Groundwater Potential Index Research Articles

Groundwater potential recharge areas delineation using groundwater potential recharge index (GPRI) within arid areas: Ghomrassen, south Tunisia

The Ghomrassen region is located in southern Tunisia, which is an arid area where the annual rainfall does not exceed 150 mm. This region suffers from water table drawdown and scarcity of surface water. Groundwater is of strategic importance to meet the population and economic needs. Groundwater recharge estimation and fundamental controlling factors assessment were utmost importance solutions for sustainable groundwater management and groundwater protect. This study aims to assess the main factors controlling groundwater recharge and delineate potential recharge area of Ghomrassen aquifer. To achieve this objective, a groundwater potential recharge index (GPRI) was computed using five parameters such as soil lithology, land use/cover, lineament density, slope, and drainage density. For each parameter a score and weight were assigned and thematic maps were developed. The results indicate that about 35% of the study area is designated as excellent potential recharge, whereas 18% of study shows a moderate recharge and lower potential recharge covers 47% of study area. A potential groundwater recharge of Ghomrassen aquifer was estimated is about 5.4 Mm3.y−1. The results show that the most favorable areas for recharging are the upstream part formed by fractured and fissured rocks and the central part of the Ghomrassen basin formed by recent alluvium. The presented GPRI methodology can be helpful for the planning of various water projects locations of artificial recharge structures and wells establishment.

Appraisal of groundwater potentiality of multilayer alluvial aquifers of the Varuna river basin, India, using two concurrent methods of MCDM

An approach has been made in this study to delineate the groundwater potential zones of the Varuna river basin, Uttar Pradesh, India, using the analytical hierarchy process (AHP) and multi-influence factor (MIF) techniques. The present groundwater estimation exhibits an increase in the draft (10%) due to expansion in population, agricultural extent, and industrialization, which ultimately causes water table depletion. This backdrop justifies the need for this particular analysis in the multilayer aquifers of the central alluvial zone. The shallow aquifers are silty and unconfined, whereas the deeper aquifers are coarse, sandy-gravelly, and semi-confined. Basement faults and highs often control the thickness of aquifers in the subsurface. The study considered an integrated approach of AHP and MIF methods with remote sensing and GIS approaches. Various themes (land use/land cover (LULC), soil type, geology, elevation, slope, rainfall, normalized difference vegetation index (NDVI), drainage density, recharge rate, groundwater depth) determined by considering different conditioning factors and eventually employed for computation of groundwater potential index (GWPI) and classified for identifying the groundwater potential zones (GWPZ). Two methods applied to capture the results in a more tangible form as the AHP model works on building a pair-wise comparison matrix to relate conditioning factors to each other. Still, the MIF model considered interrelations among the conditioning factors. The GWPZ of the study area generates with overlay weighted sum method by integrating all thematic layers. The resulting groundwater potential index map is categorized into three groundwater potential zones, namely good, moderate, and poor. Ultimately, by constructing the receiver operating characteristic (ROC) curves for both the groundwater potential models, determine the efficiency of performances and the GWPZ map validated using yield data collected from wells scattered over the study area. The findings of the present paper have important implications for ensuring exploration and sustainability groundwater plans in that particular area.

Delineation of groundwater potential zones using a parsimonious concept based on catastrophe theory and analytical hierarchy process

