Managed Aquifer Recharge Schemes Research Articles

Introducing a tailored site delineation approach to optimize the design of managed aquifer recharge surface spreading infrastructure

Managed aquifer recharge (MAR) is an emerging solution to effectively replenish overused groundwater resources, but high associated costs often hinder its uptake. There are several parameters to consider when determining the cost of MAR, including recharge types, scale of MAR schemes, land acquisition, operation and maintenance period, and the hydrogeological setting. Hydraulic conductivity and its spatial variability are the most significant hydrogeological parameters for predicting infiltration rates at MAR sites, but limited data availability makes accurate predictions often challenging. Hence, it is essential to increase data availability to optimize MAR efficiency and to better assess its economic performance. Therefore, a novel approach for MAR planning is presented in this article to efficiently enhance the data availability during the conceptual stage of MAR planning by combining site exploration, spatially resolved infiltration rate estimation, and cost analysis. The approach was applied at an actual MAR site in Vincenza, Italy, and incorporated an electromagnetic induction survey and direct push profiling as across-scale investigation methods to enhance site delineation and subsequent parameterization of the identified zones using laboratory analysis of collected samples. This MAR site is particularly suitable for its heterogeneous subsurface structure and potential to counteract groundwater depletion. The performed investigation resulted in an image of the lateral variation of subsurface conditions and allowed the delineation of three zones with different infiltration behavior, with 99.5% of infiltration occurring in just two zones, representing only 22.1% of the site. In this particular scenario, the overall cost per cubic meter of recharged water can be reduced by 59.1% by identifying and eliminating unfavorable zones. This study provides scientists and practitioners with a useful tool for MAR planning that can be applied to a wide range of sites with complex geology, thereby reducing water costs, minimizing the environmental impact of infrastructure construction, and reducing land use conflicts.

Mapping saltwater intrusion via Electromagnetic Induction (EMI) for planning a Managed Aquifer Recharge (MAR) facility in Maltese Island

In coastal areas, saltwater intrusion causes a depletion of the resource by reducing potable and irrigation freshwater supplies and causing severe deterioration of groundwater quality. This trend is observed in Pwales Valley, in the North part of Malta where the management of water resources plays a crucial role for the environmental sustainability of the area, given the importance of intensive agricultural activity along this valley. In order to tackle such phenomenon, actions or adaptation measures against climate change are strongly required. For example, Managed Aquifer Recharge (MAR) is an increasingly important water management strategy to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. To accurately plan a Managed Aquifer Recharge scheme, it is crucial to define a hydrogeological model of the studied area, with the use of traditional hydrogeological measurements and innovative unconventional techniques. In recent years, Electromagnetic Induction measurements, based on induction of em fields, have been increasingly used for investigating the saltwater intrusion dynamics due to their high sensitivity to the salinity. In the study area of Pwales Valley, a Managed Aquifer Recharge scheme is being planned and, for this aim, a hydrogeological model has been developed through an Electromagnetic Induction survey. More than 20,000 apparent electrical conductivity (ECa) data were collected to generate a quasi 3D high-resolution model of electrical conductivity of the Pwales Valley. The results highlighted the spatial extension of the tongue-shape salt water intrusion from east to west along the valley, as well as some geological-hydrogeological peculiarities such as the thickness of the salt wedge and the irregular top surface of the bottom impermeable layer, otherwise undetectable with other direct techniques at the field scale resolution. The approach was confirmed to be a useful tool for an effective hydrogeological characterisation, essential for planning adaptation measures to a changing climate, such as the implementation of a Managed Aquifer Recharge scheme.

Developing managed aquifer recharge (MAR) to augment irrigation water resources in the sand and gravel (Crag) aquifer of coastal Suffolk, UK

Managed aquifer recharge (MAR) offers a potential innovative solution for addressing groundwater resource issues, enabling excess surface water to be stored underground for later abstraction. Given its favourable hydrogeological properties, the Pliocene sand and gravel (Crag) aquifer in Suffolk, UK, was selected for a demonstration MAR scheme, with the goal of supplying additional summer irrigation water. The recharge source was a 4.6 km drainage channel that discharges to the River Deben estuary. Trialling the scheme in June 2022, 12,262 m3 of source water were recharged to the aquifer over 12 days via a lagoon and an array of 565 m of buried slotted pipes. Groundwater levels were raised by 0.3 m at the centre of the recharge mound with an approximate radius of 250 m, with no detrimental impact on local water features observed. The source water quality remained stable during the trial with a mean chloride concentration (133 mg L−1) below the regulatory requirement (165 mg L−1). The fraction of recharge water mixing with the groundwater ranged from 69% close to the centre and 5% at the boundary of the recharge mound, leading to a reduction in nitrate-N concentration of 23.6 mg L−1 at the centre of the mound. During July–September 2022, 12,301 m3 of recharge water were abstracted from two, 18 m boreholes to supplement surface irrigation reservoirs during drought conditions. However, the hydraulic conductivity of the Crag aquifer (∼10 m day−1) restricted the yield and thereby reduced the economic viability of the scheme. Construction costs for the MAR system were comparatively low but the high costs of data collection and securing regulatory permits brought the overall capital costs to within 18% of an equivalent surface storage reservoir, demonstrating that market-based mechanisms and more streamlined regulatory processes are required to incentivise similar MAR schemes.

