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A 2019 inventory of ASR projects indicates that there are a total of 233 ASR sites in the US. Of this number, 127 had sufficient information and sufficient longevity to evaluate their success. A logistic model was run using the reduced variable set, and (1) Injection Capacity, (2) Withdrawal Capacity, and (3) Ratio of Planned Pumping In/Out had slight positive effects on the odds of success; (4) Estimated start date and (5) Well Depth did not have any effect on the odds of success. All other variables reduced the odds of ASR success (the uses for the water, limestone and carbonate formations). The area’s geological formation may be the most useful parameter to predict future ASR success, but further study is required. Data on well construction is not indicative of success because wells construction accounts for the subsurface formations. Information on water quality in the formation and confinement layers was missing for many ASR sites, but both are likely to have predictive value for ASR project success.

Karst systems represent 10–15% of land surface in the world and supply around 25% of the global demand for drinking water. In Slovenia karst areas are merely covered by forest and important for their rich and unique ecosystems. However, prevailing beech and mixed fir-beech forests in the region have been exposed to severe large-scale disturbances in the past few years, e.g., ice storms and heavy snow, windthrow, severe and prolonged periods of droughts and secondary insect damage, which have caused episodes of forest decline. Modification of the vegetation cover indirectly impacts the water balance. Despite the important role of karst water resources for supplying the population with drinking water, few studies exist that adequately evaluate the impact of predicted global changes on their quantity and quality. The effects of large-scale forest disturbances have been only marginally addressed, despite evaporation of water from the soil and epikarst being recognized as a significant process affecting hydrological cycle in karst regions. In many hydrological studies, the role and importance of vegetation in infiltration mechanisms, in particular the effect of trees and their root networks, has been widely neglected. In this study we present a holistic approach to infiltration processes research. An in-situ environmental monitoring network of the atmosphere-vegetation-soil-unsaturated zone of the aquifer has been designed to better understand infiltration in different compartments of the karst aquifer. Special focus is given to different forest development phases after large-scale disturbances and karst terrain morphology. The amount of precipitation in the open, canopy interception in mature forest and in canopy gaps with varying forest development phases, soil moisture and soil temperature are measured on the surface and subsurface. These measurements are performed in the area of an eLTER site Postojna-Planina cave system, i.e., on the top and bottom of karst depressions, while in the underground water discharge and electrical conductivity are measured in cave drips. By observing the time lag of the measured parameters to the recharge events, the effective infiltration of precipitation into the aquifer is evaluated and quantified. The results enabled to distinguish the recharge conditions under different forest development phases after large-scale disturbances and under different geomorphological conditions. The findings will in the later stage of the research serve as an input information for coupled vegetation-hydrological modelling of recharge conditions. Upscaling the modelling results from local to entire catchment scale would be useful for the evaluation of impacts of large-scale forest disturbance on the water balance of the entire karst aquifer system.

The microbiome of an aquifer contaminated by landfill leachate and undergoing intrinsic remediation was characterised using 16S rRNA metabarcoding. The archaeal/bacterial V3–V4 hypervariable region of the 16S rRNA gene was sequenced using Illumina MiSeq, and multivariate statistics were applied to make inferences. Results indicate that the aquifer recharge and aquifer sediment samples harbour different microbial communities compared to the groundwater samples. While Proteobacteria dominated both the recharge and groundwater samples, Acidobacteria dominated the aquifer sediment. The most abundant genera detected from the contaminated aquifer were Polynucleobacter, Rhodoferax, Pedobacter, Brevundimonas, Pseudomonas, Undibacterium, Sulfurifustis, Janthinobacterium, Rhodanobacter, Methylobacter and Aquabacterium. The result also shows that the microbial communities of the groundwater varied spatially, seasonally and interannually, although the interannual variation was significant for only one of the wells. Variation partitioning analysis indicates that water chemistry and well distance are intercorrelated and they jointly accounted for most of the variation in microbial composition. This implies that the species composition and water chemistry characteristics have a similar spatial structuring, presumably caused by the landfill leachate plume. The study improves our understanding of the dynamics in subsurface microbial communities in space and time., Spatiotemporal dynamics of microbial communities were discovered in a landfill-leachate contaminated aquifer.

Study region This study is along an intermittent reach of the Alamosa River in the San Luis Valley of south-central Colorado, a river that is typical of the semi-arid southwestern United States with respect to climate, land use, and the impacts of upstream dam regulation. Study focus We use conceptual steady-state models to identify geologic factors that may control water loss through infiltration. These conceptual models are parameterized according to a range of conditions observed from stream discharge, topographic data, geologic data, and drone magnetometer data. New hydrological insights The introduction of a fault, variation in the alluvial aquifer hydraulic conductivity, and presence or absence of a confining unit in the numerical models were the primary geologic controls that affected infiltration across the study reach. Conversely, variation in the thickness of the streambed had little impact. This information may help determine future data collection within this and similar semi-arid regions where rivers are controlled by a combination of surface water availability (e.g. through dam regulation) and complex subsurface geology, which are often not well constrained.

Made available in DSpace on 2021-06-25T10:20:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The quantification of the groundwater recharges represents useful and important information for water resource management. The volumes of infiltrated water are essential to maintain water storage in aquifers, as well as to the discharge of groundwater towards the rivers, especially in tropical areas. The outcrop zones of the Guarani Aquifer System (GAS) in São Paulo state (Brazil) are considered as their most important recharge areas; therefore, knowledge about recharge rates and processes is essential. They are also highly vulnerable to groundwater contamination, another important reason to protect them. This study aimed to estimate spatial and temporal variations of groundwater recharge in the mentioned GAS outcrop zones. Recharge rates were estimated using the Spatial Recharge (SR) method and then compared to other two traditional methods (base flow separation and water table fluctuation method). The SR method uses the spatial distribution of the evapotranspiration and rainfall from GLDAS and TRMM databases and the runoff after the Soil Conservation Service (SCS) empirical method. All three methods revealed similar estimates for groundwater recharge, ranging from 150 to 370 mm year−1 (about 17% of the total rainfall). Despite its intrinsic limitations, the SR method allowed robust recharge estimation with ability to cope with spatial and temporal variations, as well, especially in areas lacking hydrological monitoring programs. The SR method provides valuable information for water management policymakers and stakeholders to minimize impacts related to climatic variations and inappropriate land use on recharge processes. Environmental Studies Center São Paulo State University (UNESP), Av. 24A, 1515, Bela Vista Hydrology and Territorial Management Directory (DHT) The Geological Survey of Brazil (CPRM‐SGB) Department of Environmental Enginery Institute of Technology and Exact Sciences Triangulo Mineiro Federal University School of Sciences and Engineering São Paulo State University (UNESP) Environmental Studies Center São Paulo State University (UNESP), Av. 24A, 1515, Bela Vista School of Sciences and Engineering São Paulo State University (UNESP) FAPESP: 2017/13576-9 FAPESP: 2018/06666-4

