THE SIMPLIFIED OF SUSPENDED SEDIMENT MEASUREMENT METHOD FOR PREDICTING SUSPENDED SEDIMENT LOAD AS A BASIC OF RESERVOIR CAPACITY DESIGN AS RENEWABLE ENERGY RESOURCE

Abstract

The amount of suspended sediment discharge is often required in hydraulic structures design, such as reservoirs design, irrigation-canals design, etc.; but this data is often unavailable or the availability of such data is very limited. The most appropriate and precise method for determining of suspended sediment discharge in channels (or in rivers) is by sampling of suspended sediment as well as the velocity data directly from the channels. Due to many constraints of the field measurements and of the expensive cost to get the suspended sediment discharge data, measurements of suspended sediment, and of velocity are often taken only at certain positions, which are often not in accordance with the standard sampling methods.  These conditions resulted in inaccuracies in predicting suspended sediment discharge; thus, it is necessary to find a simple and an accurate method for determining suspended sediment discharge. The purpose of this study is to find how the suspended sediment concentration and how the velocity taken at certain positions in trapezoidal channels correlate with the suspended sediment discharge. The study also aimed to determine the possibility of errors, including finding correction factors to the improper suspended sediment sampling methods, that are still often carried out in the field. Location studies are focused on nine (9) segments of trapezoidal channel in Mataram Irrigation Channel, in Yogyakarta, Indonesia. The velocity and suspended sediment concentration profiles were measured by using Propeller Current meter and Opcon probes, respectively. The results of the study show that the suspended sediment discharge of trapezoidal channel can be obtained from the measurement of velocity and suspended sediment concentration profiles at z/B = 0.25, measured from the channel side, z, with B is the channel width.

Keywords velocity, suspended-sediment concentration, trapezoid channel, suspended-sediment discharge.