A cost-effective “parsimonious” approach to delineating groundwater potential zones is proposed, based on catastrophe theory (CT) and analytical hierarchy process (AHP) in a geographic information system (GIS). Eleven indicators that influence groundwater storage (slope, drainage density, surface-water body (proximity), soil permeability, aquitard thickness, aquifer thickness, hydraulic conductivity, specific yield, recharge, aquitard resistivity and aquifer resistivity) were prepared. The suitable weights of the factors and the index values of the features of the factors were normalized using AHP and CT multicriteria decision analysis (MCDA) techniques for the development of a groundwater potential index (GWPI) map. Finally, the relative sensitivity of the factors was evaluated to develop a parsimonious groundwater potential index (P-GWPI) map using the most sensitive themes. GWPI and P-GWPI maps were validated using 14-year average annual post-monsoon depth to groundwater level data of 36 monitoring wells in a study area in Bangladesh. The generated GWPI map classified the study area as moderately good, good and very good groundwater potential covering an area of 19.5, 40.3 and 40.2% respectively. Subsequently, a modified GWPI map was developed using effective weights derived from single-parameter sensitivity analysis. The P-GWPI map developed using the most sensitive factors categorized the groundwater potential zones as moderately good (13.0%), good (38.2%) and very good (48.8%). The results of this study can serve as guidelines for future groundwater exploration, planning and management of the area, and the methodology used can also be easily adopted in other similar and data-scarce areas.

Delineation of groundwater potentials of Sfax region, Tunisia, using fuzzy analytical hierarchy process, frequency ratio, and weights of evidence models

Groundwater in semiarid regions is of extreme importance due to limited water resources and increasing population demand. Hence, a better knowledge of aquifer potentialities is required for better management of this precious resource. This study aims to assess the groundwater potential map (GPM) by both statistical methods and geographical information system (GIS) in Sfax region, Tunisia. A number of 11,868 wells in the region were mapped in GIS and divided into two data sets: 8308 wells (70%) were selected in a random way and defined as training, wells while the remaining ones (3560 as 30%) were considered as testing wells for model validation. First, the groundwater conditioning factors, namely altitude, slope, lithology, drainage density, lineament density and land use maps, were evaluated and then processed by the fuzzy analytical hierarchy process (FAHP), frequency ratio (FR), and weights of evidence (WOE) statistical models. Then, the groundwater potential index (GWPI) was generated from an overlap of the weighted and rated of all the conditioning factors for the three methods. The groundwater potential maps were produced in ArcGIS 10.3 for the three models and classified by means of the quantile classification method. As a final step, the receiver operating characteristics (ROC) curves validated these maps. The validation results show from the areas under the curves (AUC) that the WOE model (AUC = 71.4%) performs similarly to the FR model (AUC = 71.1%), and both are slightly better than the FAHP (AUC = 65.1%) model. Thus, the delineation of groundwater potential zones supports the decision makers for the management of the aquifer exploitation. The appropriate groundwater potential map is established for a suitable management and a better planning of the water resources. Preventive works in low potential coastal areas should be conducted in the present and considered for a long-term management. Given the close results of the three adopted methods, it is possible to apply them in other regions with a consideration of their specific characteristics.

Delineation of groundwater zones with contrasting quality in the fluorotic zone, around Mount Meru, northern Tanzania

ABSTRACT Arumeru district (northern Tanzania) has limited low-fluoride surface water sources for domestic use. Information on the alternative source, groundwater, is also limited in terms of occurrence and quality. Thus, resistivity data in conjunction with hydrochemical data (fluoride, F−; total dissolved solids, TDS; and electrical conductivity, EC) and lithological logs were used to delineate groundwater zones with contrasting quality in the fluorotic zone. The results reveal a thin upper aquifer (~25 m thick) and a lower major aquifer (>100 m thick). Resistivity of 35–60 Ωm represents fresh groundwater hosted in weathered and fractured mafic volcanics, tuffs and breccias. Resistivity of 25–35 Ωm indicates intermediate groundwater quality, whereas resistivity of 15–25 Ωm indicates low groundwater quality (TDS >1000 mg/L, F− >10 mg/L) hosted in lahars. The results have been integrated to develop a groundwater potential index map, to guide local communities, water authorities and government in the planning and development of groundwater resources in the region.

