Characterization of Groundwater Zones and Salinity Assessment in Aquifers of the Campo District, South Cameroon Using the GIS, AHP and PCA Approach.

In the Campo region, groundwater is critical for human consumption and social activity. Groundwater potential is influenced by a region's geological, geophysical, and hydrogeological factors. The major goals of this research are to determine which regions are ideal for productive groundwater drilling and to assess the source of salinity in the study area's coastal aquifers. The groundwater potential map was created using Geographic Information Systems (GIS) and the Hierarchical Analysis Process (AHP). The process of groundwater mineralization was studied using principal component analysis (PCA). Six variables were taken into account, and weights were assigned to them based on their impact on groundwater recharge. In a GIS environment, spatial integration and a combination of theme layers were conducted. Campo's groundwater potential map was divided into four zones: low 14.4% (389.6 km²), moderate 53.3% (1484.5 km²), high 28.3% (783.3 km²), and extremely high 4.1% (110.9 km²). The results of the PCA reveal a mechanism of water-rock interaction, as a result of geological alteration and a salinization process caused by the intrusion of seawater and human activity The source of salinity in groundwater is manmade (agricultural and residential activities) rather than seawater intrusion. Seawater infiltration is not greatly aided by the low lineament density found near the beaches.

Application of Geoelectrical Survey and Time-Lapse Resistivity with Groundwater Data in Delineating a Groundwater Potential Map: A Case Study from Phuket Island, Thailand

Phuket is well-known around the world as a popular tourist destination. Tourism-related population growth depends more on groundwater as the only available source of potable water in Phuket. The proper precautions must be taken to reduce the risk of spending large sums of money in sinking abortive boreholes, and a groundwater potential map would enhance the success rate of future groundwater exploration and exploitation in the study area. Geoelectrical surveys were carried out in this study to collect electrical properties of the subsurface, and the Dar-Zarrouk parameters (DZP) were calculated using the geoelectrical data. The first thematic groundwater potential map was constructed using the interpretation of DZP, while the second thematic groundwater potential map was created using the basis maps of the depth-of-basement and aquifer thickness parameters. Finally, two thematic maps based on geographic information system (GIS) environments were overlaid on a groundwater potential map of Phuket. However, in order to provide a reliable assessment of groundwater potential, time-lapse electrical resistivity imaging was used to confirm the area of the high-potential zone indicated on the map. The map created by this study is aimed to act as a reference for future groundwater exploration and exploitation, preventing water supplies from becoming unsustainable through botched borehole drilling for groundwater production.

GIS-Based Groundwater Potential Assessment in Varied Topographic Areas of Mianyang City, Southwestern China, Using AHP

Mianyang City is located in the varied topographic areas of Sichuan Province in southwestern China and is characterized by a complex geological background. This area is prone to disasters and its varied topography is inconvenient for emergency water storage and supply. Groundwater is essential for alleviating the demand for water and post-disaster emergency water supply in this area. This study applied AHP to integrate remote sensing, geological and hydrological data into GIS for the assessment of groundwater potential, providing a plan for the rational exploitation of groundwater and post-disaster emergency water supply in the area. Nine factors, including the spring calibration related to groundwater, were integrated by AHP after multicollinear checks. As a result, the geology-controlled groundwater potential map was classified into five levels with equal intervals. All the results were validated using borehole data, indicating the following: the areas with yield rates of , 1–20 , and 20–400 accounted for 2.66%, 36.1%, and 39.62%, respectively, whereas the areas with yield rates of 400–4000 and accounted for only 20.88% and 0.75% of the overall area. The flexibility of this quick and efficient method enables its application in other regions with a similar geological background.

Estimation of Dar-Zarrouk parameters and delineation of groundwater potential zones in Karlahi, part of Adamawa Massif, Northeastern Nigeria

Karlahi is largely underlain by granites and migmatites gneiss of the Adamawa Massif. The area lies west of Benue Trough and east of Cameroon volcanic line. The aim of this paper is to determine hydraulic properties of water bearing layer using parameters derived from Dar-Zarrouk equation and characterized them into groundwater potential zones. The resistivity values of the weathered and slightly weathered layers which make up the water bearing layers were added and an average was taken and used as the resistivity of the water bearing formation in computation of Dar-Zarrouk parameters in Karlahi area. The values of resistivity of water bearing formation ranged from 18 to 4963 Ωm with an average resistivity value of 549 Ωm and the thickness of the water bearing formation ranges from 21 to 32 m with an average thickness of 24.5 m. Conductivity values range from 0.000201 to 0.05509 (σ) while the longitudinal conductance range from 0.00483 to 1.2363 Ω-1, the transverse resistance ranges from 407 to 123504.3 Ωm2. The hydraulic conductivity and transmissivity values range from 0.14 to 25.87 m/day and 3.28 to 580.4 m2/day respectively. The longitudinal conductance values in Karlahi area revealed poor to good with an average longitudinal conductance value that is moderate. High transverse resistance values are located in the central and southern part of Karlahi area while low values are located in the eastern part. The spatial distribution map of transmissivity in the area revealed moderate to high transmissivity values in the north central part and a negligible to low transmissivity in southern part, extreme northeastern part. The groundwater potential map of Karlahi area shows negligible to weak potential groundwater zones in SW and SE, moderate potential in the central to northern part of Karlahi area.

