Author(s): V. Ruiz-Villanueva; M. Stoffel

Linked Author(s): Virginia Ruiz-Villanueva

Keywords: Large wood recruitment; Fuzzy logic; Forested river basins; GIS-based approach

Abstract: The identification of large organic matter (wood) recruitment processes and sources, and the prediction of potential wood delivery are key to support river basin planning and management, both from an ecological point of view and from a flood hazard and risk perspective. River basins are highly dynamic landscape units, where the action of multiple hydrogeomorphic processes, such as mass movements on hillslopes, flows, and floods results in important transformations of the fluvial systems. These transformations are driven by the supply, storage and routing of water, as well as by inorganic and organic loads and other biotic and abiotic interactions. In forested river basins, the role of instream large particulate organic matter (hereafter large wood, defined as pieces of wood >10 cm in diameter and > 1 m in length) is extensively documented and has been linked to higher morphological complexity, and to important and positive river ecosystem functions. However, during high magnitude events, large quantities of wood may be delivered to rivers and transported by floods, thereby enhancing their negative effects (e.g., bridge clogging, scour, backwater effects, flooding). As a river load component, large wood dynamics can be placed in a similar framework to that used for sediment dynamics, where the main processes to be analyzed are those related to wood budgeting, such as large wood contributing sources, recruitment processes, storage, and rate of transfer. This analysis requires an integrated approach covering the whole watershed, looking at the interactions between hillslopes and stream network processes and the forest and riparian forest cover. The proper identification of large wood recruitment processes and sources, and the prediction of potential large wood delivery are key to support river basin planning and management, both from an ecological point of view and from a flood hazard and risk perspective. Unfortunately, and despite recent progress made in the field, systematic assessments of large wood recruitment remain still challenging. Different processes simultaneously recruit and deliver large wood to rivers, which complicates the analysis and hampers the design of effective management measures. In this work, we propose a multi-criteria fuzzy GIS-based approach to deal with the large uncertainty related to the identification and definition of recruitment sources and the resulting large wood delivery estimates.

DOI: https://doi.org/10.3850/978-981-11-2731-1_047-cd

Year: 2018