Proposed fluvial island classification scheme and its use for river restoration

Fluvial islands are present in nearly all natural and regulated rivers. They are important from hydrological, biological, geopolitical and socio‐economic points of view. As ubiquitous as islands are, consideration of islands is relatively absent in most river restoration concepts. The natural river processes that allow for island formation can easily be integrated into typical river classifications. To begin, an island classification scheme is proposed that can become a tool for improved river classifications and restoration projects. In developing an island classification scheme, the objectives are similar to those of previous river classification methods. By observing island characteristics, inductive generalizations may be made about the river's hydrologic and ecologic potential. In river hierarchies, the distinguishing variables used to describe streams were characteristics that could easily be discerned from their appearances, i.e. field‐determinable features. A similar approach is sought for island classification. The distinguishing characteristics of any island may be sorted into three basic categories: those that can be measured from a topographic map or an aerial photograph; those that can be measured in situ at the island and those that can be inferred from either a known history of the island or from the other characteristics of the island. Once all the suitable characteristics were identified, a matrix for island classification was created which can be used to classify island origin and type. The better that the inter‐relationship between island formation, channel processes and watershed processes are understood, the better the natural bio‐physical regime of the river corridor can be identified and incorporated into restoration plans. Copyright © 2010 John Wiley & Sons, Ltd.