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1. Quantifying the Impact of Lagged Hydrological Responses on the Effectiveness of Groundwater Conservation

   https://doi.org/10.1029/2022WR032295  

   Glose, Thomas J.; Zipper, Sam; Hyndman, David W.; Kendall, Anthony D.; Deines, Jillian M.; Butler, Jr., James J. (July 2022, Water Resources Research)

   Abstract Many irrigated agricultural areas seek to prolong the lifetime of their groundwater resources by reducing pumping. However, it is unclear how lagged responses, such as reduced groundwater recharge caused by more efficient irrigation, may impact the long‐term effectiveness of conservation initiatives. Here, we use a variably saturated, simplified surrogate groundwater model to: (a) analyze aquifer responses to pumping reductions, (b) quantify time lags between reductions and groundwater level responses, and (c) identify the physical controls on lagged responses. We explore a range of plausible model parameters for an area of the High Plains aquifer (USA) where stakeholder‐driven conservation has slowed groundwater depletion. We identify two types of lagged responses that reduce the long‐term effectiveness of groundwater conservation, recharge‐dominated and lateral‐flow‐dominated, with vertical hydraulic conductivity (K_Z) the major controlling variable. When highK_Zallows percolation to reach the aquifer, more efficient irrigation reduces groundwater recharge. By contrast, when lowK_Zimpedes vertical flow, short term changes in recharge are negligible, but pumping reductions alter the lateral flow between the groundwater conservation area and the surrounding regions (lateral‐flow‐dominated response). For the modeled area, we found that a pumping reduction of 30% resulted in median usable lifetime extensions of 20 or 25 years, depending on the dominant lagged response mechanism (recharge‐ vs. lateral‐flow‐dominated). These estimates are far shorter than estimates that do not account for lagged responses. Results indicate that conservation‐based pumping reductions can extend aquifer lifetimes, but lagged responses can create a sizable difference between the initially perceived and actual long‐term effectiveness. 

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2. Decadal‐Scale Aquifer Dynamics and Structural Complexities at a Municipal Wellfield Revealed by 25 Years of InSAR and Recent Groundwater Temperature Observations

   https://doi.org/10.1029/2018WR022552  

   Grapenthin, Ronni; Kelley, Shari; Person, Mark; Folsom, Matthew (December 2019, Water Resources Research)

   Abstract Over the past 35 years the Buckman wellfield near Santa Fe, New Mexico, experienced production well drawdowns in excess of 180 m, resulting in ground subsidence and surface cracks. Increased reliance on surface water diversions since 2011 has reduced pumping and yielded water level recovery. To characterize the impact of wellfield management decisions on the aquifer system, we reconstruct the surface deformation history through the European Remote Sensing Satellite, Advanced Land Observing Satellite, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series analysis during episodes of drawdown (1993–2000), recovery (2007–2010), and modern management (2015–2018) in discontinuous observations over a 25‐year period. The observed deformation generally reflects changes in hydraulic head. However, at times during the wellfield recovery, the deformation signal is complex, with patterns of uplift and subsidence suggesting a compartmentalized aquifer system. Recent records of locally high geothermal gradients and an overall warming of the system (~0.5°C during the water level recovery) obtained from repeat temperature measurements between 2013 and 2018 constrain a conceptual model of convective heat transfer that requires a vertical permeable zone near an observed fault. To reproduce observed temperature patterns at monitoring wells, high basal heat flow and convective cooling associated with downward flow of water from cool shallow aquifers during the drawdown period is necessary. The fault, however, appears to die out southward or may be locally permeable, as conceptual cross‐sectional hydrologic modeling reproduces the surface deformation without such a structure. Our work demonstrates the importance of incorporating well‐constrained stratigraphy and structure when modeling near‐surface deformation induced by, for instance, groundwater production. 

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3. Alternative stable states and hydrological regime shifts in a large intermittent river

   https://doi.org/10.1088/1748-9326/ac7539  

   Zipper, Sam; Popescu, Ilinca; Compare, Kyle; Zhang, Chi; Seybold, Erin C (June 2022, Environmental Research Letters)

