Disappearing Delta
A: The rate at which the fertile land around the Nile delta erodes on Egypt’s Mediterranean coast is simply astounding. The erosion rate can be estimated to be 100 meters a year in some specific parts. Previously, the currents brought along by the Mediterranean Sea scoured away the land from the coast and replaced it with sediment brought by the river Nile delta. Although, it isn’t happening anymore.
B: Until now, most people blamed the land loss around the delta on the magnificent dams built at the Aswan, in the south of Egypt. It virtually holds back all the sediment that used to flow down the river earlier. Before the construction of dams, the Nile River flowed unabashedly and carried tons of sediment from the north of Africa’s interior and brought it to the Nile delta. This kept happening over 7,000 years and eventually covered over 22,000 square kilometres of a region with several layers of rich silt. Floods every year brought new and nutrient-rich soil into the delta region, substituting whatever soil the sea had washed away. This also dispensed away with the requirement of fertilizers used in all the food-growing areas of Egypt. The creation of the Aswan dam in the 20th century helped provide irrigation and electricity and protected the population of Cairo and the surrounding regions from drought and flooding. Most sediments, with their natural fertilizing features, accumulated on the top of the dam in the southern, on the upper half of Nasser Lake, instead of going down in the delta.
C: But there is more to the story. The sediment-less water from Aswan dams still has silt, and it continues to erode the riverbank and bed on the 800-kilometre way to Cairo. A renowned identity from Smithsonian Institute, known as Daniel Jean Stanley, took notice of the water samples picked from Cairo right before the river joined the delta. These samples showed sediments of over 850 grams per cubic meter of water. This was about half of the sediment weight the river carried earlier before the dam’s construction.
D: Stanley from Marine Geology said that he is ashamed not to have taken notice of the significance of the same before he went through 50-60 studies. There is significant sediment in the delta, but none comes out in the Mediterranean to help plenish the coastline. So, this sediment must get trapped in the delta within.
