Impact of climate change on sediment yield in the Mekong River basin: a case study of the Nam Ou basin, Lao PDR

Abstract

Abstract. This paper evaluates the impact of climate change on sediment yield in the Nam Ou basin located in northern Laos. Future climate (temperature and precipitation) from four general circulation models (GCMs) that are found to perform well in the Mekong region and a regional circulation model (PRECIS) are downscaled using a delta change approach. The Soil and Water Assessment Tool (SWAT) is used to assess future changes in sediment flux attributable to climate change. Results indicate up to 3.0 • C shift in seasonal temperature and 27 % (decrease) to 41 % (increase) in seasonal precipitation. The largest increase in temperature is observed in the dry season while the largest change in precipitation is observed in the wet season. In general, temperature shows increasing trends but changes in precipitation are not unidirectional and vary depending on the greenhouse gas emission scenarios (GHGES), climate models, prediction period and season. The simulation results show that the changes in annual stream discharges are likely to range from a 17 % decrease to 66 % increase in the future, which will lead to predicted changes in annual sediment yield ranging from a 27 % decrease to about 160 % increase. Changes in intra-annual (monthly) discharge as well as sediment yield are even greater (−62 to 105 % in discharge and −88 to 243 % in sediment yield). A higher discharge and sediment flux are expected during the wet seasons, although the highest relative changes are observed during the dry months. The results indicate high uncertainties in the direction and magnitude of changes of discharge as well as sediment yields due to climate change. As the projected climate change impact on sediment varies remarkably between the different climate models, the uncertainty should be taken into account in both sediment management and climate change adaptation.

Multi-model ensemble simulation and projection in the climate change in the Mekong River Basin. Part I: temperature

“…It was indicated that the rise in global-average surface air temperature (SAT) has been increased with an updated trend of 0.74°±0. 18°C during 190618°C during -200518°C during (IPCC 2007, and is likely to increase by 1.8 to 4.0 o C by the end of the twenty-first century depending on various greenhouse gas emission scenarios (Shrestha et al 2013). Global warming inevitably exerts considerable impacts on human beings, the environment, and economic and social developments, and these impacts have urged the scientific and social communities to improve the understanding of the cause and consequence of the phenomenon (Jiang et al 2008;Miao et al 2012).…”

Recent changes in climate, hydrology and sediment load in the Wadi Abd, Algeria (1970–2010)

“…Studies have compared trends in hydrological and sediment time series to land use changes (Wang et al, 2007;Memariam et al, 2012;Gao et al, 2012). Climate projections are consistent regarding warming and the acceleration of the water cycle (IPCC, 2013), however, they remain to be defined on sediment transport where projections show a high uncertainty (Shrestha et al, 2013;Lu et al, 2013). This is in part due to the fact that climate affects many factors controlling sediment yield, such as surface moisture availability, weathering processes and rates, and the nature of riparian vegetation (Nanson et al, 2002).…”

Integrated assessment of the impact of climate and land use changes on groundwater quantity and quality in the Mancha Oriental system (Spain)

“…Numerical hydrological models have been used to estimate global change impacts on the surface processes of a watershed (e.g., Caballero et al, 2007;Mango et al, 2011;Shrestha et al, 2013;Ma et al, 2014). Those models are also useful tools to deal with the uncertainties on the impacts of climate change associated with the hydrological processes (Kingston and Taylor, 2010;Xu et al, 2011).…”