Monitoring of Morphological Change in Lam Phachi River Using Geo-informatics System

Abstract

Nowadays, economic and industrial development along the Lam Phachi River in Ratchaburi and Kanchanaburi provinces is accelerating and increasing water demand. Therefore, weirs were built to preserve the water demand, and the sand extraction businesses were also carried out to support economic expansion. These activities resulted in river morphological change relative to the past. Additionally, climate change has resulted in a rapid change in river discharge and riverbank erosion each season. To monitor the morphology of the river, normalized difference water index (NDWI), soil adjusted vegetation index (SAVI), and a maximum likelihood classification were used to analyze the pattern using remotely sensed images obtained from the Thaichote satellite between 2013 and 2015 and the Sentinel-2A satellite between 2017 and 2019. The results indicated that the Lam Phachi River follows a dendritic drainage pattern, with similar characteristics of riverbank erosion in all directions. The rivers obtained from the NDWI extraction had an accuracy of 94.11% and an analytical precision of 95.15%. The SAVI results indicated an accuracy of 93.17% and a precision of 94.33%. The maximum likelihood classification results showed an accuracy of 96.67% and an analytical precision of 97.47%. The stream extraction method based on the maximum likelihood classification is the most accurate. It was found that the erosion was a lot in the middle of the river, and most of the deposition areas are found at the end of the river. However, the NDWI and SAVI extractions are less accurate in this study area due to water hyacinth and a slight difference in water content between the riverbank and the water bodies. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.