By Patrick BrayMay 31, 2019
TULSA - The U.S. Army Corps of Engineers Tulsa District is working around the clock to equalize flood pool percentages throughout its entire system of dams and reservoirs as a result of flooding this spring.
The district tries to maintain the flood pools - the pool of water that lies above the lake's conservation pool and used to regulate floodwater - at the same percentages. At both Keystone and Kaw lakes on the Arkansas River System, lake managers hold and release water in conjunction with each other.
"For example, if Keystone is at 50 percent flood pool and Kaw Lake is at 60 percent we could release a little additional water to equalize or, vice versa, hold water until we equalize," said Peat Robinson, Kaw Lake manager.
As water flows down the Arkansas River into Oklahoma, Kaw Lake is the first flood management structure designed to store water until it is released. The dam is designed to hold a greater amount of water flowing in, than what is released, allowing the Corps to minimize the impacts of high water brought on by heavy rains. During the floods this year the lake has seen record-high pools and record-high releases.
The level of Kaw Lake on May 31 was about 1,045 feet above sea level, which is about 35 feet above normal. Therefore, the dam released water at a record-setting pace of about 105,000 cubic feet per second for a period of time.
As Kaw Lake releases, further downstream near Sand Springs, Oklahoma, Keystone Lake must be ready to manage the excess water it will receive. However, only about 30 percent of the water that flows into Keystone Lake comes from Kaw, the rest is uncontrolled run-off.
Though lake managers do communicate well with each other, it is the hydrologists managing the system that maintain the vital communication link between the dams, similar to an air traffic controller controlling aircraft on an airfield.
"It is the hydrologists who make the determination on how much to open the gate as they try to keep us equal in percentage," said Robinson.
The dams in tandem act as a system by either storing or releasing water in conjunction with each other and are operated in accordance with the Tulsa District's water control manuals.
"Each lake has a water control manual that provides the guidelines for managing that reservoir," said Mike Abate, chief of the district's civil works branch. "We also have a system-wide water management plan that discusses the process of managing the entire system of water management reservoirs."
Tulsa District engineers and hydrologists are monitoring the situation 24/7 and continuing to update hydrology models to ensure public safety.
"During any flooding event, we work closely with district hydrology and hydraulics," said Kerri Stark, Tulsa District emergency management specialist. "As soon as they know they will have to make an increase in the releases at a dam, they notify us and lake personnel."
The Tulsa District emergency managers then notifies county emergency managers so they can prepare their communities.
"In the case of Keystone, we not only notified the Tulsa County EM, but we also reached out to the EMs in the communities of Sand Springs, Jenks, Bixby, and Broken Arrow," said Stark.
Meanwhile, recreation at Corps lakes has been impacted by flooding and rainfall.
"During a flood like this the number one challenge is the public safety aspect," said Dakota Allison, assistant lake manager at Kaw Lake. "Once the flood fight is over, we expect to have a lot of work ahead getting recreation sites back up and running."
Although many Corps boat ramps are closed due to flooding, the lakes remain open and at several locations commercial marinas continue to offer boat ramp access. The Tulsa District encourages all boaters to be especially aware of debris in the water in times of flooding and avoid boating over recreation areas, as there may be concrete picnic tables and other debris located directly below the surface of the water.
Tulsa District engineers continue to monitor dams to ensure they operate as designed and will continue to provide updates as the situation changes. Please visit our website for campground closure information at www.swt.usace.army.mil. A daily report of reservoir information is available at www.swt-wc.usace.army.mil.