Wednesday, January 11, 2012
Rising Sea Levels Endanger the Delta by Louise Sarant
The Nile Delta region produces no less than 65 percent of the Egypt’s total agricultural production. It is also part of the country’s most densely populated regions; half of Egypt’s ever expending population lives in this triangle of fertile land, a zone identified as one of the world’s most vulnerable to climate change. Since the Delta’s coastal cities are built at a very low elevation, a mere 0.5 centimeter rise in sea level could plunge cities like Alexandria, Damietta, Rashid and Port Said underwater, displacing millions of inhabitants from their homes and destroying the region’s thriving agriculture. But as the sea nibbles bits of coast, the sea water makes its way underground and invades delta aquifers, posing an immediate threat to crops and yields.
The Nile Delta aquifer is one of the largest groundwater reservoirs in the world. Spread over 6 million acres, it is immensely precious for Egypt. Because sea water is denser than freshwater (one cubic meter of sea water contains 35kg of salt), sea water easily migrates into the aquifer, mixing with the freshwater and corrupting it.
Mosaad Kotb is the head of the Central Laboratory for Agricultural Climate (CLAC), a central laboratory of the Agricultural Research Center. His research unit, which focuses on the implications of climate change on the agricultural sector, installed bathometers — PVC tubes that measure sea level — 6 months ago along the coasts to identify the rate of sea level increases and incursions into groundwater. “We are starting to collect the data now, but we are aware that the results won’t give us the solution on how to mitigate the seeping of saline water into the aquifer in the long term,” Kotb admits.
He explains that the construction of Aswan dam in 1973 deprived the delta of its perennial layer of silt that replenished every year with floods and restored nutrients to the soil. “The soil compacts with time, so this phenomenon combined with the sea level rise is extremely alarming,” he says. Some farmers have taken matters into their own hands by adding an extra 50-centimeter-high sand bed atop their fields to combat rising sea levels, but the results are inconclusive.
“The sand is poor in nutrients, and needs to be sprayed consistently with fertilizers to grow anything,” Kotb explains.