Understanding the global success criteria for managed aquifer recharge schemes

Water availability and quality issues will only gain importance in the future, with climate change impacts putting increasing pressure on global water resources. Dealing with these challenges requires drawing on all available water management tools, including Managed Aquifer Recharge (MAR). Although MAR has seen increasing global implementation during the last half a century, it is still often overlooked as a management tool. While technical, bio-physical, and hydrogeological aspects of MAR are well researched, this cannot be said for socio-economic and other governance factors. Where information is available, this study seeks to understand the conditions necessary for MAR success. We apply fuzzy-set Qualitative Comparative Analysis on 313 world MAR applications, and also model separately for high- and low-middle-income countries. Results show that sophisticated hydrogeological site understanding and scheme operation is paramount for MAR success, as is utilizing natural water sources for high value end uses. Successful high-income country MAR schemes tend to be large and utilize natural water sources and sophisticated water injection and treatment methods to augment potable water supply; while successful low-middle-income country schemes are not large, older than 20 years, and use gravity infiltration methods and (limited) no water treatment. These findings will help inform the future suitability of MAR application design and its likely success within various contexts.

Application of hydrogeophysics and diagnostic plots in setting up a sustainable managed aquifer recharge scheme, West Coast, South Africa

The lack of using hydrogeophysics and hydraulic data in setting up a sustainable managed aquifer recharge scheme leads to challenges in operations and maintenance of such infrastructures. Managed aquifer recharge is an engineering and technological based water management approach that is used to maximize storage and improve groundwater security. However, this approach is under-utilized in many countries and South Africa is no exception. This study aimed at improving knowledge on aquifer dynamics for managed aquifer recharge scheme using hydrogeophysics and diagnostic plots. This study argued that integrating hydrogeophysics data and diagnostic plots for setting up managed aquifer recharge schemes lead to improved operations and maintenance through improved scientific knowledge on the dynamics of the aquifer. SkyTEM and electrical resistivity tomography data were used to delineate subsurface structures. Pumping test data were used to develop diagnostic plots, for identifying flow regimes and boundary conditions in the proposed managed aquifer recharge area. Results from geophysics investigation inferred pathways for potential managed aquifer recharge and areas to avoid. The integration of hydrogeophysics and diagnostic plots provided a more practical interpretation for the study area. It is recommended that hydrogeophysics investigation should be carried out before and after setting managed aquifer recharge scheme as it leads to enhanced decisions on groundwater usage, monitoring and management.

Managed aquifer recharge for agriculture in Australia – History, success factors and future implementation

Managed aquifer recharge (MAR) is the intentional recharge of water to aquifers for subsequent recovery or environmental benefit. MAR can potentially increase security of water in drought more economically than new dams, can augment existing dams with higher efficiency storage (less evaporation), augment brackish groundwater desalination schemes, and facilitate conjunctive use of surface and groundwater resources. In Australia in 2023, there are currently 10 known operational MAR schemes used to increase agricultural activity in varying stages of development, providing a total capacity of ∼ 70 × 106 m3/year. A review of these Australian MAR schemes identified several general principles which are more likely to lead to successful implementation, including: an ongoing demand for water for high value agriculture; availability of water for recharge; a suitable aquifer for storage with the capacity to store water for recovery and use; a suitable location for the MAR scheme typically in areas of low topographic relief; and the organisational capability, institutional arrangements and supportive policies to operate the scheme sustainably and economically. If MAR schemes are to be developed to support agricultural activity in Australia, site identification, project design, economic viability, and community and regulator consultation within an investment prospectus will be required. Operational demonstration schemes in a variety of agricultural settings will encourage wider adoption. Supportive policy development is required to ensure sustainable and equitable ongoing operation of MAR to support irrigated agriculture and for drought resilience.