A Combined GIS, Remote Sensing And Geophysical Methods For Groundwater Potential Assessment Of Ilora, Oyo Central, Nigeria

This research combined GIS, Remote sensing and geophysical methods for groundwater potential investigation. The study aimed at delineating groundwater potential zones within Ilora, Oyo central, Nigeria. Unavailability of water is a major menace in these area and agricultural activities are suffering as a result. Landsat 8 OLI, ASTER DEM, geological, geophysical, and soil data of the research area were acquired for this study. In order to map groundwater potential of the area, eight thematic layers that influence groundwater occurrences and movement controlling factors such as, geology, elevation, slope, land use land cover (LULC), fault proximity, soil, lineament density, and drainage density were mapped out from the acquired data of the area. The influence of each theme and sub unit/class to groundwater recharge based on previous studies was evaluated using Analytical Hierarchical Process (AHP). The groundwater potential of the area of study was qualitatively classified into five classes, namely; very high, high, moderate, low, and very low which account for 0.3%, 7.8%, 54.8%, 35.6%, and 1.5% of the total area respectively. The results were cross-validated using well data from the area and 89% correlation was achieved. The groundwater potential map generated in this research could be used as a preliminary reference in selecting suitable sites for groundwater resource exploitation in the area in order to ameliorate the current scarcity of water in this region.

Hydrogeological Study in and around Birendranagar Municipality, Surkhet Valley, Mid-Western Nepal

This study is carried out in parts of Surkhet valley, which is one of the Dun valleys (Inner Terai) in Nepal. Tubewell data was collected, dug well inventory with water table measurement was carried out followed by the data analysis leading to the groundwater resource assessment of the study area. The subsurface sediment distribution in the study area consist clay, sand and gravel giving rise to multiple aquifer horizons. Groundwater potential map has been prepared for parts of Surkhet valley and groundwater resource assessment has been carried out for the entire valley. Groundwater potential map was prepared using various thematic layers. Weights and rank were assigned, respectively to each thematic layer and its classes based on their significance for the groundwater occurrence. Most of the study area has medium groundwater potential with low potential at north east and high potential at southeast of the study area. The groundwater resource assessment for the valley, carried out by water balance method and aquifer analysis reveals that there is good groundwater reserve in the valley that can significantly fulfill the water demand in the area if properly exploited with required management of land and water resources in the area.

USING THE GEOGRAPHICAL INFORMATION SYSTEM (GIS) AND REMOTE SENSING TECHNIQUES FOR MAPPING THE GROUNDWATER POTENTIAL ZONES IN KG TIMBANG DAYANG, KOTA BELUD, SABAH

The growing demand for groundwater is due to several reasons such as the increment of population, agriculture, pollution, industrialization and urbanization. This study aims to map the groundwater potential zones by using the Geographical Information System (GIS) with remote sensing techniques in the study area. The study area is located at Kg Timbang Dayang and its surrounding at Kota Belud, Sabah. Eight parameters were studied that affect the occurrence of groundwater in the study area. Those parameters are obtained from existing maps, remote sensing imagery and associated databases. The parameters are; lithology, rainfall distribution, drainage density, lineament density, soil types, elevation, slope steepness and landuse. All these parameters will be used to create the thematic maps based on the given weightage values. Finally, all the thematic maps will be integrated to produce the final groundwater potential map of the study area. The groundwater potential map is classified into three categories which are low, moderate and high.

Assessment of groundwater potentiality using geospatial techniques in Purba Bardhaman district, West Bengal

The word water is life, so life on this planet cannot be possible without water. Water is an essential natural resource that is a surface and groundwater device for human society. The purpose of this research is to assess the groundwater potentiality of the Purba Bardhaman district. All data (primary and secondary) are collected from different sources and analyzed in geographic information system (GIS) software to prepare thematic maps. Different geo-environmental factors like as land use and land cover, soil, lithology, rainfall and distance from the river, etc., can impact on groundwater availability directly or indirectly in Purba Bardhaman area. To identify groundwater potential zones, all these factors are composed into GIS software using multi-criteria decision analysis (MCDA) method. The groundwater potential map has been divided into five classes based on their magnitude as very high, high, medium, low and very low groundwater potential zones. It shows that the areas of very low, low, medium, high and very high groundwater potential zones are 21.54%, 35.80%, 26.47%, 10.13%, 6.06%, respectively, of the total area. Finally, validation is carried out using groundwater depth data collected from 44 drilled tube wells which are located in a scattered manner for whole Purba Bardhaman district which indicates a higher similarity with an area under curve value of 86.8%.

Groundwater Potential Mapping in Relation to Performance of Boreholes in Weathered/Fractured Basement at Afe Babalola University Ado Ekiti Nigeria

This research was carried out with the aim to check the validity and efficiency of the existing groundwater potential map of Afe Babalola University, Ado Ekiti (ABUAD). The performance rating of the drilled boreholes that spread across the institution was used to validate the groundwater potential map produced by Ademilua and Eluwole in 2013. Forty (40) boreholes that were drilled in the institution were evaluated and overlaid on the existing groundwater potential map with their coordinates serially numbered. From the results obtained, it was observed that in locations designated as having good to moderate groundwater yield (potential) on the map, 21 of drilled boreholes were active, 11 were failed/dry boreholes, meanwhile, for the locations designated as having poor groundwater yield, four of drilled boreholes were active while another four were failed/dry boreholes. This result gives a 62.5% performance rating that the existing groundwater potential map can serve as a useful guide for the purpose of site selection for groundwater exploitation but for optimal usage, an improved map is required.