...
The flexible distribution can be activated in the global properties, setting VERDELING_FLEX=Flex. For usual calculation: VERDELING_FLEX=. In case of flexibe distribution the following rule is used: if the discharge of Lobith is less than 1700 m3/s, the minimum discharge of the Nederrijn is equal to the discharge according to the fix distribution, the maximum is free. Above 1700 m3/s, the minimum discharge of the hte Nederrijn is flexible, but minimum 30 m3/s. If the discharge is more/less, it is coming 2/3 from the Waal and 1/3 from the IJssel.
...