Water Conservation with Managed Aquifer Recharge under Increased Drought Risk
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Water Conservation with Managed Aquifer Recharge under Increased Drought Risk Dat Q. Tran1 Kent Kovacs2 Steve Wallander3 ●
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Received: 6 February 2020 / Accepted: 1 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Economic analysis of managed aquifer recharge (MAR) typically focuses on identifying the quantity of water to add costeffectively to natural rates of recharge. However, to the extent that MAR is successful, higher groundwater levels or at least slower depletion are likely to influence crop choice and groundwater pumping dynamics. Using a landscape-level model, we maximize farm net returns taking into account MAR and on-farm surface reservoir storage, crop choice, and the impacts of drought on groundwater use in Eastern Arkansas, USA, over 120 years. We find that drought frequency (risk) has a stronger influence on groundwater pumping and MAR use compared with drought severity. There is evidence of a substantial slippage, the percentage of the increase in groundwater use with versus without MAR divided by the MAR use, under a range of MAR cost and drought scenarios. Total slippage ranges from about 32 to 75% of total MAR water, indicating that only 68–25% of the MAR water raises groundwater levels. Even if the costs of MAR are relatively high and slippage is present, the total net returns to farms in this region are higher, and the variability in those returns are less with MAR. Keywords Slippage (rebound) effects Agricultural managed aquifer recharge (MAR) Surface reservoir storage ●
Introduction The projected trajectory of changing climate is likely to intensify the groundwater depletion in heavily depleted aquifers (Scanlon et al. 2016). More frequent and prolonged droughts place more demand on groundwater resources in the regions that depend heavily on groundwater for sustaining crop production, such as Lower Mississippi River Basin, USA (MacDonald 2010; O’Geen et al. 2015). A changing climate affects the hydrologic cycle and intensifies drought (Barnett et al. 2008; Cayan et al. 2010; Lorenz et al. 2017). Long-term drought frequency is likely to increase by three times in the region (Seager et al. 2007; Sheffield and
* Kent Kovacs [email protected] 1
School of Public Policy, University of California, Riverside, Riverside, CA 92521, USA
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Department of Agricultural Economics and Agribusiness, University of Arkansas, Fayetteville, AR 72701, USA
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U.S. Department of Agriculture, Economic Research Service, 1400 Independence Ave., SW Mail Stop 1800, Washington, DC 20250-0002, USA
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Wood 2008). Irrigation efficiency may reduce the groundwater overdraft in the region, but the adoption is slow. In 2016, only about 20% of farmers surveyed reported that they used irrigation efficiency practices, and most of this adoption occurred over the last ten years (Edward 2016). Previous studies show that irrigation efficiency adoption alone has not been effective in reducing groundwater overdraft (Ward and Pulido-Velazquez 2008; Grafton et al. 20
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