Estimating Suspended Sediment Concentrations from SPOT Image: A Case Study in Danshuihe,Taiwan

Abstract

Remote sensing has been widely used in coastal water quality monitoring, several models have been established. High spatial and spectral resolution sensors, such as the Landsat TM, usually were used in estimating the suspended sediment concentrations in the coastal regions. But few people have used SPOT image in estimating suspended sediment concentrations. When studying the suspended sediment concentration in Danshui River in Taiwan, SPOT image was used because of its higher spatial resolution and Danshui River being not as wide enough as the coastal area. The grades map of suspended sediment concentration the entire river was acquired by use of maximum likelihood classification of SPOT band 1 and band 2. The result is tested by the measured data,and 15 samples of all 19 samples were correct, and the total accuracy is 78.8%. From the map of the river's suspended sediment grades, we can conclude that about 77% of the water quality is good. In mountain area, where the vegetation is good, the suspended sediment concentration is lower than that of city area, where the vegetation is not very good. And some drainage entrances can be found on the map.