Yazar "Dekongmen, Benjamin Wullobayi" seçeneğine göre listele

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    Evaluation of groundwater vulnerability using GIS-based DRASTIC model in Greater Monrovia, Montserrado County, Liberia
    (Elsevier, 2023) Koon, Arthur B.; Anornu, Geophrey Kwame; Dekongmen, Benjamin Wullobayi; Sunkari, Emmanuel Daanoba; Agyare, Asante; Gyamfi, Charles
    To ensure that groundwater resources are effectively protected and to improve the quality of life, it is vital to take into consideration all polluting activities that could pose a potential risk to the resource. Groundwater potential research conducted only covers 5% of Montserrado County excluding Greater Monrovia in Liberia. Although this little percentage of groundwater potential research is well known, studies on the vulnerability of the aquifer to pollution are non-existent. Therefore, this study aims at assessing groundwater vulnerability in Greater Monrovia, Mon-tserrado County, Liberia, which will help in optimizing water well drilling activities and pro-tecting the resource. A groundwater vulnerability map for the study area using the Geographic Information System (GIS) based DRASTIC Model was developed and the results suggest that 73% of the study area is very sensitive to pollution, whereas 15% and 11% are moderately and weakly sensitive to pollution, respectively. The key pollution areas identified within the study area were communities of intensive anthropogenic activities and associated geological contamination. The effectiveness of the GIS-based DRASTIC Model in groundwater vulnerability assessment was validated and nearly 60% of the wells contained fluoride concentrations that exceeded the Liberia Water Quality Standard (LWQS) permissible limit. The findings suggest that even though the water table is relatively shallow, future projects in the high and moderate sensitivity zones should be handled carefully. Planners, groundwater managers, and decision-makers may utilize the maps created by this study as a general point of reference for vulnerability when making attempts to safeguard this delicate resource.
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    Flood vulnerability assessment in the Accra Metropolis, southeastern Ghana
    (Springer Heidelberg, 2021) Dekongmen, Benjamin Wullobayi; Kabo-bah, Amos Tiereyangn; Domfeh, Martin Kyereh; Sunkari, Emmanuel Daanoba; Dile, Yihun Taddele; Antwi, Eric Ofosu; Gyimah, Rita Akosua Anima
    Floods in Ghana have become a perennial challenge in the major cities and communities located in low-lying areas. Therefore, cities and communities located in these areas have been classified as potential or natural flood-prone zones. In this study, the Digital Elevation Model (DEM) of the Accra Metropolis was used to assess the drainage density and elevation patterns of the area. The annual population estimation data and flood damages were assessed to understand the damages and population trend. This research focused primarily on the elevation patterns, slope patterns, and drainage density of the Accra Metropolis. Very high drainage density values, which range between 149 and 1117 m/m(2), showed very high runoff converging areas. High drainage density was also found to be in the range of 1117-1702 m/m(2), which defined the area as a high runoff converging point. The medium and low converging points of runoff were also found to be ranging between 1702-2563 m/m(2) and 2563-4070 m/m(2), respectively. About 32% of the study area is covered by natural flood-prone zones, whereas flood-prone zones also covered 33% and frequent flood zones represent 25%. Areas in the Accra Metropolis that fall in the Accraian and Togo series rock types experience high floods. However, the lineament networks (geological structures) that dominate the Dahomeyan series imply that the geological structures in the Dahomeyan series also channel the runoffs into the low-lying areas, thereby contributing to the perennial flooding in the Accra Metropolis.
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    Groundwater recharge estimation and potential recharge mapping in the Afram Plains of Ghana using SWAT and remote sensing techniques
    (Elsevier, 2022) Dekongmen, Benjamin Wullobayi; Anornu, Geophrey Kwame; Kabo-Bah, Amos Tiereyangn; Larbi, Isaac; Sunkari, Emmanuel Daanoba; Dile, Yihun Taddele; Agyare, Asante
    The Afram Plains watershed is one of the major watersheds located at the lower part of the Volta Basin in Ghana with high groundwater usage. Dependency on groundwater is a fast-growing concern in the plains due to the unreliable supply of surface water. This has put the groundwater resources under intense pressure and has necessitated the need for sustainable management of the groundwater resources. This study aimed to estimate the recharge, spatial distribution, and potential recharge zones of groundwater at different scales in the Afram Plains area using the Soil and Water Assessment Tool (SWAT) model and Geography Information System (GIS) approach. The SWAT model was set up (1983-2016), calibrated (1983-1990) and validated (1991-1997) using digital elevation model, soil, land use, climate datasets, and discharge data. The GIS approach was used to produce thematic maps for eight contributing factors; rainfall, elevation, land cover land use, lineaments, drainage, geology, soil and slope for mapping the recharge zones. The results showed that about 1.65% (19.3 mm) of the SWAT simulated mean annual rainfall (1176.9 mm) is converted into groundwater recharge in the watershed. The potential recharge zones categorized as very poor, poor, moderate and high zones have area coverages of 0.58% (20.8 km(2)), 22.4% (798 km(2)), 60.9% (2169 km(2)), and 16.2% (576 km(2)), respectively. The potential recharge zones after validation over boreholes and wells data indicated that the Afram Plains area is dominated by the moderate potential zone.