WSPC01188

• File Number: 8064
• Description: Indian Water Rights
• State: CO
• Date: 1/1/1987
• Author: American Indian Reso
• Title: Tribal Water Management Handbook
• Water Supply Pro - Doc Type: Report/Study

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TRIBAL WATER MANAGEMENT HANDBOOK

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watcr in the arid pans of the western United States and probably would intensify the
sentiment in some quarters against Indian water rights.

Whatever happens with the climate, it will remain variable and challenging to
predict Roods and droughts must continue to be anticipated. The current trend in
water resource planning is to try first 10 identify the risks associated with climatic and
other uncenainties, and then to put a price tag on the flood-control and drought-
mitigation measures involved with different levels of so-called "risk avoidance."
This process can be expected to continue, even though many observers think the
process is more an than science.

Cities v. Crops: Patterns of Urbanization and IrrigatWn

The population of cities generally has been expanding dramatically in recent
decades in some areas such as the Sun Belt.3 The growth in population has increased
water demand, taxing local supplies, even threatening to exhaust some imponed
supplies. Denver, Phoenix, Tucson, Albuquerque, Santa Fe, San Diego and many
other communities, large and small alike, have sought to add to their supplies. Since
irrigated farms account for 85% of the water consumption in the West,4 it is not
surprising that cities and industries have purchased irrigated farmlands to acquire
water rights. Urban areas, as centers of wealth and political power, can be expected
to continue to be aggressive competitors for water.

Since World War II, irrigated acreage has expanded in the West to the point
where now over 40 million acres are estimated to be under irrigation in 17 western
states of the conterminous United States.5 Although irrigation has been expanding in
the Southeast, the West accounts for 90% of irrigation water use in the nation. The
location of much of western irrigation has shifted gradually away from the Sun Belt
toward the Nonhem Plains. This change has occurred partially as a result of the use
of the center-pivot sprinklers to apply pumped ground water in Kansas and Nebraska.
Overall, the national rate of growth in irrigation has been declining and is likely to
continue doing so because of the cost of energy and water.

Renewable v. Nonrenewable Supplies: Ground Water Overdraft

Ground water use has been increasing rapidly in the United States for decades.
Ground water is the source of one-half of the nation's drinking water and 40% of its
irrigation water and supplies about 80% of the domestic and livestock needs of rural
America. California and Texas account for a disproportionately large share of the
total ground water use, followed by Nebraska, Idaho, Kansas and Arizona.6

Most usable ground water is "riverene"-an integral part of the surface flow of
streams and rivers-and is recharged by the percolation of water from the surface of
the land. The recharge rate in some aquifers is so slow or minimal, however, that
those aquifers contain essentially "stock" or "nonrenewable" ground water. As
explained later in this Handbook, when ground water withdrawal exceeds the
recharge, an aquifer is said to be "mined" or "overdrafted." Ground water is being
overdrafted in the West at the rate of about 22 million acre-feet per year, which is
roughly equivalent to one and a half times the mean annual flow of the Colorado
River at Lees Ferry. Whether overdrafting increases or decreases in the future will

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