Minimum ecological water supply

The ecologically justified minimum water supply (Qök) describes the minimum water requirement of the flow-sensitive species macrozoobenthos and/or fish, which is necessary to enable the assessment class 2 (good) for these biological quality components, if other parameters do not contradict it. A long-term undershooting of this outflow value is highly likely to result in a target failure. The Qök values are minimum flow values calculated using LAWA river type-specific minimum water orientation values (MOW in l/s*km2) and the catchment area size of the water sections of natural or significantly modified river OAKs. For the comprehensibility of the calculations, these necessary data bases per river section are listed. In addition, the quasi-natural mean outflows and mean low-water outflows modelled by ArcEGMO are reported for the 1991-2015 time series. This makes it possible to compare the ecologically necessary minimum runoff with the simulated hydrologically possible water supply in low water times and thus - if necessary after comparison with measured MNQ values - to determine the ecologically hydrologically justified minimum runoff (Qmin,ök) as a starting point for the official determination of a WFD-compliant minimum water supply in water law procedures.