Managed Aquifer Recharge Techniques Research Articles

From laboratory to pilot-scale: Assessing dissolved organic matter, biological stability and per- and polyfluoroalkyl substances removal on managed aquifer recharge performance

Managed aquifer recharge (MAR) is a promising technique for enhancing groundwater resources and addressing water scarcity. Particularly, this research highlights the novelty and urgent need for MAR facilities in the Chungcheongnam-do region of South Korea as a solution to augment groundwater resources and combat water scarcity. This research encompasses a comprehensive assessment, ranging from laboratory-scale column experiments to pilot-scale tests, focusing on dissolved organic matter (DOM) characterization, natural organic matter (NOM) removal, and water quality improvement, including biological stability. In the laboratory, DOM characteristics of source water and recharged groundwater were analyzed using advanced dissolved organic characteristic tools, and their potential impacts on water quality, as well as per- and polyfluoroalkyl substances (PFASs) were assessed. DOM, total cell counts, and several PFASs with molecular weights >450 Da (particularly long-chain PFASs showing >99.9 % reduction) were effectively reduced in a laboratory-scale experiment. A laboratory-scale column study revealed that most selected PFASs were not effectively removed. Moving to the pilot-scale, a series of experiments were conducted to assess NOM removal during soil passage. Similar to the results of the laboratory-scale experiment, MAR demonstrated significant potential for reducing NOM concentrations, thus improving water quality. Regarding biological stability, assimilable organic carbon in production well (i.e., final produced water by MAR process) was lower than both two sources of surface water (e.g., SW1 and SW2). This suggests that water derived from PW (i.e., production well) exhibited biological stability, undergoing effective biodegradation by aerobic bacteria during soil passage. The findings from this study highlight the critical importance of implementing MAR techniques in regions facing water scarcity, emphasizing its potential to significantly enhance future water security initiatives.

Risk assessment for the prevention of managed aquifer recharge (MAR) facility failure during the operation and the expansion phases

This comprehensive risk assessment, done for a MAR facility in Tarnów, southern Poland, covers two MAR techniques: infiltration ditches and induced bank filtration during the operation and planned potential expansion phases. Two methods were applied: the semi-quantitative risk assessment matrix and the probabilistic risk assessment – fault tree analysis (PRA-FTA), and their advantages and limitations analysed. Both methods examine a range of technical and non-technical risks that may pose a threat to the efficient functioning of the MAR facility in Tarnów, which supplies about 25% of the city’s population with drinking water. It was found that 34 of the 65 risks analysed could pose a low to high risk for the Świerczków well field. The predominant risks potentially reducing MAR efficiency or leading to MAR failure are technical ones. According to the PRA-FTA method, if no preventive measures are taken, there is a 99.5 and 99.3% probability of the MAR system failing during the operational and expansion phases, respectively. The results indicate that the most serious risk is associated with the insufficient initial removal from the recharge river water of suspended solids, which clog infiltration ditches. The risks scored as medium relate to the threat of groundwater inflow from an extensive industrial zone, lying to the east of the well field, and to climate change negatively affecting the quantity of groundwater resources. This is the first example in Poland of a risk assessment for an existing MAR facility and its expansion, based on a broad spectrum of technical and non-technical risks present at the Świerczków well field, using two methods: the risk assessment matrix and PRA-FTA. This case study is a practical example of how to perform a risk analysis for a MAR site. It can make an important contribution to existing knowledge in this field and enrich the subject literature, a particularly relevant aspect given the widespread use of MAR techniques in Central Europe for the supply of drinking water to the public.

