It has previously been noted that climatic shifts can have a significant impact on desert hydrology and in turn human occupation of the landscape. In addition to the climatic component of hydrological change there is an increasing anthropogenic component. There are four major ways in which humans are interfering with desert water resources (Laity, 2008):
1: Groundwater withdrawal. Groundwater is increasingly used for the maintenance of human settlements and plant and animal habitats. Its withdrawal by far exceeds natural rates of replenishment.
2: River flow alteration. Rivers are being diverted away from their natural cause for the purpose of land irrigation and the construction of dams to regulate flow.
3: Salinisation. Contemporary irrigation technologies have resulted in increased salinity as extremely high evaporation rates cause mineral salt precipitation. The land is severely degraded as a result and fertility is much reduced. In turn, crop yields reduce.
4: Lake disturbance. Pollution e.g. disturbances of geochemical balances through processes including eutrophication or toxic dust absorption can have long-standing impacts on closed or semi-closed basins.
References
Laity, J. (2008) Deserts and Desert Environments, Chichester: Willey-Blackwell
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