Made available in DSpace on 2021-06-25T10:22:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) In seasonal flooding isolated wetlands, the degree of wetness suggests a close synergy between soil processes, landscape evolution and hydrology along space and time. Until now, that subject has received insufficient attention despite natural wetlands supply essential environmental services to society and are surrounded by intensive agriculture that uses agrochemicals and fertilizers in their management. The objectives of this study were to propose an infiltration architecture model based on local surface and subsurface water-fluxes in isolated wetland embedded in lateritic plateau covered by savanna and qualify the environmental sensitivity as an area of aquifer recharge. Grain size, soil bulk density, and hydraulic conductivity were determined in five profiles in a soil catena. Unmanned Aerial Vehicle high-resolution images were obtained to generate a digital elevation model and discriminate areas with different vegetation, water accumulation, and environmental sensitivity. Electrical tomography was performed to unveil the soil architecture and infiltration. The soils (Plinthosols) developed on aquic conditions determine the linkage between the surface–subsurface hydrodynamics with the soil's physical properties. We have identified vertical and lateral water-flows in the soil architecture. Vertical flow occurs exclusively at the center, where the wetland is characterized as a recharge zone. Lateral flow towards the borders characterizes a discharge zone. The recharge zone is a depression surrounded by crops; therefore, it is a point of high environmental sensitivity. This hydrodynamic model is essential to support studies related to the dispersion of contaminants since soybean agriculture dominates the whole area of well-drained soils in the Brazilian Cerrado. Geosciences and Exact Sciences Institute (IGCE) São Paulo State University (UNESP), Av. 24A, 1515, Bela Vista, CP 178 Instituto de Estudos Sócio-Ambiental (IESA) Federal University of Goiás (UFG), Av. Esperança, s/n - Chácaras de Recreio Samambaia Geosciences and Exact Sciences Institute (IGCE) São Paulo State University (UNESP), Av. 24A, 1515, Bela Vista, CP 178 FAPESP: 2017/14168-1 CNPq: 43048622861

Made available in DSpace on 2022-04-28T19:49:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The inland wetlands can perform the storage of water on the surface and the recharge of aquifers. Even a small wetland can work as a local point of water infiltration, influencing and sustaining the hydrodynamics in the hydrology landscape. These zones have complex mechanisms, as they integrate soil chemical and physical characteristics, and relate both surface and groundwater systems. The study area is an inland wetland located in the Ecological Station of Itirapina, São Paulo State (Brazil). The present work aims to unveil the relationship between hydrodynamics and pedological architecture through a detailed study that combines hydraulic conductivity tests in situ, geophysical method of electrical resistivity (Electrical Resistivity Tomography technique, ERT), and morphological soil descriptions aiming the validation of the ERT and hydraulic conductivity surveys. Two-dimensional (2D) and pseudo-three-dimensional (3D) ERT have been used to investigate the water flow in the subsurface, the pedological architecture that keeps the wetland hydroperiods, and the link between surface water and groundwater that can set a recharge capacity. The results showed areas with distinct surface patterns related to the density of vegetation cover and water infiltration. The lower infiltration areas are characterized by the presence of a perched water table in grassy areas while higher infiltration is associated with exposed topsoil. ERT 2D and pseudo-3D identified these areas as zones with a connection between soil-water and groundwater systems. Hydrodynamics in the flat plateau is associated with the geochemical evolution of soil cover due to the structural complexity acquired by the iron crust dissolution (laterite) which has sustained the relief. Future studies concerning inland wetlands need to be carried out to certify the role of soil-landscape in the water cycle in the Savanna biome. São Paulo State University (Universidade Estadual Paulista) Department of Geology, Av. 24A, 1515, CEP “Luiz de Queiroz” College of Agriculture University of São Paulo (USP/ESALQ) Soil Science Department, Pádua Dias, Avenue 11, CEP Facultad de Ciencias Universidad de la República Montevideo Departamento de Montevideo, Uruguay. Iguá 4225. 11400, Montevideo São Paulo State University (Universidade Estadual Paulista) Department of Geology, Av. 24A, 1515, CEP FAPESP: 2017/14168-1 FAPESP: 2020/03207-9

The Riardo basin hosts groundwater exploited for the production of high quality, naturally sparkling, bottled water (e.g., Ferrarelle water), and circulating in a system constituted by highly fractured Mesozoic carbonates, overlain by more impervious volcanic rocks of the Roccamonfina complex. The two formations are locally in hydraulic connection and dislocated by deep-rooted faults. The study aimed at elucidating groundwater origin and circulation, using isotopic tracers (δ18O, δ2H, δ11B and 87Sr/86Sr) coupled to groundwater dating (Tritium, CFCs and SF6). Besides recharge by local precipitation over the Riardo hydrogeological basin, stable isotope ratios in water indicated an extra-basin recharge, likely from the elevated surrounding carbonate reliefs (e.g., Maggiore and Matese Mts.). The mineralization process, promoted by the deep CO2 flux, controls the B and Sr contents. However, their isotopic ratios did not allow discriminating between circulation in the volcanic and in the carbonate aquifers, as in the latter the isotopic composition differed from the original marine signature. Groundwater model ages ranged from ~ 30 years for the volcanic endmember to > 70 years for the deep, mineralized end-member, with longer circuits recharged at higher elevations. Overall, the results of this study were particularly relevant for mineral water exploitation. A recharge from outside the hydrogeological basin could be evidenced, especially for the more mineralized and valuable groundwater, and an active recent recharge was detected for the whole Riardo system. Both findings will contribute to the refinement of the hydrogeological model and water budget, and to a sustainable development of the resource.