Enhancement of Groundwater Recharge from Wadi Al Bih Dam, UAE

Groundwater and harvested rainwater represent the only conventional freshwater resources in the United Arab Emirates (UAE). Groundwater resources in Wadi Al Bih, UAE, are sustainable due to the low exploitation rate for domestic and agricultural purposes. Thus, the groundwater depletion in this area is far less than in other parts of the country. The Wadi Al Bih area is very important for achieving water security in UAE. Therefore, the possible measures of increasing groundwater recharge (e.g., managed aquifer recharge (MAR) methods) are investigated in this paper. The available water resource data were collected, reviewed, validated, and stored in a GIS database. Then, a GIS-based water budget model (WBM) was developed to evaluate the available groundwater resources in Wadi Al Bih and recharge sources. The analyses showed that only 49% of the accumulated rainwater behind the dam is recharging the underlying aquifer. Due to the absence of any direct recharge techniques, the remaining 51% is lost by direct evaporation (15%), and as soil moisture increases in the unsaturated zone (36%), it will subsequently evaporate or percolate depending on the precipitation pattern and air temperature. The results of the WBM indicated that the freshwater resources were decreasing at an alarming rate of approximately thirty-five million cubic meters (MCM) per year until 2019. The groundwater storage and salinity were governed by the rates and patterns of precipitation. For example, the recharge resulting from the two consecutive maximum monthly precipitation events in December 2019 and January 2020 has significantly increased the fresh groundwater reserve and slightly retreated the saline/brackish water toward the shoreline. Moreover, a Mann–Kendall trend analysis was conducted to assess the influence of precipitation, temperature, and evaporation on groundwater recharge. The outcomes suggested that climate variables had a significant effect on groundwater supplies. The mitigation measures include revising groundwater withdrawal rates based on the annual recharge and enhancing recharge using different MAR techniques and dam operation plans.

Aquifer Storage and Recovery Feasibility Study With Flowing Fluid Electrical Conductivity Logging in Shallow Aquifers of South Bihar, India

Growing dependence on groundwater to fulfill the water demands has led to continuous depletion of groundwater levels and, consequently, poses the maintenance of optimum groundwater and management challenge. The region of South Bihar faces regular drought and flood situations, and due to the excessive pumping, the groundwater resources are declining. Rainwater harvesting has been recommended for the region; however, there are no hydrogeological studies concerning groundwater recharge. Aquifer storage and recovery (ASR) is a managed aquifer recharge technique to store excess water in the aquifer through borewells to meet the high-water demand in the dry season. Therefore, this paper presents the hydrogeological feasibility for possible ASR installations in shallow aquifers of South Bihar with the help of flowing fluid electrical conductivity (FFEC) logging. For modeling, the well logging data of two shallow borewells (16- and 47-m depth) at Rajgir, Nalanda, were used to obtain the transmissivity and thickness of the aquifers. The estimated transmissivities were 804 m2/day with an aquifer thickness of 5 m (in between 11 and 16 m) at Ajatshatru Residential Hall (ARH) well. They were 353 and 1,154 m2/day with the aquifer thicknesses of 6 m (in between 16 and 22 m) and 2 m (in between 45 and 47 m), respectively, at Nalanda University Campus (NUC) well. Despite the acceptable transmissivities at these sites, those aquifers may not be fruitful for the medium- to large-scale (more than 100-m3/day injection rate) ASR as the thickness of the aquifers is relatively small and may not efficiently store and withdraw a large amount of water. However, these aquifers can be adequate for small (up to 20-m3/day injection rate) ASR, for example, groundwater recharge using rooftop water. For medium- to large-scale ASR, deeper aquifers need to be further explored on these sites or aquifers with similar characteristics.

Hydrogeochemical characterizations and quality evaluation of groundwater in the major river basins of a geologically and anthropogenically driven semi-arid tract of India

