Trade-off analysis of water conservation and water consumption of typical ecosystems at different climatic scales in the Dongjiang River basin, China

Abstract

Water conservation is one of the most crucial ecosystem service functions and key to evaluating watershed protection and development. Water consumption is an important part of the water cycle and maintains ecosystem stability. The trade-off relationship between water conservation and water consumption in ecosystems at different climatic scales is a significant scientific issue in hydrological studies. The Dongjiang River basin has a very important strategic position and supplies water to the eastern part of Guangdong Province and Hong Kong. This study conducted a trade–off analysis of the water conservation and water consumption of typical ecosystems in the Dongjiang River basin at different climatic scales using the Soil and Water Assessment Tool (SWAT) model. The results revealed that first, the amount of water conserved in the Dongjiang River basin was far less than that consumed over the past 50 years. Regarding typical meteorological years, water consumption followed the order of wet year > normal year > dry year. Second, the average amounts of annual, wet season, and dry season water consumption were 22.611, 17.943, and 4.668 Bm³, respectively, whereas the average amounts of water conservation were 1.198, 1.609, and −0.411 Bm³, respectively. The water conservation and water consumption of different ecosystems fluctuated significantly between the dry and wet seasons, with stronger fluctuation in the dry season. Third, in terms of ecosystem types, water conservation followed the order of arbor forest > paddy field > other forest > grassland > dry cropland, and water consumption followed the order of arbor forest > other forest > paddy field > grassland > dry cropland. Lastly, the meteorological factor driving changes in water conservation was precipitation, and the factors influencing changes in water consumption were temperature and precipitation. This study can provide theoretical reference for ecosystem protection and sustainable management of water resources, and the results and conclusions have great significance to developments in hydrological research.