Guidance on how to identify impacts of hydromorphological degradation on riparian ecosystems. Deliverable 3.4 of REFORM (REstoring rivers FOR effective catchment Management), a collaborative project (large-scale integrating project) funded by the European Commission within the 7th Framework Grant Agreement 282656

The aim of this deliverable is to address the impact of hydromorphological degradation on floodplain and riparian ecosystems, with specific focus on vegetation, fish and invertebrate responses and to provide guidance on how to identify those impacts

Analyse der zeitlichen Entwicklung österreichischer Abflussregime

Abflussregime klassifizieren Fließgewässer nach hydrologischen Merkmalen und Steuerfaktoren. Sie informieren ihre Anwender über das Abflussverhalten im Jahresgang und dienen als Informationsgrundlage oder Entscheidungshilfe. Nach der Europäischen Wasserrahmenrichtlinie und der darin geforderten Herstellung des guten Gewässerzustandes stellt das natürliche Abflussregime eine wichtige flussspezifische Eigenschaft dar. Als Bestandteil der Gewässertypisierung ist daher eine erweiterte Betrachtung von großem Interesse. In dieser Arbeit wurde die zeitliche Entwicklung österreichischer Mittelwasserregime untersucht. Die Bestimmung erfolgte basierend auf einem für österreichische Fließgewässer entwickelten Schema nach Mader et al. (1996). Die Ergebnisse der Typisierung wurden mit dem Saisonalitätsindex verglichen. Es wurden die Regimestabilität, das Trendverhalten, der Einfluss der Zeitreihenlänge und die räumliche Verteilung analysiert. Die ermittelten Regime sowie die Untersuchung nach dem Saisonalitätsindex zeigen ein Muster in der räumlichen Verteilung. Im nordöstlichen Flach- und Hügelland wurden vornehmlich mehrgipfelige pluvio-nivale Regime bestimmt. Der Alpenraum war von drei bestimmenden Aspekten geprägt: Im direkten Einflussbereich vergletscherter Gebiete wurden glaziale Regime, in den nördlichen Alpen eingipfelige nivale Regime und in den südlichen Alpen mehrgipfelige nivale Regime bestimmt. Eine hohe Anzahl war nach dem Schema von Mader et al. (1996) nicht klassifizierbar. Der Alpenhauptkamm wurde als räumlich am stärksten trennendes Element identifiziert. Die Untersuchung der Zeitreihenlänge zeigte, dass stabile Aussagen nur auf der Basis von langjährigen Beobachtungen erzielt werden können. Einflüsse des Klimawandels führten zur Entwicklung hin zu mehrheitlich pluvialen Regimen. Es zeigte sich, dass das untersuchte Typisierungsschema in der derzeitigen Form nur eingeschränkt anwendbar ist. Einige Ansätze zur Adaptierung werden in dieser Arbeit vorgestellt.Flow regimes classify streams according to their hydrological characteristics and influencing factors. As decision making tools flow regimes inform users regarding seasonal flow patterns. Concerning the European Water Framework Directive, which requires a good ecological status of streams, the natural flow regime is an essential river-specific characteristic. As a component of stream classification an extended consideration is of great interest. This thesis aims to analyse the temporal development of Austrian flow regimes based on mean flows. In this context, flow regimes were determined according to a classification approach by Mader et al. (1996), which was developed for Austrian streams. The classification results were compared to the seasonality index. For further investigations, the regime stability, trend, influence of the length of time series and spatial distribution were analysed. Both the determined flow regimes and the results of the seasonality index showed an equal spatial distribution. In the northeast lowland and hilly region especially pluvio-nival regimes with multiple peaks were determined. The Alpine region was characterised by three aspects: Glacial regimes occurred near glaciated regions, while in the northern Alps single peaked nival regimes and in the southern Alps nival regimes with multiple peaks were determined. A high number could not be classified according to the applied classification scheme. The Alpine divide was identified as the strongest spatially separating element. The investigation of the length of the time series showed, that stable results can only be achieved on the basis of long-term observations. The influence of climate change led to more pluvial flow regimes. However, the analysed technique for flow regime classification of Austrian streams in the present form has the disadvantage of limited applicability. Finally some approaches for adaptations are proposed in this work.eingereicht von Katharina LebiedzinskiMit englischer ZusammenfassungUniversität für Bodenkultur Wien, Masterarbeit, 2016(VLID)193571

Impacts of hydromorphological degradation and disturbed sediment dynamics on ecological status. Deliverable 3.1 of REFORM (REstoring rivers FOR effective catchment Management), a collaborative project (large-scale integrating project) funded by the European Commission within the 7th Framework Programme under Grant Agreement 282656.

There is an acknowledged need among stakeholders that new hydromorphological metrics are required to facilitate site remediation and for reporting at national and European levels. Pressure/ impact data were assembled from across Europe. The task was challenging, but useful information was gathered. For each major hydromorphological pressure, the physical response gradients of rivers was summarised as diagnostic diagrams. For the first time we provide evidence that metrics indicating HYMO impact could be developed from monitoring data on fish and macrophytes. For the first time we demonstrate the potential to derive metrics sensitive to fine sediment. We provide evidence that phytobenthos (diatoms), invertebrates and macrophytes have the potential to be used in combined metrics. We found that many existing macroinvertebrate metrics lack specificity and can provide false positive responses to HYMO pressure, suggesting that disentanglement of multi-stressor responses is critical to good diagnosis. There is evidence that aquatic habitats protected under the Habitats Directive will be increasingly vulnerable to hydrological pressures with the changing climate. Frequently, overlooked topics such as sediment quality and groundwater issues ought to supplement or be included in HYMO assessments due to their potential for explaining variance in biological datasets. Land-use data on a spatial scale beyond the reach scale (corridor and catchment) relates to site-specific macroinvertebrate metrics and could be a more robust way of assessing impacts