Normally the ratio of the discharge between the Nederrijn and the IJssel is given to QWAST, and it is always kept. In this option we allow flexible water distribution between these two Rhine branches. QWAST first tries to meet all the goals, including reaching the correct level of the lakes. If that is reached, then he tries to distribute the water according to the given ratios. Note that by default there is no minimum discharge set by the Nederrijn. The user can set (if necessary) a minimum discharge using the modifier "Aanvoer capaciteiten".

The flexible distribution can be activated in the global properties, setting VERDELING_FLEX=Flex. For usual calculation: VERDELING_FLEX=. In case of flexible distribution the following rule is used:

Lobith  < 1700 m³/s:

• Nederrijn has minimum so much discharge as in the original distribution
• Nederrijn can have as much discharge as necessary
• As last priority, the distribution should be as close as possible to the original one

Lobith > 1700 m³/s: 

• Nederrijn has minimum 30m³/s
• Nederrijn can have as much discharge as necessary
• As last priority, the distribution should be as close as possible to the original one