Groundwater Quality Zones Research Articles

Groundwater quality prediction and risk assessment in Kerala, India: A machine-learning approach

Despite its critical importance for health, agriculture, and the economy, and its key role in supporting climate change adaptation, groundwater quality remains vulnerable to contamination and is often neglected until significant deterioration. The groundwater resources of Kerala, one of the southernmost states of India, are under escalating stress and scarcity, despite a high well density with 62% of the population relying on groundwater from approximately 6.5 million open wells. This study investigates the detailed hydrogeochemistry and predicts groundwater quality zones of the state using machine-learning techniques viz, extreme gradient boosting (XGBoost), support vector regression (SVR), artificial neural network (ANN) and random forest (RF) regression. The hydrogeochemical analysis reveals varying groundwater quality across the state. Among the different machine learning models, RF shows higher goodness of fit (R2: 0.922) with minimal prediction error (root mean square error: 6.29 and mean absolute error: 3.12). The predicted groundwater quality was validated using the spatially distributed stiff diagrams, visually representing water composition trends of each well. The very good, good, moderate and poor groundwater quality zones occupy 31.7%, 40.4%, 20.4%, and 7.4% of the state aligning accurately with the groundwater quality scenario of the state. Additionally, groundwater drinking risk assessment was conducted, considering that 7.4% of the state experiences poor-quality groundwater. Integrating groundwater quality maps with population data, the study assessed potential health risks due to consuming untreated water. Nearly 0.59 million people across 252 local self-government bodies (LSGs) are susceptible to consuming poor quality groundwater, which may pose potential health risks. This observation provides valuable insights for sustainable groundwater management and public health safeguarding and the findings of the present study are useful for achieving sustainable development goal (SGD) 6 (clean water and sanitation) and long-term groundwater management in Kerala.

An integrated groundwater resource management approach for sustainable development in a tropical river basin, southern India.

Evaluation of aquifer potential is essential, as thepotable water demand has increased globally over the last few decades. The present study delineated different zones of groundwater potential and groundwater quality of the Kallada River basin (KRB) in southern India, using geo-environmental and hydrogeochemical parameters, respectively. Geo-environmental variables considered include relative relief, land use/land cover, drainage density, slope angle, geomorphology, and geology, while hydrogeochemical parameters include pH, electrical conductivity (EC), Cl-, Fe3+, and Al3+ concentrations. Analytical hierarchy process (AHP) was used for categorizing groundwater potential and quality zones. Nearly 50% of KRB is categorized as very high and high groundwater potential zones, occupying the western and midland regions. The central and west-central parts of KRB are characterized by excellent groundwater quality zones, while the eastern and western parts are characterized by good and poor groundwater quality zones, respectively. By integrating the groundwater potential and groundwater quality, sustainable groundwater management is observed to be necessary at about 54% of the basin, where site-specific groundwater management structures such as percolation ponds, injection wells, and roof water harvesting have been proposed using a rule-based approach. This integrated groundwater potential-groundwater quality approach helps policymakers to implement the most suitable management strategies with maximum performance.

Geostatistical investigation of groundwater quality zones for its applications in irrigated agriculture areas of Punjab (Pakistan)

Geostatistical investigation of groundwater quality zones for its applications in irrigated agriculture areas of Punjab (Pakistan)

Geochemical characteristics and quality of groundwater evaluation for drinking, irrigation, and industrial purposes from a part of hard rock aquifer of South India.

