Dimensional Basin Morphometry and Discharge in the Coastal Plains Sands of Ikpa River, Akwa Ibom State, Nigeria

Abstract

This article investigates the relationship between discharge and dimensional morphometry in Ikpa River Basin. Five-dimensional morphometric parameters were generated using topographic maps (sheet 322 NE; sheet 322 SE; sheet 323 SW; and sheet 331 NW) with Geographic Information System of the basin area. Six sub-basins were selected using stratified sampling method, gauged and discharge computed for descriptive and multivariate analyses. The descriptive analysis of discharge characteristics using percentages and ranks revealed remarkable variation between dry season 80.45 cubic meters per second representing 31.3 percent and rainy season 128.21 cubic meters per second representing 68.7 percent of the average seasonal discharge. A Linear Regression Model of the effect of stream frequency, basin intensity, relative perimeter, stream length, and basin area on mean total discharge yielded a coefficient of 0.998 representing 99.8 percent of the influence of dimensional morphometric parameters on discharge in Ikpa River Basin. ANOVA was employed for the test of significance at (0.05)5/2 confidence level. The computed F value yielded 79.044 and the F Table value of 19.30. This paper established that discharge in Ikpa River Basin is significantly influenced by stream frequency, basin intensity, relative perimeter, stream length, and basin area. This paper concluded that the prevalent seasonal flooding in the estuarine and erosion in the non-estuarine areas of the basin is associated with the nature of dimensional morphometry. Hence there is need for more studies on relief and shape parameter so as to identify appropriate (structural and non-structural) management options for the fluvio-geomorphologic hazards in the basin area.