Sediment Management for Shallow Water Habitat Creation on the Missouri River

For the last several years the Corps of Engineers has engaged in a major effort to restore Shallow Water Habitat (SWH) on the Lower Missouri River to prevent continued jeopardy of the federally-endangered Pallid Sturgeon. Much of the SWH has been restored through the mechanical creation of side channel chutes, river top-width widening, and backwater excavation. Almost all methods require the removal of previously deposited alluvial sediments existing adjacent to the river as well as in the floodplain. The number and size of these projects have created new challenges in the management of this sediment. Issues with the reintroduction of sediment into the active river system, such as nutrient loads, contaminants, impacts on downstream interests, and public perceptions, illustrate the wide variety of topics that complicate the management of those sediments. Some of the issues are not well understood and the process of sediment reintroduction can appear to be at odds with current national priorities to keep sediments out of rivers. To help clarify the issues related to sediment management associated with SWH creation and to provide guidance for future projects, the Corps of Engineers (Corps) has initiated an independent review of its practices by the Water Science and Technology Board of the National Research Council (NRC). Description of sediment displacement activities on SWH projects and details of the NRC review will be discussed.