Schweizer S.,Kraftwerke Oberhasli AG |
Tonolla D.,Bundesamt fur Umwelt BAFU |
Vollenweider S.,Wasser Agenda 21 |
Bruder A.,University of Otago
WasserWirtschaft | Year: 2015
This article attempts to summarise the state of the art with respect to the subject hydropeaking.The artificial alteration of the discharge regime causes short-and long-term impacts on the aquatic community in hydropeaking reaches. The application of several indicators allows an estimation of these impacts and a scientific based derivation of appropriate measures. Finally, the actual situation in Switzerland with respect to this topic is described.
Walker D.A.,University of Alaska Fairbanks |
Kuss P.,University of Bern |
Epstein H.E.,University of Virginia |
Kade A.N.,University of Alaska Fairbanks |
And 3 more authors.
Applied Vegetation Science | Year: 2011
Question: How do interactions between the physical environment and biotic properties of vegetation influence the formation of small patterned-ground features along the Arctic bioclimate gradient? Location: At 68° to 78°N: six locations along the Dalton Highway in arctic Alaska and three in Canada (Banks Island, Prince Patrick Island and Ellef Ringnes Island). Methods: We analysed floristic and structural vegetation, biomass and abiotic data (soil chemical and physical parameters, the n-factor [a soil thermal index] and spectral information [NDVI, LAI]) on 147 microhabitat relevés of zonal-patterned-ground features. Using mapping, table analysis (JUICE) and ordination techniques (NMDS). Results: Table analysis using JUICE and the phi-coefficient to identify diagnostic species revealed clear groups of diagnostic plant taxa in four of the five zonal vegetation complexes. Plant communities and zonal complexes were generally well separated in the NMDS ordination. The Alaska and Canada communities were spatially separated in the ordination because of different glacial histories and location in separate floristic provinces, but there was no single controlling environmental gradient. Vegetation structure, particularly that of bryophytes and total biomass, strongly affected thermal properties of the soils. Patterned-ground complexes with the largest thermal differential between the patterned-ground features and the surrounding vegetation exhibited the clearest patterned-ground morphologies. Conclusions: Characterizing the composition and structure of small-scale plant communities growing on distinctive microhabitats within patterned-ground complexes was necessary to understand the biological and physical controls of vegetation on patterned-ground morphology. Coarser-scale vegetation units, referred to here as 'zonal patterned-ground vegetation complexes' (groups of patterned-ground plant communities within zonal landscapes), were useful for landscape and regional-level comparisons and for extrapolation of information collected at plot scales to larger regions. Vegetation maps of the representative landscapes in each subzone were needed for extrapolation. Different growth characteristics of plants growing in northern and southern parts of the gradient have an important effect in stabilizing highly frost-active soils. A conceptual diagram summarizes the interactions between vegetation and patterned-ground morphology along the Arctic climate gradient. © 2011 International Association for Vegetation Science.
Sally Liu L.-J.,Swiss Tropical and Public Health Institute |
Sally Liu L.-J.,University of Basel |
Sally Liu L.-J.,University of Washington |
Tsai M.-Y.,Swiss Tropical and Public Health Institute |
And 17 more authors.
Atmospheric Environment | Year: 2012
Although recent air pollution epidemiologic studies have embraced land-use regression models for estimating outdoor traffic exposure, few have examined the spatio-temporal variability of traffic related pollution over a long term period and the optimal methods to take these factors into account for exposure estimates. We used home outdoor NO2 measurements taken from eight geographically diverse areas to examine spatio-temporal variations, construct, and evaluate models that could best predict the within-city contrasts in observations. Passive NO2 measurements were taken outside of up to 100 residences per area over three seasons in 1993 and 2003 as part of the Swiss cohort study on air pollution and lung and heart disease in adults (SAPALDIA). The spatio-temporal variation of NO2 differed by area and year. Regression models constructed using the annual NO2 means from central monitoring stations and geographic parameters predicted home outdoor NO2 levels better than a dispersion model. However, both the regression and dispersion models underestimated the within-city contrasts of NO2 levels. Our results indicated that the best models should be constructed for individual areas and years, and would use the dispersion estimates as the urban background, geographic information system (GIS) parameters to enhance local characteristics, and temporal and meteorological variables to capture changing local dynamics. Such models would be powerful tools for assessing health effects from long-term exposure to air pollution in a large cohort. © 2011 Elsevier Ltd.
Fischer F.,Bundesamt fur Umwelt BAFU |
Walker U.,Bundesamt fur Umwelt BAFU
Larmbekampfung | Year: 2013
In 2000, about 265,000 persons in Switzerland were affected by harmful or annoying railway noise. Since 2001, an extensive concept of noise remediation has been implemented for their protection which will be finalised in 2015. Mainly it comprises measures regarding rolling stock, realisation of noise barriers, and the installation of noise insulation windows. Thus, approx. 170,000 persons can be protected from excessive railway noise while keeping mostly to the deadlines and costs planned initially. However, the minimum objective concerning the number of people to be protected as established by law is just missed. Therefore additional measures have been planned in Switzerland. The railway sound emissions will be reduced with priority by introducing emission limit values for existing railway freight cars starting from 2020 and by measures to promote quiet rolling stock and a quiet infrastructure. 230 m Franken are available for the implementation of these measures. Due to this noise remediation concept, more than 50,000 persons can be protected additionally against railway noise above the immission limit values.