The two major causes of Parkinson&rsquo, s disease (PD) are genetic susceptibility and exposure to agricultural pesticides. Access to 23,224 individuals&rsquo, hospital primary discharge diagnoses of PD allowed the mapping of cases against known crop distributions and pesticides. Our main objective was to map PD risks (cases per 10,000 people) against crops and their pesticides. The ZIP Code address locations, and the 2000 and 2010 census data, were used to map the risks of PD throughout Louisiana and in relation to United States Department of Agriculture (USDA)-recorded crops. The introduction of glyphosate-resistant crops appears to have initiated the PD disappearance from northeastern parishes on the west bank of the Mississippi river. Rice and sugar cane are seemingly unassociated with PD, as is the Mississippi itself, except for Jefferson and St. Charles Parishes, which are essentially urban or industrial. The present major PD-affected areas are associated with commercial forests, woodlands, and pastures, and thus with certain arbor-pastoral pesticides, 2,4-D, chlorpyrifos, and paraquat. Human populations at maximum risk are those living in areas of moderate and high aquifer-recharge potential. The levels of estimated pesticide exposure in these recharge areas we were able to access were of variable use, but significant amounts of 2,4-D were being used.

Flood-fed aquifers along the sandy lower reach of the Kuiseb River sustain a 130-km-long green belt of lush oases across the hyperarid Namib desert. This oasis is a year-round source for water creating dense-tall woodland along the narrow corridor of the ephemeral river valley, which, in turn, supports human activity and fauna including during the long dry austral winters and multi-year droughts. Occasional floods, originating at the river's wetter headwaters, travel ∼280 km downstream, before recharging these aquifers. We analyzed the flood-aquifer-vegetation dynamics at-a-site and along the river, determining the relative impact of floods with diverse magnitude and frequency on downstream reaches. We find that flood discharge that feeds the alluvial aquifers also affects vegetation dynamics along the river. The downstream aquifers are fed only by the largest floods that allow the infrequent germination of plants; mean annual recharge volume is too low to support the aquifers level. These short-term vegetation cycles of green-up and then fast senescence in-between floods are easily detected by satellite-derived vegetation index. This index identifies historical floods and their magnitudes in arid and hyperarid regions; specifically, it determines occurrences of large floods in headwater-fed, ephemeral Namib streams as well as in other hyperarid regions. Our study reveals the importance of flood properties on the oasis life cycle, emphasizing the impact of drought and wet years on the Namib's riparian vegetation., This researc hwas funded by agrant from EU-WADE (GOCE-CT-2003-506680-WADE) and additional support from US-AIDCDRC24-026TA-MOU-04-C24-026.

Groundwater is the major water source in arid and semi-arid regions and its availability under future climatic scenarios is uncertain. In this context, the knowledge of the likely changes in aquifer recharge is very important for sustainable management of groundwater resources in these environments. This work assesses the effect of future potential changes in the climate variables on aquifer recharge in a Mediterranean semi-arid aquifer (Sierra de Las Aguilas (SAG), SE Spain). We used monthly piezometric data to validate the aquifer recharge simulated by HYDROBAL ecohydrological model over the period 2001–2016. This model was then used to simulate the aquifer recharge over the historical period 1971–2000 and over two projected periods (2039–2068 and 2069–2098) using 18 downscaled climate projections. The results show that the percentage of aquifer recharge to precipitation (PAR) decreased significantly over the historical period (− 0.3% year−1, p

Gediz Basin, located in the western part of Turkey constituting 2% land of the country, has an important groundwater potential in the area. Alasehir sub-basin, located in the southeast of the Gediz Basin and subject to the extensive withdrawal for the irrigation, constitutes the study area. Natural recharge to the sub-basin due to precipitation is numerically investigated in this study. For this purpose, 25 research wells, whose depths range from 20 to 50 m, were drilled to observe the recharge and collect the necessary field data for the numerical model. Meteorological data were collected from 3 weather stations installed in the study area. The numerical model HYDRUS was calibrated using the field water content data. Soil characterization was done on the core samples; the aquifer characterization was performed, and the alluvial aquifer recharge due to precipitation was calculated. As a result, the computed recharge value ranges from 21.78 to 68.52 mm, with an average value of 43.09 mm. According to the numerical model, this amount of recharge corresponds to 10% of the amount of annual rainfall., TUBITAK (115Y065)

Groundwater studies in the South Fork Palouse River Basin have been unable to determine recharge sources, subsystem connectivity and flow patterns due to the discontinuity of pathways in the heterogeneous and anisotropic aquifers located in Columbia River flood basalts and interbedded sediments. Major ion, &delta, 18O, &delta, 2H, &delta, 13C, &delta, 34S and temperature for groundwater collected from 28 wells of varying depths indicate a primary recharge source dominated by snowmelt along the eastern basin margin. This recharge can be separated into two distinct sources&mdash, a deeper and relatively less altered snowmelt signal (&minus, 17.3&permil, to &minus, 16.8&permil, &delta, 18O, &minus, 131&permil, 127&permil, 2H, &minus, 12.9&permil, 10&permil, 13C, 18&ndash, 23 &deg, C) and a more altered signal likely derived from a shallower mixture of snowmelt, precipitation and surface water (&minus, 16.1&permil, 15.5&permil, 121&permil, 117&permil, 15.9&permil, 13C, 12&ndash, 19 &deg, C). A mixing of the shallow and deep source waters is observed within the upper aquifer of the Grande Ronde Formation near Moscow, Idaho, which results in a homogenization of isotope ratios and geochemistry for groundwater at nearly any depth to the west of this mixing zone. This homogenized signal is prevalent in a likely primary productive zone of an intermediate depth in the overall aquifer system.

Global warming is affecting ecosystems worldwide, with mountainous regions particularly vulnerable. At mid-altitudes, changes in winter precipitation will have immediate effects on lake fun...

