A paper issued earlier this year from the Council of
Agricultural Science and Technology (CAST) examines the causes and consequences
of groundwater depletion throughout the US. “Groundwater is the Earth’s most
extracted raw material, with almost 800 million acre-feet per year of
groundwater pumped from aquifers around the world. Approximately 70% of
groundwater withdrawals worldwide are used to support agricultural production
systems. This percentage is even higher in arid and semi-arid areas, where the
only consistent source of irrigation water is groundwater. In these regions,
however, the use of groundwater typically far exceeds the rate at which it is
naturally replenished, indicating that these critical groundwater resources are
being slowly depleted.
Within the US, groundwater depletion has occurred in many
important agricultural production regions, including the Great Plains Region,
the Central Valley of California, the Mississippi Embayment Aquifer, aquifers
in southern Arizona, and smaller aquifers in many western states. This issue
paper reviews the causes and consequences of groundwater depletion, with a focus
on impacts to agriculture as the largest sector of groundwater use. This
understanding can aid in developing effective policies and practices for
groundwater development, use, and management.”
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