Wadi Rayan  Fayoum (Rayyan Valley).An evolving ecosystem.

wadi rayan fayoum  is one of the depressions in Egypt’s Western Desert and has the advantages of being near the Nile Valley, being uninhabited (unlike its twin depression of Fayoum) and having a considerable depth (60 meters below sea level at its lowest point) and volume (a storage capacity of 21 cubic kilometers of water at 50 meters above sea level).

In the late 19th century there was a debate as to whether to use wadi rayan fayoum as a reservoir for the Nile’s flood waters or to build a dam across the river in its upper reaches.

A dam at Aswan was seen as the best solution, and by 1902 the Aswan reservoir had been built, later (1912 and 1955) being raised to increase its storage capacity.

The question of wadi rayan fayoum was thus shelved.

Interest in Wadi el Rayan was revived in about 1950 in connection with the concept of “century storage”, in which it was seen as a likely reservoir basin to be used as an escape valve for flood control. and storage.

wadi rayan fayoum

A scheme was designed, encompassing an inlet canal from the Nile to the depression and an outlet canal to lead the stored water back to the Nile.

Work started in the early 1950s. In the 1960s, however, the Aswan High Dam scheme replaced all century storage schemes, and the Rayan flood-water storage project was abandoned. 

In the late 1960s agricultural drainage of the Fayoum farmland into Lake Qarun (bottom at 45 meters below sea level) increased, overflowing the lake and threatening adjacent farmland.

As a lower-lying basin (up to 60 meters below sea level), the Rayan depression seemed suitable to take part of the Fayoum drainage water, and a scheme was designed to convey water from the southern Fayoum farmland to Wadi Rayan along a channel that is partly open (7 kilometers) and partly in a tunnel (7.7 kilometers).

This drainage water created the upper lake during the 1970s and then in the early 1980s spilled over – in a waterfall that is a special attraction of the area – and formed the lower lake.

These two man-made brackish lakes added a significant feature to the Rayan landscape and provided a wetland habitat for a variety of resident and transient wildlife.

They also allowed various new land uses (farming, fisheries and recreation), while an abandoned monastery was renovated and reoccupied.

These changes brought inhabitants to the area and made it hard to manage nature conservation.

The Wadi Rayan Protected Area (WRPA)

covering a total area of 1,759 km was instituted by Prime Ministerial Decree 945 in 1989, in accordance with Law 102 of 1985.

The protected area became the focus of an active project within the framework of the Egyptian Italian Environmental Programme.

The present volume gives a general survey of the area (geology, geomorphology and Wildlife) and outlines future prospects.

Thus, Parts I and II describe fossils, landforms, habitat types and plant and animal species, and Parts III and IV discuss the conservation issues involved and plans for management of the area.

The volume is intended to provide visitors and stakeholders with basic information on the ecology and biodiversity of the area and the scientific bases for proposed management actions aimed at conserving its unique environmental and natural features, which include some remarkable fossil sites.

lt is hoped that it will ensure the positive participation of visitors and stakeholders in effective management of the area, as well as soliciting the support of policy-makers at regional and national levels.

The authors of the following chapters have been involved in studies of the area and are concerned over its future.

They thus combine scientific and technical expertise with the conviction that the area deserves special conservation attention. Wadi el Rayan is a part of Egypt’s natural heritage: it is our privilege to enjoy it and our duty to conserve it for the benefit of future generations.

Dawn: low clouds over the desert in wadi rayan fayoum.

wadi rayan fayoum

Wadi el Hitan – the valley of whales – in the wadi rayan fayoum Protected Area.

Forty million years ago there used to be a great ocean – now ancient cliffs eroded by wind and

water overlook breathtaking views of unique geological formations and represent a gateway to the

Western Desert, a part of the Great Sahara ecosystem stretching across North Africa from the Red

Sea coast of Egypt to the Atlantic coast of Mauritania.

just below the sands lie the secrets of the distant past » huge fossils of whales and other marine creatures are scattered on the ancient sea floor.

