Modelling climate change impacts on the flood pulse in the Lower Mekong floodplains

Västilä, Kaisa; Kummu, Matti; Sangmanee, Chalermrat; Chinvanno, Suppakorn

doi:10.2166/wcc.2010.008

Cited by 150 publications

(124 citation statements)

References 28 publications

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“…Although difficult to make precise comparisons with previous studies (due to the use of different performance metrics and different study periods), the SLURP model used herein appears to be at least as good as previous attempts at modelling the Mekong. For example, observed-modelled differences in mean monthly flow in the study of Kite (2001) vary between +14 and −37 %; NS values for different sub-basins in the study of vary between 0.7 and 0.83; an NS value of 0.63 was achieved for Kratie (downstream of Pakse) discharge by Västilä et al (2010).…”

Section: Calibration and Validation Of The Slurp Hydrological Modelmentioning

confidence: 94%

Uncertainty in climate change projections of discharge for the Mekong River Basin

Kingston

Thompson

Kite³

2011

Hydrol. Earth Syst. Sci.

158

140

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Abstract. The Mekong River Basin is a key regional resource in Southeast Asia for sectors that include agriculture, fisheries and electricity production. Here we explore the potential impacts of climate change on freshwater resources within the river basin. We quantify uncertainty in these projections associated with GCM structure and climate sensitivity, as well as from hydrological model parameter specification. This is achieved by running patternscaled GCM scenarios through a semi-distributed hydrological model (SLURP) of the basin. Pattern-scaling allows investigation of specific thresholds of global climate change including the postulated 2 • C threshold of "dangerous" climate change. Impacts of a 2 • C rise in global mean temperature are investigated using seven different GCMs, providing an implicit analysis of uncertainty associated with GCM structure. Analysis of progressive changes in global mean temperature from 0.5 to 6 • C above the 1961-1990 baseline (using the HadCM3 GCM) reveals a relatively small but non-linear response of annual river discharge to increasing global mean temperature, ranging from a 5.4 % decrease to 4.5 % increase. Changes in mean monthly river discharge are greater (from −16 % to +55 %, with greatest decreases in July and August, greatest increases in May and June) and result from complex and contrasting intra-basin changes in precipitation, evaporation and snow storage/melt. Whilst overall results are highly GCM dependent (in both direction and magnitude), this uncertainty is primarily driven by differences in GCM projections of future precipitation. In contrast, there is strong consistency between GCMs in terms of both increased potential evapotranspiration and a shift to an earlier

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Section: Calibration and Validation Of The Slurp Hydrological Modelmentioning

confidence: 94%

Uncertainty in climate change projections of discharge for the Mekong River Basin

Kingston

Thompson

Kite³

2011

Hydrol. Earth Syst. Sci.

158

140

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“…The Mekong originates at the Tibetan plateau and crosses China, Myanmar, Laos, Thailand, and Cambodia before entering the territory of Vietnam. The Mekong's discharge of 475 km 3 /year makes it to one of the world's largest single-peak pulsing rivers [34]. Severe flood-pulse changes are expected to occur in the future due to regulatory measures (e.g., hydropower dams) upstream [33].…”

Section: Study Area: the Mekong Deltamentioning

confidence: 99%

Flood Mapping and Flood Dynamics of the Mekong Delta: ENVISAT-ASAR-WSM Based Time Series Analyses

et al. 2013

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Satellite remote sensing is a valuable tool for monitoring flooding. Microwave sensors are especially appropriate instruments, as they allow the differentiation of inundated from non-inundated areas, regardless of levels of solar illumination or frequency of cloud cover in regions experiencing substantial rainy seasons. In the current study we present the longest synthetic aperture radar-based time series of flood and inundation information derived for the Mekong Delta that has been analyzed for this region so far. We employed overall 60 Envisat ASAR Wide Swath Mode data sets at a spatial resolution of 150 meters acquired during the years 2007-2011 to facilitate a thorough understanding of the flood regime in the Mekong Delta. The Mekong Delta in southern Vietnam comprises 13 provinces and is home to 18 million inhabitants. Extreme dry seasons from late December to May and wet seasons from June to December characterize people's rural life. In this study, we show which areas of the delta are frequently affected by floods and which regions remain dry all year round. Furthermore, we present which areas are flooded at which frequency and elucidate the patterns of flood progression over the course of the rainy season. In this context, we also examine the impact of dykes on floodwater emergence and assess the relationship between retrieved flood occurrence patterns and land use. In addition, the advantages and shortcomings of ENVISAT ASAR-WSM based flood mapping are discussed. The results contribute to a comprehensive understanding of Mekong Delta flood

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“…The 2-D EIA Lower Mekong application covers an area of 430 km by 570 km from Kratie to the Mekong Delta at a grid resolution of 1 km 2 . An earlier version of this application was presented by Västilä et al (2010). Daily water levels from the 2-D EIA model were extracted and validated at Kampong Luong, where the main water gauge on the Tonle Sap's lake is located (see Fig.…”

Section: Modeling Approachmentioning

confidence: 99%

Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia

Arias

Piman

Lauri

et al. 2014

Hydrol. Earth Syst. Sci.

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109

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Abstract. River tributaries have a key role in the biophysical functioning of the Mekong Basin. Of particular interest are the Sesan, Srepok, and Sekong (3S) rivers, which contribute nearly a quarter of the total Mekong discharge. Forty two dams are proposed in the 3S, and once completed they will exceed the active storage of China's large dam cascade in the Upper Mekong. Given their proximity to the Lower Mekong floodplains, the 3S dams could alter the flood-pulse hydrology driving the productivity of downstream ecosystems. Therefore, the main objective of this study was to quantify how hydropower development in the 3S, together with definite future (DF) plans for infrastructure development through the basin, would alter the hydrology of the Tonle Sap's Floodplain, the largest wetland in the Mekong and home to one of the most productive inland fisheries in the world. We coupled results from four numerical models representing the basin's surface hydrology, water resources development, and floodplain hydrodynamics. The scale of alterations caused by hydropower in the 3S was compared with the basin's DF scenario driven by the Upper Mekong dam cascade. The DF or the 3S development scenarios could independently increase Tonle Sap's 30-day minimum water levels by 30 ± 5 cm and decrease annual water level fall rates by 0.30 ± 0.05 cm day −1 . When analyzed together (DF + 3S), these scenarios are likely to eliminate all baseline conditions (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000) of extreme low water levels, a particularly important component of Tonle Sap's environmental flows. Given the ongoing trends and large economic incentives in the hydropower business in the region, there is a high possibility that most of the 3S hydropower potential will be exploited and that dams will be built even in locations where there is a high risk of ecological disruption. Hence, retrofitting current designs and operations to promote sustainable hydropower practices that optimize multiple river services -rather than just maximize hydropower generation -appear to be the most feasible alternative to mitigate hydropower-related disruptions in the Mekong.

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Modelling climate change impacts on the flood pulse in the Lower Mekong floodplains

Cited by 150 publications

References 28 publications

Uncertainty in climate change projections of discharge for the Mekong River Basin

Uncertainty in climate change projections of discharge for the Mekong River Basin

Flood Mapping and Flood Dynamics of the Mekong Delta: ENVISAT-ASAR-WSM Based Time Series Analyses

Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia

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