Groundwater Hydrograph Decomposition With the HydroSight Model

Feihe Kong,Olga Barron,Jon-Philippe Pigois,Jinxi Song,David Schafer,Russell S Crosbie

doi:10.3389/fenvs.2021.736400

Feihe Kong, Olga Barron + Show 4 more

Open Access

https://doi.org/10.3389/fenvs.2021.736400

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Abstract

Groundwater, the most important water resource and the largest distributed store of fresh water in the world, supports sustainability of groundwater-dependent ecosystems and resilient and sustainable economy of the future. However, groundwater level decline in many parts of world has occurred as a result of a combination of climate change, land cover change and groundwater abstraction from aquifers. This study investigates the determination of the contributions of these factors to the groundwater level changes with the HydroSight model. The unconfined superficial aquifer in the Gnangara region in Western Australia was used as a case study. It was found that rainfall dominates long-term (1992–2014) groundwater level changes and the contribution rate of rainfall reduced because the rainfall decreased over time. The mean rainfall contribution rate is 77% for climate and land cover analysis and 90% for climate and pumping analysis. Secondly, the increasing groundwater pumping activities had a significant influence on groundwater level and its mean contribution rate on groundwater level decline is -23%. The land cover changes had limited influence on long-term groundwater level changes and the contribution rate is stable over time with a mean of 2%. Results also showed spatial heterogeneity: the groundwater level changes were mainly influenced by rainfall and groundwater pumping in the southern study region, and the groundwater level changes were influenced by the combination of rainfall, land cover and groundwater pumping in the northern study region. This research will assist in developing a quantitative understanding of the influences of different factors on groundwater level changes in any aquifer in the world.

Highlights

Groundwater is an important natural resource that supplies water to humans (Döll, 2009), especially as the primary source of drinking water for over two billion people (Famiglietti, 2014)
This study focuses on long-term groundwater level change analysis in unconfined superficial aquifer to identify the controlling factors and quantitatively decompose groundwater hydrograph into different drivers, such as rainfall variability, land cover change (represented by the normalized difference vegetation index (NDVI)) and groundwater pumping, in the Gnangara region
The present study quantitatively clarifies the impacts of three drivers, namely, climate change, land cover change and groundwater pumping on the long-term groundwater level changes with HydroSight model

Summary

Introduction

Groundwater is an important natural resource that supplies water to humans (Döll, 2009), especially as the primary source of drinking water for over two billion people (Famiglietti, 2014). In arid and semiarid regions, groundwater is used for agricultural irrigation. 50% of the domestic water supply, 40% of the industrial water supply and 20% of the irrigation water supply originate from groundwater (Zektser and Lorne, 2004). Global groundwater depletion has been increasing since the 1960 (Wada et al, 2010). Groundwater is often poorly monitored and managed (Famiglietti, 2014). This has led to notable social and economic impacts (Gleeson et al, 2012). More efforts and attention are required to better understand and manage groundwater resources

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