Review of artificial recharge prospects for augmentation of groundwater in Egypt: A case study of El Bustan extension area

Artificial recharge (AR) is the process whereby surface water is directed purposely underground to augment natural replenishment of groundwater reserves. During the period 1996–1998, the Research Institute for Groundwater started artificial recharge using infiltration basins in El Bustan experimental station in the western Nile Delta region. Recently, during the period 2020–2021, artificial recharge activities have been resumed in the experimental station. In this work, changes in hydrological conditions affecting the experimental station since its inception are reviewed and assessed. Artificial recharge using the infiltration basin are then applied, where results of these experiments are evaluated and compared to the previous ones. This is achieved with the objective of making an updated evaluation of the prospects of artificial recharge considering the changes in hydrological conditions. The study revealed that rise of groundwater levels is the major change affecting aquifer conditions in the study area. Such progressive rise of groundwater levels resulted in reducing the vadose zone thickness by more than 50% of its original thickness in 1996. This rise is attributed to uncontrolled recharge due seepage from nearby canals and irrigation return flow in the western Nile Delta region for the past 25 years. In view of the impacts of uncontrolled recharge, it is concluded that future work should shift from AR to managed aquifer recharge (MAR) to store water in the aquifer for subsequent recovery. It is recommended that further studies should use numerical modeling for exploring MAR schemes that can sustain the aquifer hydrologic equilibrium. Such MAR schemes should facilitate conjunctive use of surface and groundwater for improved water use management in the western Nile Delta region.

Numerical simulation of a managed aquifer recharge system designed to supply drinking water to the city of Amsterdam, The Netherlands

Managed aquifer recharge (MAR) is increasingly used to secure drinking water supply worldwide. The city of Amsterdam (The Netherlands) depends largely on the MAR in coastal dunes for water supply. A new MAR scheme is proposed for the production of 10 × 106 m3/year, as required in the next decade. The designed MAR system consists of 10 infiltration ponds in an artificially created sandbank, and 25 recovery wells placed beneath the ponds in a productive aquifer. Several criteria were met for the design, such as a minimum residence time of 60 days and maximum drawdown of 5 cm. Steady-state and transient flow models were calibrated. The flow model computed the infiltration capacity of the ponds and drawdowns caused by the MAR. A hypothetical tracer transport model was used to compute the travel times from the ponds to the wells and recovery efficiency of the wells. The results demonstrated that 98% of the infiltrated water was captured by the recovery wells which accounted for 65.3% of the total abstraction. Other sources include recharge from precipitation (6.7%), leakages from surface water (13.1%), and natural groundwater reserve (14.9%). Sensitivity analysis indicated that the pond conductance and hydraulic conductivity of the sand aquifer in between the ponds and wells are important for the infiltration capacity. The temperature simulation showed that the recovered water in the wells has a stable temperature of 9.8–12.5 °C which is beneficial for post-treatment processes. The numerical modelling approach is useful and helps to gain insights for implementation of the MAR.

Rooftop water harvesting for managed aquifer recharge and flood mitigation in tropical cities: Towards a strategy of co-benefit evaluations in João Pessoa, northeast Brazil

Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.

Improving clogging predictions at managed aquifer recharge sites: a quantitative assessment on the vertical distribution of intrusive fines

Managed aquifer recharge (MAR) is an emerging approach to enhancing water storage capacity, improving water supply security and countering groundwater overexploitation. However, physical clogging, i.e. accumulation of suspended organic and inorganic solids within a sediment matrix, can lead to a significant reduction of infiltration rates and present difficulties in the functioning of MAR infrastructure. Clogging and subsequent reduction in infiltration capacity are often quantified based on monitoring data or field investigations, rather than on forecasts. Existing predictive models require specific parameterisation, making an application to heterogeneous sites, or under changing conditions, difficult. Hence, a generalised understanding of how intrusive fine particles distribute over depth during water recharge cycles for typical MAR infiltration basin sediments is needed to predict clogging susceptibility and clogging patterns already in the planning phase and before operation of MAR schemes. The study will contribute to operational reliability, deduce optimised management practices, and, ideally, reduce maintenance efforts. To achieve this goal, data from different soil-column clogging experiments are reviewed and complemented with experiments to establish a generally valid relationship for the vertical distribution of intrusive fines under consideration of the primary porous media’s and intruding particles’ characteristics. Obtained results allow for quantification of the amount of particles retained at the surface of the porous media, i.e. formation of a filter cake, a description of the distribution of fines over depth, and total clogging depth. Finally, the findings are applied to a real MAR case study site to showcase the quantification of clogging effects on recharge rates.

