Supply Wells Research Articles

Enhancement of the geological mapping in weathered crystalline and metamorphic rocks areas using village water supply wells data (lithology and hydrochemistry)

Enhancement of the geological mapping in weathered crystalline and metamorphic rocks areas using village water supply wells data (lithology and hydrochemistry)

A Conceptual Site Model for Per‐ and Polyfluoroalkyl Substance Water Supply Impacts in a Residential Community

ABSTRACTAt a Class 4 State Superfund site located in a densely developed residential/commercial area in a suburb of New York City, emerging contaminant sampling for PFAS was performed as part of a statewide data‐gathering project. Two per‐ and polyfluoroalkyl substances (PFAS), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), were detected at concentrations in excess of drinking water standards in bedrock and overburden monitoring wells at the State Superfund site. A bedrock private water supply well sampling program and a PFAS source investigation, consisting of overburden investigations near potential sources (i.e., sites with a history of known or suspected use, storage, or discharge of PFAS), were undertaken to assess exposures and identify and potentially eliminate sources of PFAS contaminants in the bedrock drinking water supply.Relative ratios of PFAS (i.e., PFAS signatures) were plotted geospatially to facilitate comparison of the characteristics of overburden groundwater sampling results to that of nearby bedrock private water supply sampling results. In addition, total PFAS concentrations in overburden groundwater and bedrock private water supply samples were compared to identify potential sources of bedrock groundwater impacts. The PFAS signature analysis revealed that (1) PFAS signatures of overburden groundwater samples were generally consistent with nearby bedrock private water supply samples; (2) total PFAS concentrations detected in overburden groundwater samples were marginally higher than concentrations detected in nearby bedrock private water supplies; (3) there was generally low variability in PFAS signatures throughout the study area (Assessment Area); and (4) overburden groundwater and bedrock private water supply PFAS signatures were similar to that of the nearby wastewater treatment plant effluent discharge, which represents a composite average PFAS signature for domestic wastewater from the area. Finally, septic system tracers were also detected in bedrock private water supply and overburden groundwater samples. Based on the results of the investigation, multiple lines of evidence support the Conceptual Site Model, which is likely applicable to many PFAS‐contaminated drinking water supplies with conditions similar to the Assessment Area: consumer product use and discharge to domestic septic systems in a densely developed residential area, lacking area‐wide municipal water and sewer, with shallow groundwater and bedrock, and a vertical downward groundwater gradient, have resulted in the widespread presence of PFAS in private water supply wells.

Assessing potential effects of oil and gas development activities on groundwater quality near and overlying the Elk Hills and North Coles Levee Oil Fields, San Joaquin Valley, California

Groundwater resources are utilized near areas of intensive oil and gas development in California’s San Joaquin Valley. In this study, we examined chemical and isotopic data to assess if thermogenic gas or saline water from oil producing formations have mixed with groundwater near the Elk Hills and North Coles Levee Oil Fields in the southwestern San Joaquin Valley. Major ion concentrations and stable isotope compositions were largely consistent with natural processes, including mixing of different recharge sources and water-rock interactions. Trace methane concentrations likely resulted from microbial rather than thermogenic sources. Trace concentrations of benzene and other dissolved hydrocarbons in three wells had uncertain sources that could occur naturally or be derived from oil and gas development activities or other anthropogenic sources. In the mid-1990s, two industrial supply wells had increasing Cl and B concentrations likely explained by mixing with up to 15 percent saline oil-field water injected for disposal in nearby injection disposal wells. Shallow groundwater along the western margin of Buena Vista Lake Bed had elevated Cl, B, and SO4 concentrations that could be explained by accumulation of salts during natural wetting and drying cycles or, alternatively, legacy surface disposal of saline oil-field water in upgradient ephemeral drainages. This study showed that groundwater had relatively little evidence of thermogenic gas or saline water from oil and gas sources in most parts of the study area. However, the evidence for groundwater mixing with injected disposal water, and possibly legacy surface disposal water, demonstrates produced water management practices as a potential risk factor for groundwater-quality degradation near oil and gas fields. Additional studies in the San Joaquin Valley and elsewhere could improve understanding of such risks by assessing the locations, volumes, and types of produced water disposal practices used during the life of oil fields.

