Decreased precipitation can affect stream flow, soil moisture, reservoir, lake levels and ground water recharge.
Farmers are most concerned with agricultural drought when available water supplies are not able to meet crop water demands. Agricultural droughts can occur for a variety of reasons, including low precipitation, the timing of water availability, or decreased access to water supplies.
Examples of affected sectors are drinking water supply, crop production (irrigation), waterborne transportation, electricity production (hydropower or cooling water), and recreation (water quality)
Meteorological drought refers to the level of dryness in an area, when it receives less than average precipitation. For an area to be classified as being affected by drought depends on the normal levels of precipitation. For example the great Australian desert would not be classed as a drought area because it recieves normal levels of precipitation for its climate.
Any change no matter how small in meteorological patterns can affect circulation patterns which then causes a knock on affect that can stop or daily rainy seasons in an area.
Atmospheric circulation and oceanic circulation control most climate patterns so any minor changes can have an impact, because of global warmth no causing warming of the oceans this affects where heat is distributed causing in some areas severe drought.
Desertification occurs often from poorly managed human intervention/use of certain ares this can cause severe drought and theses are some of the things humans do that cause this:
● Removal of vegetation cover.
● Uncontrolled fuel wood collection.
● Unsustainable farming practice and loss in fertility of soil.
● Excessive Agriculture
● Deforestation and tree felling.
When humans build dams this can have a detrimental impact as seen above, dams are built on rivers as flood defences, to create reservoirs, for industrial, agricultural and recreational use.
Restricting the flow of water in a river can lead to a drop of water levels further down stream- because it is no longer receiving the same amount of water it did before this can cause an area to dry up and cause drought.