High and Dry

Abstract. Increasing population, economic growth and changes in diet have dramatically increased the demand for food and water over the last decades. To meet increasing demands, irrigated agriculture has expanded into semi-arid areas with limited precipitation and surface water availability. This has greatly intensified the dependence of irrigated crops on groundwater withdrawal and caused a steady increase in groundwater withdrawal and groundwater depletion. One of the effects of groundwater pumping is the reduction in streamflow through capture of groundwater recharge, with detrimental effects on aquatic ecosystems. The degree to which groundwater withdrawal affects streamflow or groundwater storage depends on the nature of the groundwater–surface water interaction (GWSI). So far, analytical solutions that have been derived to calculate the impact of groundwater on streamflow depletion involve single wells and streams and do not allow the GWSI to shift from connected to disconnected, i.e. from a situation with two-way interaction to one with a one-way interaction between groundwater and surface water. Including this shift and also analysing the effects of many wells requires numerical groundwater models that are expensive to set up. Here, we introduce an analytical framework based on a simple lumped conceptual model that allows us to estimate to what extent groundwater withdrawal affects groundwater heads and streamflow at regional scales. It accounts for a shift in GWSI, calculates at which critical withdrawal rate such a shift is expected, and when it is likely to occur after withdrawal commences. It also provides estimates of streamflow depletion and which part of the groundwater withdrawal comes out of groundwater storage and which parts from a reduction in streamflow. After a local sensitivity analysis, the framework is combined with parameters and inputs from a global hydrological model and subsequently used to provide global maps of critical withdrawal rates and timing, the areas where current withdrawal exceeds critical limits and maps of groundwater and streamflow depletion rates that result from groundwater withdrawal. The resulting global depletion rates are compared with estimates from in situ observations and regional and global groundwater models and satellites. Pairing of the analytical framework with more complex global hydrological models presents a screening tool for fast first-order assessments of regional-scale groundwater sustainability and for supporting hydro-economic models that require simple relationships between groundwater withdrawal rates and the evolution of pumping costs and environmental externalities.

Groundwater is a vital resource for agriculture, providing irrigation water for crops and drinking water for communities. However, agricultural activities can contribute to groundwater contamination through the use of fertilizers, pesticides, and animal waste. This review presents a multidisciplinary assessment of the risks associated with groundwater contamination from agriculture and explores mitigation strategies to protect groundwater quality. The assessment begins with an overview of the sources and pathways of agricultural contamination of groundwater, emphasizing the role of geologic factors, such as soil composition and hydrogeology, in influencing the transport of contaminants. The risks posed by various contaminants, including nitrates, pesticides, and pathogens, are discussed, highlighting their potential impacts on human health and the environment. Next, the review examines the importance of multidisciplinary approaches in assessing and managing groundwater contamination risks. It emphasizes the need for collaboration between farmers, scientists, policymakers, and community members to develop effective mitigation strategies. The role of geologists, hydrologists, agronomists, and environmental scientists in monitoring and managing groundwater quality is emphasized, highlighting the importance of integrating their expertise to address complex groundwater contamination issues. Mitigation strategies for agricultural contamination of groundwater are then discussed, including the use of best management practices (BMPs) such as cover cropping, crop rotation, and precision agriculture to reduce the use of fertilizers and pesticides. The review also explores the role of regulatory measures, such as groundwater monitoring programs and land-use regulations, in protecting groundwater quality. In conclusion, this review underscores the importance of a multidisciplinary approach to assessing and mitigating groundwater contamination risks from agriculture. By integrating geologic, hydrologic, agronomic, and environmental sciences, stakeholders can develop effective strategies to protect groundwater quality and ensure the sustainability of agriculture.

Groundwater depletion and contamination: Spatial distribution of groundwater resources sustainability in China

The development of groundwater research in the past 40 years: A burgeoning trend in groundwater depletion and sustainable management