Physico-chemical and bacteriological contamination of water from some supply wells in the Mandjou and Kano neighbourhoods, Djadombè subwatershed, Bertoua, East Cameroon

Physico-chemical and bacteriological contamination of water from some supply wells in the Mandjou and Kano neighbourhoods, Djadombè subwatershed, Bertoua, East Cameroon

PFAS-Contaminated Pesticides Applied near Public Supply Wells Disproportionately Impact Communities of Color in California.

Contaminated drinking water from widespread environmental pollutants such as perfluoroalkyl and polyfluoroalkyl substances (PFAS) poses a rising threat to public health. PFAS monitoring in groundwater is limited and fails to consider pesticides found to contain PFAS as a potential contamination source. Given previous findings on the disproportionate exposure of communities of Color to both pesticides and PFAS, we investigated disparities in PFAS-contaminated pesticide applications in California based on community-level sociodemographic characteristics. We utilized statewide pesticide application data from the California Department of Pesticide Regulation and recently reported concentrations of PFAS chemicals detected in eight pesticide products to calculate the areal density of PFAS applied within 1 km of individual community water systems' (CWSs) supply wells. Spatial regression analyses suggest that statewide, CWSs that serve a greater proportion of Latinx and non-Latinx People of Color residents experience a greater areal density of PFAS applied and greater likelihood of PFAS application near their public supply wells. These results highlight agroecosystems as potentially important sources of PFAS in drinking water and identify areas that may be at risk of PFAS contamination and warrant additional PFAS monitoring and remediation.

Integrated assessment of pollution status of MSW sites: a case study of Uyo, Ikot Ekpene and Oron, Akwa Ibom State, southern Nigeria.

One of the main causes of contaminated groundwater in emerging nations is improper trash disposal in urban areas, which affects the level of groundwater contamination caused by contaminants of municipal solid waste (MSW) origin within the three local government headquarters in Akwa Ibom State, southeastern Nigeria. The main thrust of this research survey is to assess the level of groundwater contaminations and their consequences. The research used statistical data generated from the Electrical Resistivity Survey (ERS) in combination with hydrogeochemical investigations. Analysis of variance of resistivity between Uyo, Ikot Ekpene and Oron was carried out. The test result indicated significant difference in contamination among the three cities. This was followed by a t-test between each pair of dump and control sites in the three cities. The test results showed significant difference between each control and dumpsite. The results showed that leachate layer conductivity is always higher than that of the layer above it. All water samples from boreholes close to the dumpsites were identified by hydrogeochemical analysis to exhibit pH (3.70-4.15) lower than the permissible limit of the WHO; few water samples exhibit increased electrical conductivity (EC), cadmium and total dissolved solids (TDS). Similarly, the bacteriological analyses indicated a high level of microbial load due to the waste dump. Formations found in boreholes close to the dumpsite have litho-correlations which depict intercalations of comparatively impermeable and porous materials. The findings reveal that leachate (contaminate) travels slowly downward, allowing for physical, chemical and biological processes to filter out impurities before they get to the aquifer. It is recommended that no new water supply wells should be placed in areas of abnormally low resistivity and physicochemical and bacteriological parameters, until the reasons for these values are properly assessed.

Insight into Sources of Benzene, TCE, and PFOA/PFOS in Groundwater at Naval Air Station Whiting Field, Florida, through Numerical Particle-Tracking Simulations

Past waste-disposal activities at Naval Air Station Whiting Field (NASWF) have led to elevated concentrations of contaminants in the underlying sand and gravel aquifer. Contaminants include two of the most commonly detected chemicals in groundwater in many countries (benzene and trichloroethylene (TCE)) and the “forever chemicals” per- and poly-fluoroalkyl substances (PFAS) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). A MODFLOW model (the Whiting Field Groundwater Model (WFGM)) was previously developed for NASWF and the surrounding area to simulate groundwater flow. To obtain insight into groundwater flow pathways for the identification of potential source areas, the MODPATH particle-tracking application was applied to the WFGM for three public supply wells and three monitoring wells at NASWF. The travel time to recharge areas was estimated using concentrations of the groundwater age-dating solutes tritium (as helium ingrowth) and chlorofluorocarbons detected in the monitoring wells. Simulated travel times agree with the groundwater ages and indicate that the calibrated WFGM reasonably represents groundwater flow velocities and pathways. The MODPATH simulations confirm suspected on-base source areas to explain chemical detection in the monitoring wells. In contrast, the particle-tracking simulations indicate that potential source areas to the public supply wells include both on- and off-base sources. This is important because PFAS chemicals can have multiple sources, including land application of sludge-based fertilizers. This approach that combines groundwater age dating with particle-tracking simulations can be applied at similar sites characterized by benzene-, TCE-, and PFAS-contaminated groundwater.

