Estimation Of Average Suspended Sediment Concentration In A Flow Depth By One Sample

Abstract

In this research, an attempt has been made to have full understanding about thenature of the sediment in the flow. Due to the difficulties during flood periods, theattention was focused on the shortcut methods to measure the average sedimentconcentration in the water column. These methods use limited number of watersamples. Two groups of data have been utilized. The first group covers the field workin Tigris River at Sarai site and middle Euphrates canals. The second group is outsideIraq which covers Missouri River in Montana. The data of the first group has beenused for analysis of Imara’s semi-empirical equation for the measurement of theaverage concentration in the water column. In this equation, an empirical constant,(a) , was given a value of (10) in estimating the sediment load in the tributaries ofAdhaim River. A uniformity index was suggested, to analysis the vertical distributionof different kinds of sediment, and then uniformity index for different kinds ofsediment was calculated for Missouri river in the second group of data. The value ofthe empirical constant, (a) varied between (7.2) and (11.65) with an average value of(9.4) for group one data compared with the value of (10) used for the tributaries ofAdhaim River. This value was accepted with a significance level (α = 0.05). Theuniformity index gave a value close to (1.0) for clay and silt, and a value between (1.5)and (2.5) for sand depending on the sand’s grain size.