Impact of Urbanization on Channel Morphology: Some Comments

Abstract

This paper evaluates the dominant concepts that characterize stream channels in urban environments and the basis of the explanation which is predicated on the argument that larger flows beget larger channels. The paper uses observation of the Jakara stream channel in Kano metropolis, Nigeria which indicates that although urbanization has a variety of effects on stream channel morphology, other factors such as nature, age and historical evolution in urban development as well as natural factors such as climate, physiography, geology, vegetation and soils are significant in explaining the observed channel in urban areas. The paper therefore argues that many of the relationships advocated between channel form and urbanization probably are the results of combination of many temporal or geomorphic factors or of local conditions and that the relationship between channel morphology and urbanization observed in Jakara channel did not isolate the process or processes that are responsible for the pattern or a trend for all reaches of the channel. The paper recommends that in view of the significance of urban channels to aesthetics and the stream ecosystem a framework for understanding the dynamics requires continuous research especially in semi arid areas that have few empirical studies.