Impact of Climate Variability on Blue and Green Water Flows in the Erhai Lake Basin of Southwest China

Zhe Yuan,Xianyong Meng,Xiaofeng Hong,Bo Yan,Yongqiang Wang,Jijun Xu

doi:10.3390/w11030424

Abstract

The Erhai Lake Basin is a crucial water resource of the Dali prefecture. This research used the soil and water assessment tool (SWAT) and the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) to estimate blue and green water flows. Then the spatial and temporal change of blue and green water flows was investigated. With the hypothetical climate change scenarios, the sensitivity of blue and green water flows to precipitation and temperature has also been analyzed. The results showed that: (1) The CMADS reanalysis dataset can capture the observed probability density functions for daily precipitation and temperature. Furthermore, the CMADS performed well in monthly variables simulation with relative bias and absolute bias less than 7% and 0.5 °C for precipitation and temperature, respectively; (2) blue water flow has increased while green water flow has decreased during 2009 to 2016. The spatial distribution of blue water flow was uneven in the Erhai Lake Basin with the blue water flow increased from low altitudes to mountain areas. While the spatial distribution of green water flow was more homogeneous; (3) a 10% increase in precipitation can bring a 20.8% increase in blue water flow with only a 2.5% increase in green water flow at basin scale. When temperature increases by a 1.0 °C, the blue water flow and green water flow changes by −3% and 1.7%, respectively. Blue and green water flows were more sensitive to precipitation in low altitude regions. In contrast, the water flows were more sensitive to temperature in the mountainous area.

Highlights

The water resources availability has been affected by climate variability in the past decades, which has caused sustainability concerns in many parts of the world [1,2]
It can be found that the reanalysis daily temperature are quite tightly clustered around the probability density functions (PDFs) of gauge observations
Reanalysis daily temperature are quite tightly clustered around the PDFs of gauge observations

Summary

Introduction

The water resources availability has been affected by climate variability in the past decades, which has caused sustainability concerns in many parts of the world [1,2]. Previous studies have reported that climate variability can alter precipitation, evapotranspiration, soil water, and runoff [3,4,5]. Resulting in freshwater resources redistributing in spatial and temporal dimensions [6,7]. The water-holding capacity of the atmosphere has been increasing, and as a result, the hydrological cycle will be intensified [8,9] posing more challenges to water resource management. It is necessary to investigate the impact of climate variability on freshwater resources, which will assist policymakers and administrators to manage water resources in the context of climate change. Blue water, namely the surface and groundwater runoff directly generated from precipitation, has been emphasized by water resources assessment and management studies.

Results

Discussion

Conclusion