Wadi el Hitan is now considered as a palaeontological site of international importance, Which

is renowned among scientists and desert travellers the world over.

General description

The wadi rayan fayoum depression has been well known to travelers between the Nile Valley and the northern oases of Egypt’s Western Desert for centuries.

The lower part of the depression has been gradually covered by two lakes since the drainage canal was opened in 1975.

The upper lake reached its maximum level in 1978, covering approximately 5,100 hectares in the Wadi el Masakheet sub-depression.

From here the water flows through a shallow swampy area and over a waterfall into the lower lake, which is not yet full but is estimated

to cover approximately 7,700 hectares.

The water of the three natural el Rayan springs, located below Minqar el Rayan in a site known as the Oyun el Rayan or Springs area, is believed to come from the remotely charged Nubian sandstone strata (Ball, 1927).

The output has been measured as 1.6, 4.8 and 14.4 litres per minute for the northern, western and southern springs respectively (Zahran, 1970).

A new  spring was dug out by Coptic monks between the western and the southern springs in 1999. All the springs provide drinking water for wildlife.

The physical and chemical properties of the lakes and the springs, including seasonal variations, were studied in 1988 and 2000 (Saleh et al., 1988a; Saleh et al., 2000.)

The area is marked by moving belts of sand dunes and is separated from the deepest part of the depression by dune fields and rock terraces.

The dune fields consist mostly of longitudinal seg’ dunes, varying from several hundred metres to 50 kilometres in length and up to 30 metres in height.

The area has a typical hyper-arid desert climate (Ayyad & Ghabbour, 1986), hot and dry with bright sunshine throughout the year.

The temperature ranges from 12°C to 48.8°C, and annual precipitation averages 10.1 millimetres, almost totally in the form of irregular rainfall.

The potential evapotranspiration rate is extremely high throughout the year; coupled with low precipitation, this makes the area one of the most arid places in the world The revailin winds are

– P ‘ 8 ‘north-west, north or north-east, resulting in the formation of extensive sand dunes.Much wind-blown sand is deposited in the Wadi el Rayan depression and the Oyun el Rayan area. Extensive dune fields run the length of the Wadi el Rayan depression and into Wadi Muwellih and Oyun el Rayan. They are packed closely together in the southern part of the Wadi el Rayan depression, forming a huge and practically impassable mass.

Moving further westwards and southwards, they gradually separate, creating interdune valleys that vary in width from under 100 metres to over 2 kilometres, the widest being found in the Oyun el Rayan area.

Phytogenic sand mounds up to 50 metres across and 10 metres high are scattered throughout the interdune valleys.

Most of these mounds are formed around Tamarix nilotica and Calligonum comosum and to a lesser extent Nitmria refusal, and they play an important role in the ecology of the area. 

Before 1988 the area was accessible only by four-wheel drive vehicles along a track connecting the upper lake and the nearest village in the Fayoum Governorate, 22 kilometres to the east. Several roads have now been built connecting the area to the Fayoum depression and the Nile Valley and allowing a broader range of human activities. A three-dimensional elevation model of the area, showing the main points of interest..

Many of the dominant geomorphologic features in wadi rayan fayoum are a result of severe erosion of sedimentary rocks with varying degrees of hardness.

There are numerous isolated hills, such as the roundish Gabal el Medawara facing the lakes, and Garet Gehannam, a good landmark on the way to Wadi el Hitan.

There are many hillocks at Wadi el Hitan, such Akhwat el Talata (Three Sisters Hill), while curious huge globular masses are met with in many places, especially Wadi el Battikh (Valley of Water Melons).

These masses are weathered concretions that were worn by the water of the prehistoric Lake Moeris (ancestor of Lake Qarun) when its level was falling.

A large belt of longitudinal seg” dunes occupies the floor of many parts of wadi rayan fayoum.

In many places in Wadi el Hitan,

the weathering of the rocks has given rise to earth pillars and strange-shaped hillocks sculpted by the weathering action of blown sand and rain.

