Groundwater Storage Changes in China from Satellite Gravity: An Overview

Wei Feng,Yun Pan,C Shum,Min Zhong

doi:10.3390/rs10050674

Abstract

Groundwater plays a critical role in the global water cycle and is the drinking source for almost half of the world’s population. However, exact quantification of its storage change remains elusive due primarily to limited ground observations in space and time. The Gravity Recovery and Climate Experiment (GRACE) twin-satellite data have provided global observations of water storage variations at monthly sampling for over a decade and a half, and is enable to estimate changes in groundwater storage (GWS) after removing other water storage components using auxiliary datasets and models. In this paper, we present an overview of GWS changes in three main aquifers within China using GRACE data, and conduct a comprehensive accuracy assessment using in situ ground well observations and hydrological models. GRACE detects a significant GWS depletion rate of 7.2 ± 1.1 km3/yr in the North China Plain (NCP) during 2002–2014, consistent with ground well observations and model predictions. The Liaohe River Basin (LRB) experienced a pronounced GWS decline during 2005–2009, at a depletion rate of 5.0 ± 1.2 km3/yr. Since 2010, GRACE-based GWS reveal a slow recovery in the LRB, with excellent agreement with ground well observations. For the whole study period 2002–2014, no significant long-term GWS depletion is found in the LRB nor in the Tarim Basin. A case study in the Inner Tibetan Plateau highlights there still exist large uncertainties in GRACE-based GWS change estimates.

Highlights

Groundwater, as an important component of the global water cycle, is a vital resource of fresh water to sustain agricultural, industrial, and domestic development in many parts of the world, especially in arid and semi-arid regions [1,2]
By inferring column-integrated water storage changes from time-variable gravity fields observed by twin satellites, Gravity Recovery and Climate Experiment (GRACE) mission provides a new dimension for measuring groundwater storage (GWS) changes from space
In the piedmont region of the Taihang Mountains, groundwater depletion mainly occurred in unconfined aquifers; while groundwater from confined aquifers was depleted over the whole North China Plain (NCP)

Summary

Introduction

Groundwater, as an important component of the global water cycle, is a vital resource of fresh water to sustain agricultural, industrial, and domestic development in many parts of the world, especially in arid and semi-arid regions [1,2]. Groundwater supplies ~50% of drinking water and ~40% of industrial water globally [4]. More than 1.5 billion people worldwide rely on groundwater as the primary source of drinking water [1]. Due to extreme climate episodes, population growth, and extensive groundwater mining and over-exploitation, long-term groundwater depletion has occurred in many regions of the world, exacerbated by various adverse environment impacts, including groundwater quality deterioration, land subsidence, seawater intrusion, and soil salinization [5,6]. Groundwater depletion has been considered as a serious threat to sustainability of water supplies

Results

Discussion

Conclusion