This paper looks at the terrain and landforms in Anambra State. The research used both primary and secondary data. Primary data used are measurements and direct field observations. Secondary data are from Satellite imageries of the State obtained and analyzed using ArcGIS to show the variations in the terrain and landforms of the study area, and other literature. The geology, topography and soil types of the State were identified, analyzed and mapped. The result shows among other things the relationship between soil type and settlement vis-à-vis population. The slope analysis was also carried out in order to identify areas with steep slopes that limit accessibility and other economic activities. The paper concludes that there is strong influence of the physical environment particularly, the geomorphological factor in determining the spatial pattern of socio-economic activities and development in Anambra State. A disproportionately high percentage of population (71.98%) as well as developmental activities and structures are found on the higher grounds, on the smaller sand – sandstone formations covering 36.42% of the State, leaving a very small percentage of population (28.02%) as well also as developmental activities and structures on the larger flood and other low plains covering 63.58% of the area. These disparities in population distribution as a result of gromorphological factors raises the issues of the need for the government and people of the State to employ new developmental ideas in the area of science and technology to overcome the limitations on the lower surfaces in other to attract settlers and balance population distribution in the State.
Soil erosion in southeastern Nigeria has a high devastating tendency which created a natural geologic hazard is causing loss of arable farm lands, destroying properties and other social infrastructures like pipelines, roads, bridges, over head and underground cables that are being exposed and or washed away by deep gully erosions. Investigations into the underlying factors of soil susceptibility to soil erosion in southeastern Nigeria led to this work. The study areas are the twenty six Local Government Areas within the centre of the zone which are Anaocha, Orumba North, Aguata, Nnewi South and Orumba South in Anambra State; Umunneochi, Bende, Ohafia, Arochukwu and Isuikwuato in Abia State; Afikpo North, Afikpo South, Ivo, Ohaozara and Onicha in Ebonyi State; Aninri, Oji River, Ezeagu, Udi and Awgu in Enugu State, and Idea to North, Idea to South, Okigwe, Orlu, and Orsu in Imo State. The dataset for this research work are from secondary and primary sources. Secondary Data were extracted from other journal publications among others, while primary data were in the form of measurement during field visit, photographs and geophysical soil survey and verification. Descriptive Statistics, Student t-test and Chi-square test analysis were used. The result shows that the soils across the study area generally are predominantly sandy with a mean of fine sand at 28.22% and coarse sand at 43.40%, while the mean of clay and silt are very low, 17.82% and 10.56% respectively. The study concludes that high sand content in the composition of soil in the study area is responsible for high rate of soil erosion in the area and therefore recommends a policy framework from the government of Nigeria that will encourage a paradigm shift from roots and tubers crop production that exposes the soil, to orchard plantation.
<p>Landslides are major hydro-geological and anthropogenic hazards that affect not only the mountains areas but also gullies, mining areas, plateau terrain, river banks, coastal areas, and offshore as undersea slides. Slides occur as a result of ground movement, rock falls, and failure of unstable slopes; sand and debris flow on slopes which can cause lots of damage with direct and indirect impacts on human settlements and physical infrastructures. The study used secondary data that consist of other literature from which the likely triggering factors &#8211; slope angle, land use land cover change (LULCC), aspect, soil texture and type, curvature, drainage density, elevation, lineament density, normalized difference vegetation index (NDVI), normalized difference moisture index (NDMI), geology, topographic wetness index (TWI), geomorphology, rainfall, temperature, wind speed, wind pressure, settlements, rivers and roads construction were extracted, and satellite imageries (SRTM and Landsat 8 OLI-TIRS) data obtained from USGS Earth Explorer, processed and mapped based on the triggering factors using ArcGIS v10.4 and validation visit was made to confirm results. Microsoft excel 2007 was used to compute and assigned weights to the factors while weighted overlay methods in spatial analyst tool of ArcGIS v10.4 were applied in mapping the landslide vulnerable areas in the study area. The study recommended the use of laws to secure and regulate land use activities in the vulnerable areas, educating inhabitants of such areas about the dangers associated with certain land use activities and the need to avoid them, providing alternative means of livelihood that will discourage mining, deforestation, forest fire, and overgrazing, and encourage sustainable resource use and management that will not expose the areas to the triggering factors of landslide.</p><p>&#160;</p><p>Keywords: GIS-Remote Sensing, Assessment, Mapping, Landslide Vulnerability Areas, South East</p>
Almost all parts of the world are threatened by one type of hazards such as soil erosion, flooding, landslide, earthquake, among others. Various types of soil erosion exist which include splash, sheet, rill and gully erosion. Gully erosion has been recognized as an important environmental threat in many parts of the world and remains the world’s biggest problem affecting the lives of man, plants and animals. Gully erosion occurs in various parts of Nigeria under geologic, climatic and soil conditions. The purpose of this study is to look at flood and soil erosion in Nsukka Urban and the erosive activities of the floods along its path ways. The study used both primary and secondary data comprising measurements, oral interviews, photographs, and satellite imageries. This study adopted a mixed method approach in data analysis and representation with ArcGIS version 10.4 software as the major analytical tool used, other calculations were either manually performed or were calculated using Microsoft Excel 2007.The results of the satellite imageries analyzed, were rendered in tables and maps. The soil particles removed from the identified gully site in the study area were calculated and projection of further annual soil loss established, pending when the erosion problem will be addressed. The management, control of flood and soil erosion required to reduce and mitigate against the adverse effect of the gullying were also proffered.
Geomorphological constraints have led to the scarcity of lands in most urban and newly urbanizing areas by reducing land that would have been available for urban expansion. This study aims at looking at the conflict among various types of land related activities over geomorphological space of Anambra State. The data used for this study include primary and secondary data. A mixed-method approach was applied in the analysis and presentation of data, and ArcGIS 10.2 Geographic Information System (GIS) software was also used for the processing of the satellite imageries to determine the rate of land use cover change (LUCC) in the State. Conclusively, people for long are not living in the active flood plains of Idemili-Niger area and other agriculturally endowed lands, but presently, due to increase in population and pressure on land, people have now started buying and sand filling lands in these areas without considering the danger their actions may cause if there is soil failure. Mixed land use type is visibly observed, especially urban related land use like commercial and other socio-cultural land uses. The LUCC analysis shows that there is a reduction in vegetated land and disturbed vegetation, while settlements increased within a period of thirty (30) years. Presently, Anambra State is almost attaining equilibrium in all land use types in the State and if nothing is done to check the trend, there may no longer be available space for vegetation or farmland in the State in the next thirty (30) years.
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