The stratigraphy indicates that the oldest beds in this area are related to the Wadi Rayan Fayoum Formation, consisting of clay, marl and limestone, dating back to the Upper Lutetian – Lower Bartonian Age (about 41 to 45 million years ago).

These beds are fossiliferous, with plenty of Nzrmmulites gizebensis Forskal.

The Wadi Rayan Fayoum Formation is succeeded by the Gehannam Formation of the Eocene Age (Bartonian and Priabonian, about 40 to 41 million years ago), consisting of white marly limestone and gypseous clay.

This formation, like the lower part of the overlying Birket Qarun Formation, is of particular interest in yielding many skeletons of the marine archaeocetes Basilosoiurus isis and

Prozeuglodon atrox,

in addition to a variety of shark teeth, Large fossils of sea turtles and crocodilians are present but rare.

The macro-invertebrate fauna of the Gehannam Formation includes many bivalves such as Lucma and Tellina, most of which are infaunal and are typical of shallow rather than deep sea bottoms, while epifaunal elements include Lobocarcinus (crabs).

Abundant mangrove pneumatophores and anchor roots are being eroded from the top of the Gehannam Formation over a broad area in Wadi el Hitan.

The upper part of the Gehannam Formation and the lower part of the overlying Qarun Formation are unusually rich in celestite (strontium sulphate), reflecting restricted oceanographic conditions where partial evaporation of sea water

resulted in concentrated lime and strontium sulphate.

Various nummulites and planktonic foraminifera indicate that the Gehannam Formation was deposited on a shallow shelf in o_pen marine waters, and that this occurred partially during a period when the sea was at a low level.

The Gehannam Formation is followed by the Birket Qarun Formation, consisting of fossiliferous sandstone and clay with sandy limestone, with Nummulites ll 1 fmasi, Qerunm cornuta Mayer-Fymar, Cbzrdiraz 1/eqzfzesnelli Oppenheim Be ant Tzmcitella ploamonica Cossman.

Left – These huge globular masses known as “\X/ater Melons” are Weathered concretions common

in the Wadi el Hitan area.

Typical sedimentary 1′

  1. Fossils

Mohamed Abed 65 Yousifi Atrial Wadi el Hitan (or Zeuglodon Valley) is about 12 kilometres west of the prominent hill of Garet Gehannam in the wadi rayan fayoum Protected Area.

It is marked by a rich content of both vertebrate and invertebrate fossils, and is practically an open display-case in the desert.

Many whale skeletons dating back to the Eocene Age are found on or near the surface.

while thousands of nummulites of various kinds are scattered on the ground beside exposures containing macro-invertebrate fossils – a situation typical of the three formations found here (Gehannam, Birket Qarun and Qasr el Sagha).

Vertebrate fossils Cetaceans and sharks (witnessed by fossil shark teeth) are the dominant

vertebrates found in Wadi el Hitan,

 The whales known from the Eocene Age were different from those of the modern groups and are placed in a separate suborder, Archaeoceti.

The body was very long – up to 21 metres – and apparently thinner than that of modern whales. suggesting a sea-serpent form, probably fairly inefficient for swimming.

The skull was long and the nostril was some way back.

The teeth are very  interesting in that they were of the normal mammalian number (44) nd showed some signs of a heterodont arrangement, The molars had sharp crenate edges, as in other fish-eaters, and the animals were obviously carnivorous.

suggesting a possible creodont ancestry.

These animals, such as Bolsilosoiums.

persisted into the Miocene Age, but their exact connections with the two modern groups of whales are not clear.

Basi/osoiirms had a mouth that was highly specialized for eating fish, Beadnell was the first to record Zeiiglodon isis in 1906 (now Basilosaums isis, e Gingerich el al., 1990), which probably lived about 42 to 40 million yearsago.

It was named by Beadnell in Andrews (1904, p. 214), who described the best specimen, a dentary. with a total length of 85 centimetres, and stated that this “may be taken as the type”, thus making the name available.

Andrews (1904) gave the type locality as the Birket el Qarun beds of the Fayoum area, while Beadnell (1905, p. 44) added that the type came from_ cliffs near the west end of the lake.