A new method is presented to estimate average diffuse aquifer recharge of water table aquifers in temperate climates using time series analysis of water table level fluctuations. An accurate estimate of the recharge caused by rainfall requires an accurate estimate of the influence of evaporation. In temperate climates, evaporation imprints a seasonal component in the water table fluctuations. As such, recharge is estimated from time series models fitted to observed heads under the additional constraint that the seasonal harmonic of the observed head is reproduced as the sum of the transformed seasonal harmonics present in precipitation, evaporation, and pumping. An explicit equation is presented, in terms of the model parameters, for the damping and phase shift of the response to the seasonal harmonic of the stresses. Taking into account the seasonal harmonic of the observed heads results in more reliable recharge estimates compared to standard time series analysis. The method is limited to systems that are sufficiently linear and that remain unaltered over the analysis period. Head fluctuations and stresses should contain a seasonal harmonic that can be estimated with accurately. Runoff must be negligible or quantifiable. The method is applied to measured heads obtained from piezometers situated on and around the ice-pushed sand ridge of Salland in the Netherlands and compares well with recharge estimates based on the saturated zone chloride mass balance.

Extensive urbanized areas, characterized by waterproofed soils, increase runoff, which reduces the rainwater infiltration into the ground. However, water, sewer, and rainwater distribution systems leak, as there is excess irrigation in green areas, resulting in anthropic recharging in urban aquifers larger than in rural areas with equivalent climates. This scenario occurs in the Upper Tiete Watershed (UTW), an area of 5,868 km2 that drains the principal rivers of the Sao Paulo's metropolitan region in Brazil, where groundwater plays a complementary role for domestic, industrial, and agricultural supplies, totalizing extraction rates higher than 11 m3/s. In this paper, a Geographical Information System (GIS) was established to assess regional groundwater availabilities using adaptations of classic recharge methods such as soil water budget calculations and estimation of minimum sustainable river flow. For this, a surface runoff map, based on soil and slope terrain data, was evaluated using the information on water and sanitation infrastructure and meteorological data. We found that recharge in urban areas (with water and sewer mains) was 437 mm/yr and 106–407 mm/yr in rural areas. Considering the need to maintain a minimum historical flow of 20 m3/s in the hydrographic basin of the Tiete River, the total exploitable groundwater is 33 m3/s. The compilation of various GIS methods can help decision-makers develop alternative water security management plans in complex urbanized-regions such as in the metropolis of Sao Paulo.

Groundwater resources are facing increasing pressure especially in semi-arid regions where they often represent the main freshwater resource to sustain human needs. Several aquifers in the Mediterranean basin suffer from salinization and quality degradation. This study provides an assessment of Grombalia coastal aquifer (Tunisia) based on multidisciplinary approach that combines chemical and isotopic (&delta, 2H, &delta, 18O, 3H, 14C and &delta, 13C) methods to characterize the relation between groundwater quality variation and aquifer recharge. The results indicate that total dissolved solids exceed 1000 mg/L in the most of samples excepting the recharge area. In addition to water&ndash, rock interaction, evaporation and nitrate pollution contributing to groundwater mineralization, the reverse cation exchange process constitute an important mechanism controlling groundwater mineralization with enhancing risk of saltwater intrusion. Environmental isotope tracers reveal that groundwater is evolving within an open system to close system. A significant component of recent water that is recharging Grombalia aquifer system is confirmed by applying correction models based on the &delta, 13C values and 14C activities and tritium contents. However, this recharge, which is mainly associated to the return flow of irrigation water, contributes to the groundwater salinization, especially for the shallow aquifer.

1 recurso en línea (páginas 61-71)., Reconocer la conexión hidráulica entre la zona de recarga y la zona de descarga en acuíferos solo es posible mediante el uso de trazadores, y los isótopos de 18O y 2H han probado ser buenos trazadores. En Ibagué y el lago de Tota se supone que la recarga de los acuíferos en la parte baja se da no solamente por infiltración vertical directa, sino también por precipitación e infiltración en las montañas altas, para luego infiltrarse regionalmente hasta alimentar los acuíferos en la parte baja. En Tota, los valores delta (δ) para el 18O son más ligeros en la parte alta que en la parte baja; en la parte alta los valores están cerca de -10 ‰, mientras que los de la parte baja están en torno a -3 ‰. En Ibagué, los valores δ para el 18O son, igualmente, más bajos en la parte alta que en la parte baja; en la parte alta están entre -8 y -11 ‰, mientras que en la parte baja están entre -7 y -9 ‰. En ambos casos, la diferencia isotópica entre los valores de la parte alta y los de la parte baja podría indicar que no toda la infiltración de los acuíferos en la parte baja proviene de la recarga por la precipitación en la parte montañosa alta, y, por lo tanto, esa recarga adicional sería producto de la precipitación y la infiltración en la parte baja., Identifying the hydraulic connection between the area of recharge and the area of discharge in aquifers is only possible by using tracers; the 18O and 2H isotopes have proven to be good tracers to determine such hydraulic connection. It is assumed that in Ibagué and Lake Tota the recharge of the aquifers is given by two processes: vertical infiltration and precipitation, and infiltration in the high mountains followed by regional permeation that reaches the aquifers in the lower part. In Tota, the delta (δ) values of 18O are lower in the higher part than in the lower part: in the higher area, the values are close to -10 ‰, while in the lower area they are close to -3‰. In Ibagué, the delta values (δ) of 18O are also higher in the lower part: in the upper area the values are between -8 and -11 ‰, while in the lower area are between -7 and -9 ‰. In both cases, the isotopic difference between the upper and the lower areas could indicate that not all the water recharge in the lower area comes from precipitation in the high mountains, but that additional recharge can be the product of precipitation and infiltration in the lower part., Bibliografía: página 71.

