Egypt sits upon the world’s largest fossil aquifer system. But can the government exploit the Nubian Sandstone Aquifer System to relieve stress on the Nile and guarantee water for Egypt’s citizens?
“The Nile is the main source of water in Egypt, with a dependency ratio of 97 percent,” said Egyptian President Abdul Fattah el-Sisi, summing up Egypt’s water crisis during the Nile Basin Conference last month.
“In view of the other limited water resources and the natural population growth in Egypt, per capita water use has rapidly receded to nearly 640 cubic meters per annum.”
The Grand Ethiopian Renaissance Dam (GERD) is a threat to Egypt’s riparian water rights in the Nile. With the start of the filling of the GERD Lake, Egypt will lose 10 percent of its annual share of 55.5 billion cubic meters, causing an estimated 1 million acres of agricultural erosion.
“The Western Desert floats on an aquifer of fresh groundwater,” says engineer Safi Eyiad, a researcher in desert agriculture. “The Western Desert covers part of the Nubian Sandstone Aquifer System (NSAS) which is of an estimated area of about 2.4 million square kilometers and 40,000 billion cubic meters of water.
Spanning over the four countries of Egypt, Libya, Chad and Sudan, the NSAS is the world’s largest-known fossil groundwater aquifer. It covers an area of 670,000 square kilometers in the Western Desert, 130,000 square kilometers in the Eastern Desert and 50,000 square kilometers in Sinai,” says Eyiad, outlining the dimensions of Egypt’s greatest aquifer for the future.
There are two types of groundwater in Egypt, according to Eyiad. The first is non-renewable at a depth of 900-1200 meters below sea level, like the Nubian Sandstone water. The salinity level in this type ranges from 200 to 1,000 parts per million (ppm), which makes it potable.
The salinity level in the Mahra Aquifer that stretches from West Nile is relatively high (2,000-10,000 ppm). This saltier aquifer can be used for fishing and cultivation of crops and trees, activities that withstand high salinity levels.
It is difficult, however, to extract deep non-renewable water, especially the water between rock spaces under the surface. Moreover, the available extraction technology is still not cost-effective. Nonetheless, the NSAS’ water level in some places is high enough to be easily extracted through boreholes.
“The second type is renewable surface water with a very high salinity ratio and at depths of 40 to 50 meters below sea level,” says Eyiad. “Its primary source is seasonal rains, and most desert people use it in irrigating olive trees, palms and halophytes. In the government ‘One and a Half Million Acres’ project, 88 percent of the land is annually irrigated by an estimated two billion cubic meters of groundwater taken all from the NSAS, while the rest is irrigated from the Nile.
Egypt is a state with limited water resources. While its water needs are becoming increasingly acute due to population growth, per capita water use has declined during the past 200 years from 20,000 to about 600 cubic meters a year. Groundwater contributes 6.7 billion cubic meters of the total water resources in Egypt.”
Director of Village Development in Matrouh Governorate, agrarian Hussein Sawi, says the NSAS is the most important source of groundwater in Egypt. Sawi told Correspondents that Egypt shares this source with its Southern neighbours in Sudan and Chad, as well as with its Eastern neighbours in Libya. It extends from southern to northern Egypt up to a distance of approximately 100 kilometers away from the coast of the Mediterranean.
“The groundwater that can be extracted in the northern region is with very high salinity levels that exceed 40,000 ppm, and is only suitable for cultivating olive, palms, pomegranates and jojoba trees – used in the production of cosmetics,” says Sawi. “No crops that require large amounts of water can be cultivated, such as wheat, rice, vegetables of all kinds, alfalfa, and fruits, like guava, plum, mango, oranges and bananas.
Head of Agriculture in Matrouh Governorate, engineer Hussein Snini, argues that the water crisis will force Egypt to extract groundwater very carefully from the NSAS, while implementing awareness programmes for farmers. These programmes would seek to improve management of water consumption, waste prevention, and mainstream drip irrigation, as well as prevent surface irrigation that contributes to wasted water and increased land salinity.
“The Siwa Oasis, though far from the Nile, has a groundwater flow that exceeds its needs because it is a low area that has many springs of arable groundwater,” he says. “This has driven people to cultivate 30,000-50,000 acres of vegetables using surface irrigation, but it will inevitably lead to water depletion and transform the oasis into lakes of saline water resulting from agricultural drainage,” says Snini.
He adds that groundwater is suitable for irrigation of all crops, depending on the nature of the soil, provided that the salinity level is not higher than 4,000 ppm. Groundwater with higher salinity levels wastes land.
Egypt has several aquifers of renewable and non-renewable groundwater, mainly the NSAS. The annual recharge of groundwater at the NSAS in the Eastern Desert is estimated at nearly 300 million cubic meters at a salinity level of 2,000 ppm, while an aquifer with an estimated 360 billion cubic meters of water and an annual recharge of approximately five million cubic meters lies below the Sinai Peninsula.