The type is illustrated in Andrews (1906, fig. 78). Beadnelfg (1905) section of the Birket Qarun Formation at the west end of Lake Birket Qarun is shown in Figure 25.

The type specimen of Bolsilosaurus isis

may have come from the top of the Gehannam Formation, from the Birket Qarun Formation, or conceivably (but improbably) from what is here called the lower part of the Qasr el Sagha Formation.

Whether the specimen came from the Gehannam or the Birket Qarun Formation at the west end of Birket Qarunmatters little, since the age is likely to be earliest Priabonian in either case (the uppermost Gehannam Formation in this area is probably Priabonian).

Prozeiiglodoii airox was named by Andrews (1906), based on a type skull and a lower jaw collected by Beadnell from the Birket el Qarun beds in Zeuglodon Valley, or what is now called Wadi el Hitan.

The type specimen of P airox retains deciduous premolars, showing that it was a juvenile, and subadult specimens indistinguishable from the type specimen are common in

both the Gehannam and Birket Qarun Formations in Wadi el Hitan.

Beadnell (1905) did not always distinguish the Gehannam and Birket Qarun Formations lithologically, and they do overlap in time to some extent.

The age of the type specimen of P ozirox would therefore be latest Bartonian or earliest

cephalopods and plankton (Figure 8).

Its appendages allowed it to creep on land.

res show the correlation with the Eocene Busilosazzms.

while the lower figure shows the modern toothed whale.

 Specimen of Busilosaums isis, coiled in its typical death position Domdon Osiris is the largest species of Domdon from Egypt, and all are from the Qaser el Sagha Formation of the late Eocene Age (Figure 9). D. Osiris is one of three species of Dorudon recognized by Kellogg from the Qasr el Sagha Formation in 1956.

A new and more advanced archaeoceta, Ancoilecetus simonsi, is described from the Birket Qarun Formation (earliest Priabonian, late Eocene Age) of Wadi el Hitan A. simonsi is similar to 1 Dominion atrox in many ways, but differs, _V conspicuously in having fused elbows and other distinctive features of a forelimb structure, as well as a more curved malleus in the middle ear.

Ancaleceius appears to have been a viable if highly specialized evolutionary experiment, an experiment that may have contributed nothing to the subsequent evolution of cetaceans, but that does broaden our understanding.of the morphological diversity of archaeocetes.

Invertebrate fossils Macro-invertebrate fossils are commonly found in three major rock types: shale, compact white limestone and sandy hard brown limestone.

The mode of fossil’ preservation varies widely in these different types of rock.

In most cases the specimens occur as moulds, obscuring their internal structure, but usually retaining their external features. In the limestone basal beds of the Qasr el Sagha Formation, Carolia, oysters and a few other genera retain their original material and structure. In some cases in the upper beds of the Gehannam Formation and the lower beds of the Birket Qarun Formation, the shells are replaced by celestite (strontium sulphate).

As the silt and clay content increases, preservation improves, as is clearly seen in some upper Eocene beds of the Qasr el Sagha Formation.

The majority of the macro-invertebrate fossils found in the sedimentary sequence in Wadi el Hitan are related to the phylum Mollusca.

The most frequent are bivalves, followed by gastropods, while nautiloids are rare.

The following molluscs are the 1°11OSt frequent macro-invertebrate fossils found in Wadi el Hitan (see Figure 11);

A – Class: Bivalvia, Order: Pterioida, Superfamily: Anomiacea, Family:

Anomiidae Genus; Caroiia, Cantraine 1858, Carolicz plozcunoicles, Cantraine

  1. This species is typical of the basal beds of the Qasr el Sagha Formation.
  2. It is found in some exposures in the south of Wadi el Hitan where the basal pans of this formation are exposed. The shells are found crowded together and may even form a complete bed.

