15mi/25km northwest of Cairo, at the point where the Nile divides into two arms, is the Nile Dam, which at the end of the 19th C. ranked among the largest dams in the world. It was designed to keep the water level in the Delta uniform throughout the year, so as to obviate the old methods of obtaining water for irrigation and to remove the difficulties of navigation during the three months when the water was at its lowest.A plan for regulating the water supply in the Delta had been put forward by Napoleon, but work on the construction of the dam began only in 1835, in the time of Mohammed Ali. Two competing proposals were put forward by two French engineers, Linantand and Mougel. Linant's plan for constructing a dam farther north, where ground conditions seemed more favorable, was rejected as too costly, and Mougel's plan was preferred. The cost of establishing foundations in the poor soil at the south end of the Delta, however, far exceeded the original estimate, and after more than 131,000 cu. yd/100,000 cu. m of building materials had been consumed the structure was found to be insufficiently secure, and in 1867 the project was abandoned. Finally it was successfully completed by Sir Colin Scott-Moncrieff in 1885-90 at the cost of a further huge expenditure of money. After a burst in the winter of 1909-10 extensive strengthening and rebuilding was required.There are in fact two dams, one over the eastern (Damietta) arm of the Nile the other over the western (Rosetta) arm. The eastern dam is 571yd/522m long and has 71 sluices; the western one is 494yd/ 452m long, with 61 sluices. The Taufiquay and Mahmudiya Canals are spanned by bridges with sluice-gates, at the end of which are spacious basins and passages for shipping, with swing bridges. A further dam, with a lock in the middle for traffic on the Menufiya Canal, runs between the bridges over these canals. The superstructures are in a medieval castellated style. Some 240yd/220 m downstream is the Mohammed Ali Dam, built in 1936-39 to improve irrigation of the land in this area.Between the two arms of the Nile, in an area formerly occupied by fortifications, lies a beautiful landscaped garden laid out by an Englishman named Draper.
A further 12.5mi/20km northeast of the Nile Dam, just north of the provincial capital of Benha (pop. 38,000; production of attar of roses), on the right bank of the Damietta arm of the Nile, is Kom el-Atrib, a shapeless mound of rubble with the remains of ancient Athribis, capital of the 10th nome of Lower Egypt. The area has not yet been systematically investigated, but peasants digging for sebbakh (the rich soil found on ancient sites) have frequently made valuable finds, including a hoard of silver weighing almost 110lb/50kg.