Sediment Management for Shallow Water Habitat Creation on the Missouri River

摘要

For the last several years the Corps of Engineers has engaged in a major effort torestore Shallow Water Habitat (SWH) on the Lower Missouri River to preventcontinued jeopardy of the federally-endangered Pallid Sturgeon. Much of the SWHhas been restored through the mechanical creation of side channel chutes, river topwidthwidening, and backwater excavation. Almost all methods require the removalof previously deposited alluvial sediments existing adjacent to the river as well as inthe floodplain. The number and size of these projects have created new challenges inthe management of this sediment. Issues with the reintroduction of sediment into theactive river system, such as nutrient loads, contaminants, impacts on downstreaminterests, and public perceptions, illustrate the wide variety of topics that complicatethe management of those sediments. Some of the issues are not well understood andthe process of sediment reintroduction can appear to be at odds with current nationalpriorities to keep sediments out of rivers. To help clarify the issues related tosediment management associated with SWH creation and to provide guidance forfuture projects, the Corps of Engineers (Corps) has initiated an independent review ofits practices by the Water Science and Technology Board of the National ResearchCouncil (NRC). Description of sediment displacement activities on SWH projectsand details of the NRC review will be discussed.