From Sennar onwards, the canal will continue to draw water from the Blue Nile. The amount of discharge drawn by the Gezira canal is equivalent to a reduction in the water level at Aswan of approximately 5 to 6 centimeters.

In addition to the water drawn by the canal from the Blue Nile for use in Gezira, there will be a slight additional loss due to evaporation, as the surface area of the reservoir in front of the dam will be slightly larger than it would be without the dam. However, this loss is negligible compared to the quantities flowing in the river at that time.

Accordingly, the quantities drawn from the river until approximately November 1st will be limited to what the Gezira canal takes and what is lost through evaporation. By this date, November 1st, the flood will be receding and almost free of silt. Around the aforementioned January, the Sennar reservoir will begin to fill, with the level in front of the reservoir being at least 4.50 meters. The exact date varies depending on the flood. Without experiments, we cannot know at what level it is preferable to start filling the reservoir. The reservoir holds approximately 300 million cubic meters, and thus, to fill the reservoir to a level of 4.50 meters above the river level, it requires approximately 300 million cubic meters. This is sufficient for a discharge of about 10 cubic meters per second, or 864,000 cubic meters per day, for thirty days. It follows that the water drawn from the river from around November 1st for thirty days for use in Gezira is supplied by the Gezira canal, in addition to the aforementioned quantity of 10 cubic meters per second used to fill the Sennar reservoir. Once the reservoir is full, the gates are opened to allow all the water in the river, except what the Gezira needs, to pass. At this time of year, this amounts to 10 cubic meters per second, which decreases to 8 cubic meters per second in January.

In contrast, by February 15th, all the water flowing in the Blue Nile can be allowed to pass to Egypt, with the Gezira canal's needs being met by reducing the level in the Sennar reservoir. By March 1st, the Gezira crops will have reached full maturity in most years.

However, in some exceptional years, they do not mature until April 11th. By this date, the reservoir will be almost empty, with only enough water left for drinking purposes in the area irrigated by the canal until July 11th.

To clarify that irrigating 300,000 feddans of Gezira land in the manner described above does not harm Egypt and does not take water that it cannot do without, it is worth mentioning the impact this project would have on the levels of the Blue Nile if it were operating at full capacity.

The loss due to evaporation during the flood is negligible because the surface area of the reservoir at a level of 4.50 meters does not exceed 30 million square meters. Therefore, the total evaporation loss is less than 10 cubic meters per second, even without considering that evaporation loss would occur on the river's surface area regardless of whether there is a reservoir or not.

The muddy water of the Nile is known to be laden with silt during the flood. Many have expressed their fear that this will lead to the silting up of the reservoir. However, it should not be forgotten that the reservoir will not be filled with silt until the flood recedes and the water becomes clear of silt.

Silt may settle on the riverbed during the flood, but the water level during this period does not rise above the intake level of the canal.

The reservoir area is 30 million cubic meters, and the ground level at the edge of the channel is 4.50 meters. Thus, there will be three meters of water depth on the surface, which decreases to zero at the upstream end and the outer edge of the reservoir.

Let us assume that after several years, the surfaces become covered with silt deposits until only one centimeter of water depth remains. In this case, the total silt deposited would be about 300,000 cubic meters, which is the maximum possible reduction.

However, it is known that heavy sand travels near the riverbed and that only fine silt, which requires very little velocity to remain in suspension, settles on the surfaces.