WSP11971

• File Number: 8149.100
• Description: Miscellaneous Small Projects and Project Studies - NRCS-Ft Lyon Canal Co Limestone Graveyard Creeks
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 6/2/1993
• Author: Gronning Engineering
• Title: Ft Lyon Canal Company Water Transfer Alternatives Study Phase 1 Report
• Water Supply Pro - Doc Type: Report/Study

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CHAPTER 1

INTRODUCTION

Scope and Purpose of the Study

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As established by the Co rado State Constitution, water is appropriated for beneficial use. In the
development of the ate, water supplies have been appropriated for domesric, agricultural and
industria}iurpose~ As Colorado has continued to grow, the demands for domestic (municipal)
