S1_11-15-04

• Basin: Statewide
• Title: SWSI Phase 1 Report - Section 1 Introduction
• Date: 11/15/2004
• Author: CWCB
• SWSI - Doc Type: Final Report

Section 1
Introduction
tributaries, but the primary source of water is
groundwater from the Northern High Plains Aquifer, also
known as the Ogallala Aquifer.
At the time of SWSI implementation, the Republican
River Basin had just completed the settlement of a
lawsuit between Kansas and Nebraska, which eventually
also included Colorado. In general, the lawsuit resulted in
the need to reduce some of the consumptive use (CU) in
the basin in Colorado. The Colorado State Engineer is
responsible for administering the terms of the settlement.
For these reasons, at this time, the CWCB elected not to
focus on the Republican River Basin as part of SWSI.
1.2.3 Arkansas River
The Arkansas River begins in the central mountains of
the state, near Leadville. It travels eastward through the
southern part of Colorado toward the Kansas border.
Several tributaries flow from the high southern mountains
toward it from the southwest, and there is some drainage
from the higher plains north of the main stream.
The basin includes slightly less than one-third of the
state's land area. Over 20 percent of the land is publicly
owned. A high percentage of the land is devoted to
agriculture and about one-third of this land is irrigated.
Increasing urbanization is occurring in the Arkansas
River Basin.
1.2.4 Rio Grande
The Rio Grande drainage basin is located in south
central Colorado and is comparatively small with less
than 10 percent of the state's land area. Land is about
evenly divided between public and private ownership.
It is largely rural, and agriculture is the main industry in
the basin. Since it lies between two high mountain
ranges, the San Juan and the Sangre de Cristo, it is
somewhat isolated. This factor, coupled with a reduction
in logging and mining, has suppressed employment
opportunities and has resulted in a recent decline in
population.
~~
1.2.5 Overview of Supplies
In Colorado, both surface and groundwater are used for
irrigation and other agricultural uses, municipal and
industrial (M&I) supplies, and domestic uses. On the
Western Slope, although there is some domestic use of
groundwater, the main source of supply is surface water.
In the San Luis Valley, both surface and groundwater
supplies are used, while on the eastern plains the
primary source is groundwater for all uses. Front Range
cities rely mostly on surface water (some of it diverted
from the Western Slope), but many smaller towns and
more rural subdivisions use groundwater. Agriculture and
municipalities in the northeastern and southeastern parts
of the state use large amounts of surface water including
diversions from the Western Slope, but groundwater is
also heavily used.
The right to divert the unappropriated waters of any
natural stream to beneficial uses shall never be denied.
~ ~r~i~le ~~I; ~~~ti~~ 6,
~olorado Constitution
Surface water supplies depend on precipitation, much of
which originates as snowpack in the state's high
mountainous areas. The Continental Divide dictates the
direction of water flow either to the west or to the east for
each of the river systems in the state. Colorado is unique
in that each of its major river systems originates in the
state; water not captured or used in the state flows on to
neighboring states and in many cases is governed by
interstate compacts and agreements.
There are billions of gallons of groundwater in the
confined (artesian) aquifers. Some major aquifers are the
Ogallala in eastern Colorado; the Denver Basin, which
stretches from Fort Collins to Colorado Springs; and
another underlying the San Luis Valley. See Section 7 of
this report for more detailed information on water supply.
~~
Sfvtewide Woter Supoly Initiofive
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