Integrated Floodplain Management, Environmental Change, and Geomorphology: Problems and Prospects

Abstract

Recognition of the failure of old perspectives on river management and the need to enhance environmental sustainability has stimulated a new approach to river management over the past couple of decades. The manner that river restoration and integrated management are implemented, however, requires a case study approach that takes into account the influence of historic human impacts to the system, especially engineering. The process of engineering frequently results in an embanked floodplain to reduce the impact of flooding. It is increasingly recognized that floodplain embankment, while usually effective at minimizing flood risk, results in a variety of adverse consequences to the functioning of the river and associated ecosystem health. New, geomorphic-based approaches, which take into account the different modes of adjustment under the framework of integrated management, are now largely seen as the way to move forward. Implementation of such an approach, however, requires a sophisticated understanding of the fluvial system.

Changes in sediment budget and morphology in the floodplains of the braided reach of the lower Yellow River

“…Moreover, floodplains have received considerable attention to date because of the valuable social and ecological functions of these systems, such as flood control, sediment and nutrient retention, recreational opportunities, agricultural production, and wildlife habitat (Pierce & King, 2008), and their land resources have increased in value. To protect these valuable resources from flood inundation, many river control works on both sides of the main channel have been built, which considerably limit the inundation space of large floods and lead to an uneven distribution of sediment deposition areas and a more complex riverbed form (Hudson & Middelkoop, 2015;Parker, 1995;Wu, Wang, Ma, & Zhang, 2005), especially along the lower Yellow River (LYR), which is a typical case of this kind. Owing to the characteristics of "insufficient runoff and excessive sediment loads lacking sufficient coordination" (Hu, Chen, Guo, & Yan, 2017;Wang, Zhou, & Li, 2006), long-term deposition has occurred in the main channel, resulting in the continuous evolution of the river morphology and the well-known phenomenon of a "secondary suspended river" in local reaches.…”