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Journal of Atmospheric Science Research 2022年第1期5卷 1-10页

作者： Desmond Eteh edirin akpofure Solomon Otobo Department of Geology Niger Delta UniversityWilberforce IslandBayelsa StateNigeria

In watershed hydrology,the morphometric features of a river basin are vital to examine the lower Orashi River basin morphological and hydrological aspects,as well as its flood potential,based on their morphometric characteristics using remotely sensed SRTM data that was analyzed with ArcGIS *** areal,linear,and relief aspects of the Orashi River basin were examined as morphometric *** lower Orashi river basin,according to the findings,has a total size of 625.61 km2 and a perimeter of 307.98 km,with a 5th order river network based on Strahler categorization and a dendritic drainage *** of low drainage density,the drainage texture is very fine,the relief is low,and the slope is very *** ratio,circularity ratio,drainage density aspect ratio,form factor,and stream frequency values indicate that the basin is less elongated and would produce surface runoff for a longer period,while topographic changes show that the river is decreasing with depth in the land area at about the same elevation as a result of sand deposited due to lack of maintenance by dredging,which implies that the basin is morphometrically elevated and sensitive to erosion and *** understand geo-hydrological features and to plan and manage watersheds,morphometric analysis based on geographic information systems and remote sensing techniques is beneficial.

关键词： Morphometric analysis Topographic changes Hydrology Flood GIS

Comparative Assessment of Heavy Metals Pollution in Surface Water in Ikoli River and Epie Creek in Yenagoa Metropolis Using Geographical Information System

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Journal of Geographical Research 2022年第3期5卷 49-62页

作者： Egai Ayibawari O. edirin akpofure Digha Opaminola Nicholas Department of Geology Niger Delta UniversityBayelsa StateNigeria Department of Geography Jasper Boro College of Education SagbamaNigeria

The article is the investigation of heavy metals pollution on surface water in Ikoli River and Epie creek in Yenagoa,metropolis,Bayelsa ***,Cd,Ni,Cr,Fe,Zn was determined and evaluated using Geographical Information *** concentration was below the permissible limit of 3 mg/L in all the locations *** is 77.78%below the limit of WHO 2011 of 0.3 mg/L while other heavy metals examined in Ikoli River and Epie creek are highly *** pollution index for contamination index shows 11.11%sample are high and 88.89%are low while the evaluation of heavy metal index and the pollution index load of the heavy metals contain 22.11%of the sample are low and 77.78%are high which imply the Ikoli River and Epie creek is *** treatment of the result revealed a good correlation between the PCA and HCA,which showed activities of natural processes and man influenced environmental sources of the heavy metals which were mainly products of automobiles exhaust,water tank leakages as well as dumping of radioactive wastes and *** study investigated successfully the potential use of GIS with the help of multiple criteria decision analysis to predict and characterize areas of high pollution,medium,and low pollution in the study area.

关键词： Multivariate treatment GIS Pollution index Anthropogenic Geogenic Ikoli river Epie Creek

Investigation of Soil Aggressiveness towards Underground Fuel Storage Tanks and Water Pipelines in Parts of Bayelsa State, Southern Nigeria

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Engineering（科研） 2012年第11期4卷 761-767页

作者： Kenneth S. Okiongbo edirin akpofure Department of Geology & Physics Niger Delta University Amassoma Nigeria

Structural failure of buried cast/ductile iron water mains and tanks due to corrosion attacks manifests in leaks and is common in most cities throughout Nigeria. The appropriate corrective action, which aims to restore pipe/tank integrity is usually based on proper understanding of the degree of corrosiveness of the soil. In an attempt to determine the potential corrosiveness of the soil to buried metallic structures in Bayelsa State, surface geoelectrical sounding was carried out. Twenty-five Schlumberger Vertical Electrical Soundings (VES) was carried out in the freshwater and meander belt geomorphic zone and the salt water mangrove swamp and estuary complex of the state using a maximum current electrode separation ranging from 200 - 400 m. The data obtained was interpreted by computer iterative modeling using a 1D inversion technique software (1X1D, Interpex, USA). The results show a high degree of heterogeneity, both laterally and vertically, which is typical of a complex depositional environment. Generally, the sub-soil condition within the expected depth of installation of water mains and storage tanks (0 - 10 m) is slightly or moderately aggressive (effective aggressivity) in the freshwater and meander belt geomorphic zone but is very strongly aggressive in the salt water mangrove swamp and estuary complex. Corrosion cells which may lead to significant corrosion failures may occur in the vicinities of strongly aggressive stations. This poses a significant corrosion risk to metallic water pipes and storage tanks. Current day design should therefore either mandate the use of a non-metallic piping product (water mains) or cathodic protection system. Prediction of potential corrosiveness of a soil and thus the application of proper corrosion control measures will not only protect the environment from spillages but will also avert cost of repair, clean-up and replacement.

