It is understood that these two rivers are very silty during the flood season, but the White Nile is clear, and the silt causes sedimentation.

Therefore, it is not possible to build a regulator on it during the flood season.

In fact, the rapid rise of the Blue Nile leads to a great natural accumulation of water in the White Nile. When the Blue Nile begins to recede, the obstacles to this accumulated water are removed, and thus the flow of the White Nile increases. By building a reservoir dam of sufficient capacity, it becomes possible to store all the accumulated water and all the water that flows into it. When the flood reaches its peak, the discharge of the White Nile is low, but it increases greatly when the Blue Nile begins to recede.

Therefore, a dam on the White Nile, even if it greatly reduces the peak of the flood, will cause a severe shortage in the duration of the flood. The high levels in the Egyptian region will not last long at their maximum. The peak of the flood curve will be flattened, meaning a decrease in the event of its flow to the Egyptian region (see Chapter Four on the operation of regulators).

To achieve the maximum benefit expected from this work, it must be built at the confluence of the White and Blue Nile. There are three suitable locations for such a regulator in terms of construction: Khartoum, Jabal Awliya, and Al-Gebelain. As for the Al-Gebelain point, located 200 kilometers from the confluence, it is too far away to control the accumulated water in the White Nile, as this accumulation in a year of severe flooding does not extend in the White Nile south of 150 kilometers.

Add to this that the slope of the water in the White Nile is fast, and in the Blue Nile it is slow, so that the change in the Blue Nile is not apparent until a short time before it occurs. The flow from Roseires to Khartoum during the peak of the floods takes three days, while it takes thirteen days to travel from Al-Gebelain to Khartoum. This point becomes more important when we consider the issue of regulating the White Nile.

Whatever the proposed project for water storage in the upper reaches of the White Nile, it must be complemented by the construction of a regulating bridge near the confluence of the White and Blue Nile to benefit from this water. The best location for this work is at Jabal Awliya, 20 kilometers south of Khartoum.

In conclusion, building a dam at a suitable point near the confluence of the White and Blue Nile is a cornerstone of any project intended to comprehensively control the Nile's discharge. Such a dam would help protect Egypt from the dangers of high floods and provide it with stored water during periods of low discharge.

The purpose here is not to discuss the design or construction details of the dam, but our discussion is limited to issues related to water discharge.

The design of the dam has undergone basic modifications since the initial proposals were made in 1912. What was then merely an earthen embankment has since been developed into a continuous structure across the valley, raising the level of stored water for storage and flood protection higher than originally proposed, to a degree that allows for the storage of an additional 200 million cubic meters of water for the summer and also allows for doubling the degree of flood protection.

The cost of construction is estimated at 10.00 Egyptian pounds.