Search

Given the prevailing arid climate and rapid population growth, groundwater resources face unprecedented challenges globally, including depletion, seawater intrusion, and contamination. Managed aquifer recharge (MAR) technologies have emerged as valuable solutions to address these pressing issues. However, identifying suitable regions for MAR activities is a complex task, particularly at the country level. Therefore, in this study, we propose a robust approach that combines the fuzzy analytical hierarchy process (AHP) and the technique for order of preference by similarity to ideal solution (TOPSIS) to delineate suitable sites for MAR structures. The proposed model was applied to Djibouti, a hot, dry, and water-stressed country. We identified a set of nine decision criteria and conducted a pairwise comparison survey to determine their relative importance. Additionally, the TOPSIS method was employed to integrate the decision layers and prioritize the study area. The results highlight the significance of rainfall, the slope, and the NDVI as the most influential decision parameters, while the drainage density has the least impact. A suitability analysis reveals that 16.38%, 17.96%, and 30.41% of the country have a very high, high, and moderate potential for MAR activities, respectively. Furthermore, a sensitivity analysis demonstrates the stability of the proposed model, affirming the usefulness of the generated suitability map.

Drawing out too much groundwater, or overdrafting, is a serious problem in California. As a result, groundwater sustainability agencies are considering using recycled municipal wastewater to recharge aquifers. In our study, we employ suitability mapping and the models C2VSimFG and Ichnos to identify appropriate areas for managing aquifer recharge with recycled water in California’s Central Valley. The factors that influence suitability include soil properties, proximity to recycled water sources, and the residence time, or amount of time that recharged water spends underground. There are many suitable areas in the Central Valley that are immediately adjacent to water recycling facilities. However, adequate supply is an issue in most locations. Roughly half of the groundwater sustainability agencies in critically overdrafted basins of the Central Valley have enough potentially suitable locations to meet their recharge goals, but not all of them have access to enough recycled water. The methods demonstrated here can serve as tools for agencies considering using recycled water for aquifer recharging.

Over the last decades, the quality and quantity of the Mediterranean freshwater resources have significantly deteriorated due to climate change, unsustainable utilization, user conflicts, and seawater intrusions. On the small and remote island of Vis, where similar issues prevail, the need for alternative water management solutions has yielded managed aquifer recharge (MAR) as a promising option for increasing the safety and resilience of the local and autonomous water supply. By performing a cost–benefit analysis (CBA) to evaluate the feasibility of the deployment of an infiltration pond method in the Korita well field, the results evidenced a positive financial performance and sustainability of the proposed MAR solution. In addition, the overall economic benefits of the project, quantified through the willingness-to-pay method, significantly exceeded its costs, as evidenced by the high benefit/cost ratio of 2.83. The most significant uncertainty related to the infiltration pond method is represented by the high sensitivity to changes in the applied hydrological assumptions (i.e., the evaporation coefficient and number of annual infiltration pond recharges). This study aims to contribute to the understanding of interrelated socio-economic factors of MAR projects in karst aquifers, and represents the first of its kind in Croatia.

Managed aquifer recharge (MAR) refers to a suite of methods that is increasingly being applied worldwide for sustainable groundwater management to tackle drinking or irrigation water shortage or to restore and maintain groundwater ecosystems. The potential for MAR is far from being exhausted, not only due to geological and hydrogeological conditions or technical and economic feasibility but also due to its lack of acceptance by the public and policymakers. One approach to enable the safe and accepted use of MAR could be to provide comprehensive risk management, including the identification, analysis, and evaluation of potential risks related to MAR. This article reviews current MAR risk assessment methodologies and guidelines and summarizes possible hazards and related processes. It may help planners and operators select the appropriate MAR risk assessment approaches and support the risk identification process. In addition to risk assessment (and subsequent risk treatment) related to the MAR implementation phase, this review also addresses risk assessment for MAR operation. We also highlight the limitations and lessons learned from the application and development of risk assessment methodologies. Moreover, developments are recommended in the area of MAR‐related risk assessment methodologies and regulation. Depending on data availability, collected methodologies may be applicable for MAR sites worldwide. Integr Environ Assess Manag 2022;18:1513–1529. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)., Key Points: The past two decades have seen a marked increase in the literature on MAR‐related risk assessment, and a further increase is expected, since more attractive strategies are being used worldwide for integrated groundwater management. The development of holistic risk management plans can improve social acceptability and contribute to safer implementation and operation of MAR schemes. In connection with holistic risk management, MAR can be seen as a viable option for reaching the United Nations Sustainable Development Goal #6. Widely lacking regulations worldwide for risk assessment of MAR schemes is identified to hinder MAR implementation and safe operation worldwide., DEEPWATER‐CE, ENeRAG

Arizona has been at the forefront of groundwater management since the establishment of the Groundwater Management Act in 1980. The Central Arizona Groundwater Replenishment District (CAGRD) is a groundwater management mechanism that facilitates development in regions of Central Arizona where the use of groundwater is limited by law. Several stakeholders have raised concerns about some of the CAGRD’s operations; however, stakeholders have yet to agree on the definition of the problems, let alone how the CAGRD might be improved. This study uses statistical and inductive thematic content analysis of a survey to determine (1) the CAGRD issues that stakeholders view as problems and (2) whether opinions differ significantly among different stakeholder groups. This study also uses deductive thematic content analysis to examine semi-structured interviews with CAGRD experts in order to find potential solutions to the CAGRD-related issues that are considered problems by stakeholders. The survey results show that long-term uncertainties related to the availability of renewable water supplies and hydrologic disconnect, where groundwater pumping and replenishment take place in different sub-basins, are stakeholders’ chief concerns. Sector affiliation and CAGRD membership status are associated with stakeholders’ opinions on some, but not all, questions. The potential policy changes offered address problems identified by stakeholders. This research will inform forthcoming policy discussions regarding groundwater management in Central Arizona as the state’s decision makers look to improve the CAGRD in the context of water scarcity exacerbated by climate change.

Groundwater extraction in most Middle East and North Africa (MENA) countries far exceeds its renewability, which ranges from 6% to 100%. Freshwater resources to support food production are very limited in this region. Future climate predictions include more consistent and longer wet periods with increasing surplus rainfall, which will enhance flood and flash flood occurrences in the MENA. Demand management of groundwater resources and managed aquifer recharge (MAR, also called groundwater replenishment, water banking, and artificial recharge, is the purposeful recharge of water to aquifers for subsequent recovery or environmental benefits) represent essential strategies to overcome the challenges associated with groundwater depletion and climate change impacts. Such strategies would enable the development of groundwater resources in the MENA region by minimizing the stress placed on these resources, as well as reducing deterioration in groundwater quality. Groundwater augmentation through recharge dams is a common practice in different countries around the globe. Most dams in the MENA region were built to enhance groundwater recharge, and even the few protection dams also act as recharge dams in one way or another. However, the operating systems of these dams are mostly dependent on the natural infiltration of the accumulated water in the reservoir area, with limited application of MAR. This review presents analyses of groundwater renewability and the effectiveness of recharge dams on groundwater recharge, as well as the potential of MAR technology. This study indicates that the recharge efficiency of dam’s ranges between 15 to 47% and is clustered more around the lower limit. Efficiency is reduced by the clogging of the reservoir bed with fine materials. Therefore, there is a need to improve the operation of dams using MAR technology.

In this study, the removal efficiency of nitrogen and phosphorus in secondary treated wastewaters with a laboratory scale soil-aquifer treatment system prepared using two different types of soils and the effect of soil types on treatment efficiency were investigated. In the columns filled with clayey loam soil (CLS) and loamy soil (LS), secondary treated municipal wastewater taken from the effluent of Denizli province (Turkey) municipal wastewater treatment plant was used as feed wastewater. During the experimental studies, the total-N, total-P, dissolved oxygen, pH and temperature parameters were measured in the permeate samples taken from the valves at different depths attached to the columns. In the permeate samples taken from the last valves at a depth of 75 cm, total-N was 50.85% and total-P 97.07% in CLS, while these values were calculated as 36.72% and 64.43% in LS, respectively. In addition, the first 10 cm was highly effective for total-N and total-P removal in both soil types. Consequently, It was observed that TT was less effective than KTT in both total-N and total-P removal, the removal efficiency increased as the depth increased in both soils, and there was no time-dependent decrease in the removal efficiency during the experimental studies., Bu çalışmada farklı iki tip toprak kullanılarak hazırlanmış laboratuvar ölçekli bir toprak-akifer arıtma sistemi ile ikincil arıtılmış atıksulardaki azot ve fosforun toprak derinliği boyunca giderim verimi ve toprak tiplerinin arıtma verimine etkisi araştırılmıştır. Killi tınlı toprak (KTT) ve tınlı toprak (TT) ile doldurulmuş kolonlarda besleme atıksuyu olarak Denizli İli (Türkiye) kentsel atıksu arıtma tesisi çıkışından alınmış ikincil arıtılmış kentsel atıksu kullanılmıştır. Deneysel çalışmalar sırasında kolonlara takılmış farklı derinliklerdeki vanalardan alınan süzüntü numunelerinde toplam-N, toplam-P, çözünmüş oksijen, pH ve sıcaklık parametreleri ölçülmüştür. 75 cm derinliğindeki son vanalardan alınan süzüntü numunelerinde KTT’de toplam-N %50.85, toplam-P %97.07 oranında giderilirken TT’de bu değerler sırasıyla %36.72 ve %64.43 olarak hesaplanmıştır. Ayrıca, her iki toprak tipinde de toplam-N ve toplam-P giderimi için ilk 10 cm oldukça etkili olmuştur. Çalışma sonucunda TT’nin hem toplam-N hem de toplam-P gideriminde KTT’ye göre daha az etkili olduğu, her iki toprakta da derinlik arttıkça giderim veriminin de arttığı ve deneysel çalışmalar süresince giderim verimlerinde zamana bağlı herhangi bir azalmanın olmadığı görülmüştür.

