RAINFALL TRENDS AND OCCURRENCE OF FLOODS IN KATSINA STATE: IMPLICATIONS FOR INFRASTRUCTURAL DEVELOPMENT

Abstract

Increase in extreme weather events such as flooding has become an annual recurring feature in Nigeria, especially the
Northern States. This study examines the recent rainfall trends and occurrence of floods in Katsina State. Annual and
monthly rainfall data for Katsina from the period 1985 to 2014 were used to analyze the rainfall trends of the area. The
standard deviation was then used to determine the rainfall deviation from the normal. The paper focused on the floods event of 2012 and 2013 in the State and the implications for infrastructural development. A total of 404 copies of a questionnaire were administered to flood affected communities in order to obtain information of damages on infrastructures in the area. The Relative Seasonality Index of the rainfall series revealed that the rainfall is in 3 months or less. The 5-year running mean shows annual rainfall below the long-term mean lasted from the beginning of the data up to the late 1990s and above-average afterwards. The linear trend lines also show an increase in rainfall. The recent increase in annual rainfall amount in the study area is as a result of the increase in June, July and August rainfalls which is one of the factors responsible for the frequent occurrences of floods in the months of July and August in the State. Findings also revealed that most of the flood occurrences owe their reasons not only to high torrential rainfall, but also improper physical planning and erection of structures in areas of high risk. The major implication of these finding is that infrastructures built on the perceived decreasing rainfall have to be reviewed. The study recommends that, planning and designing of infrastructures should take into account the recent rainfall trends and occurrences of floods in the area for sustainable development.