Lake Nasser was formed as a result of the construction of the High Dam, first closed in 1964 and completed in 1969. It is an elongate body of water some 496 km long, 196 km of which are in Sudan (Lake Nubia), with an average width of 15 km. The water volume in the lake fluctuates greatly, seasonally and from year to year, depending on the net annual volume of water it receives. The highest water-level of 181.3 m (above sea-level) was reached in November 1998, while the lowest level recorded so far was 150.6 m in July 1988.In autumn 1996, water entered the Tushka Spillway for the first time, inundating parts of the Tushka Depression in the Western Desert and creating a huge temporary wetland, which lasted for almost a year. In 1998, the depression was inundated again, creating an even larger wetland. The spillway was built as a safety measure to divert water from behind the High Dam when water exceeded the maximum planned level of 178 m.Seasonal fluctuation in water-level ranges between 5 m and 10 m, with the level being highest in autumn then gradually receding to its lowest level in summer, depending on the amount of water released downstream from the dam, evaporation and the amount received from upstream.Lake Nasser is one of the world’s largest man-made lakes. It is of vital importance for the country, representing Egypt’s main reservoir of fresh water. Lake Nasser and the region adjoining it are seen by some of Egypt’s planners and scientists as the future food-basket for the country. To date, the region is still largely uninhabited by man. The irregular and huge fluctuations in water-level of the lake, poor soils, steep shoreline and inaccessibility are some of the factors that have led to the failure of almost all development efforts along the lake shores.However, this situation is changing rapidly. A huge and ambitious agricultural development project (known as the South Valley or Tushka Project) was initiated in 1996 to reclaim and cultivate several hundred thousand feddans of the Western Desert using water from Lake Nasser. The project involves the installation of the world’s largest pumps, which will carry water from the lake into a 300 km long canal. It was envisaged that the canal would extend all the way to Kharga Oasis in the heart of the Western Desert, and possibly beyond. Work on the project has already progressed substantially and it is planned that the pumps will be operational by 2002.Perhaps one of the most outstanding features of Lake Nasser is the very complex nature of its shoreline, composed of numerous khors, which are, essentially, inundated desert wadis. Most are narrow and meander into the desert for long distances, although some are very wide. There are some 85 major khors, 48 on the eastern side of the lake and 37 on the western side. Allaqi, Kalabsha and Tushka are the three largest khors in Lake Nasser, making up a large part of its total area. Khors support the richest habitats in the lake. Their shallow waters support aquatic flora and provide good breeding grounds for fish; and their often gently sloping shores allow vegetation to grow. Much of the rest of the lake’s shores are steep and rocky with little vegetation. A vast number of islands of various sizes, representing the tops of former hills, are scattered throughout the lake. The number, location and size of these varies greatly with fluctuations in lake-level.The vegetation of the lake banks is largely dominated by Tamarix, which grows in thin bands along the lake’s shoreline, forming dense growths at favourable habitats, usually in khors. Only a few plant species tolerate the continual alternation between flooding and desiccation, which dominates the ecology of the lake shores. When the lake-water recedes, extensive areas of waterlogged land are exposed and rapidly become colonized by dense Tamarix growths. Conversely, when the water-level rises, vast areas of Tamarix bush are inundated, creating swamp-like microhabitats that provide excellent feeding grounds for waterbirds. Dominant aquatic vegetation in the shallow margins of the lake includes water-lilies Najas.Lake Nasser is one of the most important sources of freshwater fish in Egypt, contributing from 25% to 40% of the total inland fisheries production. In 1992, the catch amounted to about 26,000 tonnes, and the number of fishermen was nearly 3,000. Tilapia dominate the fish catch from the lake, contributing about 97–98% of the total. Other commercial fish species include Bagrus bajad and Latus niloticus.
See Box for key species. Lake Nasser has become increasingly important as a wintering area for migratory Palearctic waterbirds. During January and February 1995, over 56,000 waterbirds were counted on about 20% of the lake. Thus, the total number of waterbirds wintering in the entire lake could be in excess of 200,000, making it one of the most important wetlands in Egypt. Most abundant of these were Podiceps nigricollis, Pelecanus onocrotalus, Aythya fuligula, Aythya ferina, Anas clypeata, Anas penelope and Larus ridibundus. Characteristic breeding birds include Alopochen aegyptiacus, Milvus migrans, Burhinus senegalensis, Charadrius pecuarius, Vanellus spinosus, Galerida cristata and Prinia gracilis. This is the only area where Rynchops flavirostris and Motacilla aguimp are known to breed in Egypt. During the summer months there is a significant influx of Mycteria ibis and Pelecanus rufescens into Lake Nasser.
Non-bird biodiversity: The newly established habitats in and around Lake Nasser have become of great importance for several species that have lost most of their habitats elsewhere in Egypt. Reptiles: the lake holds the only remaining populations of Crocodylus niloticus in Egypt, which is found in substantial numbers. Good populations of Varanus niloticus and Trionyx triunguis also inhabit the lake. Mammals: the shores of Lake Nasser probably now support one of the largest populations of Gazella dorcas (VU) in Egypt, a species that is rapidly declining throughout the country.
Pressure/threats to key biodiversity
Wadi Allaqi, declared a Protected Area by Prime Ministerial Decree 945/1989, encompasses a section of Khor Allaqi (part of Lake Nasser).The adoption of inappropriate development strategies and techniques in this unique and vital region, Lake Nasser being the main reservoir of fresh water in Egypt, could be ecologically disastrous. Mismanagement of agricultural pests and over-use of pesticides are potentially very grave problems for wildlife and the environment along the shores of Lake Nasser. Species such as Alopochen aegyptiacus, Galerida cristata and even Gazella dorcas are considered pests around Lake Nasser and have been persecuted by many means, including poisoning. This has led, in many instances, to the killing of vast numbers of other, non-target wildlife. Already, workers, at the South Valley Development Project have been reported in the press as ‘purifying’ newly settled desert areas of ‘vermin’ by poisoning. Victims are reported to be mostly foxes and rodents.Shooting of waterbirds is reported to take place regularly during winter, particularly by visiting European hunters, who take both game and non-game (protected) birds. Illegal hunting, collection and trade in protected species (mainly Crocodylus niloticus, Varanus niloticus and Gazella dorcas) is widespread. Development has increased in the south-eastern part of the lake, as a result of the Tushka Reclamation Project. While this has led to increased disturbance to birds and their habitats at Lake Nasser, new wetland habitats are being created in the desert, benefiting waterbirds.
BirdLife International (2022) Important Bird Areas factsheet: Lake Nasser. Downloaded from
http://www.birdlife.org on 03/12/2022.