Occurrence and concentrations of traditional and emerging contaminants in onsite wastewater systems and water supply wells in eastern North Carolina, USA.

Onsite wastewater treatment systems (OWTSs) and private wells are commonly used in Eastern North Carolina, USA. Water from private wells is not required to be tested after the initial startup, and thus persons using these wells may experience negative health outcomes if their water is contaminated with waste-related pollutants including bacteria, nitrate or synthetic chemicals such as hexafluoropropylne oxide dimer acid and its ammonium salt (GenX). Water samples from 18 sites with OWTSs and groundwater wells were collected for nitrate, Escherichia coli (E. coli), total coliform, and GenX concentration analyses. Results showed that none of the 18 water supplies were positive for E. coli, nitrate concentrations were all below the maximum contaminant level of 10 mg L-1, and one well had 1 MPN 100 mL-1 of total coliform. However, GenX was detected in wastewater collected from all 18 septic tanks and 22% of the water supplies tested had concentrations that exceeded the health advisory levels for GenX. Water supplies with low concentrations of traditionally tested for pollutants (nitrate, E. coli) may still pose health risks due to elevated concentrations of emerging contaminants like GenX and thus more comprehensive and routine water testing is suggested for this and similar persistent compounds.

Effluent treatment plants for activities with high pollutant-degradation potential: an analysis of compliance with legal requirements

Sewage treatment plants (STPs), despite being fundamental for controlling environmental pollution, are also potential causes of environmental impact, therefore requiring an efficient self-monitoring plan to verify compliance with legal conditions. In this context, this research investigated the situation of Sewage Treatment Stations of enterprises that develop activities with high polluting degrading potential, located in Juazeiro do Norte – CE, in relation to compliance with legal guidelines. To guide this analysis, conditions were considered in resolutions from the Ceará State Environmental Council and municipal laws and decrees that deal with the matter under consideration. At the Municipal Environmental Authority of Juazeiro do Norte (AMAJU), data were collected from licensed enterprises that carried out high PPD activities, from the treatment technologies for effluents generated in each activity, from the STPs self-monitoring programs, and the types and locations of bodies receivers and the operating condition and physical flow of the AMAJU monitoring sector. The processing of data relating to the delivery of self-monitoring reports was carried out using percentages of 50 and 75%. From the analysis of the results, 48 ​​enterprises were identified that carried out high PPD activities, of which 4 were located in areas that had restrictions on this type of use. It was also verified that there was an important battery of public water supply wells surrounded by such projects. It was found that there are 70 high PPD projects that are under the jurisdiction of AMAJU and that the quality of liquid effluents from their STPs is, under specific conditions, in compliance with the release standards established by COEMA Resolution Nº 02/2017. However, it was found that the majority of the enterprises surveyed were non-compliant regarding the quantity and frequency of sending self-monitoring reports to AMAJU. These weaknesses were attributed to the reduced technical staff of the environmental agency and the absence of its minimum infrastructure for the development of the actions necessary for the implementation of an efficient environmental monitoring system. To contribute to the improvement of this system, it was suggested to strengthen AMAJU's technical, financial and institutional support, in addition to establishing a distinction in relation to the requirements regarding the frequency of analyzes and the periodicity of delivery of liquid effluent self-monitoring reports, for enterprises. with different types and classes.

Optimizing Recharge Area Delineation for Small- to Medium-Sized Groundwater Systems through Coupling Methods and Numerical Modeling: A Case Study of Linfen City, China

