UPDATE: Lewis and Clark Sediment Management Plan

USACE delivers completed Phase 2 report Dec. 28, 2023

YANKTON, SD – Completion of the Phase 2 report for the Lewis and Clark Lake Sediment Management Plan (SMP) Study marks a major milestone with new answers and questions. MSAC and stakeholders will push to build upon these findings in Phase 3 expected to start this spring.

“There is no single solution and this report clearly shows the complex nature of the environment we are dealing with,” said Scott Kostal, MSAC executive director. He points out that this is the first time that a comprehensive approach has been taken to address sedimentation problems at the upper Missouri River system’s most endangered reservoir.

Annually, nearly 3.8 million cubic yards of sediment enter Lewis and Clark Lake. Additionally, an estimated one million cubic yards are deposited above the lake. Originally the open water at Lewis & Clark Lake spanned 25 miles upstream in 1955. In 2011, open water only reached 17 miles due to 30 percent of the reservoir’s storage capacity had filled with sediment.

Read the full reports here.

The process, partnerships, and products needed to complete this project will be used in future efforts on other reservoirs. An SMP is intended to be a living document. New technologies will emerge. The economic landscape will change, such as the $90 million investment planned for Nebraska state park and marina facilities on or near Lewis and Clark Lake. This is one study that can’t sit on the shelf.      It is intended to lead to one or more pilot projects and eventually outline steps toward achieving a sediment balance and reservoir/benefit sustainability.

MSAC expects to learn more about the potential cost for Phase 3 early in 2024. In November of 2023, MSAC requested full federal funding to move forward after learning about opportunities for economically disadvantaged areas. MSAC will continue to update stakeholders on the funding outlook to continue SMP development for the Lewis and Clark Lake region.