"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.