Groundwater Occurrence and Aquifer Vulnerability Assessments in Coastal Settlements of Araromi Seaside and its Environ, Southwestern Nigeria

2021 ◽  
Author(s):  
Adeatyo F. Folorunso ◽  
Hameed J. AJIBADE ◽  
Hassan Muaz
Keyword(s):  
Aquifer Vulnerability ◽  
Southwestern Nigeria ◽  
Vulnerability Assessments ◽  
Groundwater Occurrence

Groundwater occurrence and aquifer vulnerability assessment of Magodo Area, Lagos, Southwestern Nigeria

2017 ◽  
Vol 10 (5) ◽  
Author(s):  
Moroof O. Oloruntola ◽  
Olateju O. Bayewu ◽  
Ganiyu O. Mosuro ◽  
Adetayo F. Folorunso ◽  
Sefiu O. Ibikunle
Keyword(s):  
Vulnerability Assessment ◽  
Aquifer Vulnerability ◽  
Southwestern Nigeria ◽  
Groundwater Occurrence

scholarly journals Hydrogeophysical investigation of groundwater potential and aquifer vulnerability prediction in basement complex terrain – A case study from Akure, Southwestern Nigeria

2016 ◽  
Vol 63 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Opeyemi J. Akinrinade ◽  
Rasheed B. Adesina
Keyword(s):  
Low Frequency ◽  
Groundwater Potential ◽  
Aquifer Vulnerability ◽  
Hydraulic Gradient ◽  
Protective Capacity ◽  
Real Component ◽  
Southwestern Nigeria ◽  
Reconnaissance Survey ◽  
Transverse Resistance ◽  
Optimum Position

AbstractThis study provides a model for the prediction of groundwater potential and vulnerability of basement aquifers in parts of Akure, Southwestern Nigeria. Hydrogeophysical surveys involving very-low-frequency electromagnetic (VLF-EM) profiling and electrical resistivity (ER) sounding, as well as evaluation of hydraulic gradient using three-point method, were carried out. Ten VLF-EM reconnaissance survey traverses, with lengths ranging from 55 m to 75 m, at 10 m station separation, and 12 vertical electrical sounding (VES) stations were occupied. Two-dimensional map of the filtered real component reveals areas of high conductivity, indicative of linear features that can serve as a reservoir or conduit for fluid flow. Interpretation of the VES results delineates three to four geoelectric units. Two aquifer zones were identified, with resistivity values in the ranges of 20 Ωm to 310 Ωm and 100 Ωm to 3,000 Ω m, respectively. Transverse resistance, longitudinal conductance, coefficient of anisotropy and hydraulic gradient have values ranging from 318.2 Ωm2 to 1,041.8 Ωm2, 0.11 mhos to 0.39 mhos, 1.04 to 1.74 and 0.017 to 0.05, respectively. The results of this study identified two prospective borehole locations and the optimum position to site the proposed septic system, based on the aquifer’s protective capacity and groundwater flow properties.

scholarly journals GROUNDWATER VULNERABILITY ASSESSMENT TO SEAWATER INTRUSION THROUGH GIS - BASED GALDIT METHOD. CASE STUDY: ATALANTI COASTAL AQUIFER, CENTRAL GREECE

2017 ◽  
Vol 50 (2) ◽  
pp. 798 ◽  
Author(s):  
I. Lappas ◽  
A. Kallioras ◽  
F. Pliakas ◽  
Th. Rondogianni
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifer ◽  
Groundwater Resources ◽  
Groundwater Vulnerability ◽  
Aquifer Vulnerability ◽  
Hydrogeological Parameters ◽  
Groundwater Occurrence ◽  
Boundary Parameter ◽  
Groundwater Vulnerability Assessment ◽  
Galdit Method

