ENIVRONMENT ASIA

Volume 12, No. S, Month DECEMBER, Year 2019, Pages 36 - 47

Assessment of the lower ping river’s riverbank erosion and accretion, northern thailand using geospatial technique; implication for river flow and sediment load management

Nikhom Chaiwongsaen, Montri Choowong

Abstract Download PDF

The Lower Ping River downstream from the Bhumibol Dam has suffered from the excessive sedimentation. Rapid growth sandbars occur along the 129 km of the downstream reach within the succession of weirs. Severe riverbank collapses can also be detected locally. The objective of this research is to assess riverbank accretion/erosion using remote sensing and GIS techniques. Comparison of the 2007 and 2017 satellite images shows that total emerged island bar area increases up to 5,702,557 m2. The total riverbank erosion area is 1,150,943 m2 whereas the total of accretion area is over 10,561,530 m2. Digital Shoreline Analysis System (DSAS) software was used to determine the riverbank erosion/accretion rates. The DSAS output shows the average rate of erosion and accretion at 1.24 and 4.89 m/year. Rapid growth of sandbars is responsible for the shallowing and narrowing of river embankment leading to rapid overflow during flooding. The result from this study enables all authorities and stakeholders to recognize the specific locations, which have severely been affected by riverbank accretion and erosion.

Keywords

Lower Ping River, Sandbar, Riverbank erosion/accretion, Succession of weir

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