Access to clean drinking water has been acknowledged as a human right and assessing the hydrogeochemistry and groundwater quality status plays an important role in proving cleaner and safer water for human consumption. This study evaluated the sources and driving factors of the groundwater facies in the five major river basins (viz. Ajay, Mayurakshi, Kopai, Brahmani and Dwarka) of an agroeconomic semi-arid Indian tract through hydrogeochemical and principal component analyses based on 2200 groundwater samples (Ns = 2200) obtained during the pre- and post-monsoon cycles from 1100 wells (Nw = 1100). The results revealed that minerals weathering, ion/reverse ion exchange, mixing and evaporation processes along with anthropogenic inputs are responsible for the deteriorated groundwater quality of the river basins. The study has considered the cokriging approach that uses geostatistical and multivariate statistical techniques to interpolate a dataset. To determine the spatio-seasonal variabilities of the groundwater facies more accurately, the estimation accuracies of different interpolation techniques viz. inverse distance weighting, kriging/cokriging and splines techniques were compared and kriging/cokriging was found to represent the variability more accurately. Shannon's entropy theory was employed to assess the groundwater quality of the river basins as it eliminates the subjective bias and inherent uncertainties of the groundwater systems. Groundwater in ~37.45-38.42% of the total area was moderate to extremely poor for human consumption where 10.40-12.14%, 9.09-12.40%, 21.18-22.35%, 15.20-19.93% and 6.48-8.80% samples from the Ajay (Nw = 175), Brahmani (Nw = 175), Dwarka (Nw = 180), Kopai (Nw = 350) and Mayurakshi (Nw = 220) river basins exhibited unfit to drink water quality. The sensitivity of the water quality model was analyzed to identify the influences of the individual parameters which revealed that the outcome does not depend solely on one parameter. The study recommends adaptation of the treatment techniques to ensure clean drinking water for the residents. Managed aquifer recharge techniques might also improve the groundwater quality in certain areas.

Importance of the Induced Recharge Term in Riverbank Filtration: Hydrodynamics, Hydrochemical, and Numerical Modelling Investigations

While ensuring adequate drinking water supply is increasingly being a worldwide challenging need, managed aquifer recharge (MAR) schemes may provide reliable solutions in order to guarantee safe and continuous supply of water. This is particularly true in riverbank filtration (RBF) schemes. Several studies aimed at addressing the treatment capabilities of such schemes, but induced aquifer recharge hydrodynamics from surface water bodies caused by pumping wells is seldom analysed and quantified. In this study, after presenting a detailed description of the Serchio River RBF site, we used a multidisciplinary approach entailing hydrodynamics, hydrochemical, and numerical modelling methods in order to evaluate the change in recharge from the Serchio river to the aquifer due to the building of the RBF infrastructures along the Serchio river (Lucca, Italy). In this way, we estimated the increase in aquifer recharge and the ratio of bank filtrate to ambient groundwater abstracted at such RBF scheme. Results highlight that in present conditions the main source of the RBF pumping wells is the Serchio River water and that the groundwater at the Sant’Alessio plain is mainly characterized by mixing between precipitation occurring in the higher part of the plain and the River water. Based on chemical mixing, a precautionary amount of abstracted Serchio River water is estimated to be on average 13.6 Mm3/year, which is 85% of the total amount of water abstracted in a year (~16 Mm3). RBF is a worldwide recognized MAR technique for supplying good quality and reliable amount of water. As in several cases and countries the induced recharge component is not duly acknowledged, the authors suggest including the term “induced” in the definition of this type of MAR technique (to become then IRBF). Thus, clear reference may be made to the fact that the bank filtration is not completely due to natural recharge, as in many cases of surface water/groundwater interactions, but it may be partly/almost all human-made.

Managed Aquifer Recharge in the Gulf Countries: A Review and Selection Criteria.

The Gulf Cooperation Council (GCC) countries are arid with very limited availability of water resources. In recent years, these countries have started an intensive program to increase the storage of groundwater through various techniques of managed aquifer recharge (MAR). Water consisting of varying quantity and quality (derived from various sources) are used via MAR techniques to increase the groundwater storage and, if possible to enhance its quality, respectively. This paper presents a review of the MAR techniques practiced in GCC countries including the implementation strategies of the different structures. Generally, seven MAR techniques are utilized in GCC countries including dams, aquifer storage and recovery (ASR) technique, aquifer storage transfer and recovery (ASTR) technique, ponds, soil aquifer treatment (SAT) technique, rooftop rainwater harvesting, and Karez/Ain system. Results indicated that ASR using excess desalinated water or treated sewage effluent (TSE) is the most used MAR technique in GCC countries, followed by the use of ASTR, dams, and ponds. Based on this review, twelve different selection criteria have been developed for GCC countries for better MAR practice in the future.

Comparison of recharge from drywells and infiltration basins: A modeling study

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.