In light of rapid population growth and climate-change pressures on water resources, there is an urgent need in many African cities to shift to more resilient, decentralised, nature-based approaches. In response, the City of Cape Town's Water Strategy document proposes various alternative water supply sources. One is Managed Aquifer Recharge (MAR) using the Cape Flats Aquifer (CFA). Overlying the CFA are a significant number of stormwater ponds that were originally designed solely to prevent flooding. These ponds could be retrofitted to infiltrate stormwater run-off, recharging the aquifer and serving a water treatment function using nature-based approaches. Many of these mono-functional ponds are in neighbourhoods that are socio-economically disadvantaged through former apartheid spatial planning. These ponds are frequently litter-filled, used for dumping rubble and, on occasion, occupied with informal housing. It is in this context that the conversion of engineered single-purpose stormwater ponds into multi-functional space is proposed using a demonstration site in Mitchells Plain, Cape Town. The ‘Pathways to water resilient South African cities (PaWS)’ project is a collaboration between the Future Water Institute at the University of Cape Town (UCT) and University of Copenhagen (UCPH), funded through DANIDA. This research is revealing how maximum benefit could be derived from these water management systems by adopting low-cost, easy to install blue-green interventions that rely on nature-based approaches. The findings from the research have relevance across Southern Africa where several large cities have existing stormwater ponds designed for flood control or as passive open green spaces. It offers valuable strategies for how these single-purpose ponds can be transformed into multifunctional blue-green spaces in ways that build resilience while addressing the environmental injustice that is a legacy of South Africa's ‘green apartheid’.

International audience; In semi-arid regions as in India, where agriculture relies on groundwater abstraction, increase of water resources availability through managed aquifer recharge (MAR) or rainwater harvesting (RWH) is often perceived as a major solution. Studies on these structures efficiency exists but despite the interest, limited information is available on the temporal variation of their replenishment. In a monsoon driven climate, the inter-annual variations are crucial to assess the potential of water storage and multi-year management especially for these structures. Here, we aim at developing a methodology to reconstruct water storage of RWH tanks to further improve our understanding on long term efficiency and multi-years drought management. To tackle this issue, long-term monitoring of a RWH tank located in Telangana in southern India is achieved by a combination of field monitoring over 2 years (tanks surface and water levels) and a daily water balance compared to LANDSAT measurements of the tank area. The procedure allows reconstructing the tank filling dynamic over a 14-years period at a daily time step and show the extreme variability of the tank filling level. During this period, the yearly maximum tank volume ranges from 8 650 to ~ 200 000 m 3. On the 14-years period, the tank reach its maximum capacity only once and, for 1/3 of the time, yearly maximum replenishment is below 15 % of its capacity. The surface water availability remains limited in time since the tank dries-up annually, except for 2 years. However, water percolation to the aquifer is slightly enhanced for some years. During this monitoring period, very few extreme raining events (6) contribute for more than 50 % of the collected volume. This observation highlights (1) the dependency of the structure to extreme storm events, (2) the limited capacity for a multiyear's management and (3) the farmers vulnerability to successive droughts.

O crescimento populacional gera o aumento da demanda de recursos hídricos, como é o caso das águas subterrâneas – fundamentais para o abastecimento da maior parte dos municípios paulistas. Os diversos usos dos solos urbanos podem contribuir para a degradação dos recursos naturais e a impermeabilização das superfícies, que alteram o balanço hídrico. As águas subterrâneas podem ser alternativas no enfrentamento dos problemas decorrentes das mudanças climáticas globais. E para isso, um adequado gerenciamento deste recurso se faz necessário. Para aumentar a disponibilidade e reduzir a insegurança hídrica, diversos países – como Alemanha, Finlândia, Eslováquia e Austrália – têm adotado a recarga gerenciada de aquíferos. No Brasil esta prática ainda não é utilizada e faltam critérios técnicos e regulamentação para o seu uso e licenciamento. O objetivo principal desse projeto é estabelecer diretrizes que permitam que os órgãos gestores paulistas disciplinem as práticas da Recarga Gerenciada de Aquíferos (MAR), permitindo que os profissionais possam estabelecer os requerimentos mínimos para um manejo eficiente, de baixo risco de degradação das águas subterrâneas e passível de monitoramento. Como base para proposição de diretrizes serão levantadas referências internacionais de MAR em diversos países. Para a avaliação da eficiência de Soluções Baseadas na Natureza (NbS) na recarga artificial de aquíferos, sobre a qualidade e quantidade dos recursos hídricos em áreas urbanas, será desenvolvido um sistema de tratamento em escala piloto no Horto Florestal de Bauru (SP). Neste experimento serão avaliados a eficiência do tratamento e o balanço hídrico local, assim como o efeito sobre as plantas locais e a qualidade das águas. Com a instalação do sistema piloto, serão gerados dados que embasarão uma adequada avaliação de recarga gerenciada de aquíferos (MAR) para o Estado de São Paulo – e que servirão de base para o desenvolvimento à nível nacional. O experimento deverá aumentar a disponibilidade de água no subsolo, assim como gerar um balanço hídrico positivo. Os dados gerados pelo monitoramento do sistema permitirão indicar parâmetros para o aumento da eficiência do tratamento e o estabelecimento de uma estratégia para ampliar os benefícios dos serviços ecossistêmicos em áreas verdes urbanas., 4° Encontro dos Pesquisadores de Pós-Doutorado do IGc/USP, Instituto de Geociências da Universidade de São Paulo, São Paulo, SP, Brasil, 29 e 30 de novembro de 2022.

La manca d’aigua és un problema cabdal a moltes regions del món, i es preveu que ha d’empitjorar, tant en el nombre de gent que ho pateix, com en la seva intensitat. Una solució proposada és la regeneració de l’aigua, el qual consisteix a tractar aigua residual fins al punt a què es pot reutilitzar sense perjudici. Un mètode és la recàrrega d’aqüífer gestionada, acoblada al tractament per sòl d’aqüífer (MAR-SAT, per les sigles en anglès), que combinen la capacitat del sòl per a extreure contaminants amb el fet que el mateix sòl pot emmagatzemar aigua durant un temps considerable, i del qual es pot disposar en temps de falta. Per a investigar aquesta solució, s’ha construït una planta pilot a l’estació de depuració d’aigua residual (EDAR) a Palamós (Baix Empordà). El treball que es presenta se centrà en la caracterització hidràulica d’un dels sistemes d’aqüífer artificial a través d’una tomografia hidràulica. S’ha determinat que la conductivitat hidràulica del sistema és uniforme, en un rang de 1-10 m/d, el qual és coherent amb la predicció derivada de la seva relació empírica establerta amb la granulometria, i el classifica com a lleugerament permeable. També fou possible visualitzar la connectivitat hidràulica relativa, determinant que és generalment bona longitudinalment, i dolenta en secció. Per altra banda, un dels mecanismes clau darrere de l’atenuació de contaminants als aqüífers és la degradació de la matèria orgànica a través de reaccions redox. L’oxigen dissolt (OD) és un dels agents oxidants més forts dels que estan típicament disponibles en aquest context i, per aquest motiu, la concentració d’oxigen dissolt fou monitorada a quatre punts de l’aqüífer abans i durant l’execució de la tomografia hidràulica. S’han observat condicions anaeròbies ([OD] < 1 ppm) a tots els punts mostrats, i no s’ha pogut esclarir una relació clara entre la connectivitat hidràulica i el comportament de l’OD. La falta de agua es un problema importante en muchas regiones del mundo, y se prevé que tiene que empeorar, tanto en el número de gente que lo sufre, como en su intensidad. Una solución propuesta es la regeneración del agua, el cual consiste en tratar agua residual hasta el punto a que se puede reutilizar sin perjuicio. Un método es la recarga de acuífero gestionada, acoplada al tratamiento por suelo de acuífero (MAR-SAT, por las siglas en inglés), que combinan la capacidad del suelo para extraer contaminantes con el hecho que el mismo suelo puede almacenar agua durante un tiempo considerable, y del cual se puede disponer en tiempo de falta. Para investigar esta solución, se ha construido una planta piloto en la estación de depuración de agua residual (EDAR) en Palamós (Baix Empordà). El trabajo que se presenta se centró en la caracterización hidráulica de uno de los sistemas de acuífero artificial a través de una tomografía hidráulica. Se ha determinado que la conductividad hidráulica del sistema es uniforme, en un rango de 1-10 m/d, el cual es coherente con la predicción derivada de su relación empírica establecida con la granulometría, y lo clasifica como ligeramente permeable. También fue posible visualizar la conectividad hidráulica relativa, determinando que es generalmente buena, longitudinalmente, y mala en sección. Por otro lado, uno de los mecanismos clave detrás de la atenuación de contaminantes en los acuíferos es la degradación de la materia orgánica a través de reacciones redox. El oxígeno disuelto (OD) es uno de los agentes oxidantes más fuertes de los que están típicamente disponibles en este contexto y, por este motivo, la concentración de oxígeno disuelto fue monitorizada en cuatro puntos del acuífero antes y durante la ejecución de la tomografía hidráulica. Se han observado condiciones anaerobias ([OD] < 1 ppm) en todos los puntos mostrados, y no se ha podido esclarecer una relación clara entre la conectividad hidráulica y el comportamiento del OD Water scarcity is a pressing issue in many regions of the globe and is predicted to become worse, both in terms of the number of people afflicted by it, and its intensity. A proposed solution is water reclamation, which involves treating wastewater to the extent that it can once more be used without prejudice. There are many ways that water reclamation can be achieved, but currently the most commonly employed methods are costly and energy-intensive. An alternative is Managed Aquifer Recharge coupled to Soil-Aquifer Treatment (MAR-SAT), which combines the innate capability of soil to remove pollutants with its capacity to store water for considerable lengths of time, making it accessible when needed. To investigate this solution, a pilot-scale test facility has been constructed in the wastewater treatment plant (WWTP) of Palamós (Catalonia, Spain). The work presented here was centred on characterising the hydraulics of one of the artificial aquifer systems via a hydraulic tomography. It was determined that the hydraulic conductivity across the system was uniform, in the range of 1-10 m/d, which is in line with the value predicted through its empirical relationship with grain-size, and classifies it as somewhat permeable. It was also possible to map the relative hydraulic connectivity, determining that it was generally good longitudinally, and relatively poor in the transverse direction. Additionally, one of the key mechanisms behind pollutant attenuation in aquifers is degradation of organic matter via redox reactions. Dissolved oxygen (DO) is the strongest oxidising agent typically available in this context, therefore the DO concentration was monitored at four sites in the aquifer before and during the hydraulic tomography. Anaerobic conditions ([DO] < 1 ppm) were observed across all probed sites, and no clear relationship between hydraulic connectivity and DO behaviour could be elucidated.

