Estimation of behavioral change of SSC of bed profile in the river using ADCP

Abstract

Suspended sediment concentration (SSC) is one of the remarkable parameters for sediment transport calculation and their estimation. In another hand, the use of the conventional method comes with lots of limitations as compared to acoustic Doppler current profiler (ADCP). It is frequently used for velocity measurement and concentration of suspended sediment estimation (in dB) with the help of acoustic backscatter intensity. In present studying ADCP of 1200 kHz is used along with water sampler. A study area of river Ganga along Varanasi (length 10 km) is divided into six cross-sections for analysis. Suspended samples have been collected for SSC calculation in terms of mg/l. These samples were categorized into two parts; the first part was utilized for calibrating the backscatter and attributing the intensity to suspended particle concentration using a linear regression method. The second part was used for validation of acoustic intensity. Six years of observation data were used from year 2012 to 2017. As a result of backscatter intensity, it was visible that there is an increase in suspended sediment concentration load year by year along the river cross-section. When the bed profile was created, it was found that the bed profile of study cross-section has drastically changed at Raj Ghat cross-section (CS 6). This type of study is essential where river passing near any city because of the high rate of erosion and deposition may change the bed profile; this change can invite natural disaster. Also, this data can be further utilized for developing significant measures for existing Ghats and other hydraulic structures for present and future sustainability.