| Qattara Depression | |
|---|---|
  Qattara Depression Location of the Qattara Depression in Egypt | |
| Location | Egypt in theMatruh Governorate |
| Coordinates | 30°0′N27°30′E / 30.000°N 27.500°E /30.000; 27.500 |
| Type | Endorheic basin |
| Primary inflows | Groundwater |
| Primary outflows | Evaporation |
| Basin countries | Egypt |
| Max. length | 300 km (190 mi) |
| Max. width | 135 km (84 mi) |
| Surface area | 19,605 km2 (7,570 sq mi) |
| Average depth | −60 m (−200 ft) |
| Max. depth | −133 m (−436 ft) |
| Water volume | 1,213 km3 (291 cu mi) |
| Settlements | Qara Oasis |
| References | [1][2] |
TheQattara Depression (Arabic:منخفض القطارة,romanized: Munḫafaḍ al-Qaṭṭārah) is adepression in northwestern Egypt, specifically in theMatruh Governorate. The depression is part of theWestern Desert of Egypt.
The Qattara Depression lies below sea level, and its bottom is covered withsalt pans,sand dunes, andsalt marshes. The depression extends between the latitudes of 28°35' and 30°25' north and the longitudes of 26°20' and 29°02' east.[3]
The Qattara Depression was created by the interplay of salt weathering and wind erosion. Some 20 kilometres (10 mi) west of the depression lie the oases ofSiwa in Egypt andJaghbub in Libya in smaller but similar depressions.
The Qattara Depression contains the second lowest point in Africa at an elevation of 133 metres (436 ft) below sea level, the lowest point beingLake Assal in Djibouti. The depression covers about 19,605 square kilometres (7,570 sq mi), a size comparable withLake Ontario or twice as large as Lebanon. Due to its size and proximity to the shores of theMediterranean Sea, studies have been made proposing to flood the area for various usages, such as the potential to generatehydroelectricity there.
The Qattara Depression has the shape of a teardrop, with its point facing east and the broad deep area facing southwest. The northern side of the depression is characterised by steep escarpments up to 280 m (920 ft) high, marking the edge of the adjacent El Diffa plateau. To the south the depression slopes gently up to theGreat Sand Sea.
Within the Depression aresalt marshes, under the northwestern and northernescarpment edges, and extensivedry lake beds that flood occasionally. The marshes occupy approximately 300 square kilometres (120 sq mi), although wind-blown sands are encroaching in some areas. About a quarter of the region is occupied by dry lakes composed of hard crust and sticky mud. These are occasionally filled with water.
The depression was initiated by either wind or fluvial erosion in the lateNeogene, but during theQuaternary Period the dominant mechanism was a combination ofsalt weathering andwind erosion working together. First, the salts break up the depression floor, then the wind blows away the resulting sands. This process is less effective in the eastern part of the depression, due to lower salinity groundwater.[4]
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Groves of umbrella thorn acacia (Vachellia tortilis), growing in shallow sandy depressions, andPhragmites swamps represent the only permanent vegetation. The acacia groves vary widely inbiodiversity and rely on runoff from rainfall and groundwater to survive. TheMoghra Oasis in the northeastern part of the Depression has a 4 km2 (1.5 sq mi) brackish lake and aPhragmites swamp.[5][6]
The southwestern corner of the depression is part of the Siwa Protected Area which protects the wild oasis in and around theSiwa Oasis.
The Depression is an important habitat for the cheetah, with the largest number of recent sightings being in areas in the northern, western and northwestern part of the Qattara Depression, including the highly isolated, wild oases of Ain EI Qattara and Ein EI Ghazzalat and numerous acacia groves both inside and outside the depression.[7]
Gazelles (Gazella dorcas andGazella leptoceros) also inhabit the Qattara Depression, being an important food source for the cheetah. The largest gazelle population exists in the southwestern part of the Qattara Depression within a vast area ofwetlands and soft sand. The area of 900 km2 (350 sq mi), includes the wild oases of Hatiyat Tabaghbagh and Hatiyat Umm Kitabain, and is a mosaic of lakes,salt marshes,scrubland, wildpalm groves andDesmostachya bipinnatagrassland.[7]
Other common fauna include theCape hare (Lepus capensis),Egyptian jackal (Canis aureus hupstar),sand fox (Vulpes rueppelli) and more rarely thefennec fox (Vulpes zerda).Barbary sheep (Ammotragus lervia) were once common here but now they are few in number.
Extinct species from the area include thescimitar oryx (Oryx dammah),addax (Addax nasomaculatus) andbubal hartebeest (Alcelaphus buselaphus).[8] Also theDroseridites baculatus, an extinct plant known only from fossils of its pollen, was found at theGhazalat-1 Well.[9]
The climate of the Qattara Depression is highlyarid with annualprecipitation between 25 and 50 mm (0.98 and 1.97 in) on the northern rim to less than 25 mm (0.98 in) in the south of the depression. The average daily temperature varies between 36.2 to 6.2 °C (97.2 to 43.2 °F) during summer and winter months. The prevailing wind forms a largely bimodal regime with most wind coming from north easterly and westerly directions. This causes the linear dune formations in the Western desert between the Qattara Depression and the Nile valley. Wind speeds peak in March at 11.5 m/s (26 mph) and minimal in December at 3.2 m/s (7.2 mph).[4]The average wind speed is about 5 to 6 m/s (11 to 13 mph).[10] Several days each year in the months March to Maykhamsin winds blow in from the south and bring extremely high temperatures as well as sand and dust with them.