In previous investigations, the demarcation of capture zones within a specific research area predominantly relied on a singular method, leading to pronounced limitations and uncertainties. To address this challenge, an extensive field survey was conducted, focusing on the systematic classification of water sources in the Linfen City region. Building upon this classification, an intricate fusion of a hydrogeological analysis and formulaic methodology was employed. This integrated approach, coupled with independent numerical simulation methods, was applied to delineate recharge areas for both alluvial fan pore water in piedmont regions and exposed karst water in small- to medium-sized water sources. Simultaneously, precise spatial interpolation was carried out on water quality monitoring data from supply wells within the water source area for the year 2020. This meticulous analysis facilitated the determination of the spatial distribution characteristics of hydrochemical elements. To assess the water quality within the capture zone, the class III groundwater quality standards of China were employed as a pivotal tool for validating the results of the delineation of water source recharge areas. In the final analysis, a comparative study between the integrated coupling method and numerical simulation outcomes revealed the successful delineation of the boundaries for the water supply areas of Tumen and Caojiapo in Linfen City, covering areas of 5.5 km2 and 22.29 km2, respectively. Simultaneously, the combination of the three methods accurately outlined the boundary of the Hexi water supply area, encompassing an area of 2.5224 km2. These results vividly illustrate that the amalgamation of various methodologies proves more beneficial for the precise delineation of capture zones, particularly in diverse types and scales of groundwater sources. The synergy exhibited by these three methods underscores their collective efficacy, providing a more comprehensive and intuitive delineation of the recharge areas for small- to medium-sized water sources. Consequently, these findings significantly enhance the practical application value of the study and hold promise in making substantial contributions to local groundwater security and management initiatives.

Risk factors for Cryptosporidium contamination in Minnesota public supply wells.

In a recent monitoring study of Minnesota's public supply wells, Cryptosporidium was commonly detected with 40% of the wells having at least one detection. Risk factors for Cryptosporidium occurrence in drinking water supply wells, beyond surface water influence, remain poorly understood. To address this gap, physical and chemical factors were assessed as potential predictors of Cryptosporidium occurrence in 135 public supply wells in Minnesota. Univariable analysis, regression techniques, and classification trees were used to analyze the data. Many variables were identified as significant risk factors in univariable analysis and several remained significant throughout the succeeding analysis techniques. These factors fell into general categories of well use and construction, aquifer characteristics, and connectedness to the land surface, well capture zones, and land use therein, existence of potential contaminant sources within 200-feet of the well, and variability in the chemical and isotopic parameters measured during the study. These risk categories, and the specific variables and threshold values we have identified, can help guide future research on factors influencing Cryptosporidium contamination of wells and can be used by environmental health programs to develop risk-based sampling plans and design interventions that reduce associated health risks.

Road Salt Legacies: Quantifying Fluxes of Chloride to Groundwater and Surface Water Across the Chicago Metropolitan Statistical Area

AbstractFreshwater chloride concentrations have been increasing in North American surface waters for decades, largely driven by increases in the use of road salt, which is commonly applied as a deicer. In Chicago, thousands of tons of road salt are applied to roadways each winter, and increases in surface water chloride concentrations have been noted across the region since the mid‐1960s. While much of the applied salt runs directly off to nearby waterways during snowmelt events, some percolates to groundwater, affecting public supply wells and increasing the amount of chloride released to streams as baseflow during the non‐salting season. In the present study we have developed a spatially distributed chloride mass balance across the Chicago Metropolitan Statistical Area (CMSA) for a 30‐year period (1990–2020) to better our understanding of long‐term chloride fluxes and storage. Our results show that inputs of road salt to the region increased by 33% between 1990 and 2020. During this same period, riverine chloride loads across the region increased by 60%. Despite these increases in riverine chloride export, we find that chloride is accumulating in CMSA groundwater at a rate of ∼480 ktons year−1. We show that shallow aquifers, <30 m, exhibit only seasonal chloride storage, without long‐term accumulation. In contrast, at depths below 30 m, we find chloride concentrations to be increasing over time, indicating that legacy chloride is accumulating at deeper depths in CMSA groundwater. The present results highlight the importance of legacy chloride to long‐term water quality dynamics in North American cities.

Estimating Lithium Concentrations in Groundwater Used as Drinking Water for the Conterminous United States.

Lithium (Li) concentrations in drinking-water supplies are not regulated in the United States; however, Li is included in the 2022 U.S. Environmental Protection Agency list of unregulated contaminants for monitoring by public water systems. Li is used pharmaceutically to treat bipolar disorder, and studies have linked its occurrence in drinking water to human-health outcomes. An extreme gradient boosting model was developed to estimate geogenic Li in drinking-water supply wells throughout the conterminous United States. The model was trained using Li measurements from ∼13,500 wells and predictor variables related to its natural occurrence in groundwater. The model predicts the probability of Li in four concentration classifications, ≤4 μg/L, >4 to ≤10 μg/L, >10 to ≤30 μg/L, and >30 μg/L. Model predictions were evaluated using wells held out from model training and with new data and have an accuracy of 47-65%. Important predictor variables include average annual precipitation, well depth, and soil geochemistry. Model predictions were mapped at a spatial resolution of 1 km2 and represent well depths associated with public- and private-supply wells. This model was developed by hydrologists and public-health researchers to estimate Li exposure from drinking water and compare to national-scale human-health data for a better understanding of dose-response to low (<30 μg/L) concentrations of Li.

