Issues and Application of Linearized Models in Geomorphic Properties of the Ikpa Watershed, Nigeria

Abstract

Though more geomorphological researches are being conducted and previous ideas are being reviewed among geographers and earth scientists, only limited attempts are focused on coupling the relationships among geomorphic attributes on the watersheds in the Humid Tropics. These invariably induced new trends and research directions at diverging scales. This paper is guided by three specific objectives: (1) to employ the Shuttle Radar Topography Mission (SRTM) in deriving the morphologic attributes of the Ikpa Watershed (11) to assess the association and effect of discharge on basin texture, infiltration rate, length of overland flow, and rainfall amount in the Ikpa Watershed, Akwa Ibom State. (111) To describe the relationship between discharge, rainfall amount, and morphologic attributes of the Ikpa Watershed. The watershed was stratified into six sub-basins and data (rainfall and discharge) systematically generated for three months each during the dry and rainy seasons; while the topographic attributes were generated indirectly using SRTM, backup with the four topographic maps. The analysis using multiple linear regression yielded a coefficient of 0.986. Also, the R square value of 0.859 implied that 85.9 percent of the proportion of variation in discharge amount of the Ikpa watershed is accounted for by the four independent variables. A comparison of the computed ANOVA result of 8.469 with the Table value of 7.7086 implied that variation in mean discharge is attributed to the significant effect of basin texture, infiltration rate, length overland flow, and rainfall amount in the Ikpa watershed. The results of the curve estimate for linear, logarithmic, and quadratic equations suggested normal predictive ability and each significant at 0.05 confidence level. This study concluded that the dominances of gully erosion at the upstream and peak-flood discharge at the middle and downstream areas of the watershed are directly influenced by the rainfall events and morphology of the landform.