State Water Resources Research Institute Program
Project ID: 2007MO71B
Title: Relation Between Spatial Variation of Bed-Shear Stress Distribution and the Statistical Characterization of Bed Material in the Missouri River
Project Type: Research
Start Date: 3/01/2007
End Date: 2/28/2008
Congressional District: 9
Focus Categories: Sediments, Methods, Hydrology
Keywords: aggradiation, degradiation, sediments, sand-bed channels, spatial and temporal variability of bed-shear stress, grain size, surface water, hydrology,
Principal Investigators: Richardson, Jerry; Geekie, Richard
Federal Funds: $ 21,694
Non-Federal Matching Funds: $ 44,420
Abstract: Over the past decade, it has become increasingly important to accurately quantify potential aggradation and degradation in sand-bed channels. Although the interest in better quantification techniques is of primary interest to the design and evaluation of bridges for stream-stability and scour, the need to quantify aggradation and degradation is of interest to many other entities whose social or economic benefit is affected by the dynamic nature of river channels. Early work of Einstein, Colby, Shen, and others have documented that sediment transport processes vary by size fraction. Consequently, the statistical characterization of bed sediments should also vary and should differentiate whether the stream bed is aggrading or degrading. This proposal seeks to develop methods to evaluate aggradation and degradation potential based on the statistical variation of bed sediment gradations.
In this regard, both the spatial and temporal variability in boundary shear stress will be correlated to spatial and temporal variations in the statistical characterization of bed sediments. This analysis will be conducted using a one-dimensional sediment transport model which has the ability to model compute sediment transport by size fraction. Key to this study will be to use a model that characterizes the temporal at-a-station variation of boundary shear stress due to the turbulent nature of the flow.
The objective of this study will then be to develop a method to determine the spatial and temporal variability of the bed-shear stress from the statistical distribution of the sampled grain-size distributions. For this research a comprehensive set of bed sediment statistics obtained from Corps of Engineers and USGS samples from the Missouri River will be used. Hydraulic shear stress will be developed using a sediment-routing model similar to the model developed at Penn State University called (MIDAS).
It is anticipated that this research will lead to methods whereby aggradation/degradation can be predicted based on sampled bed sediments. It is anticipated that this preliminary study will be able to provide proof of concept so that additional funding can be obtained.
Progress/Completion Report, 2007 PDF
Progress/Completion Report, 2008 update, PDF