The Nile Delta (Arabic: دلتا النيل Delta n-Nīl or simply الدلتا ed-Delta) is the delta formed in Northern Egypt (Lower Egypt) where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Port Said in the east, it covers 240 km (150 mi) of Mediterranean coastline—and is a rich agricultural region. From north to south the delta is approximately 160 km (99 mi) in length. The Delta begins slightly down-river from Cairo. The Nile Delta is an area of the world that lacks the detailed ground truth data and monitoring stations. Despite the economic importance of the Nile Delta, it could be considered as one of the most data-poor regions with respect to sea level rise.
From north to south, the delta is approximately 160 km (99 mi) in length. From west-to-east, it covers some 240 km (150 mi) of coastline. The delta is sometimes divided into sections, with the Nile dividing into two main distributaries, the Damietta and the Rosetta, flowing into the Mediterranean at port cities with the same name. In the past, the delta had several distributaries, but these have been lost due to flood control, silting and changing relief. One such defunct distributary is Wadi Tumilat.
The Suez Canal is located to the east of the delta and enters the coastal Lake Manzala in the north-east of the delta. To the north-west are three other coastal lakes or lagoons: Lake Burullus, Lake Idku and Lake Mariout.
The Nile is considered to be an "arcuate" delta (arc-shaped), as it resembles a triangle or flower when seen from above. The outer edges of the delta are eroding, and some coastal lagoons have seen increasing salinity levels as their connection to the Mediterranean Sea increases. Since the delta no longer receives an annual supply of nutrients and sediments from upstream due to the construction of the Aswan Dam, the soils of the floodplains have become poorer, and large amounts of fertilizers are now used. Topsoil in the delta can be as much as 21 m (70 ft) in depth.
People have lived in the Delta region for thousands of years, and it has been intensively farmed for at least the last five thousand years. The Delta River used to flood on an annual basis, but this ended with the construction of the Aswan Dam.
There are now only two main branches, due to flood control, silting and changing relief: the Damietta (corresponding to the Phatnitic) to the east, and the Rosetta (corresponding to the Bolbitine) in the western part of the Delta.