sècheresse - Drought
Publié le 10/03/2022
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INTRODUCTION
Drought is a natural phenomenon characterized by a lack of water over a period
long enough to affect soils and vegetation.
An episode of drought can be
occasional or cyclical.
It is explained by a temporary rainfall deficit, which is not specific to the
climate of the affected area but which lasts long enough to be damaging.
THE DIFFERENT TYPES OF DROUGHT
• Meteorological (or atmospheric) drought: this corresponds to too little rainfall
over a prolonged period.
• Agricultural drought: it exists when the humidity rate in the soils (at a depth of
one meter) is too low to ensure good growing conditions.
• Hydrological drought: it manifests itself when the level of water courses
(groundwater in groundwater and surface water in rivers, lakes and rivers) drops
significantly, this is called low water.
THE DIFFERENT CAUSES OF DROUGHT
Natural causes (meteorological)
Water deficit and high temperatures are the main causes of drought.
• In the event of insufficient precipitation during winter and spring (between
September and March), the water reserves cannot be recharged as they should to
maintain a hydrological balance.
• And if this lack of water is accompanied by high temperatures, this leads to a
natural increase in evaporation and evapotranspiration of plants, resulting in soil
drying and erosion.
And global warming tends to favor these phenomena.
Human causes
Excessive water consumption for human activities can lead to worsening
drought.
When water supplies decline due to unfavorable weather conditions
(persistent high pressure), they are not always managed effectively by humans
in their agricultural, industrial and domestic operations.
Overexploitation of
water resources can cause groundwater to dry up and threaten their
sustainability.
WHAT ARE THE CONSEQUENCES OF DROUGHT
The consequences on the flora
Dry and dehydrated trees can eventually die, and very dry vegetation can
facilitate the start of fires, emitting harmful gases that pollute the atmosphere
and accentuate the greenhouse effect.
Trees become much more vulnerable to cold for up to ten years after a drought.
DROUGHT
Class 1 ère D Lycée Fatou Sylla
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