1. Strategic planning for restoration and conservation
River restoration projects need to meet many ecological and societal needs. Strategic planning can help to prioritize project goals at both the cantonal and the local scale. This chapter focuses on methods for restoration planning based on models and genetic analyses of various organism groups, which make it possible to reconstruct past and project future colonization processes along rivers. The planning tools discussed here help to determine if currently protected areas are sufficient for the long-term conservation of riparian species.
Sabine Fink and Christoph Scheidegger
2. Riparian eco-hydrodynamic habitat modelling
The availability of habitats for riparian plant species depends on climatic features and soil properties, as well as local river hydro-morphological conditions. To predict suitable habitats for the German tamarisk (Myricaria germanica), a species typical of riparian gravel banks, a large-scale ecological model was linked with a two-dimensional hydrodynamic model. This chapter includes a description of the modelling workflow, together with an application along the Moesa river (GR).
Erik van Rooijen, Davide Vanzo, David Vetsch, Annunziato Siviglia and Sabine Fink
3. Aquatic–terrestrial resource fluxes
This chapter focuses on how rivers and their surrounding landscapes are closely linked, and how resource fluxes between these systems are important for maintaining aquatic and terrestrial biodiversity. It includes a discussion of the export of biomass and specific nutrients, so-called omega-3 PUFAs, as a crucial ecosystem service provided by healthy aquatic systems. Management and restoration projects should take into account this lateral connectivity to improve the success of restoration measures.
Carmen Kowarik and Christopher T. Robinson
4. Channel response to flood diversion into floodplains
Lateral diversion structures in rivers are common measures used to divert parts of the discharge during flood events. The lateral overflow reduces discharge and thus bedload transport capacity in the main channel, resulting in sediment deposition. In this chapter, interactions between lateral discharge and changes in bed level are discussed and illustrated using 1D and 2D modelling approaches, and recommendations for practical model applications are provided. Further, aspects of ecological flooding of retention areas are briefly discussed.
Seline Frei, Eva Gerke, Robert Boes and David Vetsch
5. Aquatic refugia during floods
Refugia are habitats where organisms retreat during a disturbance (e.g. flood, drought). Due to their reduced intensity of physico-chemical conditions, refugia allow organisms to withstand a disturbance. Despite their important ecological role, refugia are poorly studied and often neglected in practical management (e.g. river restoration). Through descriptions of field and laboratory experiments, this chapter illustrates the structure and function of flood refugia and emphasizes the role of the sediment regime in refuge provision.
Cristina Rachelly, Kate Mathers, Volker Weitbrecht, David Vetsch and Christine Weber
6. Simulation of fine sediment deposition on floodplains
Rivers extend beyond the channels that are typically associated with this word. Of particular interest are floodplains, where important hydro- and morphodynamic processes occur as a result of recurrent flooding. Ecologically, they also support the establishment of many species in need of conservation. In this chapter, relevant fine sediment deposition processes are introduced and the numerical tools used to forecast fluvial responses are presented, a topic that is especially relevant for river restoration projects.
Daniel Conde, Carmelo Juez, Davide Vanzo, Christoph Scheidegger, Giovanni De Cesare and David F. Vetsch
7. Impact of substrate clogging on vertical connectivity
Connectivity between the hyporheic zone and the flow is essential for the development of benthos and the reproductive success of spawning fish. The infiltration of fine sediment leads to clogging of the riverbed, reducing porosity and vertical water exchange. Natural clogging cycle is altered by infrastructure and land use. This chapter includes a short review of the process and influencing factors, which are illustrated with some experimental results. These principles are then applied to a selection of common cases.
Romain Dubuis, Robin Schroff and Giovanni De Cesare
8. Grain size distribution and brown trout life history
Using brown trout, a dominant fish in most Swiss rivers, as a study system, the present chapter focuses on age and sex dependencies in habitat preference and local specificity of life-history traits, including female size at maturity and juvenile traits. The importance of taking these aspects into account when developing strategies to mitigate the impacts of substrate modification on ecologically and economically important species in Swiss rivers is emphasized.
Kunio Takatsu, Marcel Michel, Darryl McLennan, Lucas Aerne and Jakob Brodersen
9. Sediment continuity and augmentation measures
Impaired sediment transport can have numerous adverse impacts on the eco-morphodynamics of the riverscape. If well designed, sediment augmentation measures present a promising mitigation approach at different scales. This chapter focuses on flume experiments conducted to investigate the influence of sediment augmentation on morphological bed structures and the persistence of emerging bedforms. It also includes information about design criteria and outcome evaluation methods.
Christian Mörtl, Robin Schroff and Giovanni De Cesare