To study the influences of sand and gravel layer and groundwater velocity of Yufuhe River on atrazine migration, adsorption-desorption and sand column experiments were carried out. Results show that the adsorption capacity of montmorillonite, raw sand and washed sand to atrazine sequentially weakens. In different media, the time for atrazine concentrations to peak in washed sand with montmorillonite (WSM), raw sand and washed sand is 60, 135 and 105 minutes respectively, and the peak concentration accounts for 84, 90 and 95% of the initial concentrations. Under different flow rates, the peak time in washed sand at flow rates of 100, 150 and 200 mL/min is 135, 105 and 75 minutes, and the peak time in WSM is 90, 60 and 45 minutes, respectively. Results from this study indicate that increasing flow velocity and suspended colloids concentrations can promote the migration of atrazine in aquifers, while the presence of clay minerals in sand and gravel layers can reduce atrazine migration. Thus, during Yellow River water recharging, the sand and gravel layer of Yufuhe River is helpful to protect the aquifer, but the colloids-associated migration of atrazine can contaminate groundwater in underlying karst aquifer. HIGHLIGHTS Migrations of atrazine in porous media are related to clay minerals and colloids.; Sand and gravel layer can retard the atrazine migration during managed aquifer recharge (MAR).; Increasing groundwater velocity would accelerate atrazine migration.; This study is significant to maintain the long-term operation of the MAR.

Equitable water allocation in the context of local-scale water conflicts can be challenging. We present a holistic framework for the analysis of small-scale water disputes, contributing an integrat...

Irrigation with surface water carrying plant pathogens poses a risk for agriculture. Managed aquifer recharge enhances fresh water availability while simultaneously it may reduce the risk of plant diseases by removal of pathogens during aquifer passage. We compared the transport of three plant pathogenic bacteria with Escherichia coli WR1 as reference strain in saturated laboratory column experiments filled with quartz sand, or sandy aquifer sediments. E. coli showed the highest removal, followed by Pectobacterium carotovorum, Dickeya solani and Ralstonia solanacearum. Bacterial and non-reactive tracer breakthrough curves were fitted with Hydrus-1D and compared with colloid filtration theory (CFT). Bacterial attachment to fine and medium aquifer sand under anoxic conditions was highest with attachment rates of max. katt1 = 765 day-1 and 355 day-1, respectively. Attachment was the least to quartz sand under oxic conditions (katt1 = 61 day-1). In CFT, sticking efficiencies were higher in aquifer than in quartz sand but there was no differentiation between fine and medium aquifer sand. Overall removal ranged between < 6.8 log10 m-1 in quartz and up to 40 log10 m-1 in fine aquifer sand. Oxygenation of the anoxic aquifer sediments for two weeks with oxic influent water decreased the removal. The results highlight the potential of natural sand filtration to sufficiently remove plant pathogenic bacteria during aquifer storage.

The Hampton Roads Sanitation District is heading a Managed Aquifer Recharge project designed to build water resiliency for the district as well as meet recent regulations concerning effluent released into the Chesapeake Bay. The Sustainable Water Initiative for Tomorrow (SWIFT) project will include five injection well fields across the Virginian Coast. The first of these fields to be implemented is the James River site, scheduled to begin in 2025. A model of the Virginia Coastal Plain region was created in 2009 and has been used to simulate the combined impact of the full-scale SWIFT project. This study estimated the change in hydraulic head in the Potomac Aquifer System caused by the proposed James River recharge well field at a regional and local level. That estimation required the use of a widely accepted model of the Virginia Coastal Plain developed in 2009 which was subjected to a limited validation using USGS monitoring well data for comparison. That model was then used to establish boundary conditions for a local scale model surrounding the James River site, after which each model was used to run four pumping scenarios with varying rates of recharge. The validation of the Virginia Coastal Plain model found it to be satisfactory for the scope of this work, and it was therefore used to interpolate boundary conditions for the developed local model. The regional and local model both showed an increase in the simulated head values of the Potomac Aquifer System. The regional model simulated a sharper initial increase than the local model, however, long term the local model simulated a greater impact to the groundwater levels from the proposed recharge. Master of Science The Potomac Aquifer System (PAS) is a main water source for most of eastern Virginia and high pumping rates have caused notable drawdown in several areas. The Hampton Roads Sanitation District (HRSD) has initiated the Sustainable Water Initiative for Tomorrow (SWIFT) project that is designed to alleviate the stress on the PAS by artificially recharging the PAS through injection well. A regional groundwater model, built in 2009, has been used to estimate the impact of the proposed recharge for the SWIFT project at full capacity. This work validated the use of the regional model within the region of the first proposed SWIFT well field at the James River Site. Once the validation was complete, the regional model provided a framework to develop a more detailed model on a smaller scale. That model was then used to simulate the proposed injection well field at varying rates to estimate the effect of the James River Site. This study has shown that the regional model provides an adequate framework to build local scale models. The simulations run in both the regional and local models found that the proposed recharge increases the water levels in the PAS immediately surrounding the well field and that the impact is felt to distances exceeding 50 miles after 10 years.

The increase in the frequency of extreme precipitation events due to climate change, together with the continuous development of cities and surface sealing that hinder water infiltration into the subsoil, is accelerating the search for new facilities to manage stormwater. The Canary Islands (Spain) are taking advantage of the knowledge acquired in the construction of water mines to exploit a novel stormwater management facility, which we have defined as a dry gallery. Dry galleries are constituted by a vertical well connected to a horizontal gallery dug into highly permeable volcanic layers of the vadose zone, from where infiltration takes place. However, the lack of scientific knowledge about these facilities prevents them from being properly dimensioned and managed. In this work, we simulate for the first time the infiltration process and the wetting front propagation from dry galleries based on a 3D unsaturated flow model and provide some recommendations for the installation and sizing of these facilities. The fastest advance of the wetting front takes place during the earliest times of infiltration ( rates higher than 1000m∙d−1 and 2m3∙s−1. As time progresses, the propagation velocity and infiltration rate decrease as a consequence of the hydraulic gradient attenuation between the gallery and the aquifer. Therefore, stormwater infiltration is a highly transient process in which a sizing underestimation of 100%may be committed if unsaturated conditions or geological configuration are neglected.