Benefits and Costs of Managed Aquifer Recharge: Further Evidence

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.

Assessing Economic Feasibility of Managed Aquifer Recharge Schemes: Evidence from Cost-benefit Analysis in Poland

HighlightsManaged aquifer recharge (MAR) schemes are promising solutions in water management.It is important to ensure the economic feasibility and viability of MAR schemes.Cost-benefit analysis (CBA) is a widely used approach for the economic feasibility assessment of MAR projects.Our findings support the importance of the MAR scheme’s non-use benefits.

A numerical assessment on the managed aquifer recharge to achieve sustainable groundwater development in Chaobai River area, Beijing, China

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.

Decision-Support Groundwater Modelling of Managed Aquifer Recharge in a Coastal Aquifer in South Portugal

The Vale do Lobo sector of the Campina de Faro aquifer system in the Algarve (Portugal) is at risk of seawater intrusion. Managed Aquifer Recharge (MAR) is being considered to avoid groundwater quality deterioration. Numerical modelling was undertaken to assess the feasibility of several proposed MAR schemes. Although some data is available, many aspects of system behaviour are not well understood or measured. We demonstrate the use of a structurally simple but parametrically complex model for decision-making in a coastal aquifer. Modelling was designed to facilitate uncertainty reduction through data assimilation where possible, whilst acknowledging that which remains unknown elsewhere. Open-source software was employed throughout, and the workflow was scripted (reproducible). The model was designed to be fast-running (rapid) and numerically stable to facilitate data assimilation and represent prediction-pertinent uncertainty (robust). Omitting physical processes and structural detail constrains the type of predictions that can be made. This was addressed by assessing the effectiveness of MAR at maintaining the fresh-seawater interface (approximated using the Ghyben-Herzberg relationship) below specified thresholds. This enabled the use of a constant-density model, rather than attempting to explicitly simulating the interaction between fresh and seawater. Although predictive uncertainty may be increased, it is outweighed by the ability to extract information from the available data. Results show that, due to the limit on water availability and the continued groundwater extraction at unsustainable rates, only limited improvements in hydraulic heads can be achieved with the proposed MAR schemes. This is an important finding for decision-makers, as it indicates that a considerable reduction in extraction in addition to MAR will be required. Our approach identified these limitations, avoiding the need for further data collection, and demonstrating the value of purposeful model design.

Analysis of Potential Site for Managed Aquifer Recharge Scheme in the Upper Greater Mae Klong Irrigation Project, Thailand

This study developed a groundwater flow model to propose the possible Managed Aquifer Recharge (MAR) scheme for sustainable use of groundwater in the Upper Greater Mae Klong Irrigation Project, Thailand. The site suitability for MAR scheme was assessed through the GIS–based Multi–Criteria Decision Making (MCDM) using the Simple Additive Weighted (SAW) method. Five key relevant factors namely; groundwater drawdown, soil texture, depth to groundwater table, land slope and distance to surface water source were chosen as assessment criteria and reclassified for the analysis of site selection for MAR scheme. The results illustrate the potential site for the managed aquifer recharge scheme in the southwest of the Phanom Thuan Operation and Maintenance Project where soil texture is immensely sandy loam. The results of groundwater flow model also exhibit that 14 designated injection wells with discharge rate of 200 m3 d-1, each of which delineated in the potential area, can increase the hydraulic head in the aquifer ranging from 0.00–0.50 m during 2000–2016. In addition, a high increase of the hydraulic head in the aquifer is found nearby the locations of designated injection wells.

Using Heat as a Tracer to Detect the Development of the Recharge Bulb in Managed Aquifer Recharge Schemes

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.

Assessing the costs of Managed Aquifer Recharge options to support agricultural development

Managed aquifer recharge (MAR) can play an important role in agricultural water management and productivity where suitable aquifers exist. Yet while the benefits and costs of surface water storage have been extensively reported, the benefits and costs of MAR have been under reported and poorly conceptualised to date. In this study of ten potential MAR schemes in wet-dry tropical climates of northern Australia the estimated levelized costs ranged from US$0.04 to $0.36/m3 for MAR schemes of 0.6–5 Mm3/y capacity. The type of MAR scheme had the largest influence on cost, resulting in the following order of increasing cost for 1 Mm3/y schemes: recharge release, infiltration basin, recharge weir, aquifer storage transfer and recovery (ASTR), aquifer storage and recovery (ASR), seawater intrusion barrier. Infiltration type schemes were typically lower cost than well-injection. Scheme scale, end use and experience with similar schemes were also key influences on cost. A five-fold increase in scale reduced the levelized cost of ASR by 60%. Conceptualisation allows comparison across dissimilar schemes and revealed significant costs (20–100% of operating) associated with approvals and monitoring required for risk-based scheme development and operation. MAR can facilitate conjunctive use of surface and groundwater for improved agricultural water management. Dams typically provide considerably larger storages which results in lower levelized costs, with estimates of $0.03 to $0.18/m3 for options (annual yield 55–1248 Mm3) in the same study area. MAR is more favoured in areas of low relief, offers the benefit of reducing evaporative losses and is well suited to mosaic irrigation with incremental development and relatively low capital expenditure which may be attractive for agricultural irrigation.

