Non-renewable groundwater use and groundwater depletion: a review

Abstract

Population growth, economic development, and dietary changes have drastically increased the demand for food and water. The resulting expansion of irrigated agriculture into semi-arid areas with limited precipitation and surface water has greatly increased the dependence of irrigated crops on groundwater withdrawal. Also, the increasing number of people living in mega-cities without access to clean surface water or piped drinking water has drastically increased urban groundwater use. The result of these trends has been the steady increase of the use of non-renewable groundwater resources and associated high rates of aquifer depletion around the globe. We present a comprehensive review of the state-ofthe-art in research on non-renewable groundwater use and groundwater depletion. We start with a section defining the concepts of non-renewable groundwater, fossil groundwater and groundwater depletion and place these concepts in a hydrogeological perspective. We pay particular attention to the interaction between groundwater withdrawal, recharge and surface water which is critical to understanding sustainable groundwater withdrawal. We provide an overview of methods that have been used to estimate groundwater depletion, followed by an extensive review of global and regional depletion estimates, the adverse impacts of groundwater depletion and the hydroeconomics of groundwater use. We end this review with an outlook for future research based on main research gaps and challenges identified. This review shows that both the estimates of current depletion rates and the future availability of non-renewable groundwater are highly uncertain and that considerable data and research challenges need to be overcome if we hope to reduce this uncertainty in the near future.

Global groundwater sustainability, resources and systems in the Anthropocene

“…All wells shown in figures illustrate pumping from the system of general rather than a specific well. This review is different than other recent reviews on related topics (Aeschbach-Hertig & Bierkens & Wada, 2019;Wada, 2016) (Dalin et al 2019). Aeschbach-Hertig & Gleeson (2012) synthesized groundwater depletion and suggested the groundwater depletion be considered from diverse perspectives of hydrology, economics and policy studies.…”

“…Alternatively groundwater depletion is also more narrowly defined as the persistent decline in groundwater levels due to physically non-sustainable groundwater use (Bierkens & Wada, 2019) which is generally followed in the global hydrology literature (Petra Döll et al, 2014;Wada, 2016;Wada et al, 2012). Using the second definition, pumping may be physically sustainable (Bierkens & Wada, 2019) if it will eventually lead to the establishment of a new hydraulic equilibrium where water levels are dynamically stable ( Figure 2). This is akin to some definitions of safe yield referenced above, though we note that physical sustainability is just part of the more holistic definition of groundwater sustainability we propose below.…”

“…The threats to groundwater sustainability described in Section 1.1. motivate our review but we do not further describe them detail like other reviews (Aeschbach-Hertig & Gleeson, 2012;Bierkens & Wada, 2019) in part because finding positive approaches and elements to challenging problems, such as groundwater sustainability, is important to motivate change (Bennett et al, 2016). We do not explore in any detail related and important concepts such as water security (S. Foster & MacDonald, 2014), groundwater economics (Bierkens & Wada, 2019), food security (Dalin et al 2019 REF), virtual water (D'Odorico et al, 2019) and the food-energy-water nexus (Endo et al, 2015).…”

“…The threats to groundwater sustainability described in Section 1.1. motivate our review but we do not further describe them detail like other reviews (Aeschbach-Hertig & Gleeson, 2012;Bierkens & Wada, 2019) in part because finding positive approaches and elements to challenging problems, such as groundwater sustainability, is important to motivate change (Bennett et al, 2016). We do not explore in any detail related and important concepts such as water security (S. Foster & MacDonald, 2014), groundwater economics (Bierkens & Wada, 2019), food security (Dalin et al 2019 REF), virtual water (D'Odorico et al, 2019) and the food-energy-water nexus (Endo et al, 2015). We include groundwater quality as part of groundwater sustainability and acknowledge that groundwater quality is an important aspect of groundwater in the Earth System; (S. S. D. Foster & Chilton, 2003) include a preliminary review of groundwater quality and contamination but global groundwater quality and integrating groundwater quality and quantity are both significant research gaps that that we do not address but return to in the 'Future topics'.…”

Interplay of changing irrigation technologies and water reuse: Example from the Upper Snake River Basin, Idaho, USA

“…In the USRB, the current head level targeted for stabilization is greater than head existing in the basin prior to irrigation (Kjelstrom, 1995), and generates increased rates of baseflow from springs. This is a unique issue from many other semiarid basins relying on groundwater for irrigation that are managed against aquifer depletion below pre-irrigation heads (Bierkens and Wada, 2019). The primary adverse externality of EAR, aside from technical considerations of feasibility, is decreasing watershed discharge, which would be undesirable for downstream users.…”