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unilogo Universität Stuttgart
Institut für Wasser- und Umweltsystemmodellierung - IWS

Abstract

 
   

"An approach to simulate interstitial processes in river beds to meet biological requirements "

The quality of the hyporheic interstitial is described by multifaceted interstitial processes ranging from biological and chemical to physical and morphological processes. Regarding the ecological quality of the hyporheic zone, the dissolved oxygen concentration plays an important role in defining habitat conditions for aquatic indicator species. The oxygen supply rate for hyporheos depends on the gravel matrix of the river bed, the available pore space, deposition of fines into the gravel matrix but also on the oxygen respiration of sediments, organic material and microorganisms. The objective is to use highly sophisticated morphological models to simulate the dynamic processes affecting the gravel matrix and the changing interstitial conditions. As this is not sufficient to describe the ecological quality of the hyporheic zone in terms of habitat preferences, the results have to be linked to additional parameters like temperature, intragravel flow, organic matter, consolidation or permeability to meet biological requirements in terms of the oxygen supply rate. Therefore it is planned to apply a multivariate fuzzy-logical approach giving an imprecise range of dissolved oxygen as response for a certain combination of interstitial describing parameters and is compared to habitat demands of indicator species. As not all occurring interstitial processes can be considered due to their complexity and more than one parameter is decisive in determining the ecological quality of the interstitial, warranting the application of the fuzzy-logical approach. Thus the consideration of both biological and morphological factors can be considered.