Explore the vast range of titles available.

While the success and sustainability of managed aquifer recharge (MAR) strongly depends on many characteristics of the site, it is necessary to integrate the site characteristics and develop suitability maps to indicate the most suitable locations. The objective of this study is to integrate geographic information system (GIS) and multi-criteria decision analysis (MCDA) techniques to identify the most suitable areas for a MAR project in the Kabul city area, Afghanistan. Data for six effective criteria, including slope, drainage density, surface infiltration rate, unsaturated zone thickness, soil type and electrical conductivity, were collected and then a classification map was produced for each criterion in the GIS environment. By applying MCDA techniques, the weights of the effective criteria were obtained. A suitability map was generated from each technique separately based on a combination of all criteria weights and thematic layers. The result of the analytical network process (ANP) method was found to be more precise and reliable compared with that of the analytical hierarchy process (AHP) method. Based on the final suitability map produced from the ANP model, there is 3.7, 15.0, 37.4, 33.1 and 10.3% of the total area that is unsuitable, of low suitability, moderately suitable, suitable and very suitable for MAR application, respectively. As a final result of this work, seven sites have been prioritized based on land use. The integration of multi-criteria decision analysis and GIS is recognized as an effective method for the selection of managed aquifer recharge sites.

The evaluation of saturated hydraulic conductivity (Ks) constitutes an invaluable tool for the management and protection of groundwater resources. This study attempted to estimate Ks in the shallow aquifer of Kabul City, Afghanistan, in response to the occurring groundwater crisis caused by overexploitation and a lack of an appropriate monitoring system on pumping wells, based on datasets from well drilling logs, various analytical methods for pumping test analyses, and laboratory-based methodologies. The selection of Ks estimation methods was influenced by data availability and various established equations, including Theis, developed by Cooper–Jacob, Kruger, Zamarin, Zunker, Sauerbrei, and Chapuis, and pre-determined Ks values dedicated to well log segments exhibited the highest correlation coefficients, ranging between 60% and 75%, with the real conditions of the phreatic aquifer system with respect to the drawdown rate map. The results successfully obtained local-specific quantitative Ks value ranges for gravel, sand, silt, clay, and conglomerate. The obtained results fall within the high range of Ks classification, ranging from 30.0 to 139.8 m per day (m/d) on average across various calculation methods. This study proved that the combination of pumping test results, predetermined values derived from empirical and laboratory approaches, geological description, and classified soil materials and analyses constitutes reliable Ks values through cost-effective and accessible results compared with conducting expensive tests in arid and semi-arid areas.

The upper Kabul Sub-basin is located in the Kabul River Basin. Groundwater is the main drinking water source in the upper Kabul sub-basin. Additionally, groundwater is widely used for domestic and irrigation purposes in the sub-basin. Overexploitation of groundwater in the sub-basin causes negative effects including depletion of the aquifer storage and groundwater level decline. To assure sustainability of the sub-basin determination of groundwater balance is necessary. In this study, a water balance equation was developed based on available information and physio-geographical characteristics of the study area, and it was applied for determining groundwater balance in the sub-basin. The results showed that there is a significant negative balance (− 14.75 MCM) between recharge and discharge in the sub-basin. In addition, to geoethically evaluate water and environmental issues in the upper Kabul sub-basin, an extensive online questionnaire survey was conducted with hydro-geoscientists of the Kabul residents. The survey results showed that all respondents have a good level of awareness toward groundwater and environmental issues. Moreover, the survey results indicated that the respondents are very worried about water shortage and groundwater pollution in the study area, however, they feel medium to high respect and responsibility towards groundwater issues in the region. This was the first geoethical survey conducted in Afghanistan. This study revealed that geoethical approaches can significantly help towards awareness of Afghan hydro-geoscientists on geoethics-related issues and efficient water resources management in the Kabul Basin.

The Chakari alluvial aquifer is the primary source of water for human, animal, and irrigation applications. In this study, the geochemistry of major ions and stable isotope ratios (δ2H–H2O, δ18O–H2O, δ15N–NO3̄, and δ18O–NO3̄) of groundwater and river water samples from the Chakari Plain were analyzed to better understand characteristics of nitrate. Herein, we employed nitrate isotopic ratios and BSIMM modeling to quantify the proportional contributions of major sources of nitrate pollution in the Chakari Plain. The cross-plot diagram of δ15N-NO3̄ against δ18O–NO3̄ suggests that manure and sewage are the main source of nitrate in the plain. Nitrification is the primary biogeochemical process, whereas denitrification did not have a significant influence on biogeochemical nitrogen dynamics in the plain. The results of this study revealed that the natural attenuation of nitrate in groundwater of Chakari aquifer is negligible. The BSIMM results indicate that nitrate originated mainly from sewage and manure (S&M, 75‰), followed by soil nitrogen (SN, 13‰), and chemical fertilizers (CF, 9.5‰). Large uncertainties were shown in the UI90 values for S&M (0.6) and SN (0.47), whereas moderate uncertainty was exhibited in the UI90 value for CF (0.29). The findings provide useful insights for decision makers to verify groundwater pollution and develop a sustainable groundwater management strategy.