This surface water protection plan (plan) provides an overview of the management efforts implemented at Lawrence Livermore National Laboratory (LLNL) that support a watershed approach to protect surface water. This plan fulfills a requirement in the Department of Energy (DOE) Order 450.1A to demonstrate a watershed approach for surface water protection that protects the environment and public health. This plan describes the use of a watershed approach within which the Laboratory's current surface water management and protections efforts have been structured and coordinated. With more than 800 million acres of land in the U.S. under federal management and stewardship, a unified approach across agencies provides enhanced resource protection and cost-effectiveness. The DOE adopted, along with other federal agencies, the Unified Federal Policy for a Watershed Approach to Federal Land and Resource Management (UFP) with a goal to protect water quality and aquatic ecosystems on federal lands. This policy intends to prevent and/or reduce water pollution from federal activities while fostering a cost-effective watershed approach to federal land and resource management. The UFP also intends to enhance the implementation of existing laws (e.g., the Clean Water Act [CWA] and National Environmental Policy Act [NEPA]) and regulations. In addition, this provides an opportunity for the federal government to serve as a model for water quality stewardship using a watershed approach for federal land and resource activities that potentially impact surface water and its uses. As a federal land manager, the Laboratory is responsible for a small but important part of those 800 million acres of land. Diverse land uses are required to support the Laboratory's mission and provide an appropriate work environment for its staff. The Laboratory comprises two sites: its main site in Livermore, California, and the Experimental Test Site (Site 300), near Tracy, California. The main site is largely developed yet its surface water system encompasses two arroyos, an engineered detention basin (Lake Haussmann), storm channels, and wetlands. Conversely, the more rural Site 300 includes approximately 7,000 acres of largely undeveloped land with many natural tributaries, riparian habitats, and wetland areas. These wetlands include vernal pools, perennial seeps, and emergent wetlands. The watersheds within which the Laboratory's sites lie provide local and community ecological functions and services which require protection. These functions and services include water supply, flood attenuation, groundwater recharge, water quality improvement, wildlife and aquatic habitats, erosion control, and (downstream) recreational opportunities. The Laboratory employs a watershed approach to protect these surface water systems. The intent of this approach, presented in this document, is to provide an integrated effort to eliminate or minimize any adverse environmental impacts of the Laboratory's operations and enhance the attributes of these surface water systems, as possible and when reasonable, to protect their value to the community and watershed. The Laboratory's watershed approach to surface water protection will use the U.S. Environmental Protection Agency's Watershed Framework and guiding principles of geographic focus, scientifically based management and partnerships1 as a foundation. While the Laboratory's unique site characteristics result in objectives and priorities that may differ from other industrial sites, these underlying guiding principles provide a structure for surface water protection to ensure the Laboratory's role in environmental stewardship and as a community partner in watershed protection. The approach includes pollution prevention, continual environmental improvement, and supporting, as possible, community objectives (e.g., protection of the San Francisco Bay watershed).

Collective actions from online to offline: External public pressure or internal structural factors

Book reviewed in this article: Groundwater Contamination in the United States, by Ruth Patrick, Emily Ford, and John Quarks. Water, Sanitary and Waste Services for Buildings, by A. F. E. Wise. Ground Water Quality Protection, by Larry W. Canter, Robert C. Knox, and Debra M. Fairchild. Adults, Larvae and Pupae of British Mosquitoes (Culicidae): a Key, by P. S. Cranston, C. D. Ramsdale, K. R. Snow, and G. B. White. Cutting Water Costs, by John S. Hills.

Groundwater is the principle source of drinking water and protection of groundwater quality is an important issue meets out the increasing population and agricultural practices. The present research an attempt made to develop DRASTIC model to understand the groundwater contamination risk in Ponnaiyar River Basin (PRB), Tamil Nadu, India using geographical information system (GIS). GIS have been shown to be useful tools for assessing groundwater pollution hazard. According to Central Ground Water Board reports the PRB categorized by semi-critical groundwater development. In view of the extensive reliance on this basin, contamination of PRB groundwater became an alarming issue. To assess groundwater contamination risk in the PRB the parameters such as Groundwater depth, Net recharge, Aquifer media, Soil media, Topography, Impact of vadose zone and Hydraulic conductivity were selected. Based on the importance of groundwater contamination all the parameters were assigned to rank and weights. Then all the themes were integrated and classified into five categories such as very low (9.33%), low (26.54%), moderate (34.77%), high (22.38%) and very high (6.98) risk. To validate the DRASTIC model, nitrate concentration was selected and found that it is 81.53% accurate which reflects that, DRASTIC model is appropriate to understand groundwater pollution risk assessment. In the GSB groundwater is contaminated mainly due to extensive use of groundwater extraction for agriculture purpose. Groundwater risk index assessment is an effective tool for groundwater management in the PRB.

