The researchers say that predicting how sediment is carried in streams and rivers is difficult because a river bed is a complex arrangement of grains.
Says Dr Powell. "River gravel varies widely in size, spacing, packing and the geometrical arrangement of individual particles, and river beds often develop small-scale, temporary structures such as pebble clusters.
"Although these characteristics determine the amount of sediment that can be moved by a river, surprisingly little is known about the structural properties of river bed sediments, how they develop and how they influence the processes of water flow and sediment transport."
The researchers will use an artificial channel in a laboratory to simulate river flow under controlled conditions. A high precision laser scanner will be used to model the bed of the artificial river, including the size and arrangement of the grains from which it is made.
The flow over the bed will be measured using fluid visualisation - a technique that uses a laser to track the motion of very small neutrally buoyant particles suspended in the flow. The technique will allow the scientists to study how the flow of water changes and is changed by the shifting bed sediment. Finally, a device at the downstream end of the flume will trap sedimentary particles being rolled along the 'river' bed so that their characteristics can be identified.
"This innovative combination of measurements has not been made before," says Dr Powell. "The study represents an important opportunity to better understand how bed material character controls sediment movement in rivers."
The research is announced as the University of Leicester celebrates Big Green Week (October 25-31) which launches the University's commitment to c
|Contact: Dr Mark Powell|
University of Leicester