Abstract
Sediment budget is a scientific quantitative measure to compute sediment source and sink. Sources of sediment includes sediment yield (SY), upstream sediment inflow whereas sink of sediment are associated with sediment extraction, sediment concentration and sediment outflow. Objective in this study is to understand the stability of each segment by assigning replenishment and sediment mining in eight segments of Kangsabati River named Khatra, Raipur, Lalgarh, Dherua, Mohanpur, Kapastikri, Panskura and Rajnagar. SY is estimated through overlay of soil loss and SDR using coupling models of Revised Universal Soil Loss Equation (RUSLE) and Sediment delivery distributed model (SEDD). Ackers-White method (1973) is applied to assess the sediment transport and concentration whereas sediment extraction rate computed from District Land Revenue Office (2002–2016). Result shows that maximum sediment source concentrated in Khatra (732,003 ton/y), Lalgarh (578,810 ton/y), Raipur (115,291 ton/y), Dherua (76,644 ton/y) and minimum sediment source in Mohanpur (40,113 ton/y), Kapastikri (21,487 ton/y) and Panskura (77 ton/y). In contrary, maximum sediment sinks observed in Mohanpur (323,219 ton/y), Kapastikri (170,910 ton/y), Lalgarh (150,026 ton/y), Rajnagar (8713 ton/y) and minimum sediment sink observed in Khatra (20,721), Raipur (74,968 ton/y) and Dherua (40,831 ton/y). According to DLRO, Mohanpur, Kapastikri and Lalgarh segments shares 48, 27 and 13% rate of mining including 131 mining sites out of 186. Therefore, massive sediment mining makes negative sediment bearing segments (sediment source < sediment sink) as Mohanpur, Kapastikri, Lalgarh and Rajnagar whereas massive sandbar deposition makes positive sediment bearing segments (sediment source > sediment sink) as Khatra, Raipur, Dherua and Panskura, respectively.