HYDROLOGICAL ASPECTS OF DROUGHT IN LOKOJA, KOGI STATE, NIGERIA

Abstract

Drought existence is not new in Lokoja (Kogi State) of Nigeria, considering the fact that the entire sahel region is susceptible to climatic anomalies. The climatic phenomenon cannot be prevented nor eradicated; rather the effects on humanity can be mitigated. This study was conducted to assess the drought potential of Lokoja using long term rainfall data and then determine the most appropriate technique for the evaluation of drought in the area. The rainfall data was collected from the meteorological department of Lokoja in Kogi State. The study which covered 73- year period (1931-2003) was conducted on Lokoja in Kogi State of Nigeria using the rainfall data. Four major techniques were used for the evaluation; these are Stochastic Component Time Series, Rainfall Anomaly Index, Cumulative Rainfall Information, and the Drought Severity Index based on the quartile range. The results obtained from technique showed that 8 distinct years namely 193, 1935, 1940, 1943, 1951, 1981, 1990, 1999, 1987, 1983 and 1982 experienced severe drought while 1942, more severe drought. Drought threatened the region for many years within the period of the study but that of 1942 was most severe. Rainfall Anomaly Index is the most appropriate technique for the evaluation of drought in Lokoja because it gives the rainfall indices as well as yearly anomalies. It offers more explanations than the other techniques about the severity and impact of drought in the study area.