Effects of initial aquifer conditions on economic benefits from groundwater conservation

Abstract

Worldwide, there is growing recognition of the need to reduce agricultural groundwater use in response to rapid rates of aquifer depletion. To date, however, few studies have evaluated how benefits of conservation vary along an aquifer's depletion pathway. To address this question, we develop an integrated modeling framework that couples an agro‐economic model of farmers' field‐level irrigation decision‐making with a borehole‐scale groundwater flow model. Unique to this framework is the explicit consideration of the dynamic reductions in well yields that occur as an aquifer is depleted, and how these changes in intraseasonal groundwater supply affect farmers' ability to manage production risks caused by climate variability and, in particular, drought. For an illustrative case study in the High Plains region of the U.S., we apply our model to analyze the value of groundwater conservation activities for different initial aquifer conditions. Our results demonstrate that there is a range of initial conditions for which reducing pumping will have long‐term economic benefits for farmers by slowing reductions in well yields and prolonging the usable lifetime of an aquifer for high‐value irrigated agriculture. In contrast, restrictions on pumping that are applied too early or too late will provide limited welfare benefits. We suggest, therefore, that there are “windows of opportunity” to implement groundwater conservation, which will depend on complex feedbacks between local hydrology, climate, crop growth, and economics.

Quantifying irrigation adaptation strategies in response to stakeholder-driven groundwater management in the US High Plains Aquifer

“…Policy and management institutions developed to address this sustainability challenge differ widely across the HPA and beyond. Aquifer depletion can be costly, since the value of irrigation water should increase over time considering expected future higher yielding varieties and irrigation's ability to mitigate droughts, which are likely to become more frequent and severe with climate change (Zipper et al 2016, Foster et al 2017, Quintana Ashwell et al 2018, USGCRP 2018. At the same time, improved management could boost crop water productivity around the world (Brauman et al 2013, Rattalino Edreira et al 2018, indicating producers might obtain similar yields using less water and thus slow the rate of aquifer depletion.…”

Assessing landscape scale heterogeneity in irrigation water use with remote sensing andin situmonitoring

“…soil moisture sensors), reducing energy costs of irrigation and increasing overall farm profitability. Improved irrigation management may also contribute to regional conservation of groundwater as a buffer against future drought [16,50] and help to minimize pumping impacts on freshwater ecosystems [51], although the magnitude of these benefits would depend on the hydrological effects of changes in irrigation patterns on return flows to the underlying aquifer [52]. Conversely, we also show that there are subsets of producers who may have already adapted irrigation management practices successfully to reduce water use in times of physical or economic scarcity without impacting crop yields significantly.…”

“…Indeed, only 30% of irrigation wells in the United States are equipped with a flow meter [12]. Moreover, in many irrigated regions, agricultural groundwater pumping remains unmetered despite reductions in aquifer storage [13,14] that threaten long-term agricultural productivity and sustainability of rural economies [15,16].…”

Policy Targeting to Reduce Economic Damages From Land Subsidence

“…the externality differs with the location of groundwater pumping, a uniform policy is neither cost-effective nor corrective. In this context, a spatially differentiated policy can improve economic outcomes relative to a uniform approach (Cobourn et al, 2016;Elbakidze et al, 2012;Foster et al, 2017;Guilfoos et al, 2016;Kuwayama & Brozovic, 2013;Suter et al, 2012).…”