Identification of groundwater potential zones using geospatial approach in Sivagangai district, South India

The study area, Sivagangai district is considered as one of the drought prone districts of south India. Hence, there is a need of study to identify the groundwater potential zones in this region. Firstly, thematic layers (geomorphology, geology, drainage, lineament, slope, and soil) were produced using satellite images in Arc GIS platform. Analytical hierarchy processes (AHP) was done to compute the weightage for each layer with respect to the relative importance of groundwater potential index. All the thematic layers were reclassified according to their water-bearing properties with the weightages derived by AHP. The consistency of derived weightage is evaluated as 0.082 which is below the standard consistency ratio of 0.1 and is consistent. Through overlying analysis of all thematic layers, a groundwater potential map was produced using geographic information system (GIS). Four major groundwater potential zones were identified as very good, good, moderate, and poor. Majority of the study area were classified as moderate (38.2%) and good (30.8%) groundwater potential zones. Groundwater level map was used to validate the groundwater potential zone. The groundwater potential map can be used to identify the appropriate locations for artificial recharge. Artificial recharging structures such as percolation ponds, recharge shaft, and farm ponds have to be implemented to improve the water level in the region. The outcome of this study strengthens the knowledge of geospatial analysis for groundwater vulnerability and also allows policymakers in this drought-prone area to sustainably manage water supplies.

Modification of a groundwater prospect zone index using remotely sensed data and the analytic network process in the eastern part of Lesvos island, Greece.

Because of climate change and overpopulation, the demand for water is increasing. Groundwater constitutes an alternative renewable source of aquifer, so the spatial distribution of ground water provides important information on its qualitative and quantitative status. This paper develops a methodology for delineating potential ground water zones using remotely sensed data and GIS. The developed methodology was based on the empirical index GPI (MGPI – Modified Groundwater Potential Index) and was applied to the eastern part of Lesvos Island, Greece. To evaluate the criteria used for the result, the Analytic Network Process (ANP) was applied to weight each parameter. The dataset used consists of satellite images derived from Sentinel 2 and Landsat 8, which were combined with vector and raster data, to create the necessary thematic layers. To validate the results, existing ground water zones from the Municipal Water Company of Lesvos were used.

Identification of groundwater recharge sites in Latur district of Maharashtra in India based on remote sensing, GIS and multi‐criteria decision tools

AbstractIn this study, groundwater potential zones and artificial recharge zones were delineated and favourable sites for placing recharge structures were identified. Different thematic layers were generated using ArcGIS and were scrutinized by a multivariate technique called principal component analysis (PCA). Selected thematic layers and their features were assigned suitable weights on Saaty’s 9‐point scale and their normalized weights were obtained by Saaty’s analytical hierarchy process (AHP). Selected thematic layers were integrated by weighted linear combination method to calculate groundwater potential index (GWPI) and groundwater recharge index (GWRI). Based on calculated GWPI, the study area was delineated into five groundwater potential zones, namely “poor”, “moderate”, “good”, “very good” and “excellent”, which cover 1.61%, 71.99%, 22.77%, 3.54% and 0.09% of the study area, respectively. Also observed that, the study area has an area of 5957.89 km2 of moderate recharge zone. Further 34 artificial groundwater recharge sites are identified for effective groundwater management.

Interpretation of geophysical and GIS-based remote sensing data for sustainable groundwater resource management in the basement of north-eastern Osun State, Nigeria

This study describes the interpretation of integrated GIS-based remote sensing and electrical resistivity geophysical methods as part of the need to provide groundwater overview for sustainable management in the basement of north-eastern Osun State, Nigeria. Six groundwater conditioning factors are synthesized based on the analytical hierarchy process and multi-criteria decision analysis to produce groundwater potential index map constrained by existing borehole yields. The results indicate that the estimated groundwater potential index map can serve as a gross predictor of the groundwater distribution in the region. This study may influence town planning and land use decisions for sustainable management of groundwater resource in the area.