The current study was focused on the characterization of recharge, weathering processes and to check the aptness of groundwater for household and agriculture utility in the Chhaprola industrial area located in Gautam Buddha Nagar district of Uttar Pradesh, India. Groundwater samples (n = 33) were analyzed for major cations and anions from which (n = 22) were analyzed for stable isotopic records (δ2H and δ18O). Solute chemistry revealed neutral to moderately basic nature (pH ranged 6.4–8.8) and showed a higher (ranged 552–3130 µS/cm) of electrical conductivity. Isotopic signals ranged from − 8.7 to − 3.3‰ for δ18O and − 60.1 to − 37‰ for δ2 H. Bivariate plot of stable isotopes (δ 18O and δ2 H) showed that majority of the samples fell below the global meteoric water line (GMWL) and local meteoric water line (LMWL) of New Delhi, indicating enrichment of heavier isotopes in the aquifers, which explain that recharging water, has undergone evaporation before recharging the aquifer. Monsoonal precipitation was observed as the major source of aquifer recharge in the surveyed area. Vertical hydraulic connectivity of the aquifer layers was traced with the help of isotopic record which exhibited a more negative intercept for shallow depth tube well than the middle depth tube well. About 76% of the samples exhibited negative Schoeller index thereby indicated cation-anion exchange reactions while the remaining samples depicted the Base Exchange Reactions. Sodium-normalized Ca versus Na-normalized Mg and HCO 3, indicated an equal contribution of silicate and carbonate type weathering on global-average weathering system. About 52% of the groundwater samples fell into the Ca-HCO3- water type while remaining samples fell into 33% and 15% of Na-HCO3 and Mg-HCO3 type, respectively. Water quality indices (viz. residual sodium carbonate, Kelly index, permeability index, magnesium hazard, and Chloroalkaline indices) revealed unsuitability of the groundwater for drinking and irrigation purpose at few locations.

Karst Aquifer GIS‐based model (KAGIS model) is developed and applied to Mela aquifer, a small karst aquifer located in a Mediterranean region (SE Spain). This model considers different variables, such as precipitation, land use, surface slope and lithology, and their geographical heterogeneity to calculate both, the run‐off coefficients and the fraction of precipitation which contributes to fill the soil water reservoir existing above the aquifer. Evapotranspiration uptakes deplete water, exclusively, from this soil water reservoir and aquifer recharge occurs when water in the soil reservoir exceeds the soil field capacity. The proposed model also obtains variations of the effective porosity in a vertical profile, an intrinsic consequence of the karstification processes. A new proposal from the Nash–Sutcliffe efficiency index, adapted to arid environments, is presented and employed to evaluate the model's ability to predict the water table oscillations. The uncertainty in the model parameters is determined by the Generalized Likelihood Uncertainty Estimation method. Afterwards, when KAGIS is calibrated, wavelet analysis is applied to the resulting data in order to evaluate the variability in the aquifer behaviour. Wavelet analysis reveals that the rapid hydrogeological response, typical of a wide variety of karst systems, is the prevailing feature of Mela aquifer. This study proves that KAGIS is a useful tool to quantify recharge and discharge rates of karst aquifers and can be effectively applied to develop a proper management of water resources in Mediterranean areas. This research was funded by the Spanish Ministry of Science and Innovation, Projects CGL2013‐48802‐C3‐3‐R and CGL2015‐69773‐C2‐1‐P; and by the University of Alicante, Projects GRE15‐19 and GRE17‐12.

Climate change forecasts in a semiarid region are of much interest to academics, managers and governments. A significant decrease in annual precipitation and an increase in mean annual air temperature are expected; consequently, changes in the soil water balance and groundwater recharge to aquifers are expected as a response to climate change forecasts. In this context, our study aimed to assess the impact of climate changes on the soil water balance and natural groundwater recharge in a semiarid area (Ventós-Castellar aquifer, SE, Spain). To this end, we selected Global Climate Model HadCM3 after comparing it with two other models (ECHAM4 and CGCM2). The HadCM3 model climate data (air temperature and precipitation in two emission scenarios: A2-high and B2-low; 2011–2099) were coupled to a HYDROBAL hydrological model to determine the soil water balance. The HYDROBAL model results showed that climate change will have a significant impact on the soil water balance in the study area, especially on groundwater recharge during the latter period. In both the A2-high and B2-low scenarios, the selected years to run the HYDROBAL model showed a decrease in water balance components (precipitation, actual evapotranspiration, aquifer recharge and runoff) in relation to the baseline period (1961–1990). Over the projected period (2011–2099), we expect fewer rainfall events (>15 mm), which promote aquifer recharge, longer dry summer seasons and, consequently, reduced average annual recharge that ranged from 3% to 17%; 10–49 mm, if compared to the baseline period. The methodology developed in the present study can be beneficial for assessing the impact of predicted climate change on groundwater recharge, and can help managers and planners to devise strategies for the efficient use and conservation of freshwater resources. This research has been supported by the United Nations Educational, Scientific and Cultural Organization – France (IGCP-513), the European Commission – Belgium (PRACTICE project), the Spanish Government through the Ministry of Economy and Competitiveness – Spain (ECOBAL Project, CGL2011-30531-C03-01 and SURVIVE project, CGL 2011-30531-C02-02), the Consolider programme INGENIO 2010 (GRACCIE Project, CSD2007-00067), and the Generalitat Valenciana – Spain (FEEDBACKS-PROMETEO; ACOMP/2010/272 and GV07/143).

The atmospheric chloride mass balance (CMB) method was used to estimate net aquifer recharge in Las Cañadas Caldera, an endorheic summit aquifer area about 2000 m a.s.l. with negligible surface runoff, which hosts the largest freshwater reserve in Tenerife Island, Canary Islands, Spain. The wet hydrological year 2005–2006 was selected to compare yearly atmospheric chloride bulk deposition and average chloride content in recharge water just above the water table, both deduced from periodical sampling. The potential contribution of chloride to groundwater from endogenous HCl gas may invalidate the CMB method. The chloride-to-bromide molar ratio was an efficient tracer used to select recharge water samples having atmospheric origin of chloride. Yearly net aquifer recharge was 631 mm year−1, i.e., 69% of yearly precipitation. This result is in agreement with potential aquifer recharge estimated through an independent lumped-parameter rainfall-runoff model operated by the Insular Water Council of Tenerife. This paper illustrates basic procedures and routines to use the CMB method for aquifer recharge in active volcanic oceanic islands having sparse-data coverage and groundwater receiving contribution of endogenous halides.

In the framework of WAter Re-BOrn Project a large pond in Mereto (upper Friuli plain) was chosen as artificial recharge test site. Several geophysical investigations (GPR, Electrical Resistivity Tomography and High Resolution Seismic) were carried out to study and to characterize the vadose zone of this large infiltration basin. These geophysical integrated methods supplied us many information to characterize the vadose zone and the unconfined aquifer in the study area. The geophysical information greatly reduces the hydrogeological knowledge gaps and was used to improve the three-dimensional Finite Element numerical model to predict the effect of the artificial recharge.

