Hydrological Responses to Climate and Land Use Changes in a Watershed of the Loess Plateau, China

Rui Yan,Xuan Wang,Yanpeng Cai,Qiang Liu,Chunhui Li

doi:10.3390/su11051443

Abstract

This study researched the individual and combined impacts of future LULC and climate changes on water balance in the upper reaches of the Beiluo River basin on the Loess Plateau of China, using the scenarios of RCP4.5 and 8.5 of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The climate data indicated that both precipitation and temperature increased at seasonal and annual scales from 2020 to 2050 under RCP4.5 and 8.5 scenarios. The future land use changes were predicted through the CA-Markov model. The land use predictions of 2025, 2035, and 2045 indicated rising forest areas with decreased agricultural land and grassland. In this study, three scenarios including only LULC change, only climate change, and combined climate and LULC change were established. The SWAT model was calibrated, validated, and used to simulate the water balance under the three scenarios. The results showed that increased rainfall and temperature may lead to increased runoff, water yield, and ET in spring, summer, and autumn and to decreased runoff, water yield, and ET in winter from 2020 to 2050. However, LULC change, compared with climate change, may have a smaller impact on the water balance. On an annual scale, runoff and water yield may gradually decrease, but ET may increase. The combined effects of both LULC and climate changes on water balance in the future were similar to the variation trend of climate changes alone at both annual and seasonal scales. The results obtained in this study provide further insight into the availability of future streamflow and can aid in water resource management planning in the study area.

Highlights

Many hydrological processes, such as precipitation, evapotranspiration, and runoff, are significantly affected by climatic conditions
The combined effects of both LULC and climate changes on water balance in the future were similar to the variation trend of climate changes alone at both annual and seasonal scales
The results obtained in this study provide further insight into the availability of future streamflow and can aid in water resource management planning in the study area

Summary

Introduction

Many hydrological processes, such as precipitation, evapotranspiration, and runoff, are significantly affected by climatic conditions. Such influences are further multiplied by climate change, which is a scientific fact instead of a hypothesis. These influences are affected by land use changes, leading to a variety of complexities in forecasting and in analyzing critical water-related parameters such as baseflow and flooding frequency [1,2]. Climate and land use are two important factors causing combined effects on the hydrological cycles and associated water resource systems in specific watersheds. The generation and analysis of the synergic effects of human activities and climate change on water balance and water resource systems are desired, which calls for effective modeling tools

Objectives

Methods

Results