Tunisian salt lakes
Encyclopedia
The Tunisian salt lakes are a series of lakes in central Tunisia
, lying south of the Atlas Mountains
at the northern edge of the Sahara
. The lakes include, from east to west, the Chott el Fedjedji, Chott el Djerid
, and Chott el Gharsa.
These salt lakes are a very curious feature. They stretch with only two short breaks in a line from the Mediterranean at the Gulf of Gabès
to the Algeria
n frontier, which they penetrate for a considerable distance. The French term "chott" is a transliteration of the Arabic shat, a term for a broad canal, an estuary or lake. These shats however are, strictly speaking, not lakes at all at the present day. They are smooth depressed areas (in the case of the largest, the Shat el Jerid, lying a few feet below the level of the Mediterranean), which for more than half the year are expanses of dried mud covered with a thick incrustation of white or grey salt. This salt covering gives them at a distance the appearance of big sheets of water.
During the winter, however, when the effect of the rare winter rains is felt, there may actually be 3 or 4 ft. of water in these shats, which by liquefying the mud makes them perfectly impassable. Otherwise, for about seven months of the year they can be crossed on foot or on horseback. It would seem probable that at one time these shats (at any rate the Shat el Jerid) were an inlet of the Mediterranean, which by the elevation of a narrow strip of land on the Gulf of Gabès has been cut off from them. It is, however, a region of past volcanic activity, and these salt depressions may be due to that cause. Man is probably the principal agent at the present day in causing these shats to be without water. All round these salt lakes there are numerous springs, gushing from the sandy hillocks. Almost all these springs are at a very hot temperature, often at boiling point. Some of them are charged with salt, others are perfectly fresh and sweet, though boiling hot. So abundant is their volume that in several places they form actual ever-flowing rivers. Only for the intervention of man these rivers would at all times find their way into the adjoining depressions, which they would maintain as lakes of water. But for a long period past the freshwater streams (which predominate) have been used for irrigation to such a degree that very little of the precious water is allowed to run to waste into the lake basins; so that these latter receive only a few salt streams, which deposit on their surface the salt they contain and then evaporate. This abundant supply of fresh warm water maintains oases of extraordinary luxuriance in a country where rain falls very rarely. Perennial streams of the description referred to are found between the Algerian frontier and Gabès
on the coast. The town at Gabès itself is on the fringe of a splendid oasis, which is maintained by the water of an everrunning stream emptying itself into the sea at Gabès after a course of not more than 20 miles.
All this region round the shats has been called the "Jerid" from the time of the Arab occupation. "Jerid" means in Arabic a "palm frond" and inferentially "a palm grove." The fame of this Belad-el-Jerid, or "Country of the Date Palms", was so exaggerated during the 17th and 18th centuries that the European geographers extended the designation from this small area in the south of Tunisia to cover much of inner Africa. With this country of Jerid may be included the island of Jerba, which lies close to the coast of Tunisia in the Gulf of Gabès. The date palm
(Phoenix dactylifera) may be indigenous to this district of the Jerid, as it is to countries of similar description in southern Morocco
, southern Algeria, parts of the Tripolitania
, Egypt, Mesopotamia
, southern Persia and north-western India; but that north of the latitude of the Jerid the date did not grow naturally in Mauretania
, just as it was foreign to all parts of Europe, in which, as in true North Africa, its presence is due to the hand of man. To some extent it may be said that true North Africa lies to the north of the Jerid country, which, besides its Saharan, Arabian and Persian affinities, has a touch about it of real Africa, some such touch as may be observed in the valley of the Jordan. In the oases of the Jerid are found several species of tropical African mammals and two or three of Senegalese birds, and the vegetation seems to have as much affinity with tropical Africa as with Europe. In fact, the country between the Matmata highlands and the strait separating Jerba from the mainland is singularly African in the character and aspect of its flora. To the south of the Jerid the country is mainly desert - vast unexplored tracts of shifting sand, with rare oases. Nevertheless, all this southern district of Tunisia bears evidence of once having been subject to a heavy rainfall, which scooped out deep valleys in the original table-land, and has justified the present existence of immense watercourses - watercourses which are still, near their origin, favoured with a little water.
Tunisia
Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...
, lying south of the Atlas Mountains
Atlas Mountains
The Atlas Mountains is a mountain range across a northern stretch of Africa extending about through Morocco, Algeria, and Tunisia. The highest peak is Toubkal, with an elevation of in southwestern Morocco. The Atlas ranges separate the Mediterranean and Atlantic coastlines from the Sahara Desert...
at the northern edge of the Sahara
Sahara
The Sahara is the world's second largest desert, after Antarctica. At over , it covers most of Northern Africa, making it almost as large as Europe or the United States. The Sahara stretches from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean...
. The lakes include, from east to west, the Chott el Fedjedji, Chott el Djerid
Chott el Djerid
Chott el Djerid , also spelt Shaţţ al Jarīd, Sciott Gerid, and Shott el Jerid, is a large endorheic salt lake in southern Tunisia.-Geography:The bottom of Chott el Djerid is located between 10 and 25 meters above sea level....
