| Title: | Assessment of flow changes from hydropower development and operations in Sekong, Sesan and Srepok Rivers of the Mekong Basin |
| Authors: | Piman, T., T.A. Cochrane, M.E. Arias, A. Green and N.D. Dat |
| Year: | 2013 |
| Journal: | Journal of Water Resources Planning and Management |
| Volume (Issue): | 139(6) |
| Pages: | 723–732 |
| Article ID: | |
| DOI: | 10.1061/(ASCE)WR.1943-5452.0000286 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | model and/or data interface |
| Secondary Application Category: | reservoirs, ponds, lakes and/or other impoundment effects |
| Watershed Description: | 78,650 km^2 combined Srepok, Sesan, and Sekong (3S) Rivers, which drain portions of Cambodia, Lao PDR, and Vietnam. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | The Mekong River supports unique biodiversity and provides food security for over sixty
million people in the Indo-Burma region, but potential changes to natural flow patterns from
hydropower development are a major risk to the wellbeing of this system. Of particular
concern is the ongoing and future development of 42 dams in the transboundary Srepok,
Sesan and Sekong (3S) Basin which contributes up to 20% of the Mekong’s annual flows and
provides critical ecosystem services to the downstream Tonle Sap Lake and the Mekong
Delta. To assess the magnitude of potential changes, daily flows were simulated over 20
years using the HEC ResSim and SWAT models for a range of dam operations and
development scenarios. A 63% increase in dry season flows and a 22% decrease in wet
season flows at the outlet of the 3S Basin can result from the potential development of new
dams in the main 3S Rivers under an operation scheme to maximize electricity production.
Water level changes in the Mekong River from this scenario are comparable to changes
induced by the current development of Chinese dams in the Upper Mekong Basin and are
significantly higher than potential flow changes from the proposed 11 mainstream dams in
the Lower Mekong Basin. Dams on the upper sub tributaries of the 3S Basin have very low
impacts on seasonal flow regimes because most of those projects are run-of-river dams and
have small reservoir storages. Impacts on hourly flow changes due to intra daily reservoir
operations, sediment movement, water quality and ecology need further study. Strategic site
selection and coordinated reservoir operations between countries are necessary to achieve an
acceptable level of development in the basin and mitigate negative impacts to seasonal flow
patterns which sustain downstream ecosystem productivity and livelihoods. |
| Language: | English |
| Keywords: | Mekong; HEC-RESSIM; hydropower; dam operations; Asia |