Flood Protection by Forests in Alpine Watersheds: Lessons Learned from Austrian Case Studies

This chapter highlights the influence of mountain forests on runoff patterns in alpine catchments. We discuss the forest impact at different spatial scales and bridge to the requirements for an integrated natural hazard risk management, which considers forest as an efficient protection measure against floods and other water-related natural hazards. We present results from a wide range of research studies from Austria, which all reveal the runoff-reducing effect of forest vegetation in small and medium-size catchments ( 100 km2), e.g., by reducing surface runoff and delaying interflow, but above all by stabilising slopes and therefore reducing bedload transport during major runoff events. To avoid that forests become a hazard due to enhanced driftwood release, managing of steep riparian slopes for a permanent forest cover (“Dauerbestockung”) is a basic prerequisite. Often protective effects of forests are impaired by man-made impacts like dense forest road networks, insensitive use (e.g., false design of skid roads, compacting machinery, forest operations during adverse weather on wet and saturated soils), and delayed or omitted reforestation and regeneration. Flood risk management in mountain regions should include Ecosystem-based Disaster Risk Reduction measures, with particular emphasis on sustainable and climate change-adapted management of protective forests. This will require integral and catchment-based approaches such as comprehensive management concepts coordinated with spatial planning, and verifiable, practicable and correspondingly adapted legal guidelines as well as appropriate funding of protective forest research to close the existing knowledge gaps

Influence of Canopy Disturbances on Runoff and Landslide Disposition after Heavy Rainfall Events

As protective forests have a major control function on runoff and erosion, they directly affect the risk from hydrogeomorphic processes such as sediment transport processes or debris flows. In this context, future scenarios of climate-related canopy disturbances and their influence on the protective effect remain, however, an unsolved problem. With the individual-based forest landscape and disturbance model iLand, an ensemble of forest landscape simulations was carried out and the effects of future changes in natural disturbance regimes were evaluated. To determine peak runoff, hydrological simulations have been conducted, using the conceptual hydrological model ZEMOKOST as well as the deterministic model GEOtop. Effects of forest disturbances on hillslope stability were investigated, based on a modified Coulomb landslide model. Our results suggest no influence of the disturbance regime on the runoff. The climate-related increase in the frequency of disturbances is not reflected in increased runoff during the period under consideration. Contrary, slope stability analyses indicate that the availability of shallow landslides in steep forested torrent catchments might be decreased by the occurrence of disturbances – especially for a warm and dry climate projection. Canopy disturbances seem to accelerate the adaptation of tree species to future climate conditions, which is likely to be accompanied by a change in root systems away from flat roots that currently predominate in torrential catchments. In terms of managing the protective effect of forests against shallow landslides, such natural disturbances can thus be considered as positive interventions in the existing forest ecosystem by promoting natural succession

Identification of regulatory variants associated with genetic susceptibility to meningococcal disease.

Non-coding genetic variants play an important role in driving susceptibility to complex diseases but their characterization remains challenging. Here, we employed a novel approach to interrogate the genetic risk of such polymorphisms in a more systematic way by targeting specific regulatory regions relevant for the phenotype studied. We applied this method to meningococcal disease susceptibility, using the DNA binding pattern of RELA - a NF-kB subunit, master regulator of the response to infection - under bacterial stimuli in nasopharyngeal epithelial cells. We designed a custom panel to cover these RELA binding sites and used it for targeted sequencing in cases and controls. Variant calling and association analysis were performed followed by validation of candidate polymorphisms by genotyping in three independent cohorts. We identified two new polymorphisms, rs4823231 and rs11913168, showing signs of association with meningococcal disease susceptibility. In addition, using our genomic data as well as publicly available resources, we found evidences for these SNPs to have potential regulatory effects on ATXN10 and LIF genes respectively. The variants and related candidate genes are relevant for infectious diseases and may have important contribution for meningococcal disease pathology. Finally, we described a novel genetic association approach that could be applied to other phenotypes

Hochwasserabschützung in kleinen Einzugsgebieten - Evaluation eines österreichischen Verfahrens in der Schweiz

In den vergangenen Jahren ereigneten sich im Alpenraum vermehrt Hochwasser mit teilweise beträchtlichen Auswirkungen auf Mensch und Umwelt (BEZZOLA & HEGG 2007). Das Interesse an einer möglichst genauen Abschätzung seltener Hochwasser liegt deshalb nahe. Häufig mangelt es aber insbesondere in kleinen Einzugsgebieten (< 10 km2) an geeigneten Niederschlags- und Abflussdaten. Mit der sog. Geländeanleitung von MARKART et al. (2004) besteht ein prozessnaher, in Österreich entwickelter Ansatz, um die Abflussreaktion kleiner Einzugsgebiete bei Starkregenereignissen zu ermitteln und darauf basierend Hochwasserspitzen abzuschätzen. Kern des Verfahrens bildet die Abschätzung des Abflussbeiwertes sowie der Oberflächenrauigkeit im Gelände. Um schließlich zu einer Hochwasserabschätzung zu gelangen, müssen die im Gelände erhobenen Daten mit einem hydrologischen Modell (ZEMOKOST) oder anderen gängigen Ansätzen, z.B. HEC-HMS (SCS 1985), gekoppelt werden. Das Ziel dieser Arbeit war es, die Übertragbarkeit der Geländeanleitung von den Ostalpen auf den schweizerischen Alpenraum zu prüfen. Dazu wurde sie in zwölf schweizerischen Einzugsgebieten angewandt und evaluiert. Die Ergebnisse zeigen, dass der kombinierte Ansatz von Markart/Zemokost insgesamt auch für den schweizerischen Alpenraum geeignet ist. Zusätzlich liefert der vorliegende Aufsatz Vorschläge zur Optimierung der Geländeanleitung und zeigt, wie mit ihr seltene Scheitelabflüsse mit unterschiedlichen Wiederkehrintervallen abgeschätzt werden können

European Guidelines for soil and water bioengineering

Basic principles of soil and water bioengineering; Calculation of soil and water bioengineering stabilisation measures; Soils and water bioengineering methods; Maintenance of soil and water bioengineering structures; Eficience review of soil and water bioengineering method