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Location: Northern Africa, bordering the North Atlantic
Ocean, between Senegal and Western Sahara
Geographic coordinates: 20 00 N, 12 00 W
Map references: Africa
Area:
total: 1,030,700 sq km
land: 1,030,400 sq km
water: 300 sq km
Area - comparative: slightly larger than three times the
size of New Mexico
Land boundaries:
total: 5,074 km
border countries: Algeria 463 km, Mali 2,237 km, Senegal
813 km, Western Sahara 1,561 km
Coastline: 754 km
Maritime claims:
contiguous zone: 24 nm
continental shelf: 200 nm or to the edge of the continental
margin
exclusive economic zone: 200 nm
territorial sea: 12 nm
Climate: desert; constantly hot, dry, dusty
Terrain: mostly barren, flat plains of the Sahara; some
central hills
Elevation extremes:
lowest point: Sebkha de Ndrhamcha -3 m
highest point: Kediet Ijill 910 m
Natural resources: iron ore, gypsum, fish, copper, phosphate
Land use:
arable land: 0%
permanent crops: 0%
permanent pastures: 38%
forests and woodland: 4%
other: 58% (1993 est.)
Irrigated land: 490 sq km (1993 est.)
Natural hazards: hot, dry, dust/sand-laden sirocco wind
blows primarily in March and April; periodic droughts
Environment - current issues: overgrazing, deforestation,
and soil erosion aggravated by drought are contributing to desertification;
very limited natural fresh water resources away from the Senegal
which is the only perennial river
Environment - international agreements:
party to: Biodiversity, Climate Change, Desertification,
Endangered Species, Hazardous Wastes, Law of the Sea, Nuclear Test
Ban, Ozone Layer Protection, Ship Pollution, Wetlands
signed, but not ratified: none of the selected agreements
Geography - note: most of the population concentrated in
the cities of Nouakchott and Nouadhibou and along the Senegal River
in the southern part of the country
Mauritania
GEOGRAPHY
Size: Total area of 1,030,700 square kilometers
includes 400 square kilometers of water.
Topography: Generally flat with vast, arid plains
broken by occasional ridges and outcroppings. In center of country,
series of scarps facing southwest longitudinally bisect plains;
sandstone plateaus, some with isolated peaks, between scarps. Northeast
a vast region of dunes.
Climate: Desert climate across northern three-fourths
of country with diurnal extremes in temperatures and meager and
irregular rainfall. During rainy season (July to September), average
rainfall in far south 400 to 600 millimeters; in northern two-thirds,
0 to 100 millimeters. Desert winds throughout year cause frequent
sandstorms.
Data as of June 1988
Mauritania
PHYSICAL SETTING
Mauritania is generally flat, its 1,030,700 square kilometers forming
vast, arid plains broken by occasional ridges and clifflike outcroppings.
A series of scarps face southwest, longitudinally bisecting these
plains in the center of the country. The scarps also separate a
series of sandstone plateaus, the highest of which is the Adrar
Plateau, reaching an elevation of 500 meters. Spring-fed oases lie
at the foot of some of the scarps. Isolated peaks, often rich in
minerals, rise above the plateaus; the smaller peaks are called
guelbs and the larger ones kedias. The concentric
Guelb er Richat is a prominent feature of the north-central region.
Kediet Ijill, near the city of Zouîrât, has an elevation of 1,000
meters and is the highest peak .
Approximately three-fourths of Mauritania is desert or semidesert.
As a result of extended, severe drought, the desert has been expanding
since the mid-1960s. The plateaus gradually descend toward the northeast
to the barren El Djouf, or "Empty Quarter," a vast region of large
sand dunes that merges into the Sahara Desert. To the west, between
the ocean and the plateaus, are alternating areas of clayey plains
(regs) and sand dunes (ergs), some of which shift
from place to place, gradually moved by high winds. The dunes generally
increase in size and mobility toward the north.
The climate is characterized by extremes in temperature and by
meager and irregular rainfall. Annual temperature variations are
small, although diurnal variations can be extreme. The harmattan,
a hot dry wind, blows from the Sahara throughout most of the year
and is the prevailing wind, except along the narrow coastal strip,
which is influenced by oceanic trade winds. During the short rainy
season (hivernage), from July to September, average annual
precipitation varies from 500 to 600 millimeters in the far south
to 0 to 100 millimeters in the northern two-thirds of the country.
Belts of natural vegetation, corresponding to the rainfall pattern,
extend from east to west and range from traces of tropical forest
along the Senegal River to brush and savanna in the southeast. Only
sandy desert is found in the center and north of the country.
