How Much Water Is Withheld in the Upper Mekong's Hydropower Dams?
Abstract
The Mekong River originates in the Tibetan Plateau and flows through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. Its upper portion, the Lancang River, has abundant hydropower potential, which has been largely exploited during the three recent decades. To date, there are 10 large dams (volume larger than 100 Mm3) in the Lancang, controlling about 40% of the annual flow at Chiang Saen (the most upstream station of the Lower Mekong). The amount of water withheld in these dams is a potential source of controversy between China and downstream countries, because it affects both timing and volume of available water—it is believed, for example, that the Lancang's hydropower dams have contributed to the recent droughts in the Lower Mekong Basin. Assessing the real impacts of these dams is a challenging task owing to the chronic lack of data on reservoirs' storage and operating patterns. To overcome this challenge, we exploit satellite images and altimetry data. The analysis focuses on 10 reservoirs and is conducted in three steps. First, we estimate the relationship between water elevation and surface area (E-A curve) for each reservoir. To this purpose, we either use DEM data or water surface area data (derived from satellite images) paired with altimetry-derived water levels. Second, we convert each E-A curve into an Elevation-Area-Storage curve, with which we calculate storage variability over time. In the last part of our analysis, focusing on the period 2010-2020, we show how the total withheld storage changed over time, determine the impact of individual dams, and elucidate the role of reservoir filling strategies.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMH011.0016V
- Keywords:
-
- 1819 Geographic Information Systems (GIS);
- HYDROLOGY;
- 1855 Remote sensing;
- HYDROLOGY;
- 1856 River channels;
- HYDROLOGY;
- 1857 Reservoirs (surface);
- HYDROLOGY