The present study is a part of hard rock aquifer of Telangana, South India, where the groundwater is withdrawn heavily for drinking, irrigation, and small-scale industrial purposes. Geochemical characteristics explain the chemical processes, which control the groundwater chemistry and consequently the groundwater quality, while the chemical quality of groundwater is adversely affected by anthropogenic activities, which damage the water environment. The focus of the present study was, thus, to know the origin of geochemical characteristics and also to evaluate the quality of groundwater for various purposes for taking the suitable remedial measures to provide safe water to the local community. Geochemical relations (GR) and hierarchical cluster analysis (HCA) were used to assess the geochemical characteristics. Entropy weighted groundwater quality index (EWGQI), United States Soil Salinity Laboratory Staff (USSLS)'s diagram, and groundwater quality criteria for water supply pipes (GQCW) were used to evaluate the groundwater quality for drinking, irrigation, and industrial purposes, respectively. The study found that the water-rock interactions associated with ion exchange and evaporation were the prime geochemical factors controlling the geochemical characteristics and the anthropogenic activities as the secondary factor. These observations were further supported by HCA. According to the EWGQI, 34.97% of the spatial area was found to have the poor and very poor groundwater quality zones for drinking purpose, because of the dominance of TDS, Na+, Cl-, [Formula: see text], [Formula: see text], and F- contents in the groundwater system. Based on the USSLS's diagram, 79.55% of the present study area was observed to be poor and very poor water quality type for irrigation utilization due to salinity hazard. The GQCW demonstrated that the 7.91% and 8.82% of the areas were not suitable for industrial purpose due to influence of incrustation based on [Formula: see text] and [Formula: see text], respectively, and 1.85%, 12.32%, and 1.25 of the areas are unfit due to influence of corrosion based on pH, TDS, andCl-, respectively. Therefore, boiling, activated carbon filter, rainwater harvesting, suitable coatings on metal surfaces of water supply pipes, etc. are the important suggested effective strategic measures to provide safe water for drinking, irrigation, and industrial purposes.

Comparison of stochastic and traditional water quality indices for mapping groundwater quality zones

This study has compared the use of standard water quality overlay techniques with that of Getis-Ord Gi* statistical techniques for visualizing the spatial distribution of water quality parameters in an unconfined aquifer beneath the city of Lahore in Pakistan. The non-uniformly distributed groundwater sampling points were uniformly transformed to a grid of evenly distributed values to apply Getis-Ord Gi* statistics. An optimized neighborhood distance value of 700 m was determined for the Getis-Ord Gi* assessment, showing that the aquifer is regionally continuous and there are no barriers to lateral groundwater flow. This statistical approach was initially applied to individual parameters and was found to better define hotspots than that of the conventional method. Similarly, the use of Getis-Ord Gi* values improved the assessment of hotspots of water quality index (WQI) values than conventional overlay techniques.

Demarcation of groundwater quality domains using GIS for best agricultural practices in the drought-prone Shanmuganadhi River basin of South India.

A study was conducted to evaluate the suitability of groundwater in the drought-prone Shanmuganadhi River basin of south India for best agricultural practices since the surface water that exists in this basin is not sufficient to meet out the demand. As the quality of groundwater is not uniform in the hard rock aquifers of this basin, the work was carried out to demarcate the suitable groundwater quality zones for the agricultural activities. Sixty-one groundwater samples were collected and analyzed for various parameters such as electrical conductivity (EC), pH, TDS, major cations (Ca2+, Mg2+, Na+, and K+) and anions (Cl-, SO42-, HCO3-, PO43-, NO3-, and F-). To demarcate the feasible zones for agricultural practices, irrigation water quality parameters like EC, sodium adsorption ratio (SAR), percent sodium (Na %), residual sodium carbonate (RSC), magnesium hazard ratio (MHR), Kelly's ratio (KR), and permeability index (PI) were computed. Furthermore, the irrigation water quality representation diagrams like USSL, Wilcox, and Doneen were prepared, and their outputs were spatially plotted using the Geographical Information System (GIS) to identify the suitability domains of groundwater for irrigational practices. Interpretation of irrigation water quality parameters and diagrams indicate that 2% of groundwater samples represented "low" salinity, 26% of samples represented "medium" salinity, 66% of samples represented "high" salinity, and 6% of samples represented "very high" salinity. Similarly, about 59% of samples represented the low alkaline/sodium category and 41% of them represented the medium alkaline category. The USSL output shows that about 2% of samples of the basin signified "low salinity with low alkalinity" category (C1S1), 28% of samples signified the "medium salinity with low alkalinity" category (C2S1), 33% of samples signified "high salinity with low alkalinity" category (C3S1), 28% of samples signified the "high salinity with medium alkalinity" category (C3S2), and 10% of samples signified the "very high salinity with medium alkalinity" category (C4S2). Groundwater is suitable for irrigation in 277.52km2 area of the basin. It is moderately suitable in an area of 318.46km2 and poorly suitable over 38.64km2. This study recommends that groundwater with moderate suitability could only be used for irrigating permeable soils and for cultivating salt-tolerant crops. The addition of gypsum to soil might be helpful to increase the infiltration capacity and osmotic activity. However, poorly suitable area should be avoided for agricultural practices.

