Assessment of Soil Properties for Flood Vulnerability Zones in Parts of Obio/Akpor Local Government Area, Rivers State, Nigeria

This study is aimed at assessing soil properties on flood sensitive areas in parts of Obio-Akpor Local Government Area, Port Harcourt Metropolis, Rivers State, Nigeria. Field studies involved soil sampling while laboratory analysis involved particle size distribution, moisture content determination and hydraulic conductivity estimation. Geotechnical analysis revealed that the soils predominantly composed of silty clay, fine sandy silty clay and silty clayey sands. On average, moisture content and permeability are 27% and 2.8x10-6 cm/sec, and 20.41% and 1.3x10-3 cm/sec in Rumuigbo and Ozuoba areas, respectively. The soil properties were not significantly different from those obtained from one of the control sites. Although the soil characteristics at the control site and flood prone areas were similar, flooding does not occur at control sites because they are located at a higher topography compared with the flood prone areas located on a shallow topography. These results are confirmed by the high annual rainfall (2198.73 mm/hr on average) that occurs on average round the year in Rivers State. The buildings in these flood prone areas were constructed with concrete and blocks which are susceptible to cracking and failure when constantly immersed in water for prolonged time. It is therefore recommended that large sloping gutters be constructed within strategic places in the area in order to properly transport water to the nearby rivers and ensure that dumpsites around flood prone areas are evacuated to prevent contaminated water from recharging the aquifer. © International Journal of Ground Sediment & Water, ©Sun Jichao, The website is http://ijgsw.comze.com