Quantitative Evaluation of the Impact of Climate Change and Human Activity on Runoff Change in the Dongjiang River Basin, China

Yuliang Zhou,Xiaohong Chen,Xiaoyan Bai,Jiachao Chen,Zhaoyang Zeng,Zhaoli Wang,Chengguang Lai

doi:10.3390/w10050571

Abstract

Climate change and human activity are typically regarded as the two most important factors affecting runoff. Quantitative evaluation of the impact of climate change and human activity on runoff is important for the protection, planning, and management of water resources. This study assesses the contributions of climate change and human activity to runoff change in the Dongjiang River basin from 1960 to 2005 by using linear regression, the Soil and Water Assessment Tool (SWAT) hydrologic model, and the climate elasticity method. Results indicate that the annual temperature in the basin significantly increased, whereas the pan evaporation in the basin significantly decreased (95%). The natural period ranged from 1960 to 1990, and the affected period ranged from 1991 to 2005. The percentage of urban area during the natural period, which was 1.94, increased to 4.79 during the affected period. SWAT modeling of the Dongjiang River basin exhibited a reasonable and reliable performance. The impacts induced by human activity on runoff change were as follows: 39% in the upstream area, 13% in the midstream area, 77% in the downstream area, and 42% in the entire basin. The impacts of human activity on runoff change were greater in the downstream area than in either upstream and midstream areas. However, the contribution of climate change (58%) is slightly larger than that of human activity (42%) in the whole basin.

Highlights

Extreme weather and climate events have occurred frequently in recent decades because of global warming
Three main viewpoints can be concluded: (1) climate variability is more dominant in runoff change [10,11,12,13,14,15]; (2) human activity is more significant [16,17,18,19,20]; and (3) the effects of the two factors vary in different areas during different periods [21]
The linear regression results for the annual temperature and pan evaporation are shown in the land use data of 1990, 2000, and 2010, we set the year 1990 as the critical time point

Summary

Introduction

Extreme weather and climate events have occurred frequently in recent decades because of global warming. Water 2018, 10, 571 and increase flood risk; Sterling et al [23] indicated that human activity could considerably affect evapotranspiration, which is one of the factors for runoff change on the basis of a water balance equation. These findings indicate that land use change induced by human activity on water cycle should not be ignored. The quantitative assessment of the impact of climate variability and human activity on runoff change is important for water resource planning and management

Objectives

Results

Conclusion