Assessment of groundwater quality and its suitability for the inhabitants of Andrott Island, Lakshadweep

Groundwater serves as the main sources of drinking water for the Islanders. Now a days, the groundwater is contaminated due to sea water intusion and continuous anthropogenic activities. A proper understanding of the groundwater quality is important to meet the increasing demand and also for the future planning and development of the water resources. Andrott island is the largest Island in Lakshadweep having an area of 4.90 km2 with a population density of 2312 person/km2 (2011 Census). It lies in the east–west direction, between 10° 48′ and 10° 50′ N latitude and 73° 39′ and 73° 42′ E longitude. It is 293 km (158 nautical miles) away from Kochi (mainland). This paper aims to appraise the spatial distribution of groundwater quality of Andrott Island using geospatial approach. Detailed physico-chemical studies had been carried out to identify potential fresh groundwater resources and quantifying vulnerable parts of Andrott Island. BIS standard has been adopted to assess the quality of ground water at each sampling locations. 50 Samples were collected from water quality lab Andrott Island and GPS has been used to collect the sampling point locations. The statistical analysis has been performed using standard methods, by calculating correlation coefficients between different pairs of parameters. Spatial interpolation technique inverse distance weighted (IDW) has been used to estimate the spatial distribution of the groundwater parameters. The final integrated WQI map shows three priority classes such as good, poor and very poor groundwater quality zones of the study area and provides a guideline for the suitability of groundwater for domestic purposes. The result of the study estimated that 82% of pre Monsoon and 64% of post Monsoon samples fall under poor water category and the rest is categorized under good and very poor as per the WQI classification. The present study is helpful in proper planning and management of available water resources for drinking purposes.

Integrated assessment of groundwater resources in a semi-arid watershed of South India: implications for irrigated agriculture

Groundwater resources play a vital role in the socio-economic development of Andipatti watershed—a semi-arid region situated in Theni district of Tamil Nadu, South India. Due to a short spell of rainfall (40 days in a year) and ephemeral nature of streams, the quantum of surface water in the watershed is not found to cope with the agricultural requirements and as a result, more emphasis is given to the exploitation of groundwater. The haphazard utilization of groundwater for agricultural practices affects the quantum and quality of groundwater severely. The present study is attempted to assess the potential, level, quality, suitability and utilization level of groundwater resources in an integrated manner. Groundwater potential of the study area is assessed using resistivity, well yield and dug well data. The groundwater potential zones exhibit a strong relationship with land use pattern i.e. poor potential zones is marked by fallow lands. The spatial pattern of groundwater level and quality is examined using the data collected from 34 open wells across the study area during pre-monsoon and post-monsoon seasons. The groundwater level of the watershed varies from 0.5 to 47 m with an average fluctuation of 2 to 4 m. The long-term fluctuations of the groundwater level showed that there is a cyclic trend depending upon the rainfall pattern of the watershed. However, the declining trend of groundwater level noticed especially in the upper part of the watershed. The suitability of groundwater for irrigated agriculture is examined using the concentrations and indices of chloride, magnesium ratio, sodium adsorption ratio, residual sodium carbonate, soluble sodium percentage, and permeability index of the collected groundwater samples. A method formulated by the US Salinity Laboratory is also attempted for the classification of groundwater quality zones. In order to ascertain and suggest sustainable planning measures, utilisation pattern of groundwater is assessed on a micro-watershed scale. The spatial distribution of analyzed parameters shows the suitability of groundwater for irrigation and associated impacts in the watershed.

Estimating active storage of groundwater quality zones in alluvial deposits of Faisalabad area, Rechna Doab, Pakistan