Combining Karhunen–Loève expansion and stochastic modeling for probabilistic delineation of well capture zones in heterogeneous aquifers

The delineation of well capture zones (WCZs), particularly for water supply wells, is of utmost importance to ensure water quality. This task requires a comprehensive understanding of the aquifer’s hydrogeological parameters for precise delineation. However, the inherent uncertainty associated with these parameters poses a significant challenge. Traditional deterministic methods bear inherent risks, emphasizing the demand for more resilient and probabilistic techniques. This study introduces a novel approach that combines the Karhunen–Loève expansion (KLE) technique with stochastic modeling to probabilistically delineate well capture zones in heterogeneous aquifers. Through numerical examples involving moderate and strong heterogeneity, the effectiveness of KLE dimension reduction and the reliability of stochastic simulations are explored. The results show that increasing the number of KL-terms significantly improves the statistical attributes of the samples. When employing more KL-terms, the statistical properties of the hydraulic conductivity field outperform those of cases with fewer KL-terms. Notably, particularly in scenarios of strong heterogeneity, achieving a convergent probabilistic WCZs map requires a greater number of KL-terms and stochastic simulations compared to cases with moderate heterogeneity.

Evaluation of the Water Quality of Three Water Supply Wells in the Urban Area of Chilpancingo, Guerrero, México

Evaluation of the Water Quality of Three Water Supply Wells in the Urban Area of Chilpancingo, Guerrero, México

Relation of Hydrogeology and Contaminant Sources to Drinking Water Quality in Southern Kazakhstan

Southern Kazakhstan is one of the fastest-growing regions of this country and continued development depends on a sustainable supply of freshwater for multiple purposes. Groundwater in Southern Kazakhstan occurs in a wide variety of hydrogeological conditions with varying levels of quality and vulnerability to contamination. The aim of this paper is to investigate the present groundwater quality through sampling and laboratory analysis of source water from public supply wells, compare results to hydrogeology and known contaminant sources, and indicate where future protections may be needed. Protection from surface-borne contaminants is mainly determined by the thickness of the vadose zone, depth of the groundwater level, presence, thickness and composition of aquifers, and mobility of pollutants. Forty-five wells were sampled, yielding 106 samples of groundwater presently used for drinking water, which were evaluated to investigate the occurrence of potential pollutants and hydrogeology of the region. Of the samples collected, 46 samples were used for analysis of inorganic water chemistry, 30 for individual indicators including metals, and 31 samples for determination of petroleum products. A contaminant inventory database and geospatial database aided the interpretation of the results and allowed the prediction of future water issues. Kazakhstan’s maximum permissible concentrations (MPCs) for metals were exceeded in areas associated with industrial enterprises, while fluoride and nitrate were more closely associated with mining and agricultural sources. Groundwater quality is dependent on hydrogeology and environmental contaminants resulting from historical land uses and must be regularly monitored for drinking water safety. Petroleum hydrocarbons were not detected in any of the drinking water sources.

Uranium anomaly in groundwater of the hard rock aquifer system in southeast Brazil

This study presents a hydrogeological characterization that fills knowledge gaps in an area where a complex geological scenario connects two fractured (granite/metamorphic rocks and diabase) and one porous (sedimentary rocks) aquifer systems. Previous groundwater studies from the four local deep supply wells suggested the sedimentary aquifer as the source of uranium (∼60 μg/L) in one of the wells. Despite the water extraction interruption from this well, this finding needed to be supported by evidence provided by the geological and structural characteristics of the aquifers. Data collected through video inspection, caliper, optical (OPTV), and acoustic borehole televiewers (ATV) revealed the predominance of the crystalline aquifer in the area. As recorded by video inspection, the well's borehole with high U intersects the crystalline rocks at several open fractures and presents the highest gamma radiation values. Therefore, we infer that the origin of dissolved U is the weathering of primary minerals locally occurring in those rocks. The U leaching and complexation as calcium-uranyl-carbonates favors its solubility in that specific aqueous medium, as shown by hydrogeochemical modeling using PHREEQC. Additionally, the major ions and trace elements concentrations allow the division of the wells into two groups: a) two with higher U concentrations, influenced by the granite/metamorphic aquifer and possibly longer residence times, and b) the other two wells with lower U concentrations, higher nitrate concentrations, influenced by the diabase aquifer, possibly have younger residence times.