Land-use abuse presents a significant challenge to sustainable development in Nigeria, with far-reaching implications for environmental sustainability, economic growth, and social equity. In view of the above premise, this paper critically examines the role of good governance and policy frameworks in monitoring and managing land use abuses across Nigeria. The study explores the multifaceted nature of land use challenges, including urban sprawl, deforestation, unregulated mining, and indiscriminate land conversion for industrial and residential purposes, which exacerbate environmental degradation and socio-economic disparities. By adopting a mixed-methods approach, this paper draws on case studies and policy reviews to evaluate the effectiveness of existing governance mechanisms and land use policies. Particular attention was given to the interplay between transparency, accountability, and community participation in addressing land use abuse. The analysis highlights the gaps in policy enforcement, institutional coordination, and resource allocation that hinder effective land use monitoring and management. This research then provides actionable insights for policymakers, land professionals, and other stakeholders, contributing to the discourse on sustainable land management in Nigeria and offering a blueprint for addressing similar challenges in other developing countries. The specific objectives of this study are to: (a) examine existing land policies and governance structures to assess their effectiveness in addressing land use abuse and promoting sustainable management, (b) investigate the relationship between governance quality and land use outcomes, focusing on transparency, accountability, public participation, and institutional efficiency, (c) identify the technological, institutional, and policy innovations that can improve land use monitoring and management in Nigeria, and (d) provide a framework for multi-stakeholder collaboration in mitigating land use abuse and ensuring equitable land access. Key Findings includes: i. Governance and Institutional Weaknesses: Weak enforcement of regulations, overlapping responsibilities among government agencies, and pervasive corruption are major barriers to effective land management. Institutional capacity is often undermined by inadequate funding and a lack of technical expertise. ii. Policy Gaps: The Land Use Act of 1978, which centralizes land ownership under state governors, has led to bureaucratic inefficiencies and inequities in land allocation. It lacks provisions for modern urban planning challenges and environmental sustainability. iii. Urban and Rural Disparities: In urban areas like Lagos and Abuja, rapid urbanization drives unauthorized developments, while rural regions face issues such as land grabbing, deforestation, and illegal mining. iv. Technological Shortfalls: While Geographic Information System (GIS) and satellite technologies are increasingly used, their adoption remains limited due to high costs, lack of expertise, and inadequate infrastructure. v. Community Exclusion: Limited stakeholder participation and public awareness contribute to the disconnect between policy objectives and ground realities. The study concludes that good governance, characterized by clear accountability mechanisms, stakeholder collaboration, and the integration of digital technologies, is essential for addressing land use abuse in Nigeria. Recommendations includes: i. Policy Overhaul: Amend the Land Use Act of 1978 to incorporate decentralized land governance, stronger environmental safeguards, and clearer guidelines for equitable land allocation. ii. Technological Integration: Expand the use of GIS, drones, and AI-driven monitoring tools to improve real-time data collection, enhance transparency, and streamline enforcement mechanisms. iii. Institutional Reforms: Strengthen land governance institutions through increased funding, training, and capacity building. Establish a centralized, digital land registry to reduce conflicts and improve efficiency. iv. Public Engagement: Foster inclusive decision-making by involving community stakeholders in land governance processes. Conduct awareness campaigns to educate citizens on land rights and environmental conservation. iv. Inter-agency Collaboration: Harmonize the roles of government agencies involved in land management to eliminate overlaps and foster coordinated action. iv. Sustainable Financing: Develop financing models to support technological adoption and capacity-building programs, including public-private partnerships and international aid.

The hyporheic zone plays an important role in groundwater and stream water quality protection. To investigate the stream-groundwater interaction mechanisms in the lateral hyporheic zone, this study examined Ma’an Creek in Chongqing during the dry season from December 2015 to April 2016. The water level, water temperature, pH and Cl− concentration in the hyporheic zone and groundwater were monitored in situ . The sediment permeability coefficient, stable isotopes of hydrogen and oxygen and concentration of DOC were analyzed. The results show that the water level changes of hyporheic zone and the movement of hyporheic flow were influenced significantly by the permeability coefficient of sediment. The hyporheic flow approximately 10 cm from the stream bank was clearly affected by precipitation infiltration and evapotranspiration. During the study period, the groundwater recharged the stream, and the impact of groundwater on the hyporheic flow gradually decreased with the flow path. The hyporheic flow approximately 30 cm from the stream bank was still mainly affected by groundwater. Approximately 10–30 cm from the stream bank, the mixing of groundwater with precipitation and stream water intensified. Due to the sediment properties, moisture accumulated approximately 10 cm from the stream bank and drained into the stream via hyporheic flow, with potential impacts on stream water quality.