Summary Groundwater flow models are usually characterized as being either transient flow models or steady state flow models. Given that steady state groundwater flow conditions arise as a long time asymptotic limit of a particular transient response, it is natural for us to seek a finite estimate of the amount of time required for a particular transient flow problem to effectively reach steady state. Here, we introduce the concept of mean action time (MAT) to address a fundamental question: how long does it take for a groundwater recharge process or discharge processes to effectively reach steady state? This concept relies on identifying a cumulative distribution function, F ( t ; x ), which varies from F (0; x ) = 0 to F ( t ; x ) → 1 − as t → ∞, thereby providing us with a measurement of the progress of the system towards steady state. The MAT corresponds to the mean of the associated probability density function f ( t ; x ) = d F /d t , and we demonstrate that this framework provides useful analytical insight by explicitly showing how the MAT depends on the parameters in the model and the geometry of the problem. Additional theoretical results relating to the variance of f ( t ; x ), known as the variance of action time (VAT), are also presented. To test our theoretical predictions we include measurements from a laboratory-scale experiment describing flow through a homogeneous porous medium. The laboratory data confirms that the theoretical MAT predictions are in good agreement with measurements from the physical model.

Ecosystem services are benefits people derive from resources in ecosystems. Playa lakes in the Southern High Plains region of North America provide several ecosystem services for humans, including recharge to the Ogallala aquifer. The Ogallala aquifer occupies 450,000 km2, it is part of eight states, and provides irrigation water to over 25% of the irrigated land in the United States. The recharge provided by playas potentially makes them important and valuable in this region. We develop an econometric model (with spatial aspects) to determine how playas affect the water level of irrigation wells and estimate the economic value to farmers of playa ecosystem services in recharging the water in those wells. We find that, in some instances, additional playa surface area may have a small but statistically significant effect on well drawdown (and, we infer, on recharge) on nearby wells, but that the value of the additional water is likely too small to significantly affect private management decisions. Because of lack of appropriate data, these results are of only limited applicability. We therefore identify a need for more research on the effects of management of sedimentation of playa wetlands as a key component that may improve the findings reported here.

International audience; Changes in climate and land use affect water resources and agricultural production. It is important to document these changes and to provide prospective scenarios for improving knowledge and tools that will help stakeholders to anticipate their impacts and propose adaptations. The recharge of the aquifer in the Crau plain mainly depends on the irrigation, in excess, of grassland producing high quality hay. The sustainability of this system is challenged by possible decreases in water availability from the Durance River, the main water source for irrigation, and the decrease in irrigated grassland surfaces. We implemented a modelling system combining the STICS crop model, used in a distributed mode, and the MODFLOW aquifer model for analysing the evolution of hay production, aquifer recharge and water level in the aquifer. The modelling system was implemented for several scenarios concerning climate and land use evolutions, as well as water availability for irrigation, in a close future (2025-2035). The main results showed that the level of the aquifer is seriously threatened by a decrease in irrigation level, either because of a reduction of irrigated grassland surfaces, or because of a limitation of water availability for irrigation. Conversely, the hay production (in term of quantitative yield) would be enhanced by the increase in temperature, even in situation of reduction of irrigation.

Reclaimed water from small wastewater treatment facilities in the rural areas of the Beira Interior region (Portugal) may constitute an alternative water source for aquifer recharge. A 21-month monitoring period in a constructed wetland treatment system has shown that 21,500 m 3 year −1 of treated wastewater (reclaimed water) could be used for aquifer recharge. A GIS-based multi-criteria analysis was performed, combining ten thematic maps and economic, environmental and technical criteria, in order to produce a suitability map for the location of sites for reclaimed water infiltration. The areas chosen for aquifer recharge with infiltration basins are mainly composed of anthrosol with more than 1 m deep and fine sand texture, which allows an average infiltration velocity of up to 1 m d −1 . These characteristics will provide a final polishing treatment of the reclaimed water after infiltration (soil aquifer treatment (SAT)), suitable for the removal of the residual load (trace organics, nutrients, heavy metals and pathogens). The risk of groundwater contamination is low since the water table in the anthrosol areas ranges from 10 m to 50 m. On the other hand, these depths allow a guaranteed unsaturated area suitable for SAT. An area of 13,944 ha was selected for study, but only 1607 ha are suitable for reclaimed water infiltration. Approximately 1280 m 2 were considered enough to set up 4 infiltration basins to work in flooding and drying cycles.

Este estudo se propõe a estimar as taxas de recarga subterrânea na Bacia Hidrográfica do Rio Ibicuí, localizada no Estado do Rio Grande do Sul, a partir da utilização do método de separação do escoamento de base. O principal aquífero da Bacia é o Sistema Aquífero Guarani (SAG), nas suas áreas de confinamento (Oeste) e afloramento (Central). A separação do escoamento de base foi realizada por meio do filtro numérico de Eckhardt (2005) com dados de séries históricas de vazão disponibilizados pela Agência Nacional das Águas. As estimativas de recarga foram comparadas com as características geológicas, hidrogeológicas e pedológicas encontradas na área de estudo. As taxas de recarga variaram de 88 mm/ano a 378,7 mm/ano (13% a 47%, respectivamente da precipitação efetiva nas sub-bacias, e 6% a 21% da precipitação total). Os resultados mostraram que as maiores taxas de recargaocorreram nas unidades geológicas com transmissividades mais elevadas e solos mais permeáveis, e também com precipitações médias mais elevadas. Por outro lado, as sub-bacias com baixas taxas de recarga apresentaram unidades geológicas permeáveis e unidades cristalinas impermeáveis, solos com altos teores de argila e precipitações médias reduzidas. This study aims to estimate the groundwater recharge rates in the Ibicuí Watershed, in the state of Rio Grande do Sul, using baseflow separation method. The watershed’s main aquifer is the Guarani Aquifer System, in its confined areas (West) and outcrop (Central). The baseflow separation was made with the Eckhardt (2005) numerical filter, with historical streamflow data released by the National Water Agency. The recharge estimates were compared with the geological, hydrogeological and soil found in the study area. Recharge rates ranged from 88 mm/year to 378.7 mm/year (13% and 47% respectively of the effective precipitation in the sub-watersheds, and 6% to 21% of total precipitation). The results showed that the higher recharge rates were found in the geological units with higher transmissivity and more permeable soils, and with higher average precipitation. On the other hand, sub-watersheds with low recharge rates showed permeable geologic units and crystal units, soils with high clay content and low average precipitation.