A fuzzy based MCDM–GIS framework to evaluate groundwater potential index for sustainable groundwater management - A case study in an urban-periurban ensemble, southern India

The study encompasses the application of fuzzy based multi-criteria decision making (MCDM)- geospatial framework (GIS-Fuzzy-AHP) for evaluating index based groundwater potential assessment in two differently urbanized clusters of Northern Kerala, Southern India. The framework presents a very powerful way of managing groundwater at a regional and global level due to its succinct performance. The study area is characterized by a coastal zone with a high rate of urban development and relying on groundwater supply to meet their basic needs. In the Fuzzy-analytic hierarchy process (Fuzzy-AHP), a three-level hierarchical model is built using 8 criteria and 34 subcriteria of groundwater controlling factors. Weights and ratios of these factors have been generated by pairwise comparisons of fuzzified values in Saaty's 9-point fundamental scale, taking relative importance into account. Finally, the integration of spatial and non-spatial data into the GIS platform created a groundwater potential zone map with a unique integer value known as the groundwater potential index (GWPI). The resulting groundwater potential map classified the study area into four zones using quantile method and has shown that the very good potential zone occupies 34% and 10% of the urban and peri-urban zones of the study area, respectively. Gentle slope gradient with coastal alluvium formation, sandy loam to sandy clay textured soil type with moderate to rapid permeability favours aquifer recharge in these zones, resulting in a very high potential zone. The consistency analysis using the Eigenvector method showed that the consistency was well within the tolerance limit and validation analysis using the average depth of water level data checked the statistical efficiency and reliability of results in the overall decision-making phase. A well-balanced fuzzy framework has allowed the rapid and reliable assessment of hydrological behaviour of two differently urbanized environments.

Integrating In-Situ Data and RS-GIS Techniques to Identify Groundwater Potential Sites in Mountainous Regions of Taiwan

Due to rapid urbanization, the development of megacities and metropolises worldwide is creating water scarcity, social-environmental risk, and challenges to the regions where water supply from rivers and alluvial aquifers is insufficient and unstable. Groundwater exploration in fractured bedrock of mountainous regions is thus a crucial issue in the search for substitute water resources. To achieve cost effectiveness on groundwater exploration, the use of comprehensive remote sensing (RS)- and geographic information system (GIS)-based models appears feasible. The required parameters selected and analyzed from the literature depend on the hydrogeological characteristics. This study intends to investigate and improve the proposed parameters and data sources upon those presented in the literature. A total of 17 hydrogeological units of concern was delineated from 105 complex geological formations of the geological sections and main rock types. The other parameters related to groundwater potential were derived from the digital elevation model and Landsat imagery. In addition, 118 drilling cores were inspected and in-situ well yield data from 72 wells were employed to assess the normalized groundwater potential index in the raster-based empirical GIS model with a higher spatial resolution. The results show that the accuracy of the interpretation of groundwater potential sites improved from 48.6% to 84.7%. The three-dimensional (3D) visualization of a thematic map integrated with satellite imagery is useful as a cost-effective approach for assessing groundwater potential.

Investigation of groundwater potential and groundwater pollution risk using the multi-criteria method: a case study (the Alaşehir sub-basin, western Turkey)

Determination of the groundwater potential (GWP) and groundwater pollution risk (GWPR) areas is a very important tool in the semi-arid regions in the world. Like many countries in the world, most of the major settlements in the cities of Turkey are located in permeable alluvial plains. Therefore, significant groundwater pollution is encountered in an alluvial plain containing settlements and industrial sites. This study focuses on the determination of the GWP and GWPR areas in the Alasehir sub-basin, which is one of the economically important districts of the Aegean region, located in the Gediz River basin in western Turkey. In this study, the GWP and the GWPR areas were identified and a GWP index map was generated. The GWP areas in the study basin were determined using different proxies as a multi-criteria method based on geographic information system (GIS) integrated with remote sensing (RS). The result of the study indicates that the most GWP locations in the basin are seen in the west and southeast of the study region. Based on these results, it is understood that the significant GWP and GWPR areas are near the big settlement districts such as Alasehir and Salihli. In particular, the 115-ha organized industrial zone located in the Salihli district is an important factor of the potential for consuming and contaminating water resources. This study method is so important for the selection of both city and industrial areas as well as for regional environmental planning in terms of the GWPR management.

