Search Results (22)

Aquifer Storage and Recovery (ASR) can involve injecting available surface water into an unconfined aquifer and then extracting it to provide secondary water for irrigation. This study demonstrates a method for evaluating the appropriateness of steady injection versus unsteady injection for an assumed situation. In design, it can be important to affect the transient: the proportion of the injected water that would be subsequently extracted (versus that remaining in the aquifer) and the proportion within the extracted water that would be an injectate (versus ambient groundwater). These proportions can be predicted from the predicted value of an ASR well’s Recovery Effectiveness (REN)—the time-varying proportion of injectate that is extracted subsequently from the same fully penetrating well. Applying the demonstrated procedure with appropriately detailed data and simulation models can predict the REN values resulting from steady versus unsteady injection, followed by steady extraction. For convenience in displaying and computing REN, the injectate was assumed to have a 100 ppm conservative solute concentration. For this demonstration, a homogenous isotropic unconfined one-layer aquifer was assumed. The scenarios involved steady or unsteady injection for 61 days via a fully penetrating ASR well. Then, 91 days of steady pumping led to the extraction of a total volume equal to that injected. For the assumed hydrogeologic data—31 years of Salt Lake City, Utah, rainfall data and estimated captured runoff—the results show that steady injection is more likely to cause a predictable REN but might not cause a higher REN than daily varying injection of the same total volume. Assuming different runoff or hydrogeologic flows would lead to different REN values. Steady injection causes a predictable groundwater mound and can assure a sufficient vadose zone thickness for overlying plants. Augmentation and storage of captured rainwater can help to provide a steady injection rate. For a situation that requires REN management, appropriate simulations can help water managers design ASR systems that will achieve REN goals and increase sustainable groundwater availability. Full article

More water utilities are adopting aquifer storage and recovery (ASR) to balance long-term water supply and demand. Due to large implementation and operation costs, ASR projects need to be optimized, particularly for energy use, which is a major operating expense. This study examines the relationships among energy use, recharge, and recovery at two ASR projects in the western United States. The major finding is an economy of scale for recovery processes, but not for gravity-fed recharge processes. The economy of scale found is as follows: the energy intensity recovered decreases with volume. This suggests it is more energy-efficient to recover large volumes of water in one interval instead of recovering smaller volumes at more frequent intervals. The H2Oaks recovery process experienced a 78% decrease in energy intensity from 0 to 50,000 m³ recovered, while the Sand Hollow site experienced a 43% decrease in energy intensity from 0 to 50,000 m³ recovered. Statistical analyses of the recovery process showed p values lower than 0.0001, R² values between 0.43 and 0.57, and a RMSE value between 0.55 and 2.1, indicating the presence of a moderate correlation between energy and volume. This economy of scale has been observed in multiple instances in water and wastewater treatment. This finding not only has applications to ASR but also to all recovery or recharge wells, whether or not they are paired with each other. Furthermore, this study confirms the need for more reliable and accessible energy data to fully understand the implications of the energy–water nexus. Full article

To detect the degradation of clean water, it is necessary to characterize its quality through water quality indices using seasonal water sampling and analysis. In the present study, the initialization of the monitoring by surface and dam water sampling was conducted in multiple areas of Greece, including the Eastern Thermaikos Gulf, Mouriki, and Marathonas basins, during both the dry and wet periods of 2022. The dam reservoirs were also monitored by capturing their orthomosaic mapping. The classification of the samples according to the Canadian Council of Ministers of Environment Water Quality Index (CCME WQI) showed that all dam water samples examined and Mouriki area samples have excellent water quality in terms of physical and chemical characteristics. However, some samples from the Eastern Thermaikos Gulf and Marathonas basins suffer from seawater intrusion, which is indicated by the high concentration levels of Na⁺ and Cl⁻, and anthropogenic activities shown by the elevated concentrations of NO₃⁻. Moreover, the high concentration of As in samples from the Eastern Thermaikos Gulf is attributed to geothermal fluids. The importance of Cl⁻, NO₃⁻, and As presence in water quality at the studied areas is also verified by the sensitivity analysis performed, pointing out the requirement of sustainable management. Full article

Aquifer storage and recovery (ASR) can augment water supplies and hydrologic flows under varying climatic conditions. However, imposing drinking water regulations on ASR practices, including pre-treatment before injection into the aquifer, remains arguable. Microbial inactivation data—Escherichia coli, Pseudomonas aeruginosa, poliovirus type 1 and Cryptosporidium parvum—were used in a human health risk assessment to identify how the storage time of recharged water in the Floridan Aquifer enhances pathogen inactivation, thereby mitigating the human health risks associated with ingestion. We used a quantitative microbial risk assessment to evaluate the risks for a gastrointestinal infection (GI) and the associated disability-adjusted life years (DALYs) per person per year. The risk of developing a GI infection for drinking water no longer exceeded the suggested annual risk threshold (1 × 10⁻⁴) by days 31, 1, 52 and 80 for each pathogen, respectively. DALYs per person per year no longer exceeded the World Health Organization threshold (1 × 10⁻⁶) by days 27, <1, 43 and 72. In summary, storage time in the aquifer yields a significant reduction in health risk. The findings emphasize that considering microbial inactivation, caused by storage time and geochemical conditions within ASR storage zones, is critical for recharge water treatment processes. Full article