This study used remote sensing (RS) and geographic information system (GIS) techniques to assess groundwater potential areas by applying two multi-criteria decision-making analyses tools in the Arghandab river basin. Twelve influencing parameters summarizing basin characteristics were gathered and generated using geospatial RS and GIS tools. The analytical hierarchy process (AHP) and analytical network process (ANP) were examined to weigh, ranking, and reclassify raster to produce groundwater potential maps. Two multi-criteria decision models were applied to compare results and suitability in the study area. The results of the AHP analysis delineate five groundwater potential zones (GWPZs) classified as very poor (29%), poor (22%), moderate (17%), high (19%), and very high (14%). On the other hand, the results of the ANP analysis classified GWPZs as very poor (25%), poor (9%), moderate (25%), high (30%), and very high (11%). To validate generated GWPZs maps, a total of 270 well locations data were utilized in the receiver operating characteristic (ROC) curve analysis. ROC model accuracy in training and validation stages is marginally higher for the ANP model (0.810 and 0.823) as compared to the AHP model (0.749 and 0.742). The groundwater potential map delineated in this study offers a preliminary assessment to scientists, public authorities, and policy makers for sustainable management of groundwater resources in the study area.

The groundwater vulnerability assessment is known as a useful tool for predicting and prevention of groundwater pollution. This study targets the DRASTIC, evidential belief function (EBF), and logistic regression (LR) models to assess vulnerability in Kabul aquifers, Afghanistan Country. The growth of urban sprawl, groundwater overexploitation, and lack of suitable municipal sewage systems as anthropogenic sources have been the main potential to increase groundwater contaminants such as nitrate in the study area. The vulnerability map has been developed based on various effective factors including altitude, slope (percentage rise), aspect, curvature, land-use type, drainage density, distance from river, annual mean precipitation, net recharge, geology/lithology units, the impact of the vadose zone, aquifer media, depth to water (unsaturated zone), saturated zone, drawdown, and hydraulic conductivity. To identify groundwater pollution, the spatial variation of nitrate concentration data in 2018 was considered indication of groundwater pollution. Based on descriptive statistics, the value of 2.65 mg/l (the median of the pixel values of nitrate map) was selected as a threshold to differentiate the occurrence and non-occurrence of pollution. The groundwater quality data were selected and randomly divided into two datasets for training and validation, including 70% and 30%, respectively. The success-rate and prediction-rate curves were computed based on the receiver operating characteristic (ROC) curve and the area under the curve (AUC) to estimate the efficiency of models. The ROC-AUC of success rates for EBF, LR, and DRASTIC models were estimated to be 67%, 66%, and 52%, respectively. Moreover, the ROC-AUC of the prediction rates of the EBF, LR, and DRASTIC models were obtained 61%, 63%, and 55%, respectively. Based on correlation between mean nitrate concentration and the mean vulnerability indexes in each model, the EBF model is the most compatible with the current developed vulnerability zones as the role of mankind in changing the environment in real conditions in comparison to LR and DRASTIC models. Graphical abstract

Groundwater from shallow and deep aquifers are widely used for drinking, agricultural and industrial use in Kabul, the capital of Afghanistan. However, unplanned urbanization and rapid population growth has led to the installation of numerous unlicensed wells to meet the public demand. This has caused to extraction of huge amounts of groundwater from the subsurface and further deterioration of groundwater quality. Therefore, understanding the hydrogeochemical characteristics of groundwater in shallow aquifers and deep aquifers is imperative for sustainable management of the groundwater resource in Kabul Plain. Thus, in this study, we used a multi-parameter approach, involving hydrochemical and environmental isotopes to understand the geochemical evolution of entire groundwater system of the Kabul Plain including river and dam water. The results of this study show that shallow and deep aquifers are dominantly of Mg–(Ca)–HCO3 and Na–Cl water type, respectively. We observed that (1) water–rock interaction is the major contributing factor to the chemical compositions of groundwater in the Kabul Plain; (2) groundwater in deep aquifer is mainly influenced by silicate weathering, and dissolution of evaporitic and carbonate minerals and reverse cation exchange; (3) dissolution of carbonates and silicate weathering plays a pivotal role in the groundwater chemistry of shallow aquifer; (4) the stable isotopes of groundwater display that the shallow aquifer is principally recharged by river water and local precipitation; (5) the tritium analysis exhibited that groundwater of shallow aquifer was primarily recharged recently, whereas groundwater of deep aquifer is the mixture of pre 1953 with post 1953 groundwater. This study revealed that there are hydraulic interactions between the two aquifers and the deep aquifer is recharged through shallow aquifer. The findings of this study would be useful for Afghanistan’s water authorities to develop an effective strategy for sustainable water resources management in the Kabul Basin.

Groundwater resources are essential for providing drinking water and irrigation in Afghanistan. However, the rising demand due to population growth and climate change is putting increasing pressure on these resources. Despite this, the lack of organized groundwater monitoring and comprehensive long-term data on groundwater storage fluctuations remains a significant challenge. This study aims to address this issue by offering insights into groundwater storage fluctuations and providing a thorough overview of Afghanistan's groundwater situation. The study aims to delineate and explain the variations in groundwater storage within Afghanistan. Additionally, it seeks to evaluate the accuracy of the GRACE model's projected groundwater storage anomalies. By leveraging the GLDAS database, the study also explores several potential factors influencing changes in groundwater storage. In Kabul, where an in-situ groundwater network and monitoring wells are available for validation, the study confirms the spatio-temporal analysis of groundwater storage. The findings indicate a significant decline in groundwater storage across the region, peaking in February 2005 (exceeding 10 cm) and reaching its lowest point in January 2017 (more than -15 cm). The most affected areas are the Harirud-Murghab, Helmand, and Kabul Basins, with a total change of approximately 116 mm. The northern part of the Helmand River Basin (HRB) remains relatively unaffected. Various factors contribute to changes in groundwater storage, including reduced precipitation in the Harirud-Murghab Basin, climate change, and geological conditions. In the Kabul River Basin (KRB), urbanization, population growth, and excessive groundwater extraction play significant roles. Additionally, the study suggests a direct correlation between precipitation variability and groundwater storage changes nationwide.