipes and pumps that bring water from Fairfax County. Villegas said those improvements are still needed because Fairfax will continue to supply a large portion of Loudoun's water.
In the next few months, Loudoun Water will seek the necessary land-use permits from the county and a permit from the Army Corps of Engineers to withdraw water from the Potomac. Construction of the treatment plant is expected to start in 2012 or 2013 and be completed by 2016.