“I don’t think that’s very well understood by the public,” Col. Jeffrey Hall said during a town hall meeting to discuss the reservoir’s receding levels.
The water management program for Thurmond is based on “authorized purposes” including flood risk management, navigation, hydropower, recreation and fish and wildlife – in addition to providing drinking water and maintaining a river flow sufficient to assimilate treated industrial and municipal wastewater.
“The question that comes up is, with all those authorized purposes, how do you balance the needs?” he said.
A full lake – with a pool of 330 feet above sea level – makes it possible to fulfill all those purposes. But as water levels fall and flows into the river are reduced, water supply and water quality are on top.
Thurmond Lake – now 13.6 feet below full pool – is expected to fall to the 14-foot-low mark by early November, triggering a new level of the corps’ drought management plan that will reduce flows into the Savannah River to a weekly average of 3,100 cubic feet per second – the minimum needed to satisfy downstream needs.
The lake’s drainage basin, encompassing 3,254 square miles, has a 20.8-inch rainfall deficit over the past year, meaning it will require sustained precipitation to help it recover.
The long-range forecast shows some potential for relief, including a possibility of a weak El Nino weather pattern that could increase the chance of above-average rainfall from January through March.
Hall also told the crowd of about 300 people that funding has been obtained from South Carolina and other participants to continue the Savannah River Basin Comprehensive Study, which will focus on drought relief.
The region, he added, has a long history of droughts that include a “drought of record” in 1986-89, followed by two more from 1998 to 2002 and 2007-09.
Wednesday’s meeting was at McCormick Middle School.