Characterization of groundwater potential zones using analytic hierarchy process and integrated geomatic techniques in Central Middle Atlas (Morocco)

Analytic hierarchy process (AHP) is an invaluable tool that has been applied by different specialists to upgrade their administration capacity. Managing groundwater resources particularly under arid land faces several limitations and problems such as the implications of various spatial factors, which lead managers to utilize multicriteria decision. In this research, a consistent approach was applied to identify groundwater potential (GWP) areas through the use of AHP, geographic information system (GIS), and (RS) techniques in the Central Middle Atlas, Morocco. First of all, the efficient groundwater potential thematic layers including lithology (Lt), karst (K), height above the nearest drainage (HAND) geomorphology, which is called HG, and lineament density (LD) were derived through spatial databases. Then, the weights assigned to the thematic layers on the basis of expert knowledge were standardized by the AHP’s eigen vector technique. To calculate the groundwater potential index, the weighted linear combination (WLC) method was implemented in a GIS environment. The study found that only 3.88% of the study area had very good groundwater potential and 17.22% had a good potential, in addition to 20.20% with moderate potential, whereas in the most part of the region, 29.89% is within poor groundwater potential, and 18.60% are within very poor groundwater potential and 10.49% with non-potential. The very good GWP areas are located where the land cover majority is forests. The good, moderate, and poor GWP zones are located in areas where the land cover majority is shrublands. The poor and non-potential GWP zones are located in areas where the land cover majority is cropland.

Mapping favorable groundwater potential recharge zones using a GIS-based analytical hierarchical process and probability frequency ratio model: A case study from an agro-urban region of Pakistan

In Punjab (Pakistan), the increasing population and expansion of land use for agriculture have severely exploited the regional groundwater resources. Intensive pumping has resulted in a rapid decline in the level of the water table as well as its quality. Better management practices and artificial recharge are needed for the development of sustainable groundwater resources. This study proposes a methodology to delineate favorable groundwater potential recharge zones (FPRI) by integrating maps of groundwater potential recharge index (PRI) with the DRASTIC-based groundwater vulnerability index (VI). In order to evaluate both indexes, different thematic layers corresponding to each index were overlaid in ArcGIS. In the overlay analysis, the weights (for various thematic layers) and rating values (for sub-classes) were allocated based on a review of published literature. Both were then normalized and modified using the analytical hierarchical process (AHP) and a frequency ratio model respectively. After evaluating PRI and FPRI, these maps were validated using the area under the curve (AUC) method. The PRI map indicates that 53% of the area assessed exists in very low to low recharge zones, 22% in moderate, and 25% in high to excellent potential recharge zones. The VI map indicates that 38% of the area assessed exists in very low to low vulnerability, 33% in moderate, and 29% in high to very high vulnerability zones. The FPRI map shows that the central region of Punjab is moderately-to-highly favorable for recharge due to its low vulnerability and high recharge potential. During the validation process, it was found that the AUC estimated with modified weights and rating values was 79% and 67%, for PRI and VI indexes, respectively. The AUC was less when evaluated using original weights and rating values taken from published literature. Maps of favorable groundwater potential recharge zones are helpful for planning and implementation of wells and hydraulic structures in this region.