In this study, we present artificial neural networks (ANNs) to aid in a reconnaissance evaluation of an aquifer storage and recovery (ASR) well. Recovery effectiveness (REN) is the proportion of ASR-injected water recovered during subsequent extraction from the same well. ANN-based predictors allow rapid REN prediction without requiring preparation for and execution of solute transport simulations. REN helps estimate blended water quality resulting from a conservative solute in an aquifer, extraction for environmental protection, and other uses, respectively. Assume that into an isotropic homogenous portion of an unconfined, one-layer aquifer, extra surface water is injected at a steady rate during two wet months (61 days) through a fully penetrating ASR well. And then, water is extracted from the well at the same steady rate during three dry months (91-day period of high demand). The presented dimensionless input parameters were designed to be calibrated within the ANNs to match REN values. The values result from groundwater flow and solute transport simulations for ranges of impact factors of unconfined aquifers. The ANNs calibrated the weighting coefficients associated with the input parameters to predict the achievable REN of an ASR well. The ASR steadily injects extra surface water during periods of water availability and, subsequently, steadily extracts groundwater for use. The total extraction volume equaled the total injection volume at the end of extraction day 61. Subsequently, continuing extraction presumes a pre-existing groundwater right. Full article

In recent decades, groundwater overexploitation has caused an important aquifer level decline in arid zones each year. In addition to this issue, large volumes of effluent are produced each year in metropolitan areas of these regions. In this situation, an aquifer storage and recovery system (ASR) using the reclaimed domestic wastewater can be a local solution to these two challenges. In this research, a post-treatment of reclaimed municipal wastewater has been investigated through unsaturated–saturated porous media. A large-scale, L-shaped experimental model was set up near the second-stage wastewater treatment plant (WWTP) in the west of greater Tehran. The water, soil, and treated wastewater of the experimental model were supplied from the aquifer, site, and WWTP, respectively. The 13 physicochemical parameters, temperature and fecal coliform were analyzed every 10 days in seven points for a period of four months (two active periods of 40 days with a 12-h on–off rate (wet cycles) and a rest period of 40 days (dry cycle) between the two wet cycles). The results showed that the effects of the saturated zone were twice as great as those of the unsaturated zone and two-thirds of the total treatment efficiency. Furthermore, a discontinuous wet–dry–wet cycle had a significant effect on effluent treatment efficiency and contaminants’ reduction. In conclusion, an aquifer storage and recovery system using treated wastewater through the unsaturated–saturated zones is a sustainable water resource that can be used for agriculture, environmental and non-potable water demands. Full article

In Abu Dhabi, one of the most arid regions in the world, in recent decades, desalinated water has been identified as a prime solution in solving the water demand issues. In this study, a three-dimensional coupled density-dependent flow and solute transport model was set up in order to study the effect of the artificial recharge using desalinated water and the influence of nonconventional water with a salt concentration in the range 0.1–2 g/L The results confirm that this region demands the adoption of a more rational use of irrigation water or additional usage of desalinated water and recycled water together with optimizing groundwater pumping at locations that are vulnerable to further quality degradation and depletion. The long-term storage of desalinated freshwater with a maximum radial distance of 653 m in the dune surface is ensured with the formation of the transition zone, and change in the groundwater head up to 5 km. The maximum recovery obtained by immediate recovery is 70%. The study expresses the long-term feasibility of desalinated freshwater storage and the need for further management practices in quantifying the contribution of desalinated and recycled water for agriculture activities which might have improved groundwater quality and increased hydraulic head at some locations. Full article

Aquifer storage and recovery (ASR) refers to injecting freshwater into an aquifer and later withdrawing it. In brackish-to-saline aquifers, density-driven convection and fresh-saline water mixing lead to a reduced recovery efficiency (RE, i.e., the volumetric ratio between recovered potable water and injected freshwater) of ASR. For a layered aquifer, previous studies assume a constant hydraulic conductivity ratio between neighboring layers. In order to reflect the realistic formation of layered aquifers, we systematically investigate 120 layered heterogeneous scenarios with different layer arrangements on multiple-cycle ASR using numerical simulations. Results show that the convection (as is reflected by the tilt of the fresh-saline interface) and mixing phenomena of the ASR system vary significantly among scenarios with different layer arrangements. In particular, the lower permeable layer underlying the higher permeable layer restricts the free convection and leads to the spreading of salinity at the bottom of the higher permeable layer and early salt breakthrough to the well. Correspondingly, the RE values are different among the heterogeneous scenarios, with a maximum absolute RE difference of 22% for the first cycle and 9% for the tenth cycle. Even though the difference in RE decreases with more ASR cycles, it is still non-negligible and needs to be considered after ten ASR cycles. The method to homogenize the layered heterogeneity by simply taking the arithmetic and geometric means of the hydraulic conductivities among different layers as the horizontal and vertical hydraulic conductivities is shown to overestimate the RE for multiple-cycle ASR. The outcomes of this research illustrate the importance of considering the geometric arrangement of layers in assessing the feasibility of multiple-cycle ASR operations in brackish-to-saline layered aquifers. Full article

