Contribution of ecological conservation programs and climate change to hydrological regime change in the source region of the Yangtze River in China

• Published in: Regional environmental change 2022-03, Vol.22 (1), Article 10
• Main Author: Luo, Kaisheng
• Format: Article
• Language: English
• Subjects: Climate Change; Climate Change/Climate Change Impacts; Climate effects; Conservation; Conservation of natural resources; Earth and Environmental Science; Ecological effects; Environment; Environmental aspects; Environmental risk; Floods; Geography; Global temperature changes; Hydrologic models; Hydrologic regime; Hydrology; Nature Conservation; Oceanography; Original Article; Regional/Spatial Science; Retention capacity; Rivers; Seasons; Stream discharge; Stream flow; Streamflow; Summer; Water conservation
• ISSN: 1436-3798; 1436-378X
• DOI: 10.1007/s10113-021-01874-z

Although their effectiveness has drawn some attention, the unique impact of ecological conservation programs on hydrology and the comparative relationship between these effects and those of climate change remain unclear. We developed a method to quantitatively evaluate the hydrological effect of ecological conservation programs by combining a hydrological model and mathematical method and assessed the hydrological changes attributed to ecological conservation programs (2005–2015) in the source region of the Yangtze River in China. Through improved water retention capacity, ecological conservation programs induce annual streamflow decreased by 57% and the summer flood decreased by 78%, decreasing these streamflow amounts by 60.71 m 3 ·s −1 and 160.14 m 3 ·s −1 , respectively. The ecological conservation programs decreased the streamflow concentration degree in the summer-flood season, indicating reduced river flood risk. However, climate change increased annual streamflow by 167.44 m 3 ·s −1 , which offset a large part of the decreased annual streamflow caused by the ecological conservation programs. Streamflow and streamflow concentration degree in the summer flood season increased by 366.16 m 3 ·s −1 and 0.27, respectively, resulting in a final increase of 206.02 m 3 ·s −1 in annual streamflow in the summer-flood season and an increased flood risk, offsetting some of the positive effects of ecological conservation programs. The ecological conservation programs generally exhibited beneficial hydrological effects; however, these improvements were largely nullified by the negative effects of climate change.