Assessment of suspended sediment particles distribution pattern by using remote sensing approach and in-situ data to support coastal protection in Barito River mouth area, Indonesia

Abstract

Abstract With a total length of approximately 900 km, Barito River has become an important water transportation route in South Kalimantan Province of Indonesia for hundreds of years, by connecting major city such as Banjarmasin and other outback regions in its upstream with the Java Sea. This river is also known as mouth to other river branches such as Martapura, Kuin, Nagara and Tapin River. Unfortunately, the natural condition of Barito is degraded due to anthropogenic disturbances in the upstream. Intensified land clearing activities has caused a high volume of runoff and discharge, especially during the rainy season with a high intensity of rainfall, thus increasing the total suspended solids in waters surround the river mouth. On the contrary, the low intensity of rainfall during the dry season leads to a lower volume of runoff and discharge. This study aims to visualize the distribution pattern of Total Suspended Solids (TSS) in the coastal waters surround Barito River mouth during both rainy and dry seasons, which resulted from field observation (started from river body to the coastal waters) and Sentinel-2 image analysis. The result indicates a similar trend between satellite image analysis and in-situ measurement, where a high concentration of TSS is occurred during the rainy season and lower concentrations of TSS during dry seasons. From field observation, the concentrations of TSS ranges from 12 mg/l to 46 mg/l during the rainy season and from 1 mg/l to 65 mg/l during the dry season. From Sentinel-2 analysis, the concentrations of TSS ranges from 30 mg/l to 170 mg/l during the rainy season and from 5 mg/l to 50 mg/l during the dry season. During the rainy season, the concentration is high and distributed further towards the coastal waters due to the influence of high discharge and rainfall. While during the dry season, the concentration is lower and primarily distributed in the estuarine area due to the influence of discharge and tidal currents, both of which are equally significant. This study can be used by local government as a tool to control land use change in the upstream, protect coastal area and to mitigate the impact of natural disaster that could be caused by this event in the downstream.