Among the several options of managed aquifer recharge (MAR) techniques, the aquifer storage and recovery (ASR) is a well-known sub-surface technique to replenish depleted aquifers, which is contingent upon the selection of appropriate sites. This paper explores the potential of ASR for groundwater recharge in the hydrological, hydrogeological, social, and economic context of South Bihar in India. Based on the water samples from more than 137 wells and socio-economic surveys, ASR installations were piloted through seven selected entrepreneurial farmers in two villages of South Bihar. The feasibility of ASR in both hard rock and deep alluvial aquifers was demonstrated for the prominent aquifer types in the marginal alluvial plains of South Bihar and elsewhere. It was postulated through this pilot study that a successful spread of ASR in South Bihar can augment usable water resources for agriculture during the winter cropping season. More importantly, ASR can adapt to local circumstances and challenges under changing climatic conditions. The flexible and participatory approach in this pilot study also allowed the farmers to creatively engage with the design and governance aspects of the recharge pit. The entrepreneurial farmers-led model builds local accountability, creates avenues for private investments, and opens up the space for continued innovation in technology and management, while also committing to resource distributive justice and environmental sustainability. Full article

Managed aquifer recharge (MAR) is the intentional recharge of water to suitable aquifers for subsequent beneficial use or to achieve environmental benefits. Well injection techniques for MAR, such as Aquifer Storage and Recovery (ASR), rely on implementing appropriate design and defining the operational parameters to minimise well clogging and maintain sustainable rates of recharge over the long term. The purpose of this study was to develop water quality targets and pre-treatment requirements for recycled water to allow sustained recharge and recovery in a medium-coarse siliceous aquifer. The recharge water is a blend of 40% Class A recycled water and 60% reverse osmosis (RO)-treated Class A recycled water. Four source waters for MAR were evaluated: (1) this blend with no further treatment, and this blend with additional treatment using: (2) a 20 µm sediment cartridge filter, (3) a 5 µm sediment cartridge filter, or (4) a 5 µm granular activated carbon (GAC) cartridge filter. All four treatment options were also further disinfected with chlorine. The four blended and treated recycled waters were used in laboratory columns packed with aquifer material under saturated conditions at constant temperature (20.7 °C) with light excluded for up to 42 days. Substantial differences in the changes in hydraulic conductivity of the columns were observed for the different treatments within 14 days of the experiment, despite low turbidity (<2 NTU) of the blend waters. After 14 days, the GAC-treated water had a 7% decline in hydraulic conductivity, which was very different from the other three blend waters, which had declines of 39–52%. Based on these results and consistent with previous studies, a target biodegradable dissolved organic carbon (BDOC) level of <0.2 mg/L was recommended to ensure a biologically stable source of water to reduce clogging during recharge. Full article

Population growth and increased irrigation demand have caused a decline in groundwater levels that limit water supply in the Darwin rural area. Managed Aquifer Recharge (MAR) is a practical solution that can be adopted to augment stressed groundwater systems and subsequently increase the security of water supply. Aquifer storage capacity is considered to be the primary constraint to MAR where unconfined dolostone aquifers rapidly recharge during the tropical, wet season and drain again in the dry season. As a result, there is a general understanding that aquifers of this nature recharge to full capacity each wet season. However, the aquifer storage capacity and the potential for niche opportunities for MAR to alleviate declining groundwater levels has not previously been examined. This paper uses the Darwin rural area’s Proterozoic Koolpinyah Dolostone aquifer and the existing Koolpinyah Groundwater System to evaluate the prospects of MAR using both infiltration and injection techniques. Direct injection wells in an aquifer storage transfer and recovery (ASTR) scheme were favoured in this area, as injection wells occupy a smaller surface footprint than infiltration basins. This assessment suggested MAR during the early to mid-dry season could alleviate the impact of the dry season decline in groundwater levels in the Darwin rural area. The use of a larger aquifer storage and recovery (ASR) system (5,000,000 m³/year) was also assessed as a potentially viable technical solution in the northern part of the aquifer where it is understood to be confined. The ASR scheme could potentially be scaleable to augment the urban water system and provide strategic long-term storage. Consideration must also be given not only to the strategic positioning of the ASR water bank, but also to the hydrogeology of the aquifers in which the systems would be developed. Not all locations or aquifer systems can successfully support a strategic storage ASR system. Scheme-scale feasibility assessment of an ASR water bank is required. The study reported here is an early phase of a series of investigations that would typically be required to demonstrate the viability of any proposal to apply MAR to increase the reliability of conjunctive groundwater and surface water supplies in stressed water resources systems. It focusses on assessing suitable storage areas in a lateritic aquifer. Full article

