Assessment of Rainfall as an Element of Flooding in Makurdi, Benue State, Nigeria

Abstract

The study surveyed a 30 year rainfall data (1987- 2016) as an element of flood in Makurdi. The purpose of the study was to analyse the temporal variations in the annual and monthly amount of rainfall in Makurdi area of Benue State, Nigeria as well as attempt to predict the amount of rainfall expected in the future. The rainfall data had the following statistical value;Mean (1181.91),Median (1173.70), Range (856.50), Standard deviation (209.36), Coefficient of variation (0.18). The confidence interval at 95% confidence level was between 1102.28mm and 1261.55mm. Return periods of amount of rainfall for some of the periods that Makurdi area experienced floods were also analysed and includes; 1151mm- 2years, 1492.8mm- 12years, 1287.8mm- 4 years,1266mm - 3 years, 1000mm- 1 year and 1240.5mm – 2years. Therefore once in every 12years, Makurdi town will have 1492.8mm of rainfall. The model will help to predict the amount of rainfall expected in the coming years and assist the people in Makurdi to prepare adequately for it. The study also compared the rainfall data of past (1987-2001) and present (2002-2016) periodsusing figures and identified that apart from rainfall intensity, other factors like urbanization and land use play major roles in the flooding of the area.