Ecological Evaluation of Reach Scale Channel Configuration for Watershed Management

Abstract

Reach-scale channel configuration (RSCC) such as braided, meandering, wandering or straight channels could be use as target condition in river management of watershed scale. This study aims at revealing relations between hydro-geomorphological RSCC and ecological diversity, and suggests one methods in evaluation of river condition using only aerial photo. The investigation was conducted on the Kizu River located in central Japan, where riverbed degradation and vegetation expansion proceeded after dam construction and sand excavation over a 65-year period. In order to evaluate RSCC, we classified type of aquatic habitat structure as one of the ecological parameters and analysed relations between RSCC and habitat structures/diversity. According to relations RSCC and habitat structures, wandering channel types tended to have higher potential of lentic and lotic habitat quantity and quality than single or braided channel.