The quantification and assessment of groundwater are of great significance for the urbanization and town planning in an area. The current study has been carried out for quantification and assessment of groundwater quality zones by using geo-electrical technique in Faisalabad area (73° 06′ 08″–73° 11′ 59″ E; 31° 35′ 00″–31° 40′ 39″ N) of Pakistan. Vertical electrical soundings (VES) at six locations were conducted by Schlumberger configuration up to 300-m depth of investigation. Modeling technique is used for the interpretation of apparent resistivity, and the true resistivities of various subsurface lithologies were recorded from 2.10 to 55 Ω m for the depth of investigation. Three sand-dominant aquifers were identified at depth intervals of 0–50 m, 50–100 m, and 100–300 m. The VES results are compared and calibrated with the available borehole data taken from the tube wells drilled in the vicinity of the study area. The GIS technique is applied for the preparation of water quality zonation maps. Some of the groundwater quantification parameters such as total volume of the alluvium, total volumes of the water content, and active storage are estimated through GIS applications. Top geo-electrical layer (0–50 m) is dominated by low resistivity zone (10–25 Ω m), having an active storage of 0.71 km3. Intermediate geo-electrical layer (50–100 m) comprised coarse sand with low-to-medium resistivity zone of 10–35 Ω m, showing a low active storage (1.01 km3). Deep geo-electrical layer (100–300 m) is dominant by very low resistivity zone (< 10 Ω m) in the whole area. This 200-m-thick zone is possibly an admixture of fine sand, clay, and silt, having a high active storage (4.06 km3). The quality of water deteriorates with depth, and aquifer zones saturated with marginal-to-saline groundwater are interpreted below the fresh water zone at all the probe sites. The active storage of the lower geo-electrical layer (100–300 m) indicates a huge water potential but it is trapped in medium sand and alternative layers of clay. The intermediate geo-electrical layer (50–100 m) is comparatively better in quality but has low ground water potential.

Hydrogeochemical characterization and evaluation of groundwater quality in Kangayam taluk, Tirupur district, Tamil Nadu, India, using GIS techniques

The main objective of the present study is to evaluate the hydrogeochemical characteristics of groundwater and its suitability for drinking water supply in Kangayam taluk, Tirupur district, Tamil Nadu, India. To achieve this objective, seventy-eight groundwater samples were collected from the wells spread over the study area during December 2016. The collected groundwater samples were tested in the laboratory for various hydrogeochemical parameters such as hydrogen ion concentration (pH), electrical conductivity, total dissolved solids, total hardness, calcium, magnesium, sodium, potassium, chloride, bicarbonate, carbonate, nitrate, sulphate and fluoride. The analytical results were compared with WHO drinking water standards to assess the suitability of groundwater for drinking purposes. To understand the spatial variation of hydrogeochemical parameters over the study area, choropleth (zonation) maps were prepared using geographical information system (GIS). Overall groundwater quality zones were demarcated by overlaying and integrating all the spatial plots using GIS. Three groundwater quality zones such as (1) most desirable, (2) maximum allowable and (3) not permissible were demarcated based on the limits prescribed by the WHO for drinking purposes. This study indicates that 49% of the study area does not possess potable groundwater. About 21% of the area represents "most desirable" category, and the remaining 30% area represents "maximum allowable" category for drinking purposes. The Piper's trilinear diagram indicates that groundwater of this region is Mixed CaMgCl type. As the groundwater quality is poor nearly 49% of the total area, it is necessary to go for treatment before drinking water supply. It is also essential to recharge the aquifer artificially to improve the quantity and quality of groundwater.

Evaluating groundwater quality for irrigated agriculture: spatio-temporal investigations using GIS and geostatistics in Punjab, Pakistan

Groundwater is cornerstone of global food production, and its quality plays a vital role in crop development. Success of agriculture in Pakistan relies heavily on groundwater because of reduced surface water supplies and rainfalls. The current study was conducted to assess the spatio-temporal quality of groundwater in the Lower Chenab Canal (LCC) east area with emphasis on characterizing groundwater quality zones for irrigation applications. Groundwater samples from 289 observation wells were collected and chemically analyzed. A geostatistical approach using kriging interpolation was applied to express spatial variation and minimize estimation error in data. Three water quality parameters, electrical conductivity (EC), sodium absorption ratio (SAR), and residual sodium carbonate (RSC), were utilized to develop groundwater quality maps for two seasons including pre-monsoon and post-monsoon. To describe the spatial autocorrelation, suitable semivariogram models were identified and cross validated. The exponential model gave the best results for EC and RSC, whereas the spherical model was found to be the best fit for SAR. The overlay analysis was performed to create composite water quality maps according to which 40% LCC area is showing good groundwater quality for irrigation, 49% is exhibiting marginal quality, and 10% unsuitable during pre-monsoon and post-monsoon seasons. Groundwater quality is 100% good for Sultanpur irrigation subdivision, and only 3.75% is good for Paccadala subdivision. The results of the study may provide guidelines for the planners/policy makers to devise area-specific strategies for sustainable groundwater use.

