Riverbank changes along the Mekong River: Remote sensing detection in the Vientiane–Nong Khai area

Abstract

Riverbank erosion is a natural process, but often human activities can have a significant impact on the rates of morphological change. This paper aims to assess bank erosion problems in the Vientiane-Nong Khai section of the Mekong River, where the Mekong borders Thailand and Lao PDR. The study provides new and more accurate information about recent riverbank movement rates. The bank movement rates are quantified using two Hydrographic Atlases dated 1961 and 1992, derived originally from aerial photos and a field survey, and SPOT5 satellite images acquired on 4 December 2004 and 28 April 2005 with a resolution of 2.5 m in natural colours. Bank erosion and accretion rates on the left (Lao PDR) and right (Thailand) banks of the Mekong are analysed for two time periods: 1961-1992 and 1992-2005, respectively. The quantified average bank erosion rates were found to be slow, ranging from 0.8 to 1.0 m/a for the first and second analysis period, respectively. These average annual erosion rates are only 0.1% of the channel width, which is very low on a global scale. However, erosion rates were much higher for the islands in the river, 2.4 and 4.8 m/a for the two time periods. The quantified accretion for the main banks was 0.4 m/a during 1961-1992 and 0.7 m/a during 1992-2005, which for the islands increased from 0.6 to 6.4 m/a from the first to the second period. r

Morphological Response of the Brahmaputra–Padma–Lower Meghna River System to the Assam Earthquake of 1950

“…Conversely, the increase in width of the Jamuna River that occurred without an increase in braiding intensity during the 1990s probably did not result in additional energy dissipation. Bank erosion was found to increase along the Mekong River as a result of the trapping of sediment due to the construction of a reservoir (Kummu and Varis, 2007;Kummu et al, 2008). During the 1980s, the bank erosion rate along the Jamuna River was very high when the sediment supply dropped from its peak.…”

Analysis on River Bank Erosion-Accretion and Bar Dynamics Using Multi-Temporal Satellite Images

“…For short-term changes, the correlation between bank erosion/accretion rates and annual discharges varies from about 0.15 to 0.57 as shown in Figure 6. 0.83 5,6 0.88 5,7 0.87 7,8 0.82 6,8 r (i,j)a = Correlation between columns i and j.…”

“…Being alluvial in nature, floodplains of the rivers are predominantly formed of flood-borne sediments while their bank materials consist mostly of fine-grained cohesive sediments [4]. In such alluvial rivers, through continuous erosion accretion processes, the channels frequently change its meandering pattern from reach to reach [5]. On the other hand development works such as, bank protection measures like embankment, dam and bridge may also cause local morphological changes of river affecting the ultimate sediment balance of the river.…”

Assessing stream bank condition using airborne LiDAR and high spatial resolution image data in temperate semirural areas in Victoria, Australia

“…Several articles have also found multitemporal image data useful for identifying changes in stream and bank geomorphic characteristics. 18,22 Bank stability and bank condition have previously been mapped with some success in relatively homogenous natural tropical savanna riparian environments in the Northern Territory, Australia using the extent of bare ground and amount of canopy cover as explanatory variables mapped from high-spatial resolution satellite image data. 23 Airborne LiDAR data are important for collecting information on stream banks and riparian vegetation due to its capability to capture three-dimensional information on vegetation and banks at very fine spatial scales.…”