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Libya
Climate and Hydrology
Within Libya as many as five different climatic zones have been
recognized, but the dominant climatic influences are Mediterranean
and Saharan. In most of the coastal lowland, the climate is Mediterranean,
with warm summers and mild winters. Rainfall is scanty, and the
dry climate results in a year-round 98-percent visibility. The
weather is cooler in the highlands, and frosts occur at maximum
elevations. In the desert interior the climate has very hot summers
and extreme diurnal temperature ranges.
Less than 2 percent of the national territory receives enough
rainfall for settled agriculture, the heaviest precipitation occurring
in the Jabal al Akhdar zone of Cyrenaica, where annual rainfall
of 400 to 600 millimeters is recorded. All other areas of the
country receive less than 400 millimeters, and in the Sahara 50
millimeters or less occurs. Rainfall is often erratic, and a pronounced
drought may extend over two seasons. For example, epic floods
in 1945 left Tripoli under water for several days, but two years
later an unprecedentedly severe drought caused the loss of thousands
of head of cattle.
Deficiency in rainfall is reflected in an absence of permanent
rivers or streams, and the approximately twenty perennial lakes
are brackish or salty. In 1987 these circumstances severely limited
the country's agricultural potential as a basis for the sound
and varied economy Qadhafi sought to establish. The allocation
of limited water is considered of sufficient importance to warrant
the existence of the Secretariat of Dams and Water Resources,
and damaging a source of water can be penalized by a heavy fine
or imprisonment.
The government has constructed a network of dams in wadis, dry
watercourses that become torrents after heavy rains. These dams
are used both as water reservoirs and for flood and erosion control.
The wadis are heavily settled because soil in their bottoms is
often suitable for agriculture, and the high water table in their
vicinity makes them logical locations for digging wells. In many
wadis, however, the water table is declining at an alarming rate,
particularly in areas of intensive agriculture and near urban
centers. The government has expressed concern over this problem
and because of it has diverted water development projects, particularly
around Tripoli, to localities where the demand on underground
water resources is less intense. It has also undertaken extensive
reforestation projects (see Fishing and Forestry , ch. 3).
There are also numerous springs, those best suited for future
development occurring along the scarp faces of the Jabal Nafusah
and the Jabal al Akhdar. The most talked-about of the water resources,
however, are the great subterranean aquifers of the desert. The
best known of these lies beneath Al Kufrah Oasis in southeastern
Cyrenaica, but an aquifer with even greater reputed capacity is
located near the oasis community of Sabha in the southwestern
desert. In the late 1970s, wells were drilled at Al Kufrah and
at Sabha as part of a major agricultural development effort. An
even larger undertaking is the so-called Great Man-Made River,
initiated in 1984 (see Land Use and Irrigation , ch. 3). It is
intended to tap the tremendous aquifers of the Al Kufrah, Sarir,
and Sabha oases and to carry the resulting water to the Mediterranean
coast for use in irrigation and industrial projects.
Data as of 1987
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