In the Sahel region, temporary rivers and ponds constitute green spaces of welfare where sustainable development requires parsimonious management of water resources. The Komadugu Yobe valley in Eastern Niger is presented here as an example case of recent agricultural development based on irrigated pepper cropping. Piezometric maps indicate there that the river recharges the upper Quaternary aquifer. A simplified numerical model allows to quantify the exchanges between the river and the aquifer, based mainly on exploration geophysics data and three piezometric records, covering between 1 and 3 years of our 4 years modeling period. Recharge at the valley axis is modeled with a linear river coefficient constant for each hydrological year. The main findings are that: (i) during dry years, the river is disconnected from the aquifer and separated from it by a layer of unsaturated medium, (ii) however, this effect can be reversed, such as during the 2010–2011 wet year or after the Sahelian drought event of the 1980s and 1990s, (iii) the infiltration rate from the river amounts to 30–40 % of its total discharge and to at least four times the abstraction for pepper irrigation along its 150 km lower course at the Niger–Nigeria boundary, which implies that neither the aquifer recharge nor the river discharge is at risk due to the present agricultural development. Similar modeling near temporary river axes could provide some help in water resource management in the Sahel.

A comparative study on climate change and its impacts on coastal aquifers is performed for three Mediterranean areas. Common climate scenarios are developed for these areas using the ENSEMBLES projections that consider the A1b scenario. Temperature and precipitation data of three climate models are bias corrected with two different methods for a historic reference period, after which scenarios are created for 2020–2050 and 2069–2099 and used to calculate aquifer recharge for these periods based on two soil water budget methods. These multiple combinations of models and methods allow incorporating a level of uncertainty into the results. Groundwater flow models are developed for the three sites and then used to integrate future scenarios for three different parameters: (1) recharge, (2) crop water demand, and (3) sea level rise. Short-term predictions are marked by large ranges of predicted changes in recharge, only showing a consistent decrease at the Spanish site (mean 23 %), particularly due to a reduction in autumn rainfall. The latter is also expected to occur at the Portuguese site, resulting in a longer dry period. More frequent droughts are predicted at the Portuguese and Moroccan sites, but cannot be proven for the Spanish site. Toward the end of the century, results indicate a significant decrease (mean >25 %) in recharge in all areas, though most pronounced at the Portuguese site in absolute terms (mean 134 mm/year) and the Moroccan site in relative terms (mean 47 %). The models further predict a steady increase in crop water demand, causing 15–20 % additional evapotranspiration until 2100. Scenario modeling of groundwater flow shows its response to the predicted decreases in recharge and increases in pumping rates, with strongly reduced outflow into the coastal wetlands, whereas changes due to sea level rise are negligible.

https://doi.org/10.15447/sfews.2012v10iss4art2 We modeled the hydrology of basins draining into the northern portion of the San Francisco Bay Estuary (North San Pablo Bay) using a regional water balance model (Basin Characterization Model; BCM) to estimate potential effects of climate change at the watershed scale. The BCM calculates water balance components, including runoff, recharge, evapotranspiration, soil moisture, and stream flow, based on climate, topography, soils and underlying geology, and the solar-driven energy balance. We downscaled historical and projected precipitation and air temperature values derived from weather stations and global General Circulation Models (GCMs) to a spatial scale of 270 m. We then used the BCM to estimate hydrologic response to climate change for four scenarios spanning this century (2000–2100). Historical climate patterns show that Marin’s coastal regions are typically on the order of 2 °C cooler and receive five percent more precipitation compared to the inland valleys of Sonoma and Napa because of marine influences and local topography. By the last 30 years of this century, North Bay scenarios project average minimum temperatures to increase by 1.0 °C to 3.1 °C and average maximum temperatures to increase by 2.1 °C to 3.4 °C (in comparison to conditions experienced over the last 30 years, 1981–2010). Precipitation projections for the 21st century vary between GCMs (ranging from 2 to 15% wetter than the 20th-century average). Temperature forcing increases the variability of modeled runoff, recharge, and stream discharge, and shifts hydrologic cycle timing. For both high- and low-rainfall scenarios, by the close of this century warming is projected to amplify late-season climatic water deficit (a measure of drought stress on soils) by 8% to 21%. Hydrologic variability within a single river basin demonstrated at the scale of subwatersheds may prove an important consideration for water managers in the face of climate change. Our results suggest that in arid environments characterized by high topo-climatic variability, land and water managers need indicators of local watershed hydrology response to complement regional temperature and precipitation estimates. Our results also suggest that temperature forcing may generate greater drought stress affecting soils and stream flows than can be estimated by variability in precipitation alone.

14 pages, 14 figures, 4 tables, Flood water infiltrates ephemeral channels, recharging local and regional aquifers, and it is the main water source in hyperarid regions. Quantitative estimations of these resources are limited by the scarcity of data from such regions. The floods of the Kuiseb River in the Namib Desert have been monitored for 46 years, providing a unique data set of flow hydrographs from one of the world’s hyperarid regions. The study objectives were to: (1) subject the records to quality control; (2) model flood routing and transmission losses; and (3) study the relationships between flood characteristics, river characteristics and recharge into the aquifers. After rigorous quality-testing of the original gauge-station data, a flood-routing model based on kinematic flow with components accounting for channel-bed infiltration was constructed and applied to the data. A simplified module added to this routing model estimates aquifer recharge from the infiltrating flood water. Most of the model parameters were obtained from field surveys and GIS analyses. Two of the model parameters—Manning’s roughness coefficient and the constant infiltration rate—were calibrated based on the high-quality measured flow data set, providing values of 0.025 and 8.5 mm/h, respectively. This infiltration rate is in agreement with that estimated from extensive direct TDR-based moisture measurements in the vadose zone under the Kuiseb River channel, and is low relative to those reported for other sites. The model was later verified with additional flood data and observed groundwater levels in boreholes. Sensitivity analysis showed the important role of large and medium floods in aquifer recharge. To generalize from the studied river to other streams with diverse conditions, we demonstrate that with increasing in infiltration rate, channel length or active channel width, the relative contribution of high-magnitude floods to recharge also increases, whereas medium and small floods contribute less, often not reaching the downstream parts of the arid ephemeral river at all. For example, more than three-quarters of the floods reaching the downstream Kuiseb River (with an infiltration rate of 8.5 mm/h) would not have reached similar distances in rivers with all other properties similar but with infiltration rates of 50 mm/h. The recharge volume in the downstream segment in the case of higher infiltration is mainly contributed by floods with magnitude P93rd percentile, compared to floods in the 63rd percentile at an infiltration rate of 8.5 mm/h., The study was funded by the 6th framework of the European Community through the project ‘‘Flood Water Recharge of Alluvial Aquifers in Dryland Environments”, WADE Project (Contract No. GOCE-CT-2003-506680). In addition, this research was supported in part by Grant No. CDR C24-026 from the US-Israel Cooperative Development Research Program, Bureau for Economic Growth, Agriculture, and Trade, US Agency for International Development. Special thanks to the Desert Research Foundation of Namibia and to Gobabeb Training and Research Center for providing the necessary tools and support that allowed this project to succeed. The authors thank three anonymous reviewers for their valuable comments

Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabadell, Spain, and Nardò, Italy, were investigated for fecal-contamination indicators, bacterial pathogens, and antibiotic resistance genes over the period of 1 year. Real-time quantitative PCR assays for Helicobacter pylori, Yersinia enterocolitica , and Mycobacterium avium subsp. paratuberculosis , human pathogens with long-time survival capacity in water, and for the resistance genes ermB, mecA, blaSHV-5, ampC, tetO , and vanA were adapted or developed for water samples differing in pollutant content. The resistance genes and pathogen concentrations were determined at five or six sampling points for each recharge system. In drinking and irrigation water, none of the pathogens were detected. tetO and ermB were found frequently in reclaimed water from Sabadell and Nardò. mecA was detected only once in reclaimed water from Sabadell. The three aquifer recharge systems demonstrated different capacities for removal of fecal contaminators and antibiotic resistance genes. Ultrafiltration and reverse osmosis in the Torreele plant proved to be very efficient barriers for the elimination of both contaminant types, whereas aquifer passage followed by UV treatment and chlorination at Sabadell and the fractured and permeable aquifer at Nardò posed only partial barriers for bacterial contaminants.

Determination of the origin of recharge of the unconfined aquifer in the right side of the Souss wadi between Agadir and Taroudant (South-western of Morocco) was based on the use of hydrochemical and isotopic analysis of groundwater, surface water and springs of the contact zone between the High-Atlas Chain and the Souss plain.The correspondence in the space evolution of the various chemical elements of evaporitic origin (SO42-, Cl-, Sr2+) in groundwater, piedmont springs, and surface water reveals the existence of recharge water from the adjacent High-Atlas Chain.The various recharge modes of the different aquifers (High Atlas and Souss plain) determined by isotopic analysis, shows that the source of groundwater for the unconfined Souss aquifer seems to be composite between a direct infiltration on the High-Atlas tributaries and a remote recharge from the bordering High Atlas aquifers.La determinación del origen de los aportes de agua de la capa freática de la ribera derecha del rio Souss entre Agadir y Taroudant (Suroeste de Marruecos) se ha basado en la hidroquímica y el análisis isotópico de las aguas subterráneas, aguas superficiales y manantiales de la zona de contacto entre el Alto Atlas y la llanura de Souss.La correspondencia en la evolución espacial de los diferentes elementos químicos de origen evaporítico (SO42-, Cl-, Sr2+) en las aguas subterráneas, manantiales de pie de monte y aguas superficiales, revela la existencia de una recarga de agua procedente de la cadena del Alto Atlas. El análisis de los modos de recarga de los diferentes acuíferos (Alto Atlas y llanura de Souss) determinado por análisis isotópico, demuestra que la alimentación de la capa freática de Souss a partir del Alto Atlas parece ser mixta, compuesta por una infiltración directa de los afluentes del Alto Atlas y una alimentación lejana desde los acuiferos que limitan con el borde del Alto Atlas.

En el Mediterráneo, los recursos hídricos dependen en gran medida de las precipitaciones y éstas varían tanto a largo del año, como en secuencias hiperanuales. La gestión hídrica ha de adaptarse a este carácter cíclico para ser sostenible y se deben gestionar los diversos recursos disponibles teniendo en cuenta dichas oscilaciones. Sólo utilizando la inercia y la capacidad de almacenamiento de los acuíferos, junto a recursos no convencionales, pueden afrontarse con éxito los inevitables periodos de sequía. En las Baleares, una gestión integral de todos los recursos disponibles tanto convencionales como no convencionales, apoyada en una buena gestión de la demanda, resultó fundamental para poder superar la falta de precipitaciones (hasta un 50% por debajo de la media) del periodo 1998-2001 y se presenta como la mejor solución para la gestión de los recursos futuros. In the Mediterranean, the water resources mainly depend on rainfall which presents both, annual and hyper annual variations. Sustainable water management needs to adapt to this cycle variations and to manage the available resources according to this rainfall cycles. Only the use of the inertia and the storage capacity of the aquifers, with non conventional resources, can successfully face the inevitable drought periods. In the Balearic Islands, an integrated management of all resources, conventional and non conventional, combined with a good water demand management, resulted fundamental in overcoming the lack of precipitation (50% under the mean) during the 1998-2001 period and is presented as the best way to solve the future resources management.

Groundwater recharge is gaining ever greater importance in the context of the management of water resources. This practice can improve the quality of aquifers, or at any rate temporarily store resources that would otherwise be lost. The recent stipulation of the “Piano Direttore”, an extract from the Plan for Safeguarding Water Resources (“Piano di Tutela delle Acque”) by the Commissary appointed to deal with the environmental emergency situation in Apulia, has removed the prejudicial clause of illegality introduced by the Law Decree (D. Lgs. 152/99) of allowing rainwater runoff underground. Nevertheless, this type of plant is still rare in the territory, perhaps due to the lack of experimental data supporting the efficacy of the procedure. In the present work the experimental results obtained in an investigation campaign carried out at a recharge site are illustrated and discussed. The recharge site is equipped with suitable devices for continuous monitoring of the rainwater levels, the volume influx to the network, and the variations in the levels of the perched water. Finally, the experimental data are used as the preliminary settings for a mathematical model drawn up to represent the phenomenon.