AN INVESTIGATION INTO THE EFFECTS OF IRRIGATION DEVELOPMENT ON SOME CLIMATIC FACTORS IN TWO IRRIGATION SCHEMES IN NIGERIA

Abstract

An analysis of climatic data for two irrigation projects in Nigeria was carried out. The schemes investigated are Itoikin Rice Project (IRP) and Zauro Polder Project (ZPP located in the rain Forest and Sudan Savanna zones of Nigeria respectively.

At IRP, an annual mean rainfall of 1332mm with low variability between the years at coefficient of variation (Cv) of 17% level was recorded. Post0irrigation development relative humidity (RH) records for Itoikin indicate an annual mean 77.9% with a Cv of 1.6%. These results show that irrigation development in this area is associated with unusual scanty rainfalls in the dry months of the year due to large volume of water. There was consistent high relative humidity during the usual irrigation periods. Post-irrigation development maximum and minimum temperature records at Itoikin indicate annual means of 31.6⁰C and 22.6⁰C respectively. All these micro-climatic data affirm the effect of irrigation during the supposedly dry months of the year.

At ZZP, climatic data were largely unavailable, only the data for a few pre-irrigation development years (1974-79) were obtained. These data indicate an annual mean rainfall of 568.4mm and annual mean of 35.1⁰C and 21.3⁰C, respectively at ZZP. These micro-climatic data for ZPP area may be used as baseline for monitoring of the impact of the full blown project when it commences.