As part of an integrated water-cycle management strategy, City West Water (CWW) is conducting research to develop an aquifer storage recovery (ASR) scheme utilizing recycled water. In this contribution, we address the risk of well clogging based on two ASR bore pilots, each with intensive monitoring. Well clogging is a critical aspect of the strategy due to a projected high injection rate, a high clogging potential of recycled water, and a small diameter injection borehole. Microscopic and geochemical analysis of suspended solids in the injectant and backflushed water, demonstrate a significant contribution of diatoms, algae and colloidal or precipitating Fe(OH)₃, Al(OH)₃ and MnO₂. CWW is, therefore, testing additional prefiltration that includes a 20 μm spin Klin disc and 1–5 μm bag filter operating in series. In this paper, we present optimized methods to (i) detect the contribution of the injectant and aquifer particles to total suspended solids in backflushed water by hydrogeochemical analysis; and (ii) predict and reduce the risk of physical and biological clogging, by combination of the membrane filter index (MFI) method of Buik and Willemsen, a modification of the total suspended solids method of Bichara and an amendment of the exponential bacterial growth method of Huisman and Olsthoorn. Full article

The aquifer storage and water quality enhancement (ASWQE) method is a potential alternative to overcome the limitations of water resource policies that focus on surface water and act as an effective measure against water shortage caused by climate change. According to the physical/technical characteristics and operational complexity of the ASQWE, there are various legal/institutional issues to be considered at every stage in the development and implementation of the project. However, in Korea, there is no legislation or legal basis directly related to the ASWQE projects, resulting in large gaps between the initiatives of ASWQE and the relevant laws and statutes. In this respect, this study, to introduce approaches for the establishment of a legal system in line with the requirements of ASWQE projects, mainly analyzes the gaps between the abovementioned principal legal/institutional issues/subjects and the indispensable elements at each phase of the project’s process in the existing Korean legal system concerning the ASWQE, particularly based on the issue tree approach. Through this comprehensive, systematic, and comparative case study, large gaps have been definitely identified between the initiatives surrounding ASWQE projects and the existing Korean legal system, and to conclude, legally multilateral approaches to fill and make up for the gaps have been presented. It is expected that the Korean government will continue to pursue the establishment of a comprehensive and integrated legal system in line with the requirements of ASWQE projects based on this research’s findings. When these attempts succeed, the expected legal achievement for the development and implementation of ASWQE projects could serve as an exemplary legal case for the entire world. Full article

Un-managed surface and groundwater exploitation in coastal areas usually leads to deterioration of such sensitive ecosystems by means of water resources degradation and/or increased salinity. The coastal partof Marathon is a typical Mediterranean hydro-environment that hosts a naturally occurring coastal wetland linked to a typical coastal and today degraded hydrogeological system of a semi-arid region. A smart engineered Subsurface-Water-Solution (SWS)system composed ofan optimised Pump & Treat componentintegrated with an Aquifer Storage and Recovery (ASR) scheme in this area is envisagedcontribute to the remediationof the groundwater system and the wetland. Full article

Developing aquifers as underground water supply reservoirs is an advantageous approach applicable to meeting water management objectives. Aquifer storage and recovery (ASR) is a direct injection and subsequent withdrawal technology that is used to increase water supply storage through injection wells. Due to site-specific hydrogeological quantification and evaluation to assess ASR suitability, limited methods have been developed to identify suitability on regional scales that are also applicable at local scales. This paper presents an ASR site scoring system developed to qualitatively assess regional and local suitability of ASR using 9 scored metrics to determine total percent of ASR suitability, partitioned into hydrogeologic properties, operational considerations, and regulatory influences. The development and application of a qualitative water well suitability method was used to assess the potential groundwater response to injection, estimate suitability based on predesignated injection rates, and provide cumulative approximation of statewide and local storage prospects. The two methods allowed for rapid assessment of ASR suitability and its applicability to regional and local water management objectives at over 280 locations within 62 watersheds in Washington, USA. It was determined that over 50% of locations evaluated are suitable for ASR and statewide injection potential equaled 6400 million liters per day. The results also indicate current limitations and/or potential benefits of developing ASR systems at the local level with the intent of assisting local water managers in strategic water supply planning. Full article