Event Title

Discontinuities in sediment transport caused by flow disruption at stream flow diversions

Presenter Information

Paul Grams

Location

ECC 303/305

Event Website

http://water.usu.edu/

Start Date

4-6-2007 2:30 PM

End Date

4-6-2007 2:50 PM

Description

Individual stream flow diversions extract water from streams and have the potential to disrupt sediment flux by altering transport capacity and by extracting a portion of the sediment load. The cumulative impact of many diversions over a period of many decades has the potential to cause channel change associated with either sediment deficit or surplus conditions and decreased magnitude of floods. In 2006, we initiated a program of stream flow, sediment transport, and channel morphology measurements in the Cub River watershed in southeastern Idaho where three large diversions have been operating for more than 100 years. Highest flows and highest rates of transport in the lower part of the watershed occurred earlier in spring than runoff in the upper watershed. During the peak of the snowmelt pulse, flow and sediment transport rates were greatest in the upper watershed and decreased downstream as flow was extracted by diversions. This indicates that the flux of sediment from the upper to the lower watershed is not continuous and that some segments of the stream may have a sediment surplus while other segments may have a sediment deficit. Estimates of total sediment flux for the 2006 runoff suggest that surplus conditions might exist where the channel is affected by only one or two diversions and that deficit conditions might exist further downstream where the channel is affected by a third diversion. The impacts of these patterns of flow and transport on channel morphology are under continued investigation.

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Apr 6th, 2:30 PM Apr 6th, 2:50 PM

Discontinuities in sediment transport caused by flow disruption at stream flow diversions

ECC 303/305

Individual stream flow diversions extract water from streams and have the potential to disrupt sediment flux by altering transport capacity and by extracting a portion of the sediment load. The cumulative impact of many diversions over a period of many decades has the potential to cause channel change associated with either sediment deficit or surplus conditions and decreased magnitude of floods. In 2006, we initiated a program of stream flow, sediment transport, and channel morphology measurements in the Cub River watershed in southeastern Idaho where three large diversions have been operating for more than 100 years. Highest flows and highest rates of transport in the lower part of the watershed occurred earlier in spring than runoff in the upper watershed. During the peak of the snowmelt pulse, flow and sediment transport rates were greatest in the upper watershed and decreased downstream as flow was extracted by diversions. This indicates that the flux of sediment from the upper to the lower watershed is not continuous and that some segments of the stream may have a sediment surplus while other segments may have a sediment deficit. Estimates of total sediment flux for the 2006 runoff suggest that surplus conditions might exist where the channel is affected by only one or two diversions and that deficit conditions might exist further downstream where the channel is affected by a third diversion. The impacts of these patterns of flow and transport on channel morphology are under continued investigation.

https://digitalcommons.usu.edu/runoff/2007/AllAbstracts/43