wildlife, and other issues. In 2014 zebra mussels, an aquatic invasive mussel were discovered in the lake and have infested the reservoir and the Missouri River downstream of Gavins Point Dam. Lewis and Clark Lake is significantly impacted by sedimentation and siltation issues, diminishing the overall water surface area, water storage capacity, and recreational opportunities. Sediment carried by the Missouri River and Niobrara River is slowed and trapped within the reservoir due to the dam impounding and thus slowing the natural river flow. Studies show approximately 5.1 million tons of sediment are deposited in the lake each year, which contributes to the lake's increasing size of delta area on the western portions of the lake. Approximately 60% of the sediment comes from the Nebraska Sandhills via the Niobrara River. As of 2016, approximately 30% of the lake's overall surface area has diminished due to sedimentation deposits, and some figures project by 2045 approximately 50% of the lake will be diminished due to sedimentation deposits. Presently, there is no plan or solution to remove or slow the progression of the siltation within the lake. See also Gavins Point Dam Lake Yankton Missouri National Recreational River Santee Sioux Reservation List of dams and reservoirs in South Dakota List of dams and reservoirs in Nebraska List of dams and reservoirs in United States Further reading History of Lewis and Clark Lake - U.S. National Park Service External links U.S. Army Corps of Engineers, Gavins Point Project & Lewis and Clark Lake (Official site) Corps Lakes - Lewis and Clark Lake Recreation.gov - Lewis and Clark Lake Lewis and Clark State Recreation Area - Nebraska Game and Parks Commission Lewis and Clark Recreation Area - South Dakota Department of Game, Fish & Parks Springfield Recreation Area - South Dakota Department of Game, Fish & Parks References Reservoirs in Nebraska Reservoirs in South Dakota Lewis and Clark Bodies of water of Bon Homme County, South Dakota Bodies of water of Cedar County, Nebraska Bodies of water of Knox County, Nebraska Buildings and structures in Knox County, Nebraska Buildings and structures in Cedar County, Nebraska Bodies of water of Yankton County, South Dakota Tourist attractions in Bon Homme County, South Dakota Tourist attractions in Yankton County, South Dakota Tourist attractions in Cedar County, Nebraska Tourist attractions in Knox County, Nebraska Federal lands in Nebraska Water supply infrastructure in Nebraska Lakes of South Dakota Lakes of Nebraska