Development of soil metal criteria to preserve groundwater quality

Development of soil metal criteria to preserve groundwater quality

Restoration of Groundwater Quality to Sustain Coastal Ecosystems Productivity

Current national stormwater policy may have adverse effects on public and private water supplies. Shallow groundwater, which is increasingly being relied on for drinking water, irrigation, stream baseflow, and drought relief, is now becoming a sink for unwanted stormwater contaminants to avoid direct discharge to surface water. This policy of infiltration without properly considering implications for groundwater quality should be improved so that society's contaminants are not transferred from one water resource to another just to avoid paying the full cost of today's stormwater management. Stormwater regulatory programs and green infrastructure practices focus first on reducing pollutant loads to surface water, with minimal consideration of pollutant load diverted to groundwater. Best management practices, which provide direct recharge, such as porous pavement, retention ponds, shallow injection wells, as well as agricultural and roadway drains, are commonly used. Frequently the only design criterion for stormwater infiltration is the infiltration rate. Infiltrated stormwater can carry pollutants (nitrogen; pesticides; metals, oil, and grease from road surfaces and gas stations; hazardous waste spills; and salts used in road deicing) as well as cause hydraulic problems (mounding, slope stability, and subsurface flooding of infrastructure). Governmental and professional organizations, including the National Research Council (https://doi.org/10.17226/12465), USEPA Underground Injection Control Program, and Water Environment & Reuse Foundation (www.werf.org), have examined the groundwater impact issue, but issued often vague, general cautions about the risks. For instance, the guidance for the Underground Injection Control program only notes that infiltration through stormwater drainage wells has the potential to adversely impact groundwater supplies. State and local stormwater infiltration guidance typically focuses on avoiding “hotspots” already contaminated so as not to move contaminated groundwater in unanticipated directions. Most guidance documents recommend fixed-distance setbacks for infiltration sites instead of empirically determined or engineered structures to preclude adverse subsurface effects. While these structures may initially function as designed, without guidance and implementation of routine maintenance, they will not continue to do so. Guidance and regulation rarely include mention of groundwater monitoring. We understand that USEPA is starting to identify some key concerns regarding groundwater impacts. These include recognizing aquifer complexity and long-term groundwater monitoring needs near stormwater facilities. Finally, using shallow groundwater for the disposal of todays' stormwater problems may only be delaying a problem rather than solving it. Hydraulic loading by managed stormwater infiltration can overload natural treatment processes. Impacted groundwater can ultimately discharge to surface waters resulting in long-term degradation, especially under low flow conditions. This concept was recently addressed in a U.S. Ninth Circuit Court of Appeals decision (February 1, 2018, Hawaii Wildlife Fund v. County of Maui). The panel found that the disposal wells were “point sources” that discharged “pollutants” into groundwater, that eventually entered surface water and therefore these wells fell under the purview the National Pollutant Discharge Elimination System. On February 20, 2018, the U.S. Environmental Protection Agency issued a request for comment regarding the adequacy of its regulatory programs under the Clean Water and Safe Drinking Water Acts addressing stormwater discharges to groundwater “in direct hydrologic connection to surface water” (83 FR 7126 comments due May 21, 2018). With the complexity of the subsurface, a single approach to managing stormwater infiltration and protecting groundwater quality will not be appropriate. Most guidance documents do note that additional research into groundwater contamination is warranted. Scientific research is needed to identify less risky stormwater infiltration practices, quantify impacts on groundwater quality and quantity, develop appropriate monitoring practices, improve pollutant removal prior to infiltration, and discern sound hydrogeologic and engineering design practices in the siting and design of stormwater facilities. Research is also needed to understand the future effects and costs of stormwater disposal practices and to develop a more advantageous and desirable policy for all water users.

This research explores the intricate relationships between sanitation infrastructure, groundwater quality, and human health outcomes in the peri-urban areas of Gwazunu and Suleja, Suleja Local Government Area, Niger State. It focuses on developing evidence-based strategies to mitigate waterborne disease risks. By employing a mixed-methods approach, combining cross-sectional surveys of 200 households and water quality analysis of 10 sources, the study reveals alarming correlations between inadequate sanitation infrastructure and groundwater contamination. Notably, 75% of water sources exceed World Health Organization guidelines for E. coli, with 94.5% of samples containing over 100 CFU/100mL, indicating severe contamination. This has devastating consequences, as 63% of households reported typhoid fever episodes over the past three months. Further analysis highlights the critical role of sanitation infrastructure conditions and population density in influencing groundwater quality. Investing in improved sanitation infrastructure can significantly mitigate the risk of cholera and typhoid fever, reducing it by 35%. To address these concerns, this study recommends upgrading sanitation infrastructure, implementing decentralized wastewater treatment, and promoting community-led total sanitation initiatives. Integrating water safety planning and transition management frameworks can also protect groundwater quality and public health in peri-urban areas. This research contributes to sustainable solutions for safeguarding groundwater quality and public health, emphasizing evidence-based strategies to mitigate waterborne disease risks. The study's findings have significant implications for policymakers, practitioners, and researchers tackling peri-urban water management and public health challenges.