Landuse change and sediment yield in an urbanised tropical deltaic catchment in Port Harcourt, South-South of Nigeria

Abstract

River channel blockage due to high siltation is common in most urbanised catchments, leading to frequent flooding experiences. This is the case in the Woji River Basin. This study set out to investigate the changing landuse characteristics in the Woji River Basin and its effect on the river channel dynamics and sediment yield. Channel morphometry was determined from remotely sensed data and correlationship was measured using the Spearman ranks and Pearson's product moment co relational statistics. The result showed high influence of urban processes/landuse change on the river sediment yield, channel discharge regimes and channel morphometry characteristics. Other secondary effects of urbanisation on the river dynamics found include: urban encroachment into the floodplains; deposition of wastes into the river course; and high runoff occasioned by increasing basin surface imperviousness - culminating in downstream flooding events. Treatment of river channel and headstream wetlands protection was among recommendations.