Assessment of potential and actual sediment influx into a tropical estuary using RS and GIS approach

Abstract

Abstract Sediment yield is the possible volume of sediments that a basin is capable of delivering to its watershed outlet. It is the function of its topography, and climate, including precipitation, land use land cover, soil distribution, and other factors associated with the rate of soil formation and its transportation. Modeling of sediment yield from a watershed enables computing quantitative estimates of sediments generated precisely at the micro watershed level. Revised Universal Soil Loss Equation (RUSLE) is an efficient model in the assessment of annual soil loss from a basin using remotely sensed data in the Geographical Information System (GIS) platform due to its high reliability, easy adaptability, availability of data, especially for the mountainous watershed. In the present study, assessment of sediment yield from the Gangolli river basin of Karnataka located on the central west coast of India is attempted based on satellite data, processed in the GIS platform following the RUSLE model, and its significance is discussed in terms of the basin morphometry. The basin has a total catchment area of 1513.04km2, spread on the western face of the Western Ghat region of the South Kanara district. The basin has a relief of 1200 m. It experiences a tropical environment, hot humid climate, and ~ 355 cm of annual precipitation. The basin is divided into three physiographical subdivisions; the high relief mountainous region of the Western Ghats, the residual hilly region with low relief, and coastal plains. The total actual sediment yield has been estimated to be 6,32,976.38 tons/yr− 1 and the potential yield is 23,26,047.61 tons/yr− 1. This study will help to strategize inland soil conservation planning as well as estuarine management.