Reduced Runoff Due to Anthropogenic Intervention in the Loess Plateau, China

Yanzhong Li,Dan Zhang,Changming Liu,Kang Liang,Xinan Li,Guotao Dong

doi:10.3390/w8100458

Abstract

To maintain the sustainable utilization of water resources and reduce soil erosion in the Loess Plateau, the Chinese government has adopted a number of environmental restoration strategies since 1999, including the Grain for Green Project (GFGP) and the Natural Forest Conservation Program; these large projects greatly alter the regional water cycle. Detecting runoff changes and quantitatively assessing the contribution of anthropogenic activities (including land use/cover change (LUCC) and water diversion) and climate change (including potential evaporation and precipitation) are imperative for implementing sustainable management strategies. Using observed records from 15 hydrological stations and 85 national meteorological stations from 1980 to 2013, the decomposition method, based on the Budyko hypothesis, is used to quantify the impact of climate variation and anthropogenic interference on annual runoff for the 12 catchments in the Loess Plateau. The results show the following: (1) the observed annual runoff exhibited a negative trend in all 12 catchments (significant in eight catchments) with a range of −1.94 to −0.16 mm·year−1 and exhibited a substantial difference before and after 1999; (2) the sensitivity of runoff to vegetation change, precipitation, and potential evapotranspiration increased in most catchments after 1999, indicating that great challenges and uncertainties might be introduced to regional water resource availability; and (3) the anthropogenic interference, particularly LUCC caused by forest strategies, has become the main contribution to runoff change. We suggest that more attention should be given to water resource availability and that the hydrologic consequences of revegetation should be taken into account in future management.

Highlights

Intensifying anthropogenic interference and changing climate can greatly impact land surface processes [1], the water cycle [2]
To change the ecological environment, the Chinese government has implemented a number of ecological conservation and protection projects in the Loess Plateau
The elasticity method, which is based on the Budyko framework, was employed to assess the elasticity of runoff to climate change and land use/cover change (LUCC)

Summary

Introduction

Intensifying anthropogenic interference and changing climate can greatly impact land surface processes [1], the water cycle [2]. Temperature, and radiation, whereas the influences of anthropogenic interference are mainly manifested by water diversion [9], hydropower development [10], reservoir regulation [5,6], agricultural irrigation [7], urbanization [11], and land use/cover change (LUCC) [8,12,13] in general. Quantification of runoff changes and identifying the various factors that contribute to these changes are both a challenge and a necessity for a better understanding of the variation mechanisms in the hydrological cycle and water yield, and can be greatly beneficial in improving basin water management. There are various methods to quantitatively assess the climatic and human impact on runoff change [14], such as hydrological modeling [15,16] and the elasticity method [17,18]. The elasticity method coupled with the Budyko hypothesis is considered an effective way to separate the sensitivity and contribution of climate change and human activities to runoff [8,19,20,21]

Objectives

Methods

Results

Discussion

Conclusion