Creation of Emergent Sandbar Habitat (ESH) in the Headwaters of Lewis and Clark Lake and the Impacts on Water Quality.

摘要

The U.S. Fish and Wildlife Service (USFWS) issued a Biological Opinion (BiOp) with recommendations for the U.S. Army Corps of Engineers (Corps) operations of the Missouri River Mainstem System for protection and enhancement of threatened and endangered species. The BiOp found that the Corps' operations on the Missouri River were not likely to jeopardize the endangered interior least tern (Sterna antillarum) and threatened piping plover (Charadrius melodus) populations if the Reasonable and Prudent Alternative (RPA) set forth in the BiOp was implemented. The RPA includes recommendations for the mechanical creation and maintenance of Emergent Sandbar Habitat (ESH) as nesting habitat for these two species in terms of habitat acres per river mile. In accordance with the BiOp, the Corps is conducting ongoing efforts to create and/or reclaim a sufficient amount of ESH to stabilize, and eventually recover, interior least tern and piping plover populations along the Missouri River. The Missouri River reach from Gavins Point Dam upstream to the confluence of the Niobrara River, which includes Lewis and Clark Lake, has been identified as a priority reach for both the interior least tern and piping plover. A project to create ESH in the upper reaches of Lewis and Clark Lake was implemented by the Corps during the period September 2006 to November 2008. Hydraulic dredging was used to construct two ESH complexes. The dredged material for building the sandbars was obtained from the delta of deposited material at the inflow of the Missouri River to Lewis and Clark Lake. Lewis and Clark Lake is utilized for source water by two rural water districts that provide public drinking water; Cedar Knox Rural Water District (CKRWD) and the Bon Homme-Yankton Rural Water District (BYRWD). The City of Yankton draws source water for drinking water use from the Missouri River approximately 5 miles downstream of Gavins Point Dam.