Regulations and guidelines on water quality requirements for Managed Aquifer Recharge. International comparison

Managed Aquifer Recharge (MAR) is a promising set of techniques to cope with a variety of water management-related issues. In recent years MAR implementations have witnessed an expansion and greater social acceptance. Nonetheless, there are still some gaps in the scientific, economic and governance dimensions of MAR which need to be addressed. One of these gaps is the lack in many countries of clear regulations addressing MAR. In this paper eighteen regulations and twelve guidelines on water quality standards from around the world have been reviewed to favour the advancement of the legal framework concerning MAR. The review has demonstrated that the existing MAR regulatory frameworks are implemented at different levels (i.e. from regional to international) and consider different aspects such as planning, permitting and monitoring as well as the risk assessment. Most regulations take into account some of these aspects, but seldom all of them. The detailed study and comparison of the water quality standards enabled to define conclusions regarding the differences in maximum allowable concentrations (MACs). Furthermore, this comparison made visible the different approaches to encompass the variability of MAR systems, and also the natural conditions prevailing in the receiving groundwater body. Based on the review of the selected regulations, their advantages and shortcomings, a series of recommendations are proposed for the development of future legal framework entailing the MAR technique.

Synthesizing existing frameworks to identify the potential for Managed Aquifer Recharge in a karstic and semi-arid region using GIS Multi Criteria Decision Analysis

Imbalance between water supply and demand is increasing in many parts of the world. Lack of water security is attributed to climate change, population growth and unsustainable abstraction of groundwater. Managed Aquifer Recharge (MAR) can increase groundwater recharge, facilitate higher water availability and accessibility, and hence reduce water supply deficit. This paper investigates the potential of MAR in a karstic and semi-arid region with the use of GIS Multi Criteria Decision Analysis (GIS-MCDA). While previous studies have focused on MAR techniques and MAR suitably mapping separately, this paper combines technique selection and suitability mapping to emphasize the importance of considering both. The methodology was applied for a karstic and semi-arid region, using the Ramotswa Transboundary Aquifer Area (RTAA) as case study. MAR suitability mapping of the selected MAR technique was carried out with six thematic layers using Weighted Linear Combination (WLC) decision rule. The objective was to identify suitable areas for implementation of spreading methods and generate MAR suitability maps to guide decision-making in such implementation. The suitable areas were identified at the border between Botswana and South-Africa. The study develops a methodology for GIS-MCDA considering spreading method for a karstic aquifer, but more research is needed to assess the methodological transferability to other karstic and semi-arid regions.

Coastal Runoff in the United Arab Emirates—The Hazard and Opportunity

Properly quantifying the potential exposure of hyper-arid regions to climate extremes is fundamental to developing frameworks that can be used to manage these extremes. In the United Arab Emirates (UAE), rapid growth may exacerbate the impacts of climate extremes through urbanization (increased runoff), population and industrial development (more water demand). Water resources management approaches such as Managed Aquifer Recharge (MAR) application may help mitigate both extremes by storing more water from wet periods for use during droughts. In this study, we quantified the volumes of runoff from coastal watersheds discharging to the Gulf of Oman and the Arabian Gulf that could potentially be captured to replenish depleted aquifers along the coast and help reduce the adverse impacts of urban flooding. To this aim, we first downloaded and processed the Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (IMERG) rainfall data for a recent wide-spread storm event. The rainfall product was then used as input to hydrologic models of coastal watersheds for estimating the resulting runoff. A multi-criteria decision analysis technique was used to identify areas most prone to runoff accumulation. Lastly, we quantified the volumes of runoff that could potentially be captured from frequency storms of different return periods and how rapid urbanization in the region may increase these runoff volumes creating more opportunities for the replenishment of depleted aquifers. Our results indicate that the average runoff from watersheds discharging to the ocean ranges between 0.11 km3 and 0.48 km3 for the 5-year and 100-year storms, respectively. We also found that these amounts will substantially increase due to rapid urbanization in the coastal regions of the UAE. In addition to water supply augmentation during droughts, potential benefits of application of MAR techniques in the UAE coastal regions may include flood control, mitigation against sea-level rise through subsidence control, reduction of aquifer salinity, rehabilitation of ecosystems, cleansing polluted runoff and preventing excessive runoff into the Gulf that can contribute to red tide events.