关键词： Soil Corrosivity Potential Water Pipelines Soil Aggressivity Electrical Resistivity Cathodic Protection

Determination of Aquifer Properties and Groundwater Vulnerability Mapping Using Geoelectric Method in Yenagoa City and Its Environs in Bayelsa State, South South Nigeria

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Journal of Water Resource and Protection 2012年第6期4卷 354-362页

作者： Kenneth S. Okiongbo edirin akpofure Department of Geology & Physics Niger Delta University Wilberforce Island Nigeria

Nineteen Schlumberger vertical electrical soundings (VES) were carried out within and around Yenagoa city, South South Nigeria, using a maximum current electrode separation ranging between 300 - 400 m. The objectives of the study were 1) to evaluate the possibility of mapping Quaternary sediments to infer the geological structure from the electrical interpretation and identify formations that may hold fresh water with low concentration of conducting minerals such as iron 2) to evaluate the vulnerability of the aquifer in the study area. The interpretation of the data collected was by computer assisted iterative interpretation using 1-D inversion technique software (1X1D, Interpex, USA). The results of the interpretation revealed four distinct geoelectric layers. Sounding curve types obtained in the area are mostly of the form ρ1 > ρ2 ρ3 ρ4 (where ρ is the density) but fresh water lenses with low concentration of conducting minerals such as iron were obtained only in locations that exhibit ρ1 > ρ2 ρ3 ρ4 curve types. Depth to the aquifer ranges from 4.5 m in the vicinity of VES 05 to 27.0 m at the vicinity of VES 14. The resistivity of the aquiferous horizon varies between 60 - 2868 Ωm. High transverse resistance values obtained were associated with zones of high transmissivity which agrees with the geology of the Benin Formation (Coastal Plain sands) consisting of fine-medium-coarse sands. The aquifer vulnerability map illustrates the impermeability of the overburden clay layer. Values of >0.5 mhos indicate good protective capacity, while values <0.3 mhos indicate vulnerable zones with probable risk of contamination.

关键词： Geoelectrical Soundings Aquifer Properties Transmissivity Transverse Resistance

Application of 2-D and 3-D Geo-electrical Resistivity Tomography and Geotechnical Soil Evaluation for Engineering Site Investigation:A Case Study of Okerenkoko Primary School,Warri-Southwest,Delta State,Nigeria

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Advances in Geological and Geotechnical Engineering Research 2023年第2期5卷 1-23页

作者： U.Stanley Eze M.edirin Okiotor J.E.Ighodalo B.Jennifer Owonaro A.Saleh Saleh A.Sikiru Jamiu Department of Earth Sciences Federal University of Petroleum ResourcesEffurun330102Nigeria Department of Marine Geology Nigeria Maritime UniversityOkerenkokoWarri SouthDelta State332105Nigeria Department of Physics(Applied Geophysics program) University of BeninBenin CityEdo State300213Nigeria Department of Petroleum Engineering and Geosciences Petroleum Training InstituteEffurun330102Nigeria

In the design of building structures,joint efforts must be decided to resolve the depth of competent layers across the intended site to safeguard the durability of civil engineering structures and to avert the disastrous consequences of structural failure and *** this study,an integrated methodology that employed DC resistivity tomography involving 2-D and 3-D techniques and geotechnical-soil analysis was used to evaluate subsoil conditions for engineering site investigation at Okerenkoko primary school,in the Warri-southwest area of Delta State,to adduce the phenomena responsible for the visible cracks/structural failure observed in the *** results obtained brought to light the geological structure beneath the subsurface,which consists of four geoelectric layers identified as topsoil,dry/lithified upper sandy layer,wet sand(water-saturated)and peat/clay/sandy clayey soil(highly water-saturated).The deeply-seated peat/clay materials(ρ≤20Ωm)were delineated in the study area to the depths of 17.1 m and 19.8 m from 2-D and 3-D tomography respectively.3-D images presented as horizontal depth slices revealed the dominance of very low resistivity materials ***/clay/sandy clay within the fourth,fifth and sixth layers at depths ranging from 8.68-12.5 m,12.5-16.9 m and 16.9-21.9 m *** dominance of mechanically unstable peat/clay/sandy clay layers beneath the subsurface,which are highly mobile in response to volumetric changes,is responsible for the noticeable cracks/failure detected on structures within the study *** observations were validated by a geotechnical test of soil samples in the study ***’s limits of the samples revealed plasticity indices of ***,the soil samples within the depth analyzed were representatives of sandy soil that does not possess any *** methods justifiably provided relevant information on the subsurface geology beneath the study site and should be appropriated as major tools for

关键词： 2D and 3D resistivity tomography Engineering site/structure Atterberg limits Orthogonal lines Radar sounding