Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 4, 1995
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 and 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. In this study the sediment on the bottom of the channels of the Goodwin Creek Watershed was studied to determine its effect on the stability of the bed and banks of the channels of the watershed. The mean size of the bed sediment ranged from 0.5 to 7.4mm over the watershed. These size changes were related to the processes of movement and the location of sediment source areas. An understanding of these processes of movement and storage of the sediment is critical for improving knowledge of the factors that cause channel instability.
Technical Abstract: The Goodwin Creek Research Watershed drains a 21.3 sq. km area in the bluffline hills just east of the Mississippi River flood plain in the north central part of the state of Mississippi. In the spring of 1994 bed material was sampled in 14 reaches of the watershed. The mean length of the reaches was about 1000 m. Median grain diameter of the bed material ranged from 0.5 - 7.4 mm over the watershed. The bed material in the upper reaches of the watershed is predominantly composed of sand (D50 = 0.5 mm ). In the central parts of the watershed there are many sources of gravel and the size of the bed material coarsens. In the last 3 km of the main channel there are no major tributaries and the median size of the bed material decreases from 7 mm to 1 mm. This decrease in size is attributed to selective deposition of the coarse material in the bars on the inside of several bendways. These size variations are likely related to the mechanisms by which gravel is transported through the watershed.