Assessing the Potentials for Rainfall Erosion on the Idah-Ankpa Plateau- Nigeria Using Insufficient Data

Oparaku L.A., Iwar R.T., Ogbeh G.O.

In the tropical catchments of most developing countries, soil erosion research endeavours are hampered by sparse, short-term and inadequate weather records. This study attempted to find a part-solution to this problem by assessing the potentials for rainfall erosion on the Idah-Ankpa Plateau of the Anambra Basin, Nigeria, using a point, short-term (14 years) daily rainfall data. The variables computed and considered relevant to the study were the average monthly rainfall amount (mm), the average monthly rainy days, and the average monthly erosivity indices (EI). The EI values were computed using the Lombardi’s method.  The average monthly rainfall amount, rainy days and EI values were analyzed using descriptive statistics. Results show that the months running from May to October are the rainiest and have EI values greater than 1000 MJ.m/ha.hr, and these are the months highly prone to soil erosion wherever devegetation occurs on the landscape. September is the most erosive month with the highest average monthly rainfall amount and EI value of 242.20 mm and 1721.21 MJ.mm/ha.hr respectively. Bush burning and other land preparation practices that strip the land of its surface litter should be controlled between the months of November and March. Deforestation and construction activities occurring between May and October should be regulated.