Assessment of Turbidity-Concentration Relations in Different Sediment Sizes

Measurements of suspended sediments in rivers are important for understanding soil losses, controlling water pollution, planning and management of water storage structures,. due to temporal and spatial variation, measurement of suspended sediments is very difficult. the traditional technique for measuring concentration is direct water sampling method which has many sampling and laboratory difficulties. however, this technique is restrictive in its ability to provide continuous monitoring of suspended sediment concentration. turbidity measurement is an alternative indirect method to determined sediment concentration. changes in turbidity values depending on particles in water, sediment concentration can be estimated. this method is relatively cheap and easy, and it supply continuous monitoring with suitable calibrations. but it can be considered of particles and water properties effect on turbidity. this problem can be solved with more frequently calibration or definition of effective factors. in this study particles size affecting on turbidity values was investigated with using four different sediment sizes (0-50, 50-100, 100-200 and 200-250 micron) the highest turbidity values were determined for small size sediment and it decreased for bigger sediment size. clay content decreased of relationship between sediment and turbidity and caused reading error for high concentration (> 4 g l^-1). however r² values were obtained bigger than 0.90 for all treatments. as a result of this study it could be concluded that this method can be used for sediment concentration measurement with adequately accuracy besides cheap and easy using advantages.