A field injection experiment was performed in an anoxic sandy aquifer over 6 days to assess sorption characteristics of 7 commonly applied pesticides in agriculture and 2 frequently detected metabolites. Pesticide use changed considerably in the last decades, and there is insufficient knowledge of the fate of currently used pesticides in aquifers. Injected water arrival was monitored at 6 depth intervals of 1 m ranging from 11.4 to 32.2 m-below surface level with varying organic carbon contents (0.057–0.91%d.w.) to examine intra-aquifer variations in sorption. Observed pesticide concentrations were fit using a non-linear least squares routine to an advection-dispersion equation, from which retardation factors (R) were obtained. Pesticide degradation did not significantly influence the simulated R during the experiment. We observed that bentazon and cycloxydim were most mobile with R < 1.1 at all depths. Desphenyl chloridazon, methyl desphenyl chloridazon, and imidacloprid were, on average, less mobile, with maximum R of 1.5. Boscalid, chloridazon, fluopyram, and flutolanil showed a larger range of R, and R > 2.0 were observed in the shallowest part of the aquifer. Largest R were observed at the top of the aquifer and decreased with depth. Koc values varied similarly, which indicates that sorption is not only influenced by sedimentary organic matter (SOM) content but also by its sorption reactivity. Obtained sorption parameters were substantially lower than reported in a widely used pesticide sorption database, which suggests that sorption parameters are influenced by methodological differences and variations in the sorption reactivity of SOM. The large intra-aquifer variations in pesticide sorption highlights that aquifer heterogeneity should be considered in groundwater risk assessments.

This study proposes a hybrid fuzzy multi-criteria methodology for the selection of the most preferable site for applying managed aquifer recharge (MAR) systems by utilizing floodwaters. The use of MAR can increase water resources for later water utilization in case of drought. In this multi-criteria problem, seven recharge sites are under consideration, based on nine criteria, aiming to make a final list of their relative ranking. A fuzzy analytic hierarchy process (FAHP) based on the logarithmic fuzzy preference programming (LFFP) method is used to determine the weights of criteria. LFFP is an optimization-based method that produces a priority vector from a fuzzy pairwise comparison matrix. Furthermore, fuzzy inference systems (FIS) based on the Mamdani approach are used to estimate the rating of each alternative with respect to the criterion examined, and then the final evaluation of the alternatives is obtained. A FIS is a fuzzy if–then rule-based system where the experts’ qualitative knowledge is translated into numerical reasoning for each individual criterion. The proposed methodology is applied in the aquifer system of the agricultural plain located to the southeast of the city of Xanthi in the Prefecture of Xanthi, NE Greece.

More than two billion people and 40% of global agricultural production depend upon unsustainable groundwater extraction. Managed aquifer recharge (MAR), the practice of strategically recharging water to replenish subsurface storage, is an important subbasin scale practice for managing groundwater more sustainably. However, it is not yet reaching its full potential to counterbalance growing global groundwater demand. Agricultural managed aquifer recharge (Ag-MAR) is an emerging method for spreading large volume flows on agricultural lands and has capacity for widespread global implementation. Yet, knowledge gaps, synergies, and tradeoffs in Ag-MAR research still exist. We identify six key system considerations when implementing Ag-MAR: water source, soil and unsaturated zone processes, impact on groundwater, crop system suitability, climate change and impact on greenhouse gas emissions, and social and economic feasibility. We describe the present distribution, need for common terminology, and benefits of Ag-MAR including groundwater storage, increased environmental flows, and domestic wells support. We then outline major gaps, namely, water quality impacts, and crop health and yield. We showcase the multidisciplinary approach needed for communication and coordination of Ag-MAR programs with stakeholders and the public and provide a framework for implementation. Finally, we outline a vision for the path to Ag-MAR implementation. Ag-MAR is an important approach for achieving groundwater sustainability. However, it is one of many necessary solutions and does not offset the need for groundwater conservation.

Managed Aquifer Recharge (MAR) has been applied as Aquifer Storage, Transfer, and Recovery (ASTR) to provide fresh drinking water for local communities at 99 locations in southwest Bangladesh since 2009. Aerobic freshwater from ponds is filtered and subsequently infiltrated into anaerobic shallow brackish aquifers. At approximately 45% of these sites, relatively higher levels of Fe and As were observed in recovered water, which requires a better understanding of the hydrogeochemical processes that govern the Fe, Mn, and As levels in these MAR systems. Therefore, two representative sites with As above (74 ± 11 μg/L at site GMF11) and below (19 ± 6 μg/L at site JJS91), the Bangladesh drinking water standard of 50 μg/L were weekly monitored on hydrochemical changes from Dec 2017 to Dec 2018. Hydrogeochemical processes occurring during storage were quantified with inverse and forward geochemical mass balance models developed with PHREEQC. The following processes explained the changes in water quality: 1) mixing of infiltration water with native groundwater (∼90%:∼10%); 2) consumption of O2 by a) dissolved Fe2+ that subsequently precipitated as Fe(OH)3 at GMF11 and by b) dissolved and sedimentary organic matter (OM) at site JJS91; 3) reduction of SO4 coupled to the oxidation of OM at both sites; and 4) mixing corrosion and freshening induced cation-exchange (Ca sorption; Na desorption) triggering calcite and siderite dissolution at GMF11. Dissolution of these carbonate minerals occurred to a lesser extent at JJS91, while cation exchange (Na sorption; Ca desorption) suggested that the freshwater was displaced by brackish groundwater because of inadequate infiltration at JJS91. Distinct pH values in recovered water reflected the dominance of Fe2+ versus OM oxidation. Siderite dissolution led to 4.3 ± 3.1 and 1.0 ± 0.5 mg/L Fe in recovered water at GMF11 and JJS91, respectively. Elevated As and Mn levels in recovered water were caused for max. 20% by mixing with native groundwater and for min. 80% by mobilization processes, mainly by desorption of As from Fe-oxides and by the dissolution of Mn-bearing siderite. Recommendations are provided to improve recovered water quality.

Irrigation with surface water carrying plant pathogens poses a risk for agriculture. Managed aquifer recharge enhances fresh water availability while simultaneously it may reduce the risk of plant diseases by removal of pathogens during aquifer passage. We compared the transport of three plant pathogenic bacteria with Escherichia coli WR1 as reference strain in saturated laboratory column experiments filled with quartz sand, or sandy aquifer sediments. E. coli showed the highest removal, followed by Pectobacterium carotovorum, Dickeya solani and Ralstonia solanacearum. Bacterial and non-reactive tracer breakthrough curves were fitted with Hydrus-1D and compared with colloid filtration theory (CFT). Bacterial attachment to fine and medium aquifer sand under anoxic conditions was highest with attachment rates of max. k att1 = 765 day -1 and 355 day -1, respectively. Attachment was the least to quartz sand under oxic conditions (k att1 = 61 day -1). In CFT, sticking efficiencies were higher in aquifer than in quartz sand but there was no differentiation between fine and medium aquifer sand. Overall removal ranged between < 6.8 log 10 m −1 in quartz and up to 40 log 10 m −1 in fine aquifer sand. Oxygenation of the anoxic aquifer sediments for two weeks with oxic influent water decreased the removal. The results highlight the potential of natural sand filtration to sufficiently remove plant pathogenic bacteria during aquifer storage.

Study region: The study region is the Kamadhiya catchment (1150 km2), located in the Saurashtra region of the western state of Gujarat, India. The region has seen intensive development of check dams (CDs) for groundwater recharge with an estimated 27,000 CDs constructed up until 2018. Study focus: The impact of CDs on groundwater storage, food production and resilience are assessed for Kamadhiya catchment by estimating and comparing changes, across periods of low and high CD development, in potential recharge from CDs, rainfall trends, and irrigation demand. The analysis is carried out for the period from 1983 to 2015. New hydrological insights for the region: Groundwater storage gains observed following CD development can partly be attributed to an increase in high rainfall years after several drought years. Groundwater demand for irrigation has increased substantially, outweighing increase in groundwater recharge from CDs. This deficit in supply relative to demand is greatest in dry years, and when considered together with the low inter-annual carry-over storage of the region's hardrock aquifers, means that CDs capacity to enhance groundwater storage and mitigate the negative impacts of drought remains limited. Findings suggest that a standalone focus on MAR, unless complemented by greater emphasis on management of water demand and groundwater resources more broadly, may not be sufficient to achieve the long-term goals of sustainable groundwater and concurrently expanding agricultural crop production.

Managed aquifer recharge (MAR) refers to a suite of methods by which excess surface water or non-conventional water is stored underground for subsequent recovery or environmental purposes. MAR solutions have been largely used in unconsolidated aquifers, while their application in karst aquifers is rare. This research presents the first results of a MAR viability study on the island of Vis, a small karstic island in the Adriatic Sea. Favorable geological and hydrogeological conditions enable the formation of karst aquifers, making the island autonomous in terms of water supply. The island’s main aquifer, exploited in the Korita well field, is protected from seawater intrusion by several hydrogeological barriers. However, climate change and high seasonal pressures related to tourism pose a threat to the future availability of freshwater. Multidisciplinary field and laboratory investigations were carried out to detail the geological and hydrogeological setting of the island and its groundwater resource. Field analyses consisted of groundwater monitoring and sampling, geophysical investigations (i.e., electrical resistivity tomography), and structural measurements. Laboratory analyses included measurements of principal cations and anions and tritium activity. Despite low precipitation during the observation period (September 2019 - December 2020), the groundwater resource at the Korita site showed stable trends of physico-chemical parameters with a good storage potential and a long-term reserve. Geophysical investigations evidenced a relatively homogeneous sequence of the rock mass at a larger scale, while structural analyses indicated the occurrence of E-W karstified and open fractures that could represent a preferential flow path in the carbonate aquifer. A MAR solution for the Vis island was proposed combining an infiltration pond scheme with the direct injection of the accumulated waters into the aquifer using available wells. The potential water source could be represented by the runoff collected in an old artificial channel and the associated pond system in Korita.

