Surveying and Monitoring Constructed Chutes on the Missouri River

Science Center Objects

The construction of side-channel chutes has emerged as one method for restoring Missouri River habitat through the introduction of slow velocity and shallow depth water areas.  To better understand the processes that create and maintain this habitat, the USGS Nebraska Water Science Center in partnership with the U.S. Army Corps of Engineers, has completed hydrographic and topographic surveys of seven Missouri River chutes and three backwaters as well as monitoring suspended sediment transport in constructed chutes on the Missouri River.

Chutes and backwaters have been constructed by the U.S. Army Corps of Engineers (USACE) to increase the amount of available shallow water habitat to support threatened and endangered species along the Missouri River. The USGS Nebraska Water Science Center has cooperated with the USACE since 2005 to survey constructed shallow water habitats.  Hydrographic data from chute and backwater surveys aid the USACE in assessing the amount of available shallow water habitat, the effects of river flow on evolving morphology of the chutes and backwaters, and the functionality of the chute and backwater designs. 

Map showing hydrographic survey data for Kansas Chute along the Missouri River
Hydrographic survey data for Kansas Chute.

Hydrographic and Topographic Surveys, seven Missouri River chutes and three backwaters

Chutes and backwaters were surveyed using a singlebeam echosounder and a real-time kinematic (RTK) global navigation satellite system (GNSS). Transects were spaced 100 ft apart on chutes; a 250 foot grid was used in backwaters. Hydrographic data were collected along transects extending across the channel from top of bank to top of bank. Transect segments with water depths greater than 1 meter were surveyed using a single-beam echosounder to measure depth and a differentially corrected global positioning system to measure location. These depth soundings were converted to elevation using water-surface-elevation information collected with a RTK GNSS. Transect segments with water depths less than 1 meter were surveyed using RTK GNSS. Surveyed features included top of bank, toe of bank, edge of water, sand bars, and near-shore areas. Chutes surveyed included Council chute, Plattsmouth chute, Tobacco chute, Upper Hamburg chute, Lower Hamburg chute, Kansas chute, and Deroin chute.  Backwaters surveyed included Ponca backwater, Plattsmouth backwater, and Langdon backwater. 

Daily discharge measurements were made in the main channel of the Missouri River upstream from each chute and in the chutes. These surveys were completed yearly 2011-2015.

2011 Missouri River Flood

The effects of the 2011 Missouri River flood on these chute and backwater habitat restoration sites were substantial.  Deposition of sediment occured at Ponca Backwater, Plattsmouth Backwater and Chute, and Langdon Backwater.  Erosion occurred at Council Chute, Upper and Lower Hamburg Chute, Kansas Chute, and Deroin Chute.  Deposition, erosion, and damage to site control structures changed the structure and function of these sites, and many control structures required repair and maintenance.

Monitoring Suspended Sediment Transport, Kansas Chute and Upper Hamburg Chute

The USGS Nebraska Water Science Center, in partnership with USACE, monitored the 2012 suspended-sediment fluxes in and around Upper Hamburg chute near Nebraska City, Nebraska and Kansas chute near Peru, Nebraska.  Discrete suspended sediment samples were collected by boat from the upstream section of Kansas chute and from the downstream section of Kansas chute and Upper Hamburg chute.  In addition, discrete suspended sediment samples were collected upstream and downstream of the chute within the main-stem Missouri River.  Suspended sediment samples were also collected by autosamplers and readings of turbidity, temperature, and pH were made every 15 minute at the upstream and downstream sampling locations in the chutes.  In addition, acoustic velocimetry was recorded every 15 minutes at one location within each chute to estimate discharge and velocity.  Simple linear regression models were developed to relate turbidity data to suspended sediment and the turbidity surrogate was used to estimate sediment fluxes.  Once characterized, the flux estimates will be used to identify hydrologic conditions that generate erosional and depositional processes within the chute. 

Upper Hamburg chute along the Missouri River
Upper Hamburg chute (Public domain.)