LITTLE ROCK, Ark. – The U.S. Army Corps of Engineers is tracking Tropical Depression Cristobal’s path and is prepared to respond as the storm threatens the White River Basin with potentially heavy rains.
Cristobal enters the basin weeks after the Corps made surcharge releases from Beaver, Table Rock, Bull Shoals and Norfork Dams. Those surcharge releases ended last week as the reservoirs were dropped a foot below the top of their respective flood pools. These operations were in accordance to the White River Water Control Manual and had nothing to do with rainfall forecasts from Cristobal.
“The five White River Reservoirs are already high into their flood storage pools from heavy repeated spring rains,” said Little Rock District’s Chief of Hydraulics and Technical Services Branch, Mike Biggs. “We see Cristobal coming and are prepared to capture as much rainfall runoff as possible. If rainfall runoff exceed a reservoir’s storage capacity we’ll go into surcharge operations.”
Dam operations during a rainstorm are based on rain that has fallen and can be measured. Rainfall forecasts are not accurate enough to base operational decisions on.
“Because rainfall forecasts are inaccurate, pre-releasing would put downstream users at risk if rain developed below the dam instead of upstream,” said Biggs.
Rainfall amounts in the White River Basin are just above 140 percent of normal for the year. These totals make the spring of 2020 one of the wettest on record.
The Corps is advising areas downstream of the dams to begin assessing their respective plans and to begin taking the proper precautions. Landowners with belongings near the river’s edge should also begin making plans for high water.
Because of uncertainty in weather forecasts, releases will be made in response to the on-the-ground rainfall to best minimize flood damages. The Corps will try to give as much notice as they can before surcharge releases are required.
The Water Management staff has been and will continue to be engaged and proactive in responding to the conditions.
More information can be found on the Internet at www.swl.usace.army.mil, on Facebook at www.facebook.com/littlerockusace and on Twitter at www.twitter.com/usacelittlerock.
Release no. 20-068