The influence of bioregulation on water quality of the prefiltered stagnant water reservoir Eekhoven (Flanders, Belgium)

When the creation of a new safety reservoir for the drinking water supply of the Antwerp region was envisaged it was decided that a number of actions would be undertaken to create a favourable environment for bioregulation (biomanipulation). These were: the use of boulders for the side-walls instead of concrete or bitumen, first flooding with a shallow layer of water to leach out the minerals contained in the upper clay layer of the bottom floor, introduction of freshwater mussels and of a number of fish species (bitterlings, predators such as eels, pike-perch and pike) and of submerged, floating-leaved and emergent aquatic plant species. This paper is a report on the results of these bioregulation measures obtained so far. (C) 1998 IAWQ. Published by Elsevier Science Ltd.