Submitted to: Gravel-Bed Rivers in the Environment
Publication Type: Proceedings
Publication Acceptance Date: April 1, 1997
Publication Date: N/A
Interpretive Summary: Understanding the movement of sand and gravel through the channels of a watershed is important for a variety of reasons. Movement a nd storage of the sand and gravel may fill reservoirs and reduce their capacity, may fill channels and cause flooding, may degrade water quality, and may cause instability of the channel banks which can cause the destruction of valuable land. One critical aspect needed to understand and predict the movement of sediments in streams is an accurate knowledge of the water velocity needed to move various size mixtures of sediments. In this paper the water velocity necessary to move different sizes of sand and gravel on the bottom of a stream is discussed. Accurate knowledge of the water velocity needed to move a given size of sand or gravel on the bottom of a stream is necessary for effective management of erosion and sedimentation on agricultural watersheds.
Technical Abstract: The shape of the curve relating reference shear stress and grain size for widely graded mixtures of sand and gravel is critical for defining the sediment maintenance flows necessary to flush a gravel-bed stream of excess fine sediment. The shape of this curve for mixed size sediment beds is poorly known and discrepancies have been found when a relation was derived from different laboratory and field data sets. More study and analysis with data collected from a wider range of flow and sediment conditions is necessary to clarify this relation.