Riverbank Change Detection and Impact of Water Level Rise along Mekong River in Nong Khai Province of Northeast Thailand using Geo-Informatics Approach

Abstract

This study aims to examine the riverbank changes and the impacts of water level rise on the right bank of the Mekong River in Nong Khai province, northeast Thailand. The Normalized Difference Water Index (NDWI) technique was applied for the extraction of water features from LANDSAT imagery to detect the change. The result shows both erosion and accretion in the study area during the dry season between the year 2000 and 2014 analyzed by LANDSAT-7 TM images recorded on February 13, 2000 and LANDSAT-8 OLI images recorded on March 31, 2014. The total area of erosion is 0.89 sq.km or 555.90 Rais at average rate of 1.31 m/year whereas total area of accretion is 3.93 sq.km or 2,457.27 Rais at an average rate of 2.03 m/year. The morphological change of sandbars and river islets finds eroded/submerged area of 5.92 sq.km or 3,698.58 Rais and accreted area of 1.85 sq. km or 1,153.21 Rais. Digital Elevation Model (DEM) is applied together with the Mekong River channel data year 2014 to simulate the water level rise scenarios. The result identifies that agricultural land would be the most at risk of flooding, next are miscellaneous land (water body, sandbar, islet, etc.) and forest land respectively.