It should be of a section sufficiently large to admit the craft and steam boats that navigate the Nile, in order to allow access to the interior harbour from all points of Egypt without the inconvenience of trans-shipment. The volume of water to be supplied to the Canal should be sufficient, after allowing for all losses by evaporation, infiltration, and the passage of the locks, for the irrigation of 100,000 feddans (40,000 hectares) during the winter, and 60,000 feddans (24,000 hectares) during the summer. Lastly, the level of the water ought to be maintained at the most favourable height for the natural irrigation of the immense tracts of land in the Isthmus which now remain barren for want of water.
To fulfil these conditions, the receipt of water for the alimentary and irrigating Canal may be established a little above Boulak at Kusr el Nil where the mouth of the Kalidj Zafranieh is, which loses itself to the north of Cairo in the Kalidj Manjeh, the ancient canal of Trajan and Amrou; this canal was partly re-excavated by Mehemet Ali to nearly the same dimensions as those required for the new Canal, and as far as Tell el Zoudieh. By following this track a great economy is already obtained. The Canal also exists farther on as far as Belbeïs, but of smaller dimensions; from Belbeïs, in order to maintain the water at a suitable height, the Canal is made to pass a little more to the East outside the cultivated lands, which will give the Company an opportunity of irrigating and fertilising the bordering tracts at present uncultivated. The canal then proceeds northward as far as Ras el Wady (head of the valley), the Pitoum of the Bible. This course exists of small dimensions, but in several parts of its route it may be turned to account. There will not be great expense in completing the line as far as Lake Timsah; life would thus be given to Cairo by traversing it with a navigable passage, of which it is destitute at present. It would then be necessary, during the time of the low water, to raise the waters of the Nile to a height of three metres by means of steam pumps of 500 horse power; and when the barrage, for which His Highness Mohammed Saïd Pacha has a project, is completed, the reflux will facilitate, with the assistance of steam power, the introduction of the waters of the Nile into the Canal during the six months of the low waters.
The width of the Canal has been fixed at 25 met., measured on the water line at the time of the inundation. This width is sufficient to allow two steam boats to pass each other without inconvenience. Moreover, precautionary measures may be adopted at the entrances of the locks, to prevent collisions, if it should become necessary hereafter.
The depth of the bed of the Canal below the natural surface of the ground in the first part or first dam, as far as the north of Tell el Zondieh, is 7 metres, that is to say, at the level of the low waters of the river, and at 14 metres above the level of low water in the Mediterranean, the fall of the Canal has been fixed at 0,03 in a 1000 metres, in order to secure a speed that shall not exceed O m., 65 per second, and that shall not destroy the banks of the Canal. This arrangement will enable us to supply, during the high waters of the increase, a volume of water for inundating the lands, of 40 to 50 cubic metres per second, or 3,500,000 to 4,000,000 cubic metres per diem. As the inundation has to be continued during 100 days at the most, and each feddan of land ought to have a quantity of 8,400 cubic metres of water, that is to say, two cubic metres of water to each square metre of land, 47,600 feddans might thus be inundated during the 100 days. This quantity of water is given to irrigate the lands and leave upon them the deposits of the river, or the mud which is the manure of the Egyptian soil; but when the lands which the Company will bring into cultivation have been thus improved by two or three complete inundations, there will be a greater disposable quantity of water, and the number of feddans to be brought into cultivation may be augmented.
The lands being thus fertilised and cultivated in two ways; first by inundations as we have just said, afterwards by irrigation during the second part of the year, that is to say, during the low waters; then in order to secure sufficient water for the Canal of which the receipt of water is above the actual low water, steam machines will be employed at the backwater of the barrage.
In order to have during the heats of summer a volume of water that shall be sufficient for the irrigation of 60,000 feddans (24,000 hectares), for the loss by evaporation, and the waste at the last locks of Lake Timsah, there will be required—
| met. cub. | |
|---|---|
| per diem | 1,200,000 |
| For the passage of the locks, the dimensions of which are:— length 54 met. breadth 12 met. mean fall 3 met. | |
| Taking forty passages per diem, the amount will be | 80,000 |
| For evaporation, infiltration and other losses, say 15 per cent. of the serviceable quantity, viz. | 192,000 |
| Total quantity of water to be supplied per diem | 1,472,000 |
The height that the water has to be raised being 2 metres, and a pump of one horse power, raising 60 litres per second for one metre, pumps of five and six horse power will give the required quantity.
We establish therefore steam pumps of five and six horse power at the head of the Canal, as well as a barrage lock with gates both ways, in order to guard against the great risings of the Nile, and to retain the waters of the Canal when the river has subsided.