Application of temporal GIS to track areas of significant concern regarding groundwater contamination

This study is intended to explain discrimination of permanent and temporary groundwater quality zones using temporal geographic information system. The test area for this work is Lahore, Pakistan, where both quality and quantity of underground aquifer are under pressure due to anthropogenic activities. The analysis has been performed after developing precise interpolated surfaces, and verified through cross-validation, for the quality parameters of pH, TDS, Ca, Mg, Cl and HCO3. All the parameters have been studied from the year 2010–2013 for their individual as well as combined geographic distribution in the form of water quality index (WQI). Time series maps of individual parameters with same spatial scale have led the analysis to the extreme behavior of pH and Mg in the year 2011 and concentration of TDS crossing WHO limits in year 2010 (1323 mg/L), etc. Spatio-temporal analysis of WQI figured out temporary as well as permanent epicenters of groundwater pollution, the one around Anarkali region is not only permanent but also expanding gradually. On the basis of WQI scores, five categories have been introduced; WQI 110 is “poor.” It is found that categories attributed to “good” and “moderately good” are spatially transforming to “moderate” and “poor.” The results are endorsed by WQI for the year 2014, exhibiting the same contamination plume with an expansion rate even higher than the previous years. This study can be useful to channelize the limited resources of developing countries for preservation of existing aquifer.

Assessment of Groundwater Quality using GIS: A Case Study of Walayar Watershed, Parambikulam-Aliyar-Palar Basin, Tamilnadu, India

Good groundwater quality is essential for crop yield, soil productivity and environmental protection. Suitability of groundwater for irrigation purposes is determined by its geochemistry. Groundwater geochemistry explains links between chemical composition of groundwater and subsurface geological and non-geological pollutants. Subsurface rock formations control the composition of soil and hence that of water and vegetation. The ground water samples were analyzed for physico-chemical parameters like Electrical Conductivity (EC), Hydrogen ion concentration (pH), Bicarbonate (HCO3-), Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+), Sulphate (SO42-), Nitrate (NO3-), and Chloride (Cl-). Inverse distance weighted method of the Geographical Information Systems is used to prepare the distribution map of physio-chemical parameters of groundwater while overlay method is used to assess spatial, temporal changes and prepare groundwater quality zones of Walayar watershed in Parambikulam-Aliyar-Palar basin situated in Coimbatore district, Tamil Nadu, India. The results of study show that the quality of groundwater varies both spatially and temporally in Walayar watershed. The groundwater samples in some of the wells showed deviation from water quality standards indicating groundwater contamination. Hence, proper care must be taken to avoid any contamination of groundwater and its quality be monitored periodically.

Identification of Groundwater Quality Zones in Tindivanam Taluk, Tamilnadu with the Integrated Approach of Remote Sensing and GIS

Identification of Groundwater Quality Zones in Tindivanam Taluk, Tamilnadu with the Integrated Approach of Remote Sensing and GIS

Remote Sensing and GIS Approach for Delineation of Groundwater Potential and Groundwater Quality Zones of Western Doon Valley, Uttarakhand, India

Groundwater exploration in the Western Doon valley has been carried out to delineate the groundwater potential and groundwater quality zones suitable for domestic purposes based on the integrated use of Remote Sensing and Geographical Information Systems (GIS). The Western Doon Valley, occupying broad synclinal troughs in the evolving fold-thrust system of sub-Himalaya, which is filled by post-Siwalik fluvial and debris flow deposits in the late Quaternary-Holocene. The Western Doon Valley area is bounded by the Mussoorie range in the north with 1800–2800 m elevation and in the south by young topographic relief of the frontal Siwalik range with ~800 m average elevation. Groundwater quality of Western Doon valley through pictorially representation in the GIS environment, it is inferred that calcium, magnesium, total hardness and nitrate at some locations above the desirable limit. The groundwater prospects map has been prepared by integrating the hydrogeomorphologic, land use/land cover from satellite data (IRS-ID, LISS-III data) slope, soil, drainage density, depth to water table of pre-monsoon and post-monsoon periods (unconfined aquifer), water table fluctuation, static water level (confined to semi-confined aquifers), specific capacity, discharge and drawdown maps using index overlay method in the GIS environment. The groundwater prospects are depicted in five categories Very high, high, moderate, low and very low (runoff zone) integrated with the groundwater quality zones which have been prepared from hydrochemical data. The results indicated that 16.82 % of the area is under Very high potential zone category with 16.11 % and 0.71 % of desirable and undesirable quality of groundwater and 18.65 %, 42.06 %, 6.96 % and 15.46 % classified as high, moderate, low and very low potential zones with desirable and undesirable quality of groundwater for domestic purposes. This study be useful for designing the groundwater prospects and management plan for the sustainable development of study area.

