Impacts of land use/land cover and climate change on hydrological cycle in the Xiaoxingkai Lake Basin

Study region: The Xiaoxingkai Lake Basin in China.Study focus: Watershed hydrological simulation is a prominent aspect of hydrology, however, comprehensive analysis of lake basins based on hydrological simulation is rarely conducted. Therefore, we used the Soil and Water Assessment Tool (SWAT+) with dynamic land use/land cover (LULC) input and time-varying parameters to simulate streamflow of the Xiaoxingkai Lake Basin and estimate the impacts of LULC and climate change on streamflow during 1961-2017. We also evaluated the contributions of LULC and climate change to water volume in Lake Xiaoxingkai through a lake water balance analysis.New hydrologic insights for the region: The simulated streamflow agrees well with observations at most stations (Nash-Sutcliffe Efficiency, NSE > 0.5, and goodness of fit, R2 > 0.8). Climate change has a positive effect on streamflow which dominates the streamflow variations during 1981-1995 and 2006-2017, whereas LULC change has a negative effect with a dominant role during 1996-2005. The volume of Lake Xiaoxingkai increased slightly at a rate of 0.12 x 106 m3 yr � 1, with climate change contributing the most (77.25 %) to the increase, followed by direct human activities (47.50 %) and LULC change (-24.76 %). This study facilitates a better understanding of the hydrological cycle in the Xiaoxingkai Lake Basin under changing environments and is helpful for regional water resource management.

Automated summary

A hydrological simulation study in the Xiaoxingkai Lake Basin, China, reveals that climate change has a greater impact on streamflow than land use/land cover changes. The volume of Lake Xiaoxingkai slightly increased during 1961-2017, with climate change contributing the most, followed by direct human activities and land use/land cover changes having a negative effect.