Managed Aquifer Recharge (MAR), the intentional recharge of aquifers, has surged worldwide in the last 60 years as one of the options to preserve and increase water resources availability. However, estimating the extent of the area impacted by the recharge operations is not an obvious task. In this descriptive study, we monitored the spatiotemporal variation of the groundwater temperature in a phreatic aquifer before and during MAR operations, for 15 days, at the LIFE REWAT pilot infiltration basin using surface water as recharge source. The study was carried out in the winter season, taking advantage of the existing marked difference in temperature between the surface water (cold, between 8 and 13 °C, and in quasi-equilibrium with the air temperature) and the groundwater temperature, ranging between 10 and 18 °C. This difference in heat carried by groundwater was then used as a tracer. Results show that in the experiment the cold infiltrated surface water moved through the aquifer, allowing us to identify the development and extension in two dimensions of the recharge plume resulting from the MAR infiltration basin operations. Forced convection is the dominant heat transport mechanism. Further data, to be gathered at high frequency, and modeling analyses using the heat distribution at different depths are needed to identify the evolution of the recharge bulb in the three-dimensional space.

In view of heightened climate change (CC), adaptation strategies are imperative to diminish the impacts on social and environmental assets. Two approaches are commonly used to formulate adaptation measures, namely bottom-up and top-down, each with inherited limitations. A sound bridge between both approaches is low-regret adaptive measures, which result in win-win scenarios, as they provide solutions to current pressures and contribute to building CC adaptive capacity. Managed aquifer recharge (MAR) is a term that includes a series of techniques that enhance groundwater storage for later use or environmental purposes. MAR is often mentioned in the literature as a CC adaptation measure. Nonetheless, few examples explicitly prove this point. We show through the Los Arenales MAR systems (Central Spain) that MAR is a low-regret CC adaptive measure. We evaluate a series of social and environmental challenges that MAR systems contribute to solving, as well as their attributes that diminish the expected impacts of CC in the study area. MAR in the Los Arenales groundwater body has resulted in an overall increase in groundwater levels; a reduction in groundwater pumping energy and costs and CO2emissions; restoration of a surface water body; improvement in rural population indexes; and enhanced groundwater demand control and CC adaptive capacity through irrigation communities. To cope with CC, the Los Arenales MAR systems can be operated even if decreasing streamflow precludes the use of river water surpluses; they provide surface storage volume to mitigate flooding; and they decrease the impacts of droughts and water scarcity. This research proves that MAR is a water management tool capable of providing solutions to several pressures simultaneously in the present and future, an attribute particularly useful when dealing with adaptation gaps in developing countries, rural areas, or regions lacking long-term climatic data.

An aquifer storage transfer and recovery (ASTR) system was studied in which tile drainage water (TDW) was injected with relatively high NO3 (about 14 mg/L) concentrations originating from fertilizers. Here we present the evolution of denitrification kinetics at 6 different depths in the aquifer before, and during ASTR operation. First-order denitrification rate constants increased over time before and during the first days of ASTR operation, likely due to microbial adaptation of the native bacterial community and/or bioaugmentation of the aquifer by denitrifying bacteria present in injected TDW. Push-pull tests were performed in the native aquifer before ASTR operation. Obtained first-order denitrification rate constants were negligible (0.00–0.03 d−1) at the start, but increased to 0.17–0.83 d−1 after a lag-phase of about 6 days. During the first days of ASTR operation in autumn 2019, the arrival of injected TDW was studied at 2.5 m distance from the injection well. First-order denitrification rate constants increased again over time (maximum >1 d−1). Three storage periods without injection were monitored in winter 2019, fall 2020, and spring 2021 during ASTR operation. First-order rate constants ranged between 0.12 and 0.61 d−1. Denitrification coupled to pyrite oxidation occurred at all depths, but other oxidation processes were indicated as well. NO3 concentration trends resembled Monod kinetics but were fitted also to a first-order decay rate model to facilitate comparison. Rate constants during the storage periods were substantially lower than during injection, probably due to a reduction in the exchange rate between aquifer solid phases and injected water during the stagnant conditions. Denitrification rate constants deviated maximally a factor 5 over time and depth for all in-situ measurement approaches after the lag-phase. The combination of these in-situ approaches enabled to obtain more detailed insights in the evolution of denitrification kinetics during AS(T)R.

Degradation of 7 common pesticides (bentazon, boscalid, chloridazon, fluopyram, flutolanil, imidacloprid, and methoxyfenozide) and 2 metabolites of chloridazon (desphenyl-chloridazon, and methyl-desphenyl-chloridazon) was studied in an anoxic and brackish sandy aquifer before and during Aquifer Storage Transfer and Recovery (ASTR) operation. Fresh tile drainage water was injected and stored for later re-use as irrigation water. We hypothesized that electron acceptors (O2, NO3), dissolved organic carbon (∼24.7 mg/L), nutrients (NO3: ∼14.1 mg/L, NH4: ∼0.13 mg/L, PO4: ∼5.2 mg/L), and biodegrading bacteria in tile drainage water could stimulate degradation of the pesticides and metabolites (ranging between 0.013 and 10.8 μg/L) introduced in the aquifer. Pesticide degradation was studied at 6 depths in the aquifer using push-pull tests lasting ±18 days before the onset of ASTR operation. Degradation was too limited to quantify and/or could not be assessed because of the potential occurrence of pesticide retardation. Utilizing push-pull tests to obtain degradation constants should only be considered in future studies for non-retarding pesticides with relative low half-lives (here

Intensive groundwater exploitation has depleted groundwater storage and led to a series of geo-environmental problems in Beijing Plain, China. Managed Aquifer Recharge (MAR) has been endorsed to mitigate the groundwater storage depletion and achieve groundwater sustainability. A pilot MAR has been tested in the Chaobai River catchment since 2015. An innovative large-scale MAR consisting of 9 cascade terraced infiltration ponds was proposed and its effectiveness was assessed in this study using an integrated modelling approach. The integrated model coupled the regional and local transient flow and transport processes. The transient regional flow model simulated historical groundwater level declines and storage depletion in the Beijing Plain from 1995 to 2018. The coupled regional and local flow model was used to simulate the pilot MAR test in the Chaobai River from 2015 to 2018. A significant groundwater level increase was observed nearby the pilot MAR since 2015. The transport model results indicate that approximately 40% of the infiltrated water was captured by pumping wells in the No.8 well field. The models were further used to assess the long-term effects of the large-scale MAR from 2020 to 2050. The simulation results show that the groundwater system will reach a new equilibrium state under the implementation of the large-scale MAR scheme. Almost 91% of the abstracted water in the No. 8 well field will come from the MAR infiltration. The proposed large-scale MAR is very effective in restoring the depleted aquifer storage and maintaining the groundwater abstraction in the No.8 well field. However, with the increase of the groundwater level, the infiltration rate of several ponds will decrease. Therefore, it is important to maintain a dynamic balance between artificial recharge and groundwater abstraction in order to achieve a sustainable long-term MAR operation in the region.

This research was undertaken as part of the project "Impact, monitoring and assessment of global and climate change on water resources in high-mountain National Parks (CCPM) ", with reference number CANOA-51.3.00.43.00 and funded by Organismo Autonomo Parques Nacionales from the Ministerio para la Transicion Ecologica y el Reto Demografico. The authors thank the Ibero-American Science and Technology for Devel-opment Programme (CYTED) for its financial support to the network "Wa-ter Sowing and Harvesting in Protected Natural Areas" (419RT0577) . This work is a contribution to the Research Group RNM-126 of the Junta de Andalucia. Special thanks goes to the irrigation community in Berchules and the Sierra Nevada National Park for their collaboration. We also appre-ciate the support of AEMET and REDIAM, who provided meteorological and hydrological data. The authors would also like to thank the anonymous reviewers for their constructive comments and suggestions which led to a substantial improvement of the paper., The acequias de careo are ancestral water channels excavated during the early Al-Andalus period (8th–10th centuries), which are used to recharge aquifers in the watersheds of the Sierra Nevada mountain range (Southeastern Spain). The water channels are maintained by local communities, and their main function is collecting snowmelt, but also runoff from rainfall fromthe headwaters of river basins and distributing it throughout the upper parts of the slopes. Thismethod of aquifer artificial recharge extends the availability of water resources in the lowlands of the river basins during the dry season when there is almost no precipitation and water demand is higher. This study investigates the contribution of the careo channels in the watershed of Bérchules concerning the total aquifer recharge during the 2014–2015 hydrological year. Several channels were gauged, and the runoff data were compared with those obtained from a semi-distributed hydrological model applied to the same hydrological basin. The natural infiltration of meteoric waters accounted for 52%of the total recharge, while the remaining 48% corresponded to water transported and infiltrated by the careo channels. In other words, the careo recharge system enhances by 92% the natural recharge to the aquifer. Our results demonstrate the importance of this ancestral and efficient channel system for recharging slope aquifers developed in hard rocks. The acequias de careo are nature-based solutions for increasing water resources availability that have contributed to a prosperous life in the Sierra Nevada. Its long history (>1200 years) suggests that the system has remarkable resilience properties, which have allowed adaptation and permance for centuries in drastically changing climatic and socioeconomic conditions. This recharge system could also be applied to—or inspire similar adaptation measures in— semi-arid mountain areas around the world where it may help in mitigating climate change effects., Organismo Autonomo Parques Nacionales CANOA-51.3.00.43.00, Ibero-American Science and Technology for Devel-opment Programme (CYTED) 419RT0577 RNM-126, Junta de Andalucia