Carolia has a diameter that would indicate the lake constitute vital feeding and Wildlife The significance of the wildlife of Wadi Rayan, together with the urgent need to preserve it, was first pointed out by the present author and his colleagues (Saleh, 1984, 1985; Fouda & Saleh, 1987). After surveying gazelle habitats in Egypt, Saleh (1987) reported the small size of the population of Slender-horned ‘ gazelle Gozzelloz Z. leptoceros in Wadi ei Rayan, one of the few remaining wild populations of this species in the world. The structure of the sand dune ecosystem of Wadi el Rayan was also described and analysed (Saleh el al., 1988b).

The fish of the lakes were covered by Fouda and Saleh (1988), while the birds of the lakes were studied by Saleh (1998) in relation to seasonal changes in the vegetation on their shores.

Information on the wildlife and ecology of the wadi rayan fayoum area is scarce and incomplete, except for a limited number of publications and graduate theses by the author, his research team and colleagues.

The flora and fauna of the Wadi el Rayan

depression and those of Oyun el Rayan prior to the formation of the lakes have never been fully described, although an inventory by of the flora and vertebrate fauna of the Oyun el Rayan area, particularly those of sand dune habitats and their local distribution and ecological affinities, has been published (Saleh et al., 1988b). Saleh (1985) has provided a tentative list of the phyto~ and zooplankton, insects and other arthropods, molluscs, fish, birds and mammals of the Rayan lakes and adjoining area.

Most of the wildlife species of Oyun el Rayan and Wacii Muwellih are highly specialized desert forms, although only a few species are specifically adapted to sandy habitats (Kassas, 1984).

Following the formation of the fakes, a number of animal species typical of the mesic habitats of the Nile Valley reached the Oyun el Rayan area These include the jackai, Canis aureus lztpozsten which invaded the Wadi el Rayan and Oyun el Rayan areas in 1985 when the expanding lake reduced the barren desert expanse separating these areas from the Fayoum farmland, a more typical habitat for the species, but the impact of the arrival of this relatively large and powerful predator on the ecology of the area is unknown.

The Egyptian mongoose, Hefpestes ic/meumon, has also invaded the lakeshores since the early 1980s, and is now common on the shores of both lakes.

A large number of bird species has also occupied niches in and around the lakes and in wadi rayan fayoum

More animal and plant species will certainly occupy the newly created habitats in the future.

wadi rayan fayoum

Some of the animal species found in the area provide intriguing examples of adaptation to arid habitats, but very little – and in some cases nothing – is known about their ecology, physiology or even the most basic aspects of their biology.

One of these is the ubiquitous Sand fox,

Vufbes meppelli. Nothing is known of its physiology and there is only one recent report on its ecology.

Others include the Fennec fox, Vufves zerdoz. Of the two gazelle species inhabiting the area,  Gaze!/cz dorcczs is listed as an endangered species, while Gczzelloz leptoceros Zeptoceros, is extremely rare (Saleh, 1987) and is now probably locally extinct.

The conditions in Wadi el Hitan, 12 kilometres west-southwest of Garet Gehannam, are of special interest. The brown sandstone of the Birket Qarun Formation is divided here by a narrow band of fine-bedded grey clay.

Most of the fantastically shaped hills on the south-western slope of the valley are carved out of the lower division of the sandstone.

Remains of cetaceans of the species Basilosaums isis and Prozeuglodon atrox are remarkably abundant and are found in every stage of weathering.

Basilosaums is the more common, and series of vertebrae are often found.

In one instance a large portion of a Basilosaums skull measuring about one metre in length was found enclosed in a large block of nodular rock.

The basal beds of the Upper Eocene Age Qasr el Sagha

Formation with Carolia placunoides can be detected in some of the upper pans of exposures in the Wadi Rayan area, such as those found at Garet Gehannam, Minqar el Hut, Sandouk el Borneta and Minqar el Abyad.

Their richness in molluscan fauna reflects conditions favourable to growth (currents rich in oxygen).

The Qasr el Sagha Formation in this area shows a shallow marine environment, unlike that in northern parts of the Fayoum depression, where it shows a fluvio-marine environment.

 

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