Groundwater resources assessment has resulted in development of models that help identify the vulnerable zones. This paper presents a GIS-based hydrogeological index, named GALDIT, aiming at the assessment of aquifer vulnerability to seawater intrusion in Atalanti coastal aquifer, Central-Eastern Greece. The above acronym is formed from the most important factors controlling seawater intrusion, that is, four intrinsic hydrogeological parameters, one spatial parameter and one boundary parameter including Groundwater occurrence (aquifer type), Aquifer hydraulic conductivity, depth to groundwater Level above the sea (hydraulic head), Distance from the shore, Impact of seawater intrusion and aquifer’s Thickness. These factors nclude the basic requirements needed to assess the general salinization potential of each hydrogeological setting. Each parameter is evaluated with respect to the other to determine the relative importance of each factor. GALDIT model is described to assess and quantify the significance of vulnerability to seawater intrusion due to excessive groundwater withdrawals. Different thematic maps are prepared for seawater intrusion indicators and overlaid to develop the final vulnerability map. The derived map can be used as a tool for coastal groundwater resources management and areas’ determination of potential saltwater intrusion since the result of GALDIT ndex is classified based on vulnerability rate.

scholarly journals Geohydraulic and vulnerability assessment of tropically weathered and fractured gneissic aquifers using combined electrical resistivity and geostatistical methods

2021 ◽  
Author(s):  
Adedibu Sunny AKINGBOYE
Keyword(s):  
Electrical Resistivity ◽  
Vulnerability Index ◽  
Aquifer Vulnerability ◽  
Fractured Aquifer ◽  
Protective Capacity ◽  
Southwestern Nigeria ◽  
Fractured Bedrock ◽  
Geostatistical Methods ◽  
Lithostratigraphic Units ◽  
Groundwater Yield

Abstract Sustainable potable groundwater supplied by aquifers depends on the protective capacity of the strata overlying the aquifer zones and their thicknesses, as well as the nature of the aquifers and the conduit systems. The poor overburden development of the Araromi area of Akungba-Akoko, in the crystalline basement of southwestern Nigeria, restricts most aquifers to shallow depths. Hence, there is a need to investigate the groundwater quality of the tropically weathered and fractured gneissic aquifers in the area. A combined electrical resistivity tomography (ERT) and Schlumberger vertical electrical sounding (VES) technique were employed to assess the groundwater-yielding potential and vulnerability of the aquifer units. The measured geoelectric parameters (i.e., resistivity and thickness values) at the respective VES surveyed stations were used to compute the geohydraulic parameters, such as aquifer resistivity (\({\rho }_{o}\)), hydraulic conductivity (K), transmissivity (T), porosity (\(\phi\)), permeability (\({\Psi }\)), hydraulic resistance (\({\text{K}}_{R}\)), and longitudinal conductance (S). In addition, regression analysis was employed to establish the correlations between the K and other geohydraulic parameters to achieve the objectives of this study. The subsurface lithostratigraphic units of the studied site were delineated as the motley topsoil, weathered layers, partially weathered/fractured bedrock units, and the fresh bedrock, based on the ERT and the A, H, AK, HA, and KQ curve models. The K model regression-assisted analysis showed that the \({\rho }_{o}\), T, \(\phi\), \({\Psi }\), and S contributed about 81.7%, 3.31%. 96.6%, 100%, and 11.63%, respectively, of the determined K values for the study area. The results, except T and S, have strong high positive correlations with the K of the aquifer units; hence, accounted for the recorded high percentages. The aquifer units in the area were classified as low to moderate groundwater-yielding potential due to the thin overburden, with an average depth of <4 m. However, the deep-weathered and fractured aquifer zones with depths ranging from about 39–55 m could supply high groundwater yield for sustainable exploitation. The estimated S values, i.e., 0.0226–0.1926 mho, for aquifer protective capacity ratings rated the aquifer units in the area as poor/weak to moderately high with extremely high to high aquifer vulnerability index, based on the estimated low Log \({\text{K}}_{R}\) of about 0.01–1.77 years. Hence, intended wells/boreholes in the study area and its environs, as well as any environments with similar geohydraulic and vulnerability characteristics, should be properly constructed to adequately prevent surface and subsurface infiltrating contaminants.

