Experimental study of hydraulic-sediment properties on deltaic sedimentation in reservoirs

ABSTRACT: In investigation on the process of delta formation and its progress in the reservoir has been conducted. The process depends on hydraulic, sediment, and physical parameters of the reservoir and their associated parameters in the river. In this research, a number of influencing parameters, such as water and sediment discharges in the river, the reservoir flow depth and the entrance diverging angle of reservoir have been studied. For each run, the rate of bed changes and progression of bottom set and crest of a delta in specific stations have been observed and recorded. Submerged angle of sediment with d50= 1mm has been obtained between the range of 30-35 degrees. Using dimensional analysis and SPSS software for the independent variables (progression of bottom set and crest of delta) and the dependent variables (dimensionless time, water and sediment discharges, reservoir flow depth), a multiple linear regression model to experimental data is fitted. Regression analysis of experiment showed that the data in the range of observations and calculations during the middle and end are moving forward with a good match. Result showed that the average and standard deviation of discrepancy ratio (?) for the bottom set of delta are 0.97 and 0.141, and those for the crest are 1.007 and 0.216 which show a good prediction of model. Sensitivity analysis of the new model showed that the discrepancy ratio, (?), for the bottom set and the crest of delta are not sensitive to water discharge and flow depth in the reservoir. However, the parameter is sensitive to the bottom set and the crest of delta in high and low sediment rates, respectively