Nile Delta flooded savanna

• Category: Marine and Oceanic Biomes.
• Geographic Location: Africa.
• Summary: A magnet for millions of migratory birds and once an amazing papyrus reed expanse, the Nile River Delta’s flooded savanna biome is at risk of disappearing entirely under the rising waves of the Mediterranean Sea.

The flooded savanna of the Nile River has historically contained some of the richest soils in the world, that in turn support a rich, biodiverse ecosystem. In modern times, however, dams along the river and the impacts of global warming have been threatening the entire biome. Land continues to slip into the sea, and habitats are being threatened or eradicated by increased salinity, pollution, and haphazard water management.

The fertile soil surrounding the Nile River Delta lends itself to agriculture and draws people to the banks. In Egypt, about half of the nation’s 100 million people have settled within the Nile River Delta region, the generally low-lying area toward the mouth of the Nile where it flows into the Mediterranean Sea. This area is approximately 109 miles (175 kilometers) long and 162 miles (260 kilometers) wide. The flooded savanna, a dominant habitat form here, is considered critically endangered.

In general, the grasslands and wooded shrublands of the delta are flooded during the annual summer rains. This was far more dramatic historically, but since major dams have gone up on the Nile River, most flooding is prevented from taking place—with the result that the characteristic Cyperus papyrus swamps of the wettest areas are mostly gone. The flooded areas that still exist tend to be along the lakes and lagoons that form alongside of the Nile in and around its branching delta. The chief lakes located within the Nile Delta in modern times are El Mannah, El Qatta, Faraontya, Sinnéra, and Sanel Hagar. The main coastal lagoons are Manzala and Miheishar.

The Nile Delta has a mediterranean climate, with temperatures averaging 86 degrees F (30 degrees C) and scant rainfall of 4–8 inches (100–200 millimeters) annually. During the summer, temperatures can rise to 118 degrees F (48 degrees C), and in the winter they dip to 50–66 degrees F (10–19 degrees C).

Biodiversity

The Nile Delta Flooded Savanna biome is home to a variety of localized ecosystems, some of them attracting millions of birds that use the delta as a landing point on their migrations between Europe, Africa, and Asia. The wetland areas of Egypt are a major migration site for the white and black stork, European crane, and white pelican. Endangered species include the red-breasted goose, white-headed duck, and sociable lapwing.

Flooded savannas tend to attract birds of prey, and those that frequent the Nile Delta include various types of eagle, including the short-toed, booted, steppe, and lesser-spotted eagle; steppe and honey buzzard; and levant sparrowhawk. Hundreds of thousands of waterbirds spend the winter months in these flooded savanna areas, including what is thought to be the largest concentration of little gulls and whiskered terns in the world. Other waterbirds include the shoveler, teal, wigeon, garganey, grey heron, pochard, ferruginous duck, Kentish plover, and cormorant. Additionally, the largest breeding population of slender-billed gulls in the Mediterranean is found in the Nile delta.

In the area around Lake Manala is a large population of swamp cats, and elsewhere are otter mongoose, red fox, and the Nile monitor lizard. The delta has one endemic (found nowhere else) frog species, various aquatic reptiles, two types of marine turtles—the endangered loggerhead and green turtles—and the endangered Egyptian tortoise. In the water are sole and striped mullet.

Experts suggest that only 10 percent of waters from the Nile River now flow into the Mediterranean, resulting in many species of fish being prevented from reaching their traditional breeding grounds. In 1972, there were 72 fish species in the delta region, but only 25 remain in the twenty-first century. Only tilapia, which survives in the current environment, has thrived, now making up three-fourths of the total catch. Invasive bird species that threaten the ecosystem by their feeding habits and ability to crowd out native avians include the cattle egret, rock pigeon, mute swan, purple swamp hen, and Eurasian collared-dove.

Like the water systems of Niger and Chad, which were connected to the Nile River in the ancient past, the delta has a rich ecosystem of plants. It is home to at least 552 plant species, eight of which are endemic. Once known for its large papyrus swamps that are now largely absent, the Nile Delta flora now consists predominantly of reeds (Phragmites australis and Typha capensis), and sea rush (Juncus maritimus), with some small sedges.

Hornwort (Ceratophyllum demersum) and pondweeds (Potamogeton crispus and P. pectinatus) grow along the southern shore areas, while Najas pectinata, Eichhornia crassipes, and Cyperus and Juncus spp. grow along lakes and small lagoons. The salt-tolerant Halocnemum spp. and Nitraria retusa grow in marshes along the Mediterranean coast, while Phragmites and Typha grow along riverbanks that were previously bare. Reed swamp, which attracts various waterfowl, grows on the islands along the river between Luxor and Kom Ombo.

Environmental Threats

Throughout the area, the soils of the delta have become poor. The use of chemical fertilizers is on the rise, and runoff from these pollutants, along with wastewater and sewage, is seeping into the sediments of the flooded savanna. Studies have revealed that one species of catfish has begun to accumulate mercury, iron, copper, and other metals within its muscles and liver. One lake has been tainted with the pesticide DDT and other toxins. Oil industries are adding their own pollutants to the delta.