The oldest managed aquifer recharge system in Europe: New insights from the Espino recharge channel (Sierra Nevada, southern Spain)

In Sierra Nevada (southern Spain), the highest mountain range in southern Europe, the application of an ancestral Integrated Water Resources Management system (IWRM), based on the conjunctive use of groundwater and surface water, provides water resources for irrigation and supply in the driest months of the year in this semiarid mountain region. Meltwater is derived from the headwaters of the mountain streams and rivers through a set of uncoated channels excavated in the ground (locally known as acequias de careo) to infiltrate at the upper part of the valleys. Water infiltrated along the acequias de careo slowly flows down the hillsides, through the weathered zone of the hard rock aquifer and the glacial and periglacial sediments. The recharge accomplished through this Managed Aquifer Recharge technique (MAR) activates numerous springs located halfway down the hillside and increases the base flow of the rivers. In this study, focused on a careo channel located on the southern slope of Sierra Nevada called Acequia de El Espino, different archaeological, sedimentological, geophysical and hydrogeological techniques are applied to determine the age and the efficiency of this ancestral example of a MAR and IWRM system. Results suggest that the acequias de careo may be the oldest MAR system in Europe, and that this MAR technique could be applied in other high mountain alpine watersheds to mitigate the effects of climate change.

Coupling Riverbank Filtration with Reverse Osmosis May Favor Short Distances between Wells and Riverbanks at RBF Sites on the River Danube in Hungary

Bank filtration and other managed aquifer recharge techniques have extensive application in drinking water production throughout the world. Although the quality of surface water improves during these natural processes, residence time in the aquifer and length of the flow paths are critical factors. A wide range of data is available on the physical–chemical processes and hydraulic conditions, but there is limited knowledge about the top layer of the porous media. An investigation was conducted on the hydraulic behavior and on the change of microbiological indicator parameters in the filter cake. The purpose of the experiment was to: (1) investigate if the reverse osmosis is sustainable when fed with only slow filtered water, and (2) show that a short travel distance can provide extensive pathogen removal and beneficial conditions for the reverse osmosis. A slow sand filter was operated over a one-year long period while changes in head loss and microbiological parameters were being monitored. Head loss and membrane permeability were monitored between 3 November 2016 and 24 October 2018 and microbiological sampling was performed from 19 July 2017 to 6 November 2018. The filtered water was fed to a reverse osmosis (RO) filter as the water above the sand filter had been spiked with dissolved iron. Results show that even a thin biofilm cake of 1–3 mm thickness can result in a significant (10–100%) reduction in microbiological activity in the infiltrate, while favorable short retention times and oxic conditions are maintained. Avoiding anoxic conditions, subsequent iron and manganese dissolution and precipitation is beneficial for membrane processes. Building on these results, it can be stated that when reverse osmosis is directly fed with slow filtered or bank filtered water, (1) a short distance from the surface water body is required to avoid dissolved iron and manganese from entering the groundwater and (2) proper pathogen rejection can be achieved even over short distances.

MAR Technique to Reverse the Declining Trend of Groundwater Level in Barind Area, NW, Bangladesh

The study was carried out in the drought prone water stressed Barind area to know the state of rainfall, trend of groundwater level and groundwater management options including Managed Aquifer Recharge (MAR) techniques. Rainfall and groundwater level data have been used and shown a decreasing trend in Godagari and Mohonpur Upazila. But in Niamatpur Upazila rainfall is in reverse condition of rising trend. Decreasing trend of groundwater level (GWL) has been found in the entire study area. The decreasing trend of GWL demands judicious management of groundwater for the area. For recovery of GWL as well as groundwater management, a recharge well as MAR structure has been installed and observed that the situation is better than the before and increasing GWL. More research and study are necessary to know about the trend of groundwater level for the whole Barind area and to introduce proper designed and modified MAR techniques to reverse the declining situation of GWL.

