Application of Landsat 8 OLI Image and Empirical Model for Water Trophic Status Identification of Riam Kanan Reservoir, Banjar, South Kalimantan

Abstract

Remote sensing has a potential for observing, mapping and monitoring the quality of lake water. Riam Kanan is a reservoir which has a water resource from Riam Kanan River with the area width of its watershed about 1043 km2. The accumulation of nutrient in this reservoir simultaneously deteriorates the condition of waters, which can cause an increasingly growth of harm micro algae or Harmful Algal Blooms (HABs). This research applied Carlson’s trophic status index (CTSI) at Riam Kanan Reservoir using Landsat-8 OLI satellite image. The Landsat 8 OLI image was recorded on 14 August 2016 and was used in this research based on its surface reflectance values. The result of correlation test shows that band 3 of the image as coefficient of chlorophyll-a parameter, channel 2 as coefficient of phosphate, and band ratio of SDT as coefficient of SDT. Based on the result of modelling using CTSI, the majority scale of CTSI score at Riam Kanan Reservoir is between 60 to70 in medium eutrophic class. The class of medium eutrophic at Riam Kanan Reservoir potentially emerges the threat both of the improvement of water fertility and the reduction of water quality. Improvement of the fertility is apprehensive since it can trigger an explosion of micro algae which will endanger the ecological condition at the area of Riam Kanan Reservoir.