GeoEra HOVER WP7 – Harmonized vulnerability to pollution mapping of the upper aquifer

2020 ◽  
Author(s):  
Andreas Günther ◽  
Stefan Broda ◽  
Klaus Duscher ◽  
Jörg Reichling ◽  
Susanne Schomburgk ◽  
...  
Keyword(s):  
Cross Sections ◽  
Research Area ◽  
Aquifer Vulnerability ◽  
Nitrate Contamination ◽  
Data Sets ◽  
Geological Surveys ◽  
Vulnerability Assessments ◽  
The Status ◽  
Vulnerability Maps ◽  
Upper Aquifer

&lt;p&gt;45 Geological Survey Organisations (GSOs) from 32 European countries developed an ERA-NET Co-Fund Action: Establishing the European Geological Surveys Research Area to deliver a Geological Service for Europe (GeoERA). The GeoEra project HOVER (&lt;strong&gt;H&lt;/strong&gt;ydrogeological processes and Geological settings &lt;strong&gt;over &lt;/strong&gt;Europe controlling dissolved geogenic and anthropogenic elements in groundwater of relevance to human health and the status of dependent ecosystems) aims to gain understanding of the controls on groundwater quality across Europe using the combined expertise and data held by member states. Objectives of the HOVER work package 7 (WP7) are i) review of existing index methods for assessing the vulnerability of the upper aquifer to pollution and selection of the methods to be applied at the pilot and pan-EU scale, ii) compilation and harmonization of input data sets required for assessing vulnerability, and iii) assessment of aquifer vulnerability to pollution (both in maps and 2-d schematic cross sections).&lt;/p&gt;&lt;p&gt;The selected methodology adopted in this project is DRASTIC, which will be applied in ten pilot areas and at the pan-European scale. In karst regions, however, the COP method will be applied in the pilots. This is accompanied with comparisons with the outcomes of existing national vulnerability assessments. It is anticipated to validate the resulting vulnerability maps at the pilot level using available groundwater nitrate contamination information.&lt;/p&gt;

scholarly journals Groundwater Occurrence from Hydrogeomorphological Study of Hard Rock Terrain of Part of Southwestern Nigeria

2018 ◽  
Vol 65 (3) ◽  
pp. 131-143
Author(s):  
Akanbi Olanrewaju Akinfemiwa
Keyword(s):  
Vegetation Index ◽  
Hard Rock ◽  
Geographical Information ◽  
Fracture Density ◽  
River Channels ◽  
Southwestern Nigeria ◽  
Hard Rock Terrain ◽  
Porphyritic Granite ◽  
Groundwater Occurrence ◽  
Gis Methods

Abstract Studies of structural and hydrogeomorphological units (HGU) that are indicators of groundwater occurrence were carried out across an area extent of more than 700 km2 within the hard rock terrain of southwestern Nigeria. These studies integrated geological remote sensing techniques (RST) and geographical information system (GIS) methods to generate thematic maps that included elevation, drainage, lineaments and vegetation index for characterising the attributes of groundwater occurrence across the area. The results revealed that the lineament system is mainly rectilinear with major trends of NNW-SSE and NE-SW on the gneiss, NW-SE and NE-SW on porphyritic granite and NNE-SSW, NW-SE and E-W on migmatite. The discharge zones in the area are the lowland terrains underlain by gneiss and amphibolite. Similarly, variably directional discontinuities that are related to rock contacts are equally laden with groundwater. Conversely, the recharge areas are the high-lying terrains characterised by higher fracture density and underlain by porphyritic granite and migmatite. Additionally, there are evidences of groundwater seepage along the major river channels. Therefore, besides the rock structures, landform is another crucial factor that guides groundwater distribution in the study area.

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