Assessment of Dredging Techniques for LCLSMS

The U.S. Army Corps of Engineers is currently evaluating sediment flushing at Gavins Point Dam in Phase II of its Lewis and Clark Lake Sediment Management Study (LCLSMS) in support of the Missouri River Recovery Program (MRRP).

The Corps initiated the Phase II study in late 2012 and has completed the initial numerical modeling analysis of ten different management scenarios that range from annual flushing to major dam modifications and dredging.

In an effort to ensure the modeling results are as accurate as possible, the Corps is expanding the study and building a numerical model of the annual reservoir flush that occurs on the Niobrara River at Spencer Dam, near Spencer, Neb.

“The sediment that is flushed through Spencer Dam is the same sediment that is delivered to the Missouri River above Gavins Point Dam,” said Paul Boyd, Omaha District Hydraulic Engineer. “If this study can show that the numerical model accurately predicts a measured flush at Spencer Dam, our confidence in the results of the numerical model for Lewis and Clark Lake will be increased greatly.”

While the study is being expanded to include a model on the Niobrara River, Boyd says that the study will not analyze Spencer Dam management or quantify any downstream changes on the Niobrara River.

The Corps will develop and test the computer-based numerical model of Spencer Dam after collecting data in the coming months and integrate the lessons learned into the LCLSMS Phase II report, now scheduled for release in late summer 2015.

In addition to the numerical modeling in the LCLSMS, the Corps is currently completing a broad assessment of dredging techniques for sediment management at Lewis and Clark Lake.

Publication of that report is expected in early winter 2014.

[mappress]

Press Release, September 30, 2014