Amherst town to withdraw water from county-owned lake due to drought

Town staff plan to place a diesel-powered pump at Thrasher Lake to pump into the Buffalo River should drought conditions worsen and threaten the town’s public water supply. In the long term, the town requests permission from the county to design a permanent controlled release structure at the lake like an existing system at Mill Creek Lake, which would eliminate the need for temporary pumps and generators during future drought emergencies.

The release of water will not exceed 1 million gallons per day. The Amherst County Service Authority will assist town representatives whenever outlet valves are being adjusted, and the water release will continue until such time as the drought has abated to the extent the town can withdraw from the Buffalo River in amounts sufficient to meet its demands.

Town Manager Sara McGuffin said Thrasher Lake is a better emergency alternative, and it experiences substantially less recreational activity than Mill Creek Lake and provides sufficient storage capacity to address drinking water needs in times of extreme drought.

“Southwest and Central Virginia continue to experience drought conditions,” McGuffin said in a memo to county officials. “While the Town's water treatment system is operating normally and water quality remains excellent, river flows have declined significantly.”

The town’s water treatment plant has a capacity of a million gallons per day, while its average daily demand is about half that total, according to McGuffin. The town has mandatory water restrictions in place for its utility customers and should permitted withdrawals decline to a certain point it would enter emergency operating conditions, McGuffin said.

“At that point, the Town would have little operational flexibility to respond to equipment failures, fires, leaks, unusually high demand, or other unexpected events,” McGuffin wrote in the memo. “At 0.5 [million gallons per day], the Town has reached its operational average, leaving no reserve capacity. Currently, the Town does not anticipate an interruption in water service. However, prudent planning requires preparing now for the possibility that river levels could decline to the point where supplemental flows become necessary to maintain a safe and reliable public water supply.”

This year’s river flow is the lowest that has been seen in several years and is being compared to the drought of record in 2002, McGuffin said.

Under the town’s water withdrawal permit through the Virginia Department of Environmental Quality, water released from Thrasher Lake would increase the flow of the Buffalo River and become available for withdrawal at the town's downstream intake, and increase the amount the town is permitted to withdraw on a one-to-one basis, McGuffin said.

“Any release would occur only after consultation with County staff and only if Buffalo River conditions threaten the Town's ability to maintain an adequate drinking water supply,” McGuffin’s memo states. “Water would be released only in the quantity and for the duration necessary to protect the public water system. This advance authorization would allow both local governments to respond immediately should conditions worsen, rather than delay action while approvals are sought during an emergency.”

Based on current projections, any emergency pumping would be temporary and limited to the amount necessary to maintain essential public water service. Thrasher Lake's normal pool capacity equates to 155 million gallons, according to county documents.

The effect on Thrasher Lake would be roughly a 4-foot reduction in lake elevation, McGuffin said. 

“Town staff believes these temporary impacts would be minimal compared to the importance of ensuring a continuous supply of safe drinking water for residents, businesses, schools, healthcare facilities, and industry throughout the region,” McGuffin wrote to county leaders. “This request represents a contingency planning measure intended to ensure that our regional water system remains resilient during extraordinary drought conditions while preserving the County's recreational assets whenever possible.”

McGuffin said the town hopes improving weather conditions will make the authorization unnecessary.

“When the Buffalo gets low, we don't have a lot of other options," she said of the need for another water source. 

The town utility’s interconnection with the service authority cannot serve all the town, according to McGuffin. She said recent rainfall got the river back to an allowable withdrawal level, but it dropped by the Sept. 1 meeting.

“With this dry weather, if we continue to see that decrease, we will be going into emergency water restrictions, and we'll be looking at this withdrawal point, so it really is just contingent on the weather,” McGuffin told the board. “Statistically, most droughts last approximately 90 days, and they are most likely during July, August, and September. We're really hoping that this is going to end soon, but right now, it's still very low, and we would run it only the amount we needed to.”

Supervisor Claudia Tucker said she is glad Mill Creek Lake is not being used as a backup source. 

“If we can't get what we want from Thrasher’s, as big and as deep as [the lake] is, we got a lot more problems, and I don't think that Mill Creek is a solution,” Tucker said.

McGuffin said Thrasher Lake is an extremely deep lake.

The town’s official Facebook page on Thursday said due to ongoing drought conditions and reduced water availability, the town utility will temporarily purchase water from the Amherst County Service Authority to help maintain an adequate and reliable water supply.

As the town transitions to the ACSA water supply and makes adjustments to the system, customers may temporarily notice changes in the appearance, taste, or odor of the water; changes or fluctuations in water pressure, temporary discoloration or other minor changes.

The water remains safe to drink and use, the town’s Facebook page notice said.

Town customers who experience any water-related issues or have questions or concerns can call (434) 946-7885.