191 research outputs found
Improved understanding of dynamic water and mass budgets of highâalpine karst systems obtained from studying a wellâdefined catchment area
Large areas of Europe, especially in the Alps, are covered by carbonate rocks and in many alpine regions, karst springs are important sources for drinking water supply. Because of their high variability and heterogeneity, the understanding of the hydrogeological functioning of karst aquifers is of particular importance for their protection and utilisation. Climate change and heavy rainfall events are major challenges in managing alpine karst aquifers which possess an enormous potential for future drinking water supply. In this study, we present research from a highâalpine karst system in the UNESCO Biosphere Reserve GroĂes Walsertal in Austria, which has a clearly defined catchment and is drained by only one spring system. Results show that (a) the investigated system is a highly dynamic karst aquifer with distinct reactions to rainfall events in discharge and electrical conductivity; (b) the estimated transient atmospheric CO2 sink is about 270ât/a; (c) the calculated carbonate rock denudation rate is between 23 and 47âmm/1000a and (d) the rainfallâdischarge behaviour and the internal flow dynamics can be successfully simulated using the modelling package KarstMod. The modelling results indicate the relevance of matrix storage in determining the discharge behaviour of the spring, particularly during lowâflow periods. This research and the consequent results can contribute and initiate a better understanding and management of alpine karst aquifers considering climate change with more heavy rainfall events and also longer dry periods.The investigated karst system contributes to the transient atmospheric CO2 sink with about 270ât/a.
Carbonate denudation rates vary between 23 and 47âmm/1000a.
Rainfallâdischarge modelling results indicate the importance of matrix storage particularly during lowâflow periods.
imageBundesministerium fĂŒr Bildung und Forschung
http://dx.doi.org/10.13039/501100002347FP7 People: MarieâCurie Actions
http://dx.doi.org/10.13039/10001126
Recommended from our members
Fischschutz- und Fischabstiegsanlagen: Bemessung, Gestaltung, Funktionskontrolle
Recommended from our members
Fish Passes: Design, Dimensions, and Monitoring
Many fish species undertake more or less extended migrations as part of their basic behaviour. Amongst the best known examples in Europe are salmon (Salmo salar) and sturgeon (Acipenser sturio), which often swim several thousands of kilometres when returning from the sea to their spawning grounds in rivers. In addition to these long-distance migratory species other fish and invertebrates undertake more or less short-term or small-scale migrations from one part of the river to another at certain phases of their life cycles. Fish passes are of increasing importance for the restoration of free passage for fish and other aquatic species in rivers as such devices are often the only way to make it possible for aquatic fauna to pass obstacles that block their up-river journey. The fish passes thus become key elements for the ecological improvement of running waters. Their efficient functioning is a prerequisite for the restoration of free passage in rivers. However, studies of existing devices have shown that many of them do not function correctly. Therefore, various stakeholders, e.g. engineers, biologists, and administrators have declared great interest in generally valid design criteria and instructions that correspond to the present state-of-the-art of experience and knowledge. The present Guidelines first refer to the underlying ecological basics and discuss the general requirements that must be understood for sensible application of the complex interdisciplinary matters. These general considerations are followed by technical recommendations and advice for the design and evaluation of fish passes as well as by proposals for choosing their hydraulic dimensions correctly and testing the functioning. Fishways can be constructed in a technically utilitarian way or in a manner meant to emulate nature. Bypass channels and fish ramps are among the more natural solutions, while the more technical solutions include conventional pool-type passes, slot passes, fish lifts, hydraulic fish locks, and eel ladders. All these types are dealt with in this book. Furthermore, particular emphasis is laid on the importance of comprehensive monitoring. These Guidelines deal with mitigation of the upstream migration only as data on improvement of downstream passage was scarce at the time of preparation of the first edition, published in German in 1996. Therefore, the complex theme of downstream migration is ony touched on but not developed in depth
DVWK Jahresbericht 1984
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
- âŠ