Data as of June 1988
Mauritania
Major Geographic and Climatic Zones
Mauritania has four ecological zones: the Saharan Zone, the Sahelian
Zone, the Senegal River Valley, and the Coastal Zone. Although the
zones are markedly different from one another, no natural features
clearly delineate the boundaries between them. Sand, varying in
color and composition, covers 40 percent of the surface of the country,
forming dunes that appear in all zones except the Senegal River
Valley. Fixed sand dunes are composed of coarse, fawn-colored sand,
while shifting ("mobile") dunes consist of fine, dustlike, reddish-colored
sands that can be carried by the wind. Plateaus generally are covered
with heavier blue, gray, and black sands that form a crusty surface
over layers of soft, loose sand.
Data as of June 1988
Mauritania
Saharan Zone
The Saharan Zone makes up the northern two-thirds of the country.
Its southern boundary corresponds to the isohyet (a line on the
earth's surface along which the rainfall is the same) that represents
annual precipitation of 150 millimeters. Rain usually falls during
the hivernage, which lasts from July to September. Often,
isolated storms drop large amounts of water in short periods of
time. A year, or even several years, may pass without any rain in
some locations.
Diurnal variations in temperature in the Saharan Zone may be extreme,
although annual variations are minimal. During December and January,
temperatures range from an early morning low of 0°C to a midafternoon
high of 38°C. During May, June, and July, temperatures range
from 16°C in the morning to more than 49°C by afternoon.
Throughout the year, the harmattan often causes blinding sandstorms.
The administrative regions (formerly called cercles) of
Tiris Zemmour in the north, Adrar in the center, and northern Hodh
ech Chargui in the east, which make up most of the Saharan Zone,
are vast empty stretches of dunes alternating with granite outcroppings.
After a rain, or in the presence of a well, these outcroppings may
support vegetation. In the populated Adrar and Tagant plateaus,
springs and wells provide water for pasturage and some agriculture.
In the western portion of the Saharan Zone, extending toward Nouakchott,
rows of sand dunes are aligned from northeast to southwest in ridges
from two to twenty kilometers wide. Between these ridges are depressions
filled with limestone and clayey sand capable of supporting vegetation
after a rain. Dunes in the far north shift with the wind more than
those in the south.
The Saharan Zone has little vegetation. Some mountainous areas
with a water source support small-leafed and spiny plants and scrub
grasses suitable for camels. Because seeds of desert plants can
remain dormant for many years, dunes often sprout sparse vegetation
after a rain. In depressions between dunes, where the water is nearer
the surface, some flora--including acacias, soapberry trees, capers,
and swallowwort--may be found. Saline areas have a particular kind
of vegetation, mainly chenopods, which are adapted to high salt
concentrations in the soil. Cultivation is limited to oases, where
date palms are used to shade other crops from the sun.
Data as of June 1988
Mauritania
Sahelian Zone
The Sahelian Zone extends south of the Saharan Zone to within approximately
thirty kilometers of the Senegal River. It forms an east-west belt
with its axis running from Boutilimit through 'Ayoûn el 'Atroûs
to Néma, made up of steppes and savanna grasslands. Herds of cattle,
sheep, and goats move across this zone in search of pasturage.
The hivernage begins earlier in the Sahelian Zone than
in the Saharan Zone, often lasting from June until October. Because
farmers and herders depend on annual rains, a delay of one month
in the beginning of the rainy season can cause large losses and
lead to mass migrations from Hodh ech Chargui and Hodh el Gharbi
into Mali. Although temperature extremes are narrower than in the
Saharan Zone, daily variations range from 16°C to 21°C.
The harmattan is the prevailing wind.
In the northern Sahel, dunes are covered with scrub grasses and
spiny acacia trees. Farther south, greater rainfall permits more
dense vegetation. Sands begin to give way to clay. Large date palm
plantations are found on the Tagant Plateau, and savanna grasses,
brushwood, balsam, and spurge cover fixed dunes. Occasional baobab
trees dot the flat savanna grasslands of the southern Sahel. Forest
areas contain palm trees and baobabs. Vast forests of gum-bearing
acacia grow in Trarza and Brakna regions. Farther south, particularly
in Assâba and the northern portion of Guidimaka regions, rainfall
is high enough to support forms of sedentary agriculture.
Data as of June 1988
Mauritania
Senegal River Valley
The Senegal River Valley, sometimes known as the Chemama
(see Glossary) or the pre-Sahel, is a narrow belt of land that extends
north of the Senegal River. Before the droughts of the 1960s, 1970s,
and 1980s, the belt ranged from sixteen to thirty kilometers north
of the river. By the late 1980s, desertification had reached the
northern bank of the river in some parts of the valley. The valley
is wider in Guidimaka Region and is completely dominated by the
seasonal cycle of the river. Almost all of the valley's economically
active population engages in sedentary agriculture or fishing along
the Senegal River and its main tributaries--the Karakoro, the Gorgol,
and the Garfa. This area supplies most of the country's agricultural
production.
