The reservoir is at an elevation of a few feet above the level of -Waladkar. The considerations that led to the determination of the storage level.

Sudd is a vast, almost entirely flat area, such that if the level were to rise one or two feet, the surface area would expand.

Evaporation amounts to hundreds of square kilometers, as can be seen from the attached diagram of land elevations.

It is believed that this area greatly assists the reservoir in performing its function as a flood drain, as the excess water would flow away quickly.

Based on these considerations, the storage level was set at 0.90 meters. Thus, the contents of the reservoir above the average river level on January 1st, which is a suitable date to begin emptying, would be approximately 5 million cubic meters.

All of this water would be drawn from the Nile at a time when it would otherwise flow into the sea. The quantity of this water would be such that, taking evaporation into account during the emptying process, it would flow naturally into the river, reaching Egypt. The amount drawn from the river would far exceed the aforementioned 5 million cubic meters, because the increases in evaporation and transpiration (which are higher than what occurs in the natural river) account for a loss of about 3 million cubic meters during filling, which would otherwise have flowed to the sea.

The following table shows the effect the reservoir would have had in a typical year between 1914-1918.