Simulation of the impact of managed aquifer recharge on the groundwater system in Hanoi, Vietnam

A transient numerical groundwater flow model using MODFLOW-NWT was set up and calibrated for Hanoi city, Vietnam, to understand the local groundwater flow system and to suggest solutions for sustainable water resource management. Urban development in Hanoi has caused a severe decline of groundwater levels. The present study evaluates the actual situation and investigates the suitability of managed aquifer recharge (MAR) to stop further depletion of groundwater resources. The results suggest that groundwater is being overexploited, as vast cones of depression exist in parts of the study area. Suitable locations to implement two MAR techniques—riverbank filtration and injection wells—were identified using multi-criteria decision analysis based on geographic information system (GIS). Three predictive scenarios were simulated. The relocation of pumping wells towards the Red River to induce riverbank filtration (first scenario) demonstrates that groundwater levels can be increased, especially in the depression cones. Groundwater levels can also be improved locally by the infiltration of surplus water into the upper aquifer (Holocene) via injection wells during the rainy season (second scenario), but this is not effective to raise the water table in the depression cones. Compared to the first scenario, the combination of riverbank filtration and injection wells (third scenario) shows a slightly raised overall water table. Groundwater flow modeling suggests that local overexploitation can be stopped by a smart relocation of wells from the main depression cones and the expansion of riverbank filtration. This could also avoid further land subsidence while the city’s water demand is met.

Web-based global inventory of managed aquifer recharge applications

Managed aquifer recharge (MAR) is being successfully implemented worldwide for various purposes: to increase groundwater storage, improve water quality, restore groundwater levels, prevent salt water intrusion, manage water distribution systems, and enhance ecological benefits. To better understand the role of MAR in sustainable water management and adaptation to climate and land use change, about 1200 case studies from 62 countries were collected and analyzed with respect to historical development, site characterization, operational scheme, objectives and methods used, as well as quantitative and qualitative characterization of in- and outflow of water. The data harvested was used for the compilation of a global inventory of MAR schemes, whose main goal is to provide access to existing MAR projects and techniques and demonstrate their benefits. To increase the availability and facilitate continuous update of the MAR inventory, an MAR web-based portal was developed and integrated into IGRAC’s Global Groundwater Information System. The MAR portal contains a “data layer catalog” containing the data arranged in a systematic way, a “map viewer” to visualize the selected data on a geographic location, and a “features panel” providing tabular output of the selected data. By facilitating access and promoting international sharing of information and knowledge on MAR, the web-based MAR portal aims to increase awareness of MAR as a viable solution for sustainable groundwater resources development and management, and to provide a new tool for better planning of MAR at regional and global scale.

Application of a GIS Multi-Criteria Decision Analysis for the Identification of Intrinsic Suitable Sites in Costa Rica for the Application of Managed Aquifer Recharge (MAR) through Spreading Methods

Costa Rica’s annual mean precipitation is above 3300 mm, but this precipitation is not evenly distributed in time or space, producing clear differentiated wet and dry seasons in most of the country. Droughts are also common phenomena which greatly affect the availability of water resources. Managed aquifer recharge (MAR) schemes are being taken into consideration to enhance the underground water storage capacity of the country. The present study constitutes the first assessment for the identification of suitable sites for the implementation of MAR technology spreading methods (SM) in Costa Rica. The suitable sites are identified by means of a geographic information system multi-criteria decision analysis (GIS-MCDA) based on four criteria: hydrogeological aptitude, terrain slope, top soil texture and drainage network density. Four steps are performed in order to identify these sites: problem definition, screening for suitable areas, suitability mapping, and sensitivity analysis. The suitability map was divided in two zones after the screening: suitable and unsuitable, the first zone was further divided in five classes according to the weighted linear combination (WLC) ranking. The results indicate that 61% of the country is suitable for conducting SM. This map is a tool for future implementation of MAR techniques in the country.

