Influence of Stratification and Shoreline Erosion on Reservoir Sedimentation Patterns

Şebnem Elçi, Paul A. Work, Earl J. Hayter
2007 Journal of Hydraulic Engineering  
Sedimentation in the main pool of a deep ͑maximum depth: 50 m͒, 227 km 2 hydropower reservoir was modeled using a three-dimensional numerical model of hydrodynamics and sedimentation for different wind, inflow, and outflow conditions. Short-term velocity measurements made in the reservoir were used to validate some aspects of the hydrodynamic model. The effects of thermal stratification on sedimentation patterns were investigated, since the reservoir is periodically strongly stratified.
more » ... stratified. Stratification alters velocity profiles and thus affects sedimentation in the reservoir. Sedimentation of reservoirs is often modeled considering only the deposition of sediments delivered by tributaries. However, the sediments eroding from the shorelines can contribute significantly to sedimentation if the shorelines of the reservoir erode at sufficiently high rates or if sediment delivery via tributary inflow is small. Thus, shoreline erosion rates for a reservoir were quantified based on measured fetch, parameterized beach profile shape, and measured wind vectors, and the eroded sediments treated as a source within the sedimentation modeling scheme. The methodology for the prediction of shoreline erosion was calibrated and validated using digital aerial photos of the reservoir taken in different years and indicated approximately 1 m / year of shoreline retreat for several locations. This study revealed likely zones of sediment deposition in a thermally stratified reservoir and presented a methodology for integration of shoreline erosion into sedimentation studies that can be used in any reservoir. JOURNAL OF HYDRAULIC ENGINEERING © ASCE / MARCH 2007 / 255 J. Hydraul. Eng., 2007, 133(3): 255-266 Downloaded from by IZMIR YUKSEK TEKNOLOJI ENSTITUSU on 10/18/16. Copyright ASCE. For personal use only; all rights reserved. Fig. 8. The sediment deposition thicknesses at Transects A and B with and without eroding shoreline sediments after 10 days of simulation JOURNAL OF HYDRAULIC ENGINEERING © ASCE / MARCH 2007 / 263 J. Hydraul. Eng., 2007, 133(3): 255-266 Downloaded from by IZMIR YUKSEK TEKNOLOJI ENSTITUSU on 10/18/16.
doi:10.1061/(asce)0733-9429(2007)133:3(255) fatcat:rkvo2ykunnaj3p6hb4u7zip4ea