The ecosystems of the flooded savanna also are being threatened by erosion as the sea-level rises. Away from the water, the outer rims of the delta are dry-eroding. High salinity levels are threatening ecosystems that have thrived in the area for centuries. Hunters are shooting and trapping within this fragile ecosystem. As elsewhere, global warming is a constant threat, as air and water temperatures rise toward habitat and species tipping points.

In the late 1980s, scientists around the world became deeply concerned about the ecological situation in the Nile Delta. Daniel J. Stanley, an oceanographer with the Smithsonian Institution, predicted that in 2100, major flooding would occur in the area. Stanley believes that the key flood will occur at a point between the Suez Canal (to the east) and somewhere just to the west of the Nile River, immersing a swath up to 20 miles (32 kilometers) long in the delta.

Although the gradual sinking (subsidence) of the delta in conjunction with rising sea levels has been occurring on the Nile for thousands of years, the process was accelerated by the building of the Aswan Dam, along with a vast network of drainage and irrigation canals. The deposits of sediment and silt from the Nile that used to offset the sinking of the delta have been interrupted by the Aswan Dam, which diverts those silts far upstream, mainly into Lake Nasser.

In 1990, a team of experts from the Smithsonian Institution and National Geographic learned that the northern area of the delta is sinking into the Mediterranean Sea at a rate of 0.2 inch (5 millimeters) each year, further threatening the ecosystem of the flooded savanna. By 2009, both independent agencies and the Egyptian environment minister had issued warnings that suggested that the entire fertile area of the northern delta could disappear if steps were not taken to halt the pace of global warming and climate change.

Significant areas of the Nile Delta, encompassing urban areas, farms, and great areas of the flooded savanna biome, are under threat by Mediterranean Sea waters, which are rising 0.06 inches (1.6 millimeters) a year. About half of this sea level rise is due to global climate change, while the rest is related to subsidence; the latter concern is increased by extraction of groundwater and oil. By the 2020s, about 15 percent of the most fertile farmland in Egypt had been damaged by saltwater due to sea level rise. The United Nations Environment Programme (UNEP) contends that as many as six million people could be displaced in the short term. Also, many of the ecosystems within the flooded savanna biome could be eradicated, and altered migration patterns of birds could create environmental problems of international proportions.

Of note in the 2020s is the completion of the Grand Ethiopian Renaissance Dam (GERD), which is both an environmental and political concern. Ethiopia began construction of the hydroelectric dam on the Blue Nile in 2011 and opened it in 2020, although construction was expected to continue for several years until the upper sections were about 700 yards (640 meters) above sea level. Both Egypt and Sudan objected to Ethiopia creating the dam and reservoir, with researchers predicting negative effects on crop yields, ground and surface water, and soil salinity.

Conservation Efforts

The richest habitats remaining in the Nile Delta region associated with the flooded savanna biome are in the lake and coastal lagoon areas. Over the past several decades, much of these lands have been converted to agricultural fields—and the government generally has been reluctant to declare delta areas protected, as a consequence. Several such areas have gained reserve designation––the Ashtoun el Gamil-Tanee Island Natural Area, devoted chiefly to protecting gravid fish and their young; Lake Burullu, a Ramsar Wetland of International Importance; and the Nile River Islands protected area, which encompasses islands in cities along the Nile including several in the Nile Delta.

To halt erosion, walls of rocks have been placed along the banks of the Nile. Other attempts are focusing on building concrete walls around beaches. The Ministry of Water Resources and Irrigation, the United Nations Development Programme, and the Green Climate Fund have launched a project in stall 43 miles (69 kilometers) of dikes along the shores of the Nile Delta to protect communities from coastal flooding. The most ambitious plan to mitigate the possible loss of the Nile Delta has involved building an entire new river in the desert, via a complex system that would pump water from the Nile and channel it into a fertile valley on somewhat higher ground.

Bibliography

Aziz, Sherien Abdel, Martina Zelenakova, Peter Mesaros, Pavol Purcz, and Hany F. Abd-Elhamid. "Assessing the Potential Impacts of the Grand Ethiopian Renaissance Dam on Water Resources and Soil Salinity in the Nile Delta." Sustainability, vol. 11, no. 24, 2021. MDPI, doi.org/10.3390/su11247050. Accessed 2 Jan. 2025.

Collins, Robert O. The Nile. New Haven, CT: Yale University Press, 2002.

Godana, Bonaya Adhi. Africa’s Shared Water Resources: Legal and Institutional Aspects of the Nile, Niger, and Senegal River Systems. London: F. Pinter, 1985.

Hoke, Franklin. “Nile Delta Losing Ground.” Environment 32, no. 10 (1990).

Mayton, Joseph. “Egyptian Officials, Farmers Debate Effect of Climate Change on Fertile Nile Delta.” Washington Report on Middle East Affairs 28, no. 1 (2009).

Wohl, Ellen E. A World of Rivers: Environment Change on Ten of the World’s Great Rivers. Chicago: University of Chicago Press, 2011.

Yassin, Fatma Elzahraa. "Protecting the Nile Delta." United Nations Egypt, 13 June 2021, egypt.un.org/en/131231-protecting-nile-delta. Accessed 2 Jan. 2025.

Zane, Damian. "River Nile Dam: Why Ethiopia Can't Stop It Being Filled." BBC, 8 July 2021, www.bbc.com/news/world-africa-53432948. Accessed 2 Jan. 2025.