The climate of the Senegal River Valley contrasts with that of
the Saharan and Sahelian zones. Rainfall is higher than in other
regions, ranging from 400 millimeters to 600 millimeters annually,
usually between May and September. This rainfall, combined with
annual flooding of the river, provides the basis for agriculture.
Temperatures are cooler and subject to less annual and diurnal variation
than in other regions.
The Senegal is the only permanent river between southern Morocco
and central Senegal. From its source in Guinea, it flows north and
west 2,500 kilometers, reaching the Atlantic Ocean at Saint Louis,
Senegal. From its mouth, the river is navigable as far as Kayes,
Mali, during the rainy season and Podor, Senegal, during the rest
of the year. Heavy rains, beginning in April in Guinea and May and
June in Senegal and Mali, bring annual floods. These floods cover
the entire valley up to a width of twenty-five to thirty-five kilometers,
filling numerous lakes and sloughs (marigots) that empty
back into the river during the dry season. When the waters recede
from the bottomlands, planting begins.
The Senegal River Valley, with its rich alluvial and clayey soil,
is comparatively abundant in flora. Moreover, higher rainfall, irrigation,
and abundant side channels and sloughs tend to produce a lush, near-tropical
vegetation, with baobab and gonakie trees and abundant rich grasses.
Ddounm and barussus palms are also found here.
Much of the flood plain is cultivated.
Data as of June 1988
Mauritania
Coastal Zone
The Coastal Zone, or Sub-Canarian Zone, extends the length of the
approximately 754-kilometer-long Atlantic coast. Prevailing oceanic
trade winds from the Canary Islands modify the influence of the
harmattan, producing a humid but temperate climate. Rainfall here
is minimal; in Nouadhibou it averages less than three centimeters
annually and occurs between July and September. Temperatures are
moderate, varying from mean maximums of 28°C and 32°C for
Nouadhibou and Nouakchott, respectively, to mean minimums of 16°C
and 19°C.
Battering surf and shifting sand banks characterize the entire
length of the shoreline. The Ras Nouadhibou (formerly Cap Blanc)
peninsula, which forms Dakhlet Nouadhibou (formerly Lévrier Bay)
to the east, is fifty kilometers long and up to thirteen kilometers
wide. The peninsula is administratively divided between Western
Sahara (see Glossary) and Mauritania, with the Mauritanian port
and railhead of Nouadhibou located on the eastern shore (see
fig. 11). Dakhlet Nouadhibou, one of the largest natural harbors
on the west coast of Africa, is fortythree kilometers long and thirty-two
kilometers wide at its broadest point. Fifty kilometers southeast
of Ras Nouadhibou is Arguin. In 1455 the first Portuguese installation
south of Cape Bojador (in the present-day Western Sahara) was established
at Arguin. Farther south is the coastline's only significant promontory,
seven-meter-high Cape Timiris. From this cape to the marshy area
around the mouth of the Senegal River, the coast is regular and
marked only by an occasional high dune.
On coastal dunes vegetation is rare. At the foot of ridges, however,
large tamarisk bushes, dwarf acacias, and swallowworts may be found.
Some high grass, mixed with balsam, spurge, and spiny shrubs, grows
in the central region. The north has little vegetation.
Data as of June 1988
Mauritania
Expansion of the Desert
The climate has altered drastically since the onset of the prolonged
drought in the 1960s, part of a recurrent pattern of wet and dry
cycles common to Sahelian Africa. Experts agree, however, that overgrazing,
deforestation, denuding of ground cover around wells, poor farming
methods, and overpopulation have aggravated the drought. In Mauritania
the isohyet indicating annual rainfall of 150 millimeters--considered
the minimum for pastoralism--has shifted southward about 100 kilometers
to a point well south of Nouakchott. During the 1980s, the desert
was advancing southward at an estimated rate of six kilometers a
year. Each major climatic zone had shifted southward, and in some
cases near-desert conditions had reached the banks of the Senegal
River.
By the late 1980s, desertification had fundamentally altered agro-pastoral
and human settlement patterns (see Population
, this ch.). Loss of ground cover in the Sahelian Zone had driven
animals and people southward in search of food and water and had
given rise to new fields of sand dunes. The advancing dunes threatened
to engulf wells, villages, and roads; they had even invaded Nouakchott
on their march to the sea. The government secured international
help to stabilize the dune field around Nouakchott and planted 250,000
palm trees to create a barrier against the encroaching desert. To
further combat desiccation, the government constructed dams on the
Senegal River and its tributaries to increase the amount of cultivable
acreage.
Data as of June 1988
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