Double Correction Technique for Characterising Groundwater Quality Zones: A Case Study from Granitic Setting, India

Today’s dual contamination (water–rock interaction and anthropogenic impact) in groundwater system is a common problem worldwide. Abundant amount of work has been carried out to assess groundwater quality; however, a very limited work is released towards delineation of fluoride zones by water–rock interaction (WRI) and anthropogenic causes.

HYDROGIOLOGIC CONDITIONS WITHIN AL-ANBAR GOVERNORATE

This study covers the examination of the hydrogeologic conditions and the hydraulic characteristics of the aquifers within the hydrologic regime of Al-Anbar Governorate. Also, the research shed light on the flow behavior regime and its effectiveness on the groundwater movement, considering the regional geologic settings including, geomorphologic, structural and sediment logical phenomena. The results that derived from this study are:1-Determination of groundwater quality zones throughout the distribution maps of hydrochemical facies (Water Type) and TDS. 2-Compilation of various hydraulic parameters and hydro chemical characteristics of the groundwater.3-determination of main productive aquifers. 4-Compilation the hydraulic parameters and hydro- chemical characteristics of groundwater in unite maps from the available previous hydrogeologic studies.5-determination & selection groundwater zones depending on preferable procedures for future significant exploitation aiming to various groundwater uses.

GIS based spatial distribution mapping and suitability evaluation of groundwater quality for domestic and agricultural purpose in Kaithal district, Haryana state, India

Groundwater is a major resource for meeting huge domestic and agricultural requirements of Kaithal district in Haryana. Therefore, evaluation of its quality in terms of suitability for domestic and agricultural sectors is necessary for sustainable management of the resource. The present study has analyzed pre- and post-monsoon physico-chemical data of groundwater samples from bore wells spread over the entire district. Spatial distribution maps were generated for hydrogen ion concentration, total dissolved solids, total hardness, electrical conductivity, sodium adsorption ratio, residual sodium carbonate and percent sodium using the geographic information system. Furthermore, the study area was demarcated into different groundwater quality zones for domestic and agricultural use by applying various national and international standards. It was observed from the study that the groundwater was predominantly hard, alkaline and saline in nature. However, it was within safe limits for domestic use. Further, it was also experienced from the analysis that in about two-third parts of the district, groundwater was in desirable-to-permissible quality class for agricultural use but hazardous for soil as well as for crops in the remaining part. Also, a moderation in water quality was observed after the monsoon season, which can be attributed to a possible dilution due to groundwater recharge.

Quantitative Assessment of Regional Rock Aquifers, South-Western Quebec, Canada

The population of the St. Lawrence Lowlands platform in south-western Quebec, Canada, is heavily dependent on groundwater. The present study summarizes the quantity, quality and sustainability estimations of the groundwater resources found mainly in sedimentary rock aquifers. Results show that the regional groundwater flow in the considered domain of 1,500 km2 is 97.7 Mm3/y with: 86.6% infiltration from precipitation, 9.6% inflow from neighboring aquifers, and 3.8% induced recharge. The regional sustainability is defined with simulated drawdowns from uniform withdrawal scenarios. The current withdrawal rate of 18 Mm3/y results in median drawdown of 0.6 m, compared to pre-development conditions. This drawdown is situated well in the sustainable range, an indication that regional aquifers are not overexploited. Hypothetical pumping rate of 24 Mm3/y resulting in an average drawdown of 2.2 m is estimated as sustainable limit. Increasing exploitation from 24 to 51 Mm3/y would need tight control and planning. Pumping rates beyond 51 Mm3/y are judged not sustainable as regional drawdowns become high, ∼8 m. The water levels in recharge areas are the most sensitive to groundwater extraction. Combining drawdown maps, groundwater quality zones, and aquifer vulnerability to surface contamination delineated the areas most suitable for future groundwater developments.