There is one permanent settlement in the Qattara Depression, theQara Oasis. The oasis is located in the westernmost part of the depression and is inhabited by about 300 people.[11] The Depression is also inhabited by the nomadicBedouin people and their flocks, with the uninhabitedMoghra Oasis being important in times ofwater scarcity during the dry seasons.
The Qattara Depression contains many oil concessions, and several operationaloil fields. The drilling companies includeRoyal Dutch Shell and theApache Corporation.
The elevation of the depression was first measured in 1917 by an officer of the British Army leading a light car patrol into the region. The officer took readings of the height of the terrain with ananeroid barometer on behalf ofJohn Ball, who later would also publish on the region. He discovered that the spring Ain EI Qattara lay about 60 metres (200 ft) below sea level. Because the barometer got lost and the readings were so unexpected, this find had to be verified. During 1924–25, Ball again organised a survey party, this time with the sole purpose totriangulate the elevation on a westerly line fromWadi El Natrun. The survey was led by G.F. Walpole who had already distinguished himself by triangulating the terrain across 500 km (310 mi) from theNile toSiwa viaBahariya. He confirmed the earlier readings and proved the presence of a huge area below sea level, with places as deep as 133 m (436 ft) below sea level.[3]
Knowledge about the geology of the Qattara Depression was greatly extended byRalph Alger Bagnold, a British military commander and explorer, through numerous journeys in the 1920s and 1930s. Most notable was his 1927 journey during which he crossed the depression east to west and visited the oases ofQara andSiwa. Many of these trips used motor vehicles (Ford Model Ts) which used special techniques for driving in desert conditions. These techniques were an important asset of theLong Range Desert Group which Bagnold founded in 1940.[12]
After the discovery of the depression, Ball published the triangulation findings about the region in October 1927 inThe Geographical Journal. He also gave the region its name "Qattara" after the spring Ain EI Qattara where the first readings were taken. The name literally means "dripping" in Arabic. Six years later in 1933, Ball was the first to publish a proposal for flooding the region to generate hydroelectric power in his article "The Qattara Depression of the Libyan Desert and the possibility of its utilisation for power-production".[3]
DuringWorld War II, the depression's presence shaped theFirst andSecond Battles of El Alamein. It was considered impassable bytanks and most other military vehicles because of features such as salt lakes, high cliffs and/orescarpments, andfech fech (very fine powdered sand). The cliffs in particular acted as an edge of the El Alamein battlefield, which meant the Allied forces could not beoutflanked to the south. Both Axis and Allied forces built their defences in a line from theMediterranean Sea to the Qattara Depression. These defences became known as theDevil's gardens, and they are for the most part still there, especially the extensive minefields.
No large army units entered the Depression, although GermanAfrika Korps patrols and the BritishLong Range Desert Group did operate in the area, since these small units had considerable experience in desert travel.[12][13] The RAF's repair and salvage units (e.g. 58 RSU) used a route through the depression to salvage or recover aircraft that had landed or crashed in the Western desert away from the coastal plain.
The RSUs included six-wheel-drive trucks, Coles cranes, and large trailers, and were particularly active from mid-1941 whenAir Vice-Marshal G.G. Dawson arrived in Egypt to address the lack of serviceable aircraft.[14]
A German communications officer stationed in the depression was cited byGordon Welchman as being unintentionally helpful in the breaking of theEnigma machine code, due to his regular transmissions stating there was "nothing to report".[15]
The large size of the Qattara Depression and the fact that it falls to a depth of 133 m (436 ft) below mean sea level has led to several proposals to create a massivehydroelectric power project in northern Egypt rivalling that of theAswan High Dam. This project is known as theQattara Depression Project. The proposals call for a large canal or tunnel being excavated from the Qattara due north of 55 to 80 kilometres (34 to 50 mi) depending on the route chosen to theMediterranean Sea to bring seawater into the area.[16]
An alternative plan involved running a 320-kilometre (200 mi) pipeline northeast to thefreshwaterNile River atRosetta.[17][18] Water would flow into a series of waterpenstocks which would generate electricity by releasing the water at 60 m (200 ft) below sea level. Because the Qattara Depression is in a very hot dry region with very little cloud cover, the water released at the −70 metres (−230 ft) level would spread out from the release point across the basin and evaporate from solar influx. Because of evaporation, more water can flow into the depression, thus forming a continual source of power. Eventually this would result in a hypersaline lake or a salt pan as the water would evaporate and leave behind the salt that it contained.
Plans to use the Qattara Depression for the generation of electricity date back to 1912 from Berlin geographerAlbrecht Penck.[19] The subject was discussed in more detail byDr. John Ball in 1927, who estimated a hydroelectric potential of 125 to 200 megawatts.[20] In 1957, the AmericanCentral Intelligence Agency proposed to PresidentDwight Eisenhower that peace in the Middle East could be achieved by flooding the Qattara Depression. The resulting lagoon, according to the CIA, would have four benefits:[21][citation needed]
In the 1970s and early 1980s, several proposals to flood the area were made byFriedrich Bassler and theJoint Venture Qattara, a group of mainly German companies. They wanted to make use ofpeaceful nuclear explosions to construct a tunnel, drastically reducing construction costs compared to conventional methods. This project proposed to use 213H-bombs, with yields of one to 1.5megatons, detonated at depths of 100 to 500 metres (330 to 1,640 ft). That fit within theAtoms for Peace program proposed by US PresidentDwight Eisenhower in 1953. The Egyptian government turned down the idea.[22]
Planning experts and scientists intermittently put forward potentially viable options, whether of a tunnel or canal, as an economic, ecological, and energy solution in Egypt, often coupled with the idea of new settlements.[22][23][24]
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