Identification of Groundwater Potential Zones Using RS, GIS and AHP Techniques: A Case Study in a Part of Deccan Volcanic Province (DVP), Maharashtra, India

This article deals with the remote sensing and geographic information system techniques in assessing groundwater potential zones by the manipulation and analysis of the individual layer of spatial controlling data in a part of Deccan Volcanic Province, Maharashtra. Available geology, geomorphology, and soil maps were collected. Land use and land cover (LULC) and Lineament maps had been prepared using the LANDSAT-8 (TM and OLI) Satellite Image (November 2015). The SRTM DEM (resolution: 30 m) data had been employed for the preparation of slope and drainage maps. These maps were converted into the raster format. Analytic hierarchy process was applied to weight, ranking, and reclassify these maps in the ArcGIS version 10.4. Then, groundwater prospect map had been prepared by overlaying the maps. The results show that five groundwater potential zones such as very poor (11.77%), poor (21.73%), moderate (30.13%), good (25.34%), and very good (11.02%) exit. Sensitivity analysis reveals that the lineament density, LULC, and slope increase the area slightly only in the very poor to poor potential zones. Besides, the well yields, groundwater level fluctuation corresponding rainfall data had been utilized to validate. The yield values vary from 5.94 to 14.88 l/s in the good to very good potential zones, whereas 0.38 to 1.37 l/s within the poor to very poor potential zones. In addition, cross-correlation coefficients among groundwater level and rainfall is well-related to the groundwater potential index (R2 = 0.84), which will help to construct artificial recharge structures and the planning of sustainable groundwater management.

A parsimonious approach to delineating groundwater potential zones using geospatial modeling and multicriteria decision analysis techniques under limited data availability condition

This study delineates groundwater potential zones by following an “equifinality” approach and adopting a standard methodology using remote sensing, geospatial modeling, geographic information system (GIS) and multicriteria decision analysis (MCDA) techniques. A total of 11 thematic layers (ie, rainfall, topographic elevation, slope, slope length, slope steepness, soil, geomorphology, geology, drainage density, and pre‐ and post‐monsoon groundwater levels) which have an influence on the occurrence of the groundwater are developed. The suitable weights to themes and their features are assigned and then normalized by using an analytic hierarchy process (AHP)—MCDA technique. All themes are integrated in GIS for generating a groundwater potential index (GPI) map, which classifies the study area into three zones of “good” (588.5 km2, 34.1%), “moderate” (933.4 km2, 54.1%), and “poor” (203.3 km2, 11.8%) groundwater potential. Furthermore, the accuracy of the developed GPI map is verified from the coherent estimates of rainfall‐recharge. Unlike earlier studies, this study further evaluates relative sensitivity of the themes, and develops a novel “parsimonious” groundwater potential index (PGPI). The PGPI is a cost‐effective and time‐efficient method that excludes redundant parameters from the analysis and employs only the most sensitive themes in assessing groundwater potential. The results of both GPI and PGPI are found in good harmony over 86.7% area, which confirms the efficacy of the developed PGPI. The results of this study may be of interest to planners and policymakers as a guideline for locating appropriate groundwater development sites and managing sustainable water supplies, especially under data scarcity conditions and/or in developing countries.

Investigating groundwater recharge potential zones using a cross-correlation technique in a part of Deccan Volcanic Province (DVP), Central India

Groundwater recharge potential zones were identified using a cross-correlation assessment to determine how depths to groundwater levels varied with rainfall in a part of Deccan Volcanic Province (DVP), Central India. The estimated correlation coefficients at 38 well sites vary from − 0.18 to − 0.83, and there is typically a 0–2-month lag between water-level responses with rainfall. The magnitude of water-level responses generally decreases with the decreasing suitability of potential groundwater zones, which were determined using remote-sensing and GIS techniques. The calculated coefficients range from − 0.83 to − 0.67, − 0.66 to − 0.60, − 0.59 to − 0.53, − 0.52 to − 0.45, and − 0.44 to − 0.18 in the “very good”, “good”, “moderate”, “poor”, and “very poor” groundwater potential zones, respectively. A good correlation has been observed between the cross-correlation coefficients and the groundwater potential index with the value of R2 = 0.84. Therefore, the specific emphasis needs are explored in both groundwater potential and recharge potential zones, where groundwater levels are declining, and water scarcity is being experienced for constructing artificial recharge structures and planning for sustainable groundwater management.