Application of borehole cameras in the field of Engineering Geology and Hydrogeology

The use of borehole cameras in Bulgaria is increasingly used in hydrogeology and engineering geology. The resulting photographs and movies contribute to solving problems related to the study and assessment of the condition of water supply wells, as well as to obtain a clear picture on the assessment of rock massifs for their suitability for various types of construction. Borehole cameras on the territory of our country are more widely used in the field of hydrogeology compared to engineering geology. The purpose of this article is to present the possible applications of this technology, which has been improved over the years, for the study of rock massifs in their study for various infrastructure objects. Also. to shed light on the benefits of using boreholes in surveying the various water sources.

Wireline log stratigraphy of the lower Cambrian Læså Formation, Bornholm, Denmark.

A detailed correlation of the lower Cambrian Læså Formation on southern Bornholm, Denmark, is based on gamma ray and formation resistivity wireline logs from 25 water supply wells and 5 scientific boreholes. The interpretation hinges on comparison with the wireline log suite obtained in the fully cored Borggård-1 borehole that penetrated the formation in its entirety. The Norretorp Member, 102.9 m thick in Borggård-1, consists predominantly of intensively bioturbated siltstone. Several levels are strongly glauconitic and usually also contain phosphorite nodules. Fine-grained sandstone beds, 0.5–20 cm thick and interpreted as tempestites, occur throughout the unit; a few thicker sandstone layers consist of stacked tempestites. However, many sandstone beds, primarily in the upper 2/3 of the member, have been partly or totally obliterated by the pervasive bioturbation. The overlying Rispebjerg Member, 3.5 m thick in Borggård-1, is dominated by well-cemented medium to coarse-grained quartz sandstone. The variable lithology of the Læså Formation is illustrated by photos of core samples from Borggård-1. The studied wells are located on different fault blocks with 18 km between the easternmost and westernmost well sites. The Norretorp Member is of almost similar thickness throughout the study area whereas the Rispebjerg Member is 2.2–5.6 m thick. The essentially unchanging thickness of the Læså Formation and the sheet like distribution of tempestites demonstrate that the intense faulting of southern Bornholm post-dates deposition. The Norretorp Member is divided into a lower log-unit (57 m thick in Borggård-1) characterized by a moderately variable gamma ray log pattern and an upper log-unit (46 m thick in Borggård-1) exhibiting a more uniform gamma radiation of overall lower intensity. The log-units reflect a more common occurrence of glauconite and phosphorite in the lower part of the member and a higher sand content in the upper part. These lithological differences are also reflected by a generally higher resistivity and P-wave velocity in the upper log-unit. Seven thicker sandstone horizons (15–80 cm thick), labelled S1 to S7, are laterally persistent within the Norretorp Member. Four additional horizons, referred to as MGL [multiple gamma low], MGH [multiple gamma high], MM [middle marker] and GH [gamma high], are also laterally widespread. A readily identifiable red-brown horizon is located at 4.4–5.9 m above the base of the Læså Formation in Borggård-1: it appears to be developed throughout the study area.

Thousands of domestic and public supply wells face failure despite groundwater sustainability reform in California’s Central Valley

Across the world, declining groundwater levels cause wells to run dry, increase water and food insecurity, and often acutely impact groundwater-dependent communities. Despite the ubiquity and severity of these impacts, groundwater research has primarily focused on economic policy instruments for sustainable management or the quantification of groundwater depletion, rather than assessing the impacts of management decisions. In particular, how definitions of groundwater sustainability shape the fate of resource users remains unexplored. Here, we examine one of the world’s largest-scale environmental sustainability reforms, the California Sustainable Groundwater Management Act (SGMA), and estimate the impact of sustainability definitions proposed in groundwater sustainability plans (GSPs) on well failure. We show that locally-proposed sustainability criteria are consistent with business as usual groundwater level decline, and if reached, could impact over 9000 domestic wells and around 1000 public supply wells. These findings highlight the necessity of careful and critical evaluation of locally-developed sustainability definitions and their implementation to prevent detrimental impacts, such as threats to household and municipal water supply.