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Title: Hydropower’s hidden transformation of rivers in the Mekong
Abstract

Despite efforts to understand the hydrologic impact of hydropower dams, their influence on downstream river temperatures has gone unnoticed in data limited regions. Using 30 years of Landsat thermal infrared observations (1988–2018), we identified a relationship between dry season water temperature cooling trends and dam development in the 3S Basin, a major tributary of the Mekong River. Within a year of the beginning of operations of major dams in the 3S River Basin, rapid decreases in annual average dry season river temperature were observed ranging between 0.7 ° C and 2 ° C. Furthermore,in situwater temperature observations confirmed decreasing river temperature for two major dam development events. Evidence was found that the 3S outflow has been cooling the Mekong River downstream of the confluence, by as much as 0.8 ° C in recent years. Our findings are critically important for understanding how fish and aquatic ecosystems will behave in the future as more hydropower dams are built in the Mekong River Basin.

Authors:
; ; ;
Publication Date:
NSF-PAR ID:
10303264
Journal Name:
Environmental Research Letters
Volume:
15
Issue:
4
Page Range or eLocation-ID:
Article No. 044017
ISSN:
1748-9326
Publisher:
IOP Publishing
Sponsoring Org:
National Science Foundation
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