DAMAGE ASSESSMENT OF 2017 URBAN FLOODING IN THE LOWER BENUE VALLEY: CASE STUDY OF MAKURDI

Abstract

Flood is a major weather related natural disaster in the Lower Benue valley, especially in Makurdi, which has occurred severally with devastating effects. As a result, this study assessed and documents the effects of 2017 flood in Makurdi. This was achieved by assessing the hydroclimatology of the lower Benue valley, flood risk zones, the damages and vulnerability to the 2017 flood in Makurdi. Primary and secondary data were acquired to model the loss due to 2017 flooding. 400 copies of questionnaire were administered to obtain information on the socioeconomic status, vulnerability and damage incurred by the respondents. Precipitation and River discharge data were obtained from the Nigerian Meteorological Agency (NiMet) and the Nigerian Hydrological Service Agency (NiHSA) respectively. Soil data were acquired from the Harmonised World Soil Database. Scanned geology map of Makurdi was acquired from the Nigeria Geological Survey Agency. Landsat 8, OLI and SRTM DEM data were acquired from the USGS Website. Rainfall trend for 1960 – 2017 was analyzed to show their monthly, dry season, wet season and annual patterns which showed a declining trend over the period. Standardized Precipitation Index (SPI) and Precipitation Concentration Index (PCI) were used to determine the flood years and years with high concentration of rainfall, from 1960 to 2017, respectively. Flood hazard zones were mapped and flood risk map developed using fuzzy membership and it was discovered that 62.97%, 27.03% and 10.00% of Makurdi area are low, medium and high hazard zones respectively. Analysis showed that the commercial land use incurred the higher loss between the residential and commercial land uses considered. Loss function was developed for both residential and commercial land uses. 68.3% of the respondents within the study area fell within low income earners with Wurukum showing the highest percentage. 38.8%, 63.8% and 64.3% of respondents had had long stay in the area, past flood experience and flood-hazard awareness respectively. Despite long stay of respondents in the area, high level of past flood experience and awareness, the people of Makurdi still experience high level of flood damage. This may be due to adverse effect of socio-economic indicators such as unemployment and low income earning identified with respondents. This study concluded that the commercial areas were at more risk than the residential areas and should be prioritize in taking any measure that will be directed to curb the menace of flooding in Makurdi.