Journal metrics

Journal metrics

  • IF value: 4.256 IF 4.256
  • IF 5-year value: 4.819 IF 5-year 4.819
  • CiteScore value: 4.10 CiteScore 4.10
  • SNIP value: 1.412 SNIP 1.412
  • SJR value: 2.023 SJR 2.023
  • IPP value: 3.97 IPP 3.97
  • h5-index value: 58 h5-index 58
  • Scimago H index value: 99 Scimago H index 99
Hydrol. Earth Syst. Sci., 18, 5303-5315, 2014
https://doi.org/10.5194/hess-18-5303-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
18 Dec 2014
Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia
M. E. Arias1,5, T. Piman2, H. Lauri3, T. A. Cochrane1, and M. Kummu4 1Department of Civil and Natural Resources Engineering, University of Canterbury, Christchurch, New Zealand
2Mekong River Commission, Vientiane, Laos
3EIA Finland Ltd, Espoo, Finland
4Water & Development Research Group, Aalto University, Espoo, Finland
5Sustainability Science Program, Harvard University, Cambridge, USA
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 (1986–2000) 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.

Citation: Arias, M. E., Piman, T., Lauri, H., Cochrane, T. A., and Kummu, M.: Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia, Hydrol. Earth Syst. Sci., 18, 5303-5315, https://doi.org/10.5194/hess-18-5303-2014, 2014.
Publications Copernicus
Download
Short summary
Hydrological modeling and assessment tools were used to provide evidence of the expected hydrological alterations that hydropower development in the lower Mekong tributaries could bring to the Tonle Sap. The most significant alterations are in terms of water levels during the dry season and rates of water level rise/drop which are crucial for tree seed germination and fish migrations, and therefore major ecological disruptions are likely to follow.
Hydrological modeling and assessment tools were used to provide evidence of the expected...
Share