Monday, September 12, 2016

Goose Creek

Goose Creek Reservoir was created by building a 20 foot high dam on Goose Creek in 1961. The reservoir was designed to hold 325 million gallons of water, but that was soon reduced by the buildup of silt. As water demand continued to grow, it was necessary to expand the water storage by building a second dam and reservoir on the same creek to provide an emergency 120 day supply of water.

Beverdam Creek Reservoir was finished in 1972 and added over 1,340,000 million gallons of water storage. As the watershed for Beaverdam Creek Reservoir is small, pumps allow it to pump water from Goose Creek to fill the reservoir. The reservoir was not designed to refill during times of drought, but to be the backup water supply when Goose Creek River flow got too low.

In January 2014, Loudoun Water acquired all the water infrastructure located in Loudoun County from the City of Fairfax, including Beaverdam Creek Dam and Goose Creek Dam. As the new reservoir owner, Loudoun Water assumed the responsibility to maintain and repair the dams to protect public safety, meet operational objectives and meet ecological needs for water. How Goose Creek is being used to meet water supply demands in Loudoun County has come into question. Until last year the Beaverdam Reservoir had always released water during dry periods in August and September and during droughts to maintain the flow in Goose Creek. However, according to the Loundoun Soil and Water Conservation District on September 9th of last year and again on September 27th Goose Creek ran dry during the day.
from LSWCD
When the City of Fairfax owned Beaverdam Creek Dam and Goose Creek Dam they pumped water out of the reservoir over a 24-hour shift at a relatively low rate. When Loudoun Water took over the operation of the dams they switched from a 24 hour pumping to a 12 hour pumping cycle. This shorter pumping cycle required a higher pumping rate and while Loudoun never allowed Goose Creek to go dry over a 24-hour period; on the 12-hour cycle, they were pumping more water than was freely flowing last September and the Creek ran dry during the pumping.

Various stakeholders held a series of meetings with Loudoun Water this past spring. What came out of the meetings is that Loudoun Water believed that they can cut off flow of Goose Creek, and are not responsible to supplement creek flow when it falls naturally. In meetings with the Conservation District Loudoun Water stated that the flow through Goose Creek is not Loudoun Water’s mission, rather their mission is water supply. Goose Creek is a state waterway and is regulated by Virginia’s Department of Environmental Quality (DEQ), and though DEQ requires a permit if average daily withdrawal of water exceed 10,000 gallons a day in any month, the regulation does not apply to them. The Beverdam Creek Dam and Goose Creek Dam reservoir operations were grandfathered under the regulations.

Loudoun Water is a state chartered Utility Company. It is a political subdivision of the commonwealth and not a department of Loudoun County. Loudoun Water is governed by a nine-member board who serve four-year terms and are appointed by the county’s Board of Supervisors. The company is funded by its customers water bills and it is required to spend money only its mission or delivering clean, safe water to its customers 24/7 and building and maintaining the infrastructure to do that. Loudoun Water was once primarily a wholesale customer of Fairfax Water, as the county has grown Loudoun Water has expanded rapidly to supplying 50 million gallons of water a day to customers, and faced new challenges.

Though, last spring Loudoun Water stated that the reason they switched to a 12-hour shift last summer was because staff needed to use a disinfectant in the water and that a 12-hour shift was necessary to keep the disinfectant active. This summer Loudoun Water switched back to operating the Goose Creek water plant 24 hours a day, which should allow them to operate at a lower pumping level during this month, the time when groundwater levels (which naturally supplement the creek are lowest). In addition, Loudoun Water plans to augment the flow in Goose Creek with water from Beaverdam Reservoir to keep Goose Creek flowing.

This appeares to be a significant change from Loudoun Water’s operating plans from last spring as reported by the Loudoun Conservation District. However, it may be that Loudoun Water has realized that if they were not withdrawing water from Goose Creek for water supply, the flow would always be adequate. Maintaining the natural resources including the river ecology of their essential resources is an essential portion of their mission. It appears that the operating philosophy of the Interstate Commission on the Potomac River Basin (ICPRB) has been incorporated into Loudoun Water’s management of Goose Creek.

The ICPRB manages the withdrawals of water from the Potomac River for all the utilities in the region while still maintaining a minimum flow in the river for sustaining aquatic resources. ICPRB allocates and manages water resources of the river through the management of the jointly owned Jennings Randolph Reservoir (built in 1981), Potomac River Low Flow Allocation Agreement (1978) and the Water Supply Coordination Agreement in 1982 which designated a section of the ICPRB as responsible for allocating water resources during times of low flow. These steps improved reliability of the water supply and ensured maintenance of in-stream flows to meet minimum aquatic habitat requirements.

Segments of Goose Creek are the subject of a plan to reduce bacterial contamination, and a government working group has been meeting to develop management measures to address the contamination. Loudoun Water has been working on the plan with the ICPRB, DEQ, Loudoun and Fauquier counties, the Soil and Water Conservation District, and other groups. In addition, Loudoun Water is currently engaged in building a new raw water intake in the Potomac River and a new raw water pumping station adjacent to the Leesburg Water Filtration Plant. These are scheduled to be operational in 2017. To help them meet future water demands though times of drought Loudoun Water will be able to store more than 8 billion gallons of water in quarries that are being acquired and converted to reservoirs.

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