Rivers Naturally Dynamic Systems

Rivers are naturally dynamic systems, with their dynamism and morphology dependent on a variety of factors including climate and tectonics (Korpak, 2010). It is expected then, that a change in climate and tectonics will cause a change to the river channel. Change is therefore a natural and inevitable part of most river systems. Under normal circumstances channel evolution occurs at a slow pace. Human disturbance has, however accelerated the rate of channel modification and this has subsequently impacted the geomorphic and biotic conditions of river systems (Kirstie & Fryirs, 2005).

Over the last 5000 years, disturbance to the fluvial environment can largely be attributed to human modifications. Modifications, such as river engineering and dam construction have altered the rate at which river adjustments occur; subsequently affecting river processes (Kirstie & Fryirs, 2005). More than half of the world’s largest river systems have been regulated by the construction of dams and other river engineering structures. As result, a great deal of research has been conducted in the last 80 years particularly, in order to document the effects of large dams on downstream hydrogeomorphic processes (Hupp, et al., 2009). As necessary as dams are for water supply, irrigation and the reduction of flooding downstream; they have been known to alter the natural flow of rivers and sediment fluxes resulting in channel simplification and a reduction in channel dynamism amongst other things (Alexander, et al., 2012).

In some instances, however, the responses may be irreversible causing a change that has implications on the long term evolutionary trends of the rivers. This in turn has a major impact on how the rivers function presently and how they will develop in the future as their fluvial geomorphology is may be