Correlating pattern of river discharge with degree of urbanization in sub-catchments of River Asa in Ilorin, Nigeria

Abstract

The study examined the hydrological response pattern of urbanized streams to landuse in sub-catchment areas of River Asa in Ilorin, Nigeria. Data for the study were collected directly from the field over a period of one hydrological year. Rainfall data were collected in each basin using a standard rain gauge of 20cm orifice while basin discharge was computed from a rating equation generated from stage readings on staff gauge mounted at the outlet of each of the study basin. Landuse map of the study area was prepared from satellite imagery obtained from Regional Centre for Training in Aerospace Survey (RECTAS), Obafemi Awolowo University, Ile-Ife. Result obtained indicates that runoff discharge in all the studied basins reflects closely the rainfall pattern with periods of peak discharge coinciding with periods of heavy rainfall. The study further reveals that basin landuse characteristics have profound influence on pattern of river discharge. Based on the result obtained, the study recommends a number of options to efficient basin management in the city. Keywords: Pattern, Discharge, Landuse, Urbanization, Sub-catchment