The mismatch between water availability and demand has led planners and the technical scientific community to seek strategies to increase water security in watersheds that suffer from the water deficit. Thus, Managed Aquifer Recharge (MAR) represents a viable alternative that can provide greater resilience to drought with the intentional recharge of water for future use. This study aimed to recommend areas with potential for MAR with water from rivers and domestic effluents treated in the Gramame River basin and part of the lower course of the Paraíba River (BRG-BRP) from a multicriteria decision analysis in System of Geographic Information (GIS). A group decision-making approach (Hierarchical Analysis Process) generated the weights of a set of criteria and, consequently, used these weights through a weighted linear combination (WLC) in GIS to recommend such areas. A sensitivity analysis of the weight of the criteria assisted in verifying which of them influenced the suitability mapping and checking the robustness of the very high-class areas indicated by the multicriteria model of the two water sources analyzed. The spatial multicriteria model for MAR with river waters suggested that areas with high and very high potential represent 51.54% of the study area. The areas with high and very high potential for MAR with treated domestic effluent water cover 14.85% of BRG-BRP. The areas classified with very high suitability were east of the BRG-BRP, where the Alluvial Deposits are. High and very high suitability class areas also occur over the Barreiras Formation, situated on agricultural land ideal for MAR. In addition to the geology and water table depth criteria, the criteria distance from the rivers and distance from the treatment plant were sensitive to changes in weight in the models, with the least sensitive being land use and cover in both. The sensitivity analysis performed also allowed us to observe the uncertain and more robust areas, depending on the decision maker's preference for the criteria in the model. The results of this study are promising for the implementation of MAR schemes by infiltration basins with river waters and treated effluents. The maps generated in this work are helpful to aid decision making and, in practice, can compose the water management plan and be used in MAR preliminary planning stage. These maps also act as a policy guideline to improve water management in BRG-BRP. Nenhuma O descompasso entre a disponibilidade e a demanda hídrica tem levado os planejadores e a comunidade técnico-científica a buscar estratégias para aumentar a segurança hídrica em bacias hidrográficas que sofrem com o déficit hídrico. Assim, a Recarga Gerenciada de Aquíferos (RGA) representa uma alternativa viável que pode conferir uma maior resiliência à seca com a recarga intencional de água para uso futuro. Este estudo teve como objetivo recomendar áreas com potencial para RGA com águas de rios e de efluentes domésticos tratados na bacia hidrográfica do rio Gramame e parte do baixo curso do rio Paraíba (BRG BRP) a partir de uma análise de decisão multicritério em Sistema de Informação Geográfica (SIG). Para recomendar tais áreas, uma abordagem de tomada de decisão de grupo AHP (Processo de Análise Hierárquica) foi utilizada para gerar os pesos de um conjunto de critérios e, consequentemente, usá-los mediante uma combinação linear ponderada (CLP) em SIG. A análise de sensibilidade do peso dos critérios foi realizada para verificar quais critérios influenciavam no mapeamento de adequação e para checar a robustez das áreas de classe muito alta indicadas pelo modelo multicritério das duas fontes hídricas analisadas. O modelo multicritério espacial para RGA com águas de rios sugeriu que as áreas com potencial alto e muito alto representam 51,54% da área de estudo. Já as áreas com potencial alto e muito alto para RGA com águas de efluentes domésticos tratados cobrem 14,85% da BRG-BRP. As áreas classificadas com adequação muito alta estão situadas em geral ao leste da BRG-BRP, onde estão presentes os Depósitos Aluvionais. As áreas de classe de adequação alta e muito alta também ocorrem sobre a Formação Barreiras, situadas em terrenos agrícolas que são ideais para RGA. Além dos critérios geologia e profundidade do lençol freático, os critérios distância a partir dos rios e a distância a partir da planta de tratamento se mostraram sensíveis às mudanças de peso nos modelos, sendo o menos sensível o uso e cobertura do solo em ambos. A análise de sensibilidade realizada também permitiu observar as áreas incertas e mais robustos, a depender da preferência dos critérios no modelo pelo tomador de decisão. Os resultados deste estudo são promissores para implementação de esquemas de RGA por bacias de infiltração com as águas de rios e efluentes tratados. Os mapas gerados são úteis para auxiliar na tomada de decisão e, na prática, podem compor o plano de gestão de águas e ser utilizados no planejamento preliminar da RGA, além de servir como uma diretriz de política para melhorar a gestão das águas na BRG-BRP.

Groundwater : : journal of the Association of Ground-Water Scientists and Engineers, a division of the National Ground Water Association (2021). doi:10.1111/gwat.13087, Published by Wiley-Blackwell, Oxford [u.a.]

Managed aquifer recharge (MAR) is a strategy to address dwindling water availability that is used to recharge stressed groundwater systems for recovery or adaptation purposes. Glacial moraine complexes can host large groundwater volumes in thick coarse-grained sandy and gravelous aquifers, and therefore are often suitable for MAR. In this research, the impact of 20 years of MAR (infiltration) in the Veluwe glacial moraine complex in the Netherlands is evaluated through time-series analysis and water quality modeling. The research enhances the understanding of hydrological processes in a glacial moraine complex and thus supports effective MAR design. The results show that MAR in the Veluwe area has raised nearby groundwater heads, and that 20 years of infiltration did not significantly deteriorate the groundwater quality. In addition, the analysis revealed an unexpected hydraulic interaction between the glacial complex and the underlying aquifer. The results suggest that MAR in a glacial moraine complex can be an effective strategy for storage of surplus surface water, compensation of groundwater abstraction, or water quality improvement. Monitoring and evaluation of groundwater heads and quality will improve the understanding of the hydrology and hydrochemistry of the water system and the used water resource, which is essential to design effective MAR systems.

Most of Australia has low rainfall. The population is small (25 ​M) but growing at 1.5%/yr. Water limitations are being exacerbated by climate change. By 1990, restraints placed on wastewater treatment plant (WWTP) discharges to receiving waters became an incentive for water recycling. The millennium drought (2000–2009) was a further driver for water recycling and desalination. Water reform policies, led to guidelines for recycled water, including stormwater and augmentation of drinking water. Advanced purified recycled water plants for indirect potable reuse were built in Brisbane. Dual pipes for drinking and recycled water were installed in new suburbs in Sydney, Melbourne and Adelaide. Agricultural, industrial and amenity recycled water use was expanded. Seawater desalination plants were installed in Gold Coast, Sydney, Melbourne, Adelaide and Perth. After the drought, economics further influenced the future use of recycled water. Since catchment water was cheaper than recycled or desalinated water, desalination plants were mothballed or maintained at low processing rates. and Brisbane’s advanced water treatment plants were shut. Water policy complacency followed. However, Western Australia, which had declining rainfall, demonstrated to an accepting community that recycled water could be used for groundwater replenishment in Perth’s water supply. By 2019, drought conditions had returned to eastern Australia. Desalination plants were reactivated and Brisbane’s indirect potable recycling scheme prepared for reinstatement. Regional towns faced water shortages and were looking for diversity of water supply. Reviews have been undertaken of the future for direct potable recycling, a debate that needs to be initiated with the consuming public.

Managed aquifer recharge can store surface water as safe and reliable groundwater for later recovery. However, most options are problematic in karstic aquifers due to complex hydrodynamics reducing their effectiveness and hence general applicability. River bank filtration and urban stormwater infiltration systems are among the main managed recharge approaches to cope with this complexity. Experiences in Lebanon demonstrate the viability of these and other options in karstic domains.

Column experiments were conducted to examine the clogging effects of colloids under controlled conditions of solution ionic strength (IS) and porous media roughness. The results showed that colloids in recharge water play an important role in the clogging process of saturated porous media, such that even a small amount of colloid may cause a large reduction in the permeability of the porous medium. Clogging at the pore throat was inferred to be the main reason for the severe permeability reduction of porous media. The characteristics of colloid clogging were clearly influenced by both IS and medium roughness. Recharge water with a higher IS facilitated greater attachment of colloids to the surface of the saturated porous medium, which lead to superficial clogging, while collectors with a rough surface resulted in greater clogging than collectors with a smooth surface.

Managed Aquifer Recharge (MAR) provides an integrated solution that allows aquifer storage to complement surface water storage. Cost–benefit analysis provides a systematic method for comparing alternative water infrastructure options. When market valuations of water infrastructure are unavailable, levelised cost is a widely accepted method of comparing MAR with alternative solutions. Benefits of MAR can be estimated by the cost of the cheapest alternative source of supply or the value of production using MAR. This article presents quantitative analysis of levelised costs and benefit cost ratios of 21 MAR schemes from 15 countries, and qualitative assessment of additional social and environmental benefits. MAR schemes recharging aquifers with natural water using infiltration basins or riverbank filtration are relatively cheap with high BCRs. Schemes using recycled water and/or requiring wells with substantial drilling infrastructure and or water treatment are more expensive, while offering positive BCRs. Most MAR schemes have positive or neutral effects on aquifer storage and condition, water quality, and environmental flows. Energy requirements are competitive with alternatives. This paper demonstrates strong returns to investment in the reported MAR schemes. MAR provides valuable social benefits and contributes to sustaining groundwater resources where extraction is managed.

