Abstract

Quantifying the long term impacts of climate and land cover change on streamflow is of great important for sustainable water resources management in inland river basins. The Soil and Water Assessment Tool (SWAT) model was employed to simulate the streamflow in the upper reaches of Heihe River Basin, northwestern China, over the last half century. The Sequential Uncertainty Fitting algorithm (SUFI-2) was selected to calibrate and validate the SWAT model. The results showed that both Nash-Sutcliffe efficiency (NSE) and determination coefficient (R2) were over 0.93 for calibration and validation periods, the percent bias (PBIAS) of the two periods were—3.47% and 1.81%, respectively. The precipitation, average, maximum, and minimum air temperature were all showing increasing trends, with 14.87 mm/10 years, 0.30 °C/10 years, 0.27 °C/10 year, and 0.37 °C/10 years, respectively. Runoff coefficient has increased from 0.36 (averaged during 1964 to 1988) to 0.39 (averaged during 1989 to 2013). Based on the SWAT simulation, we quantified the contribution of climate and land cover change to streamflow change, indicated that the land cover change had a positive impact on river discharge by increasing 7.12% of the streamflow during 1964 to 1988, and climate change contributed 14.08% for the streamflow increasing over last 50 years. Meanwhile, the climate change impact was intensive after 2000s. The increasing of streamflow contributed to the increasing of total streamflow by 64.1% for cold season (November to following March) and 35.9% for warm season (April to October). The results provide some references for dealing with climate and land cover change in an inland river basin for water resource management and planning.

Highlights

  • Water resource pressure has become one of the important factors that affect social and economic sustainable development and ecosystem security [1,2]

  • Over the last 50 years, the streamflow induced by climate change in the cold season increased 15.2 mm and in warm season (April to October) increase by 8.5 mm

  • The increasing of streamflow contributed to the increasing of total streamflow by 64.1% for cold season and 35.9% for warm season

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Summary

Introduction

Water resource pressure has become one of the important factors that affect social and economic sustainable development and ecosystem security [1,2]. There are numerous studies that investigate the impacts of climate and land use/cover changes on water resources availability based on hydrological model [10,23,24,25,26], but few address how climate change impacts streamflow at a long time period and what role land cover change plays in runoff change. These issues remain to be resolved [16,27]. In order to know what changes have happened for the hydro-meteorological processes in this area, we choose several variables—precipitation, days of precipitation, air temperature (average, minimum, and maximum), and streamflow—to analysis the variation trends

Study Area
Mann-Kendall Trend Test
Model Performance
Identifing the Effects of Land Cover Change on Streamflow
Conclusions
Full Text
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