, and Chott el Gharsa.
These salt lakes are a very curious feature. They stretch with only two short breaks in a line from the Mediterranean at the Gulf of Gabès
Gulf of Gabès
The Gulf of Gabès is a gulf on Tunisia's east coast in the Mediterranean Sea, off North Africa. The gulf roughly spans the coast from modern day the town of Mahrès in Sfax Gouvernorate to Djerba...
to the Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
n frontier, which they penetrate for a considerable distance. The French term "chott" is a transliteration of the Arabic shat, a term for a broad canal, an estuary or lake. These shats however are, strictly speaking, not lakes at all at the present day. They are smooth depressed areas (in the case of the largest, the Shat el Jerid, lying a few feet below the level of the Mediterranean), which for more than half the year are expanses of dried mud covered with a thick incrustation of white or grey salt. This salt covering gives them at a distance the appearance of big sheets of water.
During the winter, however, when the effect of the rare winter rains is felt, there may actually be 3 or 4 ft. of water in these shats, which by liquefying the mud makes them perfectly impassable. Otherwise, for about seven months of the year they can be crossed on foot or on horseback. It would seem probable that at one time these shats (at any rate the Shat el Jerid) were an inlet of the Mediterranean, which by the elevation of a narrow strip of land on the Gulf of Gabès has been cut off from them. It is, however, a region of past volcanic activity, and these salt depressions may be due to that cause. Man is probably the principal agent at the present day in causing these shats to be without water. All round these salt lakes there are numerous springs, gushing from the sandy hillocks. Almost all these springs are at a very hot temperature, often at boiling point. Some of them are charged with salt, others are perfectly fresh and sweet, though boiling hot. So abundant is their volume that in several places they form actual ever-flowing rivers. Only for the intervention of man these rivers would at all times find their way into the adjoining depressions, which they would maintain as lakes of water. But for a long period past the freshwater streams (which predominate) have been used for irrigation to such a degree that very little of the precious water is allowed to run to waste into the lake basins; so that these latter receive only a few salt streams, which deposit on their surface the salt they contain and then evaporate. This abundant supply of fresh warm water maintains oases of extraordinary luxuriance in a country where rain falls very rarely. Perennial streams of the description referred to are found between the Algerian frontier and Gabès
Gabès
Gabès , also spelt Cabès, Cabes, Kabes, Gabbs and Gaps, the ancient Tacape, is the capital city of the Gabès Governorate, a province of Tunisia. It lies on the coast of the Gulf of Gabès. With a population of 116,323 it is the 6th largest Tunisian city.-History:Strabo refers to Tacape as an...
on the coast. The town at Gabès itself is on the fringe of a splendid oasis, which is maintained by the water of an everrunning stream emptying itself into the sea at Gabès after a course of not more than 20 miles.
All this region round the shats has been called the "Jerid" from the time of the Arab occupation. "Jerid" means in Arabic a "palm frond" and inferentially "a palm grove." The fame of this Belad-el-Jerid, or "Country of the Date Palms", was so exaggerated during the 17th and 18th centuries that the European geographers extended the designation from this small area in the south of Tunisia to cover much of inner Africa. With this country of Jerid may be included the island of Jerba, which lies close to the coast of Tunisia in the Gulf of Gabès. The date palm
Date Palm
The date palm is a palm in the genus Phoenix, cultivated for its edible sweet fruit. Although its place of origin is unknown because of long cultivation, it probably originated from lands around the Persian Gulf. It is a medium-sized plant, 15–25 m tall, growing singly or forming a clump with...
(Phoenix dactylifera) may be indigenous to this district of the Jerid, as it is to countries of similar description in southern Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, southern Algeria, parts of the Tripolitania
Tripolitania
Tripolitania or Tripolitana is a historic region and former province of Libya.Tripolitania was a separate Italian colony from 1927 to 1934...
, Egypt, Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...
, southern Persia and north-western India; but that north of the latitude of the Jerid the date did not grow naturally in Mauretania
Mauretania
Mauretania is a part of the historical Ancient Libyan land in North Africa. It corresponds to present day Morocco and a part of western Algeria...
, just as it was foreign to all parts of Europe, in which, as in true North Africa, its presence is due to the hand of man. To some extent it may be said that true North Africa lies to the north of the Jerid country, which, besides its Saharan, Arabian and Persian affinities, has a touch about it of real Africa, some such touch as may be observed in the valley of the Jordan. In the oases of the Jerid are found several species of tropical African mammals and two or three of Senegalese birds, and the vegetation seems to have as much affinity with tropical Africa as with Europe. In fact, the country between the Matmata highlands and the strait separating Jerba from the mainland is singularly African in the character and aspect of its flora. To the south of the Jerid the country is mainly desert - vast unexplored tracts of shifting sand, with rare oases. Nevertheless, all this southern district of Tunisia bears evidence of once having been subject to a heavy rainfall, which scooped out deep valleys in the original table-land, and has justified the present existence of immense watercourses - watercourses which are still, near their origin, favoured with a little water.