Norfolk Island, like many islands in the subtropical Pacific, is at increasing risk of drought. To test the hypothesis that desalination is the most cost-effective technology for providing potable water during ‘water emergencies’, this study calculated and compared the levelised cost on Norfolk Island of seven ‘centralised’ intervention options and two ‘diffuse’ options for increasing groundwater accessions. Gully dams were the ‘centralised’ intervention option found to have the lowest levelised cost but had the largest percentage reductions in yield (i.e., 39% for 1 ML storage) under a projected drier future climate, greater than twice the percentage reduction in rainfall (16%) but less than the percentage reduction in runoff (44%). Cluster-scale roof-harvested rainwater systems with ‘turkey nest’ earth embankment had the second lowest levelised cost but are probably socially unacceptable due to siting on the community’s premier sporting oval. Desalination had the third lowest levelised cost, followed by the use of existing deep groundwater bores to pump and store water exclusively for use during a water emergency. Although desalination was not the most cost-effective technology, it is likely to be more socially acceptable than the two more cost-effective options. After gully dams, rainwater harvesting intervention options had the second highest proportional reductions in yield under a projected drier future climate (~10%); however, the reductions were less than the percentage reductions in rainfall. The yield from desalination and groundwater were unaffected under a drier future climate projected for ~2060.

Groundwater artificial recharge and medium characteristics represent the major factors in controlling the groundwater flow processes in managed aquifer recharge areas. According to the depositional features of alluvial fans, an analogous homogeneous phreatic sand tank aquifer and the corresponding inhomogeneous scale numerical models were established to investigate the groundwater flow under the combined influence of artificial recharge (human activities) and decaying hydraulic conductivity (medium characteristics). In this study, groundwater flow through a managed aquifer recharge area in an alluvial fan was analyzed under the conditions of decaying hydraulic conductivity (K) with depth or length from apex to apron. The results showed that groundwater flow processes induced by artificial recharge were significantly controlled by the increasing decay exponents of K. The decaying K with depth or length in alluvial fan areas expanded the degree of influence of artificial recharge on groundwater flow. With the increase of decay exponents, the flow directions gradually changed from a horizontal to vertical direction. Groundwater age and spatial variability could also be increased by the increasing decay exponents. The residence time distributions (RTDs) of ambient groundwater and artificially recharged water exhibited logarithmic, exponential, and power law behavior. Penetration depth and travel times of ambient groundwater flow could be affected by artificial recharge and decay exponents. Furthermore, with the increase of decay exponents, the thickness of the artificially recharged water lens and travel times of artificially recharged water were increased. These findings have important implications for the performance of managed aquifer recharge in alluvial fan areas as well as the importance of considering the gradual decrease of K with depth and length.

Critical groundwater overdraft is one of the greatest water issues of our time. In California, decades of overdraft have resulted in the passage of the 2014 Sustainable Groundwater Management Act, which requires critically overdrafted groundwater basins to create groundwater sustainability plans for future groundwater management. Many managers are using managed aquifer recharge (MAR) in their overall sustainability portfolio, in an attempt to balance groundwater use. Soil maps have been used in the past to determine viability of managed aquifer recharge sites. However, soil maps do not account for the high permeability pathways that exist in the subsurface, which have the potential to provide high efficiency recharge to the water table. This paper emphasizes the utility of creating data dense fine resolution geostatistical models and generating many realizations of the subsurface, which can then be used for analysis to understand the variability in recharge potential for specific recharge sites. These geostatistical realizations were investigated using connectivity metrics to evaluate the spread of highly conductive pathways throughout the subsurface. Connectivity analyses of high conductivity pathways show confidence that the study site- three vineyards located in the floodplain between the Cosumnes River and Deer Creek in Elk Grove, CA - has the potential to provide efficient recharge to the water table. These connectivity analyses can be completed prior to running computationally expensive and time intensive groundwater models and can be used as a way to understand variance between realizations of these geostatistical models.

Many arid and semi-arid regions of the world face challenges in maintaining the water quantity and quality needs of growing populations. A drywell is an engineered vadose zone infiltration device widely used for stormwater capture and managed aquifer recharge. To our knowledge, no prior studies have quantitatively examined virus transport from a drywell, especially in the presence of subsurface heterogeneity. Axisymmetric numerical experiments were conducted to systematically study virus fate from a drywell for various virus removal and subsurface heterogeneity scenarios under steady-state flow conditions from a constant head reservoir. Subsurface domains were homogeneous or had stochastic heterogeneity with selected standard deviation (σ) of lognormal distribution in saturated hydraulic conductivity and horizontal (X) and vertical (Z) correlation lengths. Low levels of virus concentration tailing can occur even at a separation distance of 22m from the bottom of the drywell, and 6-log10 virus removal was not achieved when a small detachment rate (kd1=1×10⁻⁵min⁻¹) is present in a homogeneous domain. Improved virus removal was achieved at a depth of 22m in the presence of horizontal lenses (e.g., X=10m, Z=0.1m, σ=1) that enhanced the lateral movement and distribution of the virus. In contrast, faster downward movement of the virus with an early arrival time at a depth of 22m occurred when considering a vertical correlation in permeability (X=1m, Z=2m, σ=1). Therefore, the general assumption of a 1.5-12m separation distance to protect water quality may not be adequate in some instances, and site-specific microbial risk assessment is essential to minimize risk. Microbial water quality can potentially be improved by using an in situ soil treatment with iron oxides to increase irreversible attachment and solid-phase inactivation.

To improve its resilience to increasing climatic uncertainty, the City of Cape Town (the City) aims to become a water sensitive city by 2040. To undertake this challenge, a means to measure progress is needed that quantifies the urban water systems at a scale that enables a whole-of-system approach to water management. Using an urban water metabolism framework, we (1) provide a first city-scale quantification of the urban water cycle integrating its natural and anthropogenic flows, and (2) assess alternative water sources (indicated in the New Water Programme) and whether they support the City towards becoming water sensitive. We employ a spatially explicit method with particular consideration to apply this analysis to other African or Global South cities. At the time of study, centralised potable water demand by the City amounted to 325 gigalitres per annum, 99% of which was supplied externally from surface storage, and the remaining ~1% internally from groundwater storage (Atlantis aquifer). Within the City’s boundary, runoff, wastewater effluent and groundwater represent significant internal resources which could, in theory, improve supply efficiency and internalisation as well as hydrological performance. For the practical use of alternative resources throughout the urban landscape, spatially explicit insight is required regarding the seasonality of runoff, local groundwater storage capacity and the quality of water as it is conveyed through the complex urban landscape. We suggest further research to develop metrics of urban water resilience and equity, both of which are important in a Global South context. Significance: This research provides the initial groundwork of quantifying the magnitude of the urban water cycle of the City of Cape Town at an annual timescale, in relation to becoming a water sensitive city. The urban water metabolism framework used in this study provides important insight to assess whole-of-system urban water dynamics and to benchmark progress towards becoming water sensitive. By quantifying the magnitude of flows into and out of the urban system, this research sheds light on the opportunities to improve circularity in the urban water cycle. The spatial approach adopted here provides a platform to interrogate the urban landscape and its role in the urban water cycle. By using data products that are available via national data sets or remote sensing, this approach can be applied to other African or Global South where data is characteristically scarce. Further work is required to establish metrics that can adequately describe urban water resilience and equity.

Agricultural managed aquifer recharge (AgMAR) is a strategy whereby surface water is used to intentionally flood croplands to recharge underlying aquifers. However, nitrate (NO3−) contamination in agriculturally intensive regions poses a threat to groundwater resources under AgMAR. We use a reactive transport model to understand the effects of AgMAR management strategies (i.e., by varying the frequency, duration between flooding events, and amount of water) on NO3− leaching to groundwater under different stratigraphic configurations and antecedent moisture conditions. We examine the potential of denitrification and nitrogen retention in deep vadose zone sediments (∼15m) using variable AgMAR application rates on two-dimensional representations of differently textured soils, soils with discontinuous bands/channels, and with preferential flow paths characteristic of agricultural fields. Simulations indicate finer textured sediments, alone or embedded within/adjacent to high flow regions, are important reducing zones providing conditions needed for denitrification. Simulation results suggest that applying water all-at-once rather than in increments transports higher concentrations of NO3− deeper into the profile, which may exacerbate groundwater quality. This transport into deeper depths can be aggravated by wetter antecedent soil moisture conditions. However, applying water all-at-once also increases denitrification within the vadose zone by promoting anoxic conditions. We conclude that AgMAR can be designed to enhance denitrification in the subsurface and reduce NO3− leaching to groundwater, while specifically accounting for lithologic heterogeneity, antecedent soil moisture conditions, and depth to the water table. Our findings are potentially relevant to other systems that experience flooding inundation such as floodplains and dedicated recharge basins.