Assessment of alternative groundwater flow models for Beijing Plain, China

Three alternative groundwater flow models were evaluated for Beijing Plain, China. The first model (AM1) was constructed with the “thin layer approach” in which all 9 model layers, including five aquifers separated by four aquitards, are continuously present in the same model area. The second model (AM2) was constructed with the “quasi-3D approach” in which the hydrogeological formations were classified into five aquifer units consisting of mixed permeable and semi-permeable layers at different depth ranges. The third model (AM3) was constructed with the “true layer approach” in which aquifers and aquitards were defined according to hydrostratigraphic properties, and model layers are absent in the area where corresponding hydrogeological formations intersect bedrocks. All 3 models were calibrated with the parameter optimization method under the steady state flow condition with the same hydrological stresses and observation data. All three models fit to observations well with the similar calibration criteria values. Furthermore, AIC and BIC information criteria could not distinguish three alternative models. Only KIC could identify AM3 as the best model. Major differences of the three alternative models were identified from a hydrogeological perspective. The AM1 model depicted an illusion through contour maps that groundwater was present everywhere in the deep aquifers. The model computed larger vertical leakages because more abstraction rates were assigned improperly in deep aquifers. The AM2 model was able to compute regional groundwater balances and depicted spatial groundwater level variations. However, the AM2 model computed longer groundwater travel times around the wellfield and should not be used for the delineation of the well field protection zones and contaminant transport simulation. The AM3 model could not only compute the regional groundwater balances and describe spatial groundwater distribution in deep confined aquifers, but also delineate the capture zone of the wellfield. It can therefore be used for simulating contaminant transport. Furthermore, the AM3 model is suitable to construct a coupled regional and local flow model for simulating a managed aquifer recharge scheme.

Australian exemplars of sustainable and economic managed aquifer recharge

Managed aquifer recharge (MAR) can improve water security by using aquifers to store water when it is abundant until required for future use and can increase the use of urban stormwater and treated wastewater to reduce the demand on traditional surface water and groundwater supplies. Recently, two Australian examples were showcased internationally as sustainable and economic MAR: Perth’s groundwater replenishment scheme (GWRS) with recycled water to increase security of urban water supply and a multi-site urban stormwater MAR scheme for suburban non-potable water supply in Salisbury, Adelaide. This paper provides a synopsis of these Australian exemplars of sustainable and economic MAR.

Assessing and Managing Large‐Scale Geochemical Impacts From Groundwater Replenishment With Highly Treated Reclaimed Wastewater

AbstractReuse of wastewater through a combination of advanced wastewater treatment (AWT) and managed aquifer recharge (MAR) is an important water management option. As an integral part of any AWT‐MAR system, the geochemical compatibility of the recharged water with the targeted aquifer must be assessed to avoid groundwater quality deterioration. Although short‐term field experiments may uncover potentially concerning sediment‐water disequilibria, an advanced analysis is often required to understand the long‐term geochemical impacts of large‐scale MAR. Here, we develop and apply a pragmatic approach to upscale and verify the previously derived local‐scale geochemical understanding to the spatial and temporal scale required for assessing and managing large‐scale and long‐term impacts resulting from the recharge of AWT‐processed water. We use Australia's largest MAR scheme, in which aerobic, purified water is injected into deep, anaerobic, pyritic aquifers as an illustrative example. In this case, the local‐scale understanding was derived from a comprehensive field trial and the interpretation of the data through a trial‐scale high‐resolution reactive transport model (RTM). Based on (i) the trial‐scale RTM, (ii) new data from the early phase of the full‐scale MAR, and (iii) downscaling of an existing, regional‐scale flow model, we developed an upscaled RTM to assess two critical issues for the large‐scale groundwater replenishment of Perth deep aquifers, that is, the sustainability of native pH buffering processes and the dynamics of fluoride release and attenuation. In a final step we illustrate how the upscaled RTM can be applied to assess how changes in the AWT affect long‐term groundwater pH changes.