Rain Could Prompt Large Releases from White River Basin Lakes
LITTLE ROCK, Ark. –– The Army Corps of Engineers is advising people in flood plains downstream of Beaver, Table Rock, Bull Shoals and Norfork dams in northern Arkansas and southern Missouri to maintain awareness and monitor lake levels and weather. These lakes remain nearly full from spring rains, and more rain is forecast in the coming days.
In the last 180 days, between 25-50 inches of rain has fallen across the White River Basin. The average is between 20-25 inches. During May and June much of the rainfall fell in areas that are not controlled by the White River dams. The uncontrolled runoff from those rains have kept the river high at Newport and Georgetown reducing our ability to lower lake levels without impacting farmers during their crucial planting time.
So what does this all mean?
“Our water control manual dictates how and when we can release water from our White River dams and we have been making maximum allowable releases from our lakes this spring although they have been holding more and more water,” said Col. Robert Dixon, Little Rock District commander. “Our lakes are performing as intended but they have limitations and cannot prevent all flooding.”
Once a lake is full, it has reduced capacity to lower downstream flood crests. Water still flowing into the lake must be released from the dam because there is no storage space left. This is sometimes referred to as “passing inflow.”
When passing inflow, a dam does not make conditions downstream any worse than what the natural condition the river would be without the dam in place. It is just that the dam is unable to do as much to reduce downstream flooding under those conditions.
“The reservoirs have limitations that Mother Nature can exceed, and sometimes she does,” said Dixon. “If the National Weather Service’s forecast for the next seven days holds true, we may need to make releases from Beaver, Table Rock, Bull Shoals and Norfork lakes.”
People in at-risk areas should stay in contact with local emergency officials. If larger than normal releases are required from a dam, warnings will go out through local emergency management channels.