A two-dimensional sand tank experiment was designed to explore the mechanism of water distribution and silt clogging of Yellow River water whilst replenishing groundwater in ‘open window’ reach of the piedmont river and strong seepage area consisting of a gravel and karst layer from top to bottom. Water released through the reach was divided into surface, pore and fracture karst water, of which karst water was an effective recharge from the surface water. A reasonable released water plan is necessary in recharging to avoid invalid recharge. The karst water accounted for 60–70% of the amount of water released before clogging, and this value was reduced to approximately 10–20% whilst a thin clay layer formed from suspended particles on the surface layer of the medium after clogging. The removal rate of suspended solids along vertical and lateral directions in the medium can reach over 96%. The retained amount of suspended particles was mainly distributed on the surface and upper layer region of the medium. A rubber dam can improve effective infiltration whilst promoting suspended solid deposition in the medium. The fitting degree of the numerical simulation and measured results was above 0.9, which proves the reliability of the sand tank model results.

The vadose zone plays a significant role during artificial recharge via the infiltration basin. Its thickness, lithology, heterogeneity, among others greatly affect the recharge efficiency. The main objective of this research is to establish the role of the vadose zone and the impacts of infiltration basin features and vadose zone factors on water distributions. In this work, an ideal conceptual model was considered, and mathematical models were built using HYDRUS (2D/3D) software package version 2.05. A total of 138 numerical experiments were implemented under seven types of experimental conditions. The experimental data were analyzed with the aid of correlation and regression analysis. The results showed that infiltration basin features and vadose zone factors had various impacts on water distribution, low permeability formation had various effects on evaporation depending on its depth, and there were consistent, similar, or different variation trends between infiltration and recharge. In conclusion, it is recommended that when the vadose zones are to be chosen as an infiltration basin site, the trade-off among the infiltration, recharge, storage, and evaporation should be seriously considered. This paper may contribute to a better understanding of the vadose zone as a buffer zone for artificial recharge.

Rising levels of impervious surfaces in densely populated cities and climate change-related weather extremes such as heavy rain events or long dry weather periods provide us with new challenges for sustainable stormwater management in urban areas. The Special Issue consists of nine articles and a review and focuses on a range of relevant issues: different aspects and findings of stormwater runoff quantity and quality, including strategies and techniques to mitigate the negative effects of such climate change impacts hydraulically, as well as lab-scale and long-term experience with pollutants from urban runoff and the efficiency of stormwater quality improvement devices (SQIDs) in removing them. Testing procedures and protocols for SQIDs are also considered. One paper analyses the clogging of porous media in the use of stormwater for managed aquifer recharge. The Special Issue demonstrates the importance and timeliness of the topic of sustainable rainwater management, especially with regard to growing cities and the challenges posed by climate change.

To study the temporal and spatial variations of the groundwater quantity and quality in response to intensive groundwater exploitation from the Quaternary aquifer in UAE, a water budget model with a cell size of one km2 was developed. The available historical records of groundwater levels and salinity have been used to develop the water table and salinity maps of UAE for the years 1969, 2005, 2010, and 2015. The available water resources and soil information system was used to facilitate validity, cogency, and consistency of the groundwater analysis. The spatial analysis module of GIS was used to define the aquifer setting, saturated thickness, aquifer base elevation, effective porosity, and groundwater salinity at each grid cell. The obtained results indicated that the volume of fresh groundwater resources in the Quaternary aquifer in UAE has decreased from 238 km3 in 1969 to around 10 km3 in 2015. A major part of these depleted fresh groundwater resources was replaced by brackish water, and, therefore, the total groundwater storage in this aquifer has only decreased from 977 in 1969 to 922 km3 in 2015, respectively. If the same groundwater exploitation continues, the freshwater storage in the surficial aquifer might be totally depleted in agricultural areas. Most probably, the brackish groundwater resources will be exploited. In such areas, more attention should be devoted to the management of brackish water resources to avoid the exacerbation of the saltwater intrusion problem. Despite the fact that the obtained results indicate the negative impacts of the improper water resources management in a small part of the arid area, the learned lessons are valid for other arid countries, in particular, using the proper steady state boundary conditions for the initial conditions in modeling the available future management alternatives.

With aquifers around the world stressed by over-extraction, water managers are increasingly turning to managed aquifer recharge (MAR), directly replenishing groundwater resources through injection wells, recharge basins, or other approaches. While there has been progress in understanding the geological and infrastructure-related considerations to make MAR more effective, critical evaluations of its institutional design and implementation are limited. This study assesses MAR projects, using a case study of projects proposed by groundwater sustainability agencies (GSAs) in California to comply with the state's Sustainable Groundwater Management Act of 2014; these projects will almost double the number of MAR projects in the United States. We draw on content analysis of groundwater sustainability plans that propose these projects. We first assess the types of recharge projects proposed and the stated aims of the projects, to assess when and why agencies are turning to MAR as a solution. We find that recharge basins are by far the most common approach, and that GSAs hope these basins will improve water table levels, reduce subsidence, and improve water quality. We then analyze potential barriers to project implementation and assess the projects' ability to achieve the stated goals. Primary concerns identified include a potential lack of available water, a potentially challenging legal framework, and minimal consideration of funding and cumulative land needs. To conclude, we discuss broader considerations for ensuring that MAR is an effective water management tool.

Drywells (DWs) and infiltration basins (IBs) are widely used as managed aquifer recharge (MAR) devices to capture stormwater runoff and recharge groundwater. However, no published research has compared the performance of these two engineered systems under shared conditions. Numerical experiments were conducted on an idealized 2D-axisymmetric domain using the HYDRUS (2D/3D) software to systematically study the performance of a circular IB design (diameter and area) and partially penetrating DW (38 m length with water table > 60 m). The effects of subsurface heterogeneity on infiltration, recharge, and storage from the DW and IB under constant head conditions were investigated. The mean cumulative infiltration (μI) and recharge (μR) volumes increased, and the arrival time of recharge decreased with the IB area. Values of μI were higher for a 70 m diameter IB than an DW, whereas the value of μR was higher for a DW after 1-year of a constant head simulation under selected subsurface heterogeneity conditions. A comparison between mean μI, μR, and mean vadose zone storage (μS) values for all DW and IB stochastic simulations (70 for each MAR scenario) under steady-state conditions demonstrated that five DWs can replace a 70 m diameter IB to achieve significantly higher infiltration and recharge over 20 years of operation. Additional numerical experiments were conducted to study the influence of a shallow clay layer by considering an IB, DW, and a DW integrated into an IB. The presence of such a low permeable layer delayed groundwater recharge from an IB. In contrast, a DW can penetrate tight clay layers and release water below them and facilitate rapid infiltration and recharge. The potential benefits of a DW compared to an IB include a smaller footprint, the potential for pre-treatments to remove contaminants, less evaporation, less mobilization of in-situ contaminants, and potentially lower maintenance costs. Besides, this study demonstrates that combining both IB and DW helps to get the best out of both MAR techniques.

Clean water is becoming an increasingly scarce resource, and its availability is already compromised in many cities. Several techniques for increasing urban water availability are under consideration, but how their life cycle environmental impacts compare amongst one other remain largely unknown. For cities in developing countries, which are more susceptive to water shortages, this is particularly true. Furthermore, to directly compare these technologies, they must be evaluated using the same methodological framework. This paper compares, for the first time, the life cycle environmental impacts of the following three techniques: i) seawater desalination by reverse osmosis (SWRO); ii) indirect potable wastewater reuse (IPR) through an upflow anaerobic sludge blanket digestion reactor, oxidation ditch, ozonation, and managed aquifer recharge; and iii) rainwater harvesting (RWH) to substitute drinking water from the local distribution network. These techniques were evaluated in the Brazilian southern city of Florianopolis. Life cycle assessment (LCA) was used to calculate 15 environmental impact categories with the ReCiPe methodology. Variations in electricity consumption according to technical developments, effluent quality, and pumping efficiency were taken into consideration with parametric analysis. Furthermore, a sensitivity analysis was carried out regarding the direct emissions of methane and nitrous oxide during IPR, and the electricity mix. SWRO indicates the highest results for 12 out of the 15 impact categories, and IPR indicates the lowest values in nine categories. Electricity consumption is the main contributor to most impact categories during SWRO and IPR. Out of six categories (including climate change and human toxicity), RWH is the preferable option whilst comparatively also presenting the worst results for water depletion and marine eutrophication, with glass fibre produced for storage tanks being the main contributor. In the climate change potential category, for instance, SWRO, IPR and RWH have mean results of 751, 998, and 591 kg CO2 eq./1000 m3, respectively. However, the sensitivity analysis showed that if direct emissions of CH4 and N2O in IPR are low, then the IPR technique will have better results than the SWRO method, resulting in 710 kg CO2 eq./1000 m3. Additionally, the country electricity mix was found to be highly influential in the environmental impacts, especially for SWRO and IPR. The results obtained from this research will inform stakeholders, particularly those in developing countries, about possibilities of adopting new techniques for increasing water supplies, without comprising the environmental sustainability of these systems.