PUB00013

• Year: 1985
• Title: Estimated Use of Water in Colorado 1985
• CWCB Section: Water Conservation & Drought Planning
• Author: David W. Litke and Cynthia L. Appel
• Description: Water-Resources Investigations Report 88-4101
• Publications - Doc Type: Brochure

file. The well-permit file includes a land net location and water-use
category code for each of the permitted wells (about 110,000) in Colorado;
these data have been tabulated by township showing the number of permitted
wells for each category of water use (Theodore Hurr, U.S. Geological Survey,
written commun., 1986). From this tabulation, the number of wells within each
county cataloging unit was estimated. This well-location information was used
as a rough check against ground-water withdrawal estimates made for each
county cataloging unit. The surface-water diversion file includes daily
withdrawal quantities, location of withdrawal point, and category of water use
for each of the ditches (about 14,000) in Colorado. The annual withdrawal
quantities for each water-use category were aggregated for each of the State
Engineer's water-resources divisions (roughly equivalent to hydrologic
subregion). The water-resources division withdrawal totals were compared with
hydrologic subregion totals estimated by this study, and, where necessary,
subregion estimates were adjusted to agree with data from the State Engineer's
Office.

It was estimated that 20,800 million gallons per day of water was used
in Colorado during 1985. Of this quantity, 89 percent came from surface-water
sources, and 11 percent came from ground-water sources.

Information about water-supply method also was gathered for this study.
Water-supply method was categorized as either self supply or public supply.
In general, self-supplied water is that which is withdrawn directly by the
user and not purchased from another party. For this report, self-supplied
water includes all water that does not come from public-supply systems.
Irrigation, mining, and livestock water users are considered to be entirely
self-supplied. Commercial, domestic, industrial, and power users may obtain
water by one or both methods. Water that is self supplied often is referred
to as a withdrawal, while water from a public-supply system is referred to as
a delivery.

Public-supply systems, also called "municipal-supply systems" or
"community water systems," are monitored by the Colorado State Department of
Health and are legally defined as those systems that serve 25 year-round
residents or maintain at least 15 service connections. Public-supply systems
deliver water to commercial, domestic, industrial, and power users.
Information about these systems, including population served, source of water,
and average system production, was obtained from the Colorado Department of
Health.

For each public-supply system, the following information was needed:
location of service area, population served, source of water, quantity of
water withdrawn, and quantity of water delivered to each water-use category.
There are approximately 750 public-supply systems in Colorado. About 160 of
the largest were contacted directly, and it is estimated that together these
largest systems accounted for about 90 percent of the total water delivered
and 90 percent of all the people served by public-supply systems during 1985.
Each supplier was asked to provide the information listed above. Often, not
all the requested information was available. Public-supply systems using
surface water were better able to quantify water-production data rather than

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