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Schumann A.,Ruhr University Bochum | Klein B.,Bundesanstalt fur Gewasserkunde BfG | Schulte M.,Ruhr University Bochum | Petry U.,Niedersachsischer Landesbetrieb fur Wasserwirtschaft
WasserWirtschaft | Year: 2010

The German Standard for reservoirs DIN 19 700 admits retention in dam safety proofs. To characterize the hydrological loads beside the peak, other characteristics as shape and volume of the floods are needed. As statistical return periods of floods are defined by peak flows only, new multiple statistical characteristics are needed to characterize such hydrological loads. An option are Copula functions which characterize bivariate probability distribution functions. Source

Ludewig K.,University of Hamburg | Ludewig K.,Justus Liebig University | Donath T.W.,Justus Liebig University | Donath T.W.,University of Kiel | And 7 more authors.
PLoS ONE | Year: 2015

Background: Floodplain meadows along rivers are semi-natural habitats and depend on regular land use. When used non-intensively, they offer suitable habitats for many plant species including rare ones. Floodplains are hydrologically dynamic ecosystems with both periods of flooding and of dry conditions. In German floodplains, dry periods may increase due to reduced summer precipitation as projected by climate change scenarios. Against this background, the question arises, how the forage quantity and quality of these meadows might change in future. Methods: We report results of two field trials that investigated effects of experimentally reduced summer precipitation on hay quantity and quality of floodplain meadows at the Rhine River (2011-2012) and at two Elbe tributaries (2009-2011). We measured annual yield, the amount of hay biomass, and contents of crude protein, crude fibre, energy, fructan, nitrogen, phosphorus, and potassium. Results: The annual yield decreased under precipitation reduction at the Rhine River. This was due to reduced productivity in the second cut hay at the Rhine River in which, interestingly, the contents of nitrogen and crude protein increased. The first cut at the Rhine River was unaffected by the treatments. At the Elbe tributaries, the annual yield and the hay quantity and quality of both cuts were only marginally affected by the treatments. Conclusion: We conclude that the yield of floodplain meadows may become less reliable in future since the annual yield decreased under precipitation reduction at the Rhine River. However, the first and agriculturally more important cut was almost unaffected by the precipitation reduction, which is probably due to sufficient soil moisture from winter/spring. As long as future water levels of the rivers will not decrease during spring, at least the use of the hay from the first cut of floodplain meadows appears reliable under climate change. © 2015 Ludewig et al. Source

Beuthe M.,Catholic University of Louvain | Jourquin B.,Catholic University of Louvain | Urbain N.,Catholic University of Louvain | Lingemann I.,Bundesanstalt fur Gewasserkunde BfG | Ubbels B.,Panteia NEA
Transportation Research Part D: Transport and Environment | Year: 2014

This paper measures the potential effects of low water levels on the Rhine and Danube navigation in the context of weather variability and a number of climate change scenarios. A long-term multimodal network transport analysis over the period 2005-2050 is presented; it analyzes the impact of changes on the water depth conditions on transport costs and the modal splits between three competing modes. The results indicate that the impact of climate change until 2050 should be limited. © 2013 Elsevier Ltd. Source

Prasse C.,University of California at Berkeley | Ternes T.A.,Bundesanstalt fur Gewasserkunde BfG
Comprehensive Analytical Chemistry | Year: 2016

This chapter provides a general overview of the application of high-resolution Orbitrap mass spectrometry (MS) for the investigation of the transformation of trace organic contaminants in the urban water cycle. Discussed approaches include target, suspect and nontarget screening methodologies. Biodegradation of the antiviral drug penciclovir and transformation of the antiviral drug acyclovir during ozonation are used as case studies to highlight the advantages and main challenges of Orbitrap MS for the elucidation of transformation products. Future research needs are outlined, particularly emphasising the importance of the analysis of highly polar compounds and the application of complementary analytical techniques such as nuclear magnetic resonance for the unambiguous identification of transformation products. © 2016 Elsevier B.V. Source

Ludewig K.,Justus Liebig University | Zelle B.,Justus Liebig University | Eckstein R.L.,Justus Liebig University | Mosner E.,Bundesanstalt fur Gewasserkunde BfG | And 2 more authors.
Seed Science Research | Year: 2014

Floodplain meadow ecosystems are characterized by high water level fluctuations and highly variable soil water potentials. Additionally, climate change scenarios indicate an increasing risk for summer drought along the northern Upper Rhine and the Middle Elbe River, Germany. While adult plants often persist even after strong changes in water availability, early life phases, such as seed germination and seedling establishment, might be more vulnerable. Therefore we tested whether reduced soil water potentials will affect the germination of meadow species and whether the response varies between (1) forbs indicative of wet and dry habitats and (2) seeds originating from sites along the rivers Elbe and Rhine. We exposed seeds of 20 floodplain meadow species with different moisture requirements from five plant families to a water potential gradient ranging from 0 to -Â 1.5Â MPa. While across species germination percentage and synchrony decreased, germination time increased at reduced water potentials. Germination of the species indicative of dry habitats decreased more strongly, was slower and less synchronous at reduced water potentials than that of species indicative of wet habitats. Seeds from sites along the rivers Elbe and Rhine did not differ in their germination characteristics. We propose that species of wet sites follow an all-or-nothing-strategy with fast and synchronous germination to maximize competitive advantages, betting on a high probability of moist conditions for establishment (optimists). In contrast, species from dry sites appear to follow a bet-hedging strategy with a moisture-sensing mechanism for unsuitable conditions (pessimists), resulting in a slower and less synchronous germination. Copyright © Cambridge University Press 2014. Source

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