A multi-year study of problems with sediment at Lewis & Clark Lake shows, essentially, there are no easy answers.
The U-S Army Corps of Engineers held a public meeting this week to present its findings on the lake, which sits between northeast Nebraska and southeast South Dakota.
John Remus, chief of the Corps’ hydrologic engineering office in Omaha, says it was a complete evaluation on the lake.
The study was launched five years ago and the Corps promised it would let the public know what was found, Remus says.
The proposal was looking at the feasibility of removing sediment out of the delta near the Niobrara area, pushing it through the dam and downstream.
While the study indicates that some sediment, mostly fine particles, could be moved out of the lake, Remus says it would be very difficult to move any heavier material.
He says there’s no engineering feasibility for getting sand-sized sediment through the dam without extreme modifications.
Scenarios include lowering the lake eight-to-ten feet, while water release rates would range up to 176,000 cubic feet per second for anywhere from eight to 25 days.
Remus says no further action appears to be the best option. Corps officials estimate the lake has an effective life span of 175 years.
Jerry Oster, WNAX, Yankton