Generation of Groundwater Zones for Selection of Prospective Suitable Water Harvesting Structure Sites for Sustainable Water Supply Towards the Agricultural Development

Identification of groundwater potential is important for the preparation of management plan of groundwater resource in watershed scale. Groundwater potential zone in watershed scale is identified using GIS, remote sensing satellite data, and Multi-Criteria Decision Analysis technique. Different thematic layers, i.e. geological formation, lineament, soil, etc. were used for the identification of groundwater potential zones, while groundwater quality parameters, i.e. hardness, pH, etc. were used for the preparation of groundwater quality index map. The present study focused on identification of possible groundwater potential zones and groundwater quality index both in terms of quantity and quality. The Analytic Hierarchy Approach is utilized to identify the groundwater potential zones. Conclusively, 27.1% area falls under low–medium groundwater potential zone and 9.3% area falls under above the permissible limit of water quality. In total, 240 suitable water harvesting structures, namely storage tank (120 nos), percolation tank (70 nos), stop dam (34 nos) and check dam (16 nos) with their sites, were identified and suggested for water harvesting to enhance the groundwater conditions to meet the scarcity of water resources in agriculture and domestic use.

Application of Remote Sensing, GIS and Hydrogeophysics to Groundwater Exploration in parts of Lagos Metropolis: A case study of Oshodi/Isolo LGA

Productivity through groundwater is quite high as compared to surface water, but groundwater resources have not yet been properly exploited. The present study is used to delineate various groundwater potential zones for the assessment of groundwater availability in Lagos metropolis using remote sensing and GIS and hydrogeophysics techniques. Landsat 8, SRTM, geological, soil, and rainfall data were used in the study to prepare various thematic maps, viz., geomorphological, slope, soil, lineament density, rainfall and land use maps. On the basis of relative contribution of each of these maps towards groundwater potential, the weight of each thematic map have been selected and assigned to each map. Hydrogeophysics investigation using Vertical Electric Sounding (VES) was applied to validate the remote sensing and GIS results. All the thematic maps have been registered with one another through ground control points and integrated using the weighted overlay method in GIS for computing groundwater potential index. Based on the methological approach, the ground water potential zones were delineated. The results showed that there are five categories of groundwater potential zones within the study area in which percentage values were contained in each of the categories thereby making major portion of the study area “high” and “moderate” prospect while a few scattered areas have “low” prospect. The very high potential areas are mainly concentrated along the River Alluvium while the “very low” prospect are majorly where there is sand and clay. The best groundwater potential zone is in the southern part due to the presence of fractures, swamp soils which have high infiltration ability and the presence of waterbody which is chiefly accountable for the groundwater recharge in any area. The VES data showed the depth of the aquifer for good water and the polluted aquifer within the study area.

Potencial para la exploración de aguas subterráneas en la Demarcación Hidrográfica Puyango Catamayo, Ecuador, utilizando un proceso de análisis jerárquico basado en SIG y teledetección

<p>The objective of this study is to apply geographic information systems and remote sensing techniques to map potential areas for groundwater exploration in the Puyango Catamayo hydrographic demarcation, based on free input data. The research’s primary data are a digital elevation model, satellite images, regional geology and rainfall. From the methodological point of view, Multi-Criteria Decision Analysis is applied, using an Analytic Hierarchy Process, which takes as thematic layers the rock permeability, the rainfall, the drainage density, the terrain slope, and the normalized difference vegetation index. Thus, the Groundwater Potential Index is obtained, which is used to map potential areas for groundwater exploration. The resulting map is compared with the existing data of the water point inventory, generated by the Ecuador’s National Institute of Meteorology and Hydrology. Data validation by this method shows that 30% of the water points are located in areas not suitable for groundwater exploration, while 70% are in favorable areas.</p>