Describing Damage to Stream Modification Projects in Constrained Settings

Abstract

Complex relationships between stream functions and processes make evaluation of stream modification projects difficult. Informed by vague objectives and minimal monitoring data, post-construction project evaluations can often be a subjective attribution of success or failure. This article provides a simple framework to rapidly describe the degree of damage in stream modification projects performed in constrained settings. Based on widely accepted evaluations of physical habitat quality and stream stability, the damage states framework describes a continuum of damage in multiple categories that relate natural stream functions to the often desired state of static equilibrium. Given that channel form is closely related to stream function, it follows that changes to the channel form result in changes in function. The damage states focus on damage to flow hydraulics, sediment transport and channel equilibrium, hydraulic, and geomorphic parameters that describe basic stream functioning and support higher level functions in the modified channel. The damage states can be used in decision making as a systematic method to determine the need for repair and design adjustments.

Long-term temporal trajectories to enhance restoration efficiency and sustainability on large rivers: an interdisciplinary study

“…channelization or damming), aimed at flood control, navigation improvement, expansion of agriculture or hydropower production, have altered the functioning of European large rivers (Brookes, 1988;Petts et al, 1989;Kondolf and Larson, 1995), including aquatic and riparian habitats and biodiversity (Bravard et al, 1986;Amoros and Petts, 1993;Dynesius and Nilsson, 1994). In order to balance these impacts by recovering fluvial processes (Knighton, 1984;Bravard et al, 1986;Naiman et al, 1993Naiman et al, , 1988Corenblit et al, 2007;Hering et al, 2015) and ecosystem services (Loomis et al, 2000;Acuña et al, 2013;Large and D. Eschbach et al: Long-term temporal trajectories of large rivers Gilvear, 2015), an increasing number of restoration projects have been carried out over recent decades (Kondolf and Micheli, 1995;Wohl et al, 2005). In Europe, this trend has been supported by the Water Framework Directive (IKSR-CIPR-ICBR, 2005;WFD, 2000).…”

“…In Europe, this trend has been supported by the Water Framework Directive (IKSR-CIPR-ICBR, 2005;WFD, 2000). Restoration activities progressively target hydromorphological processes and functioning rather than "static" fluvial forms (Jenkinson et al, 2006;Beechie et al, 2010;Arnaud et al, 2015;Jones and Johnson, 2015). Numerous studies have shown that current river functioning results from complex long-term trajectories driven by natural and anthropogenic factors at different spatio-temporal scales (e.g.…”