Site investigation and design of the monitoring system at the Sant`Alessio Induced RiverBank Filtration plant (Lucca, Italy)

Innovative water management strategies such as the storage of reclaimed water or excess water from different sources in Managed Aquifer Recharge (MAR) schemes can greatly increase water availability and therefore improve water security in the Mediterranean area. The Sant'Alessio well field will be used, within the framework of the MARSOL EU FPVII-ENV-2013 project, to demonstrate the sustainability, by a technical, social and market point of view, and the benefits of managing Induced Riverbank Filtration, one of the most common MAR techniques, versus the unmanaged option. Along with a detailed hydrogeological and hydrogeochemical site characterization a Wireless Sensor Network to monitor quantitatively and qualitatively the hydrologic variables in the river water, in the aquifer and in the well field has been designed. In this paper we present the test site, the investigations performed and the design of the monitoring system along with a brief overview of the Decision Support System (DSS) under development to control the whole monitoring devices. The DSS along with the monitoring system will constitute a prototype whose potential market exploitation will be tested.

Economic Assessment of Opportunities for Managed Aquifer Recharge Techniques in Spain Using an Advanced Geographic Information System (GIS)

This paper investigates the economic aspects of Managed Aquifer Recharge (MAR) techniques considered in the DINA-MAR (Depth Investigation of New Areas for Managed Aquifer Recharge in Spain) project. This project firstly identified the areas with potential for MAR for the whole of the Iberian Peninsula and Balearic Islands of Spain using characteristics derived from 23 GIS layers of physiographic features, spanning geology, topography, land use, water sources and including existing MAR sites. The work involved evaluations for 24 different types (techniques) of MAR projects, over this whole area accounting for the physiographic features that favor each technique. The scores for each feature for each type of technique were set based on practical considerations and scores were accumulated for each location. A weighting was assigned to each feature by “training” the integrated score for each technique across all the features with the existing MAR sites overlay, so that opportunities for each technique could be more reliably predicted. It was found that there were opportunities for MAR for 16% of the area evaluated and that the additional storage capacity of aquifers in these areas was more than 2.5 times the total storage capacity of all existing surface water dams in Spain. The second part of this work, which is considered internationally unique, was to use this GIS methodology to evaluate the economics of the various MAR techniques across the region. This involved determining an economic index related to key physiographic features and applying this as an additional GIS overlay. Again this was trained by use of economic information for each of the existing MAR sites for which economic data and supply or storage volume were available. Two simpler methods were also used for comparison. Finally, the mean costs of MAR facilities and construction projects were determined based on the origin of the water. Maps of potential sites for Managed Aquifer Recharge (or “MAR zones”) in the Iberian Peninsula and Balearic Islands of Spain and the results of the previous economic studies developed at the beginning of the project were used as the foundation for the economic analysis. Based on these data, a new specific mapping of the total expected costs for all “MAR zones” (€/m3) was proposed based on the techniques that were considered most appropriate for each Spanish study case. Capital costs ranged from Euro 0.08–0.58 per m3/year. Overall, this study investigates the opportunity and economic feasibility of implementing new MAR projects and provides support to decision makers in Spain. The novel mapping provides valuable guidance for the future development of Managed Aquifer Recharge projects for water managers and practitioners.

Hydrogeological analysis of the upper Dupi Tila Aquifer, towards the implementation of a managed aquifer-recharge project in Dhaka City, Bangladesh

A preliminary feasibility assessment of managed aquifer-recharge (MAR) techniques was undertaken for Dhaka City, Bangladesh. Considering the top impermeable-layer (TIL) thickness and the land-use classification, four primary MAR techniques have been suggested: (1) soil-aquifer treatment (SAT) for TIL thickness 0–8 m, (2) cascade-type recharge trenches/pits for TIL thickness 9–30 m, (3) aquifer storage, transfer and recovery (ASR/ASTR) for TIL thickness 31–52 m, and (4) use of natural wetlands to recharge water collected from open spaces. The study suggests that recharge trenches and pits will be the most appropriate MAR techniques, which can be implemented in most parts of the recharge area (ca. 277 km2). In case of a recharge trench, the lower parts (15–20 m) that are in direct contact with the aquifer can be backfilled with biosand filters with a reactive layer containing metallic iron (Fe0) to offer pre-treatment of the infiltrated water. In addition to the suggested four techniques, the regional groundwater flow direction, from the northwest and northeast towards Dhaka City, may allow use of the aquifer as a natural treatment and transport medium for groundwater, if spreading basins are installed in the greater Dhaka area.