   Abstract Non-perennial rivers and streams make up over half the global river network and are becoming more widespread. Transitions from perennial to non-perennial flow are a threshold-type change that can lead to alternative stable states in aquatic ecosystems, but it is unknown whether streamflow itself is stable in either wet (flowing) or dry (no-flow) conditions. Here, we investigated drivers and feedbacks associated with regime shifts between wet and dry conditions in an intermittent reach of the Arkansas River (USA) over the past 23 years. Multiple lines of evidence suggested that these regimes represent alternative stable states, including (a) significant jumps in discharge time series that were not accompanied by jumps in flow drivers such as precipitation and groundwater pumping; (b) a multi-modal state distribution with 92% of months experiencing no-flow conditions for <10% or >90% of days, despite unimodal distributions of precipitation and pumping; and (c) a hysteretic relationship between climate and flow state. Groundwater levels appear to be the primary control over the hydrological regime, as groundwater levels in the alluvial aquifer were higher than the stream stage during wet regimes and lower than the streambed during dry regimes. Groundwater level variation, in turn, was driven by processes occurring at both the regional scale (surface water inflows from upstream, groundwater pumping) and the reach scale (stream–aquifer exchange, diffuse recharge through the soil column). Historical regime shifts were associated with diverse pressures including network disconnection caused by upstream water use, increased flow stability potentially associated with reservoir operations, and anomalous wet and dry climate conditions. In sum, stabilizing feedbacks among upstream inflows, stream–aquifer interactions, climate, vegetation, and pumping appear to create alternative wet and dry stable states at this site. These stabilizing feedbacks suggest that widespread observed shifts from perennial to non-perennial flow will be difficult to reverse. 

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4. Optimal Irrigation Strategies and Adaptive Decision‐Making Under Groundwater Pumping Restrictions and Precipitation Uncertainties

   https://doi.org/10.1029/2024WR039682  

   Yu, Qiuyun Cecilia; Li, Qi; Hu, Guiping; Marston, Landon T (July 2025, Water Resources Research)

   Innovative groundwater management strategies are needed to preserve aquifers for crop irrigation. For sustainability to be lasting, any strategy must balance environmental goals with the economic aims of farmers. These tradeoffs are difficult to manage due to the inherent uncertainty in farming. To address these challenges, we develop a transferable two‐stage stochastic modeling framework to support optimal multi‐year crop and irrigation planning under groundwater pumping restrictions and uncertain precipitation. This modular framework is broadly applicable to regions facing groundwater overuse, helping to balance aquifer sustainability and farmer profitability under uncertainty. We illustrate the model using a case study from western Kansas, USA, where irrigators self‐imposed 5‐year groundwater pumping limits to extend the aquifer's lifespan. While these multi‐year allocation periods offer flexibility, they introduce a temporal dimension to decision‐making beyond typical annual planning. Optimal cropping and irrigation strategies from the stochastic model significantly outperform observed farmer behavior during the first two 5‐year allocation periods (2013–2022), and outperform a deterministic model assuming long‐term average precipitation during dry conditions. We show that optimal crop choices shift from corn to sorghum under more stringent pumping restrictions. Under these constraints, irrigators benefit by conserving water in earlier years and using more in later years, whereas the reverse holds under more lenient restrictions. Extending the allocation window further enhances profitability, though marginal gains diminish beyond 7 years. This modeling framework offers insights for agricultural regions seeking to improve long‐term groundwater management through strategies that support both economic resilience and hydrologic sustainability. 

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5. An Exploration of Groundwater Resource Ecosystem Service Sustainability: A System Dynamics Case Study in Texas, USA

   https://doi.org/10.3390/systems12120583  

   Leal, Julianna; Bishop, Morgan; Reed, Caleb; Turner, Benjamin L (December 2024, Systems)

   Groundwater, a crucial natural resource on a global scale, plays a significant role in Texas, impacting various essential ecosystem services either directly or indirectly. Despite efforts of state- and community-level regulations and conservation efforts, there is an ongoing trend of declining groundwater levels in the state of Texas. In this study, we utilized the systems thinking and system dynamics modeling approach to better understand this problem and investigate possible leverage points to achieve more sustainable groundwater resource levels. After conceptualizing a causal loop diagram (CLD) of the underlying feedback structure of the issue (informed by the existing literature), a small system dynamics (SD) model was developed to connect the feedback factors identified in the CLD to the stocks (groundwater level) and flows (recharge rate and groundwater pumping) that steer the behaviors of groundwater systems across time. After completing model assessment, experimental simulations were conducted to evaluate the current state relative to simulated treatments for improved irrigation efficiency, restricted pumping rates, cooperative conservation protocols among users, and combination strategy (of all treatments above) in the long-term. Results showed that groundwater stress (and the associated repercussions on related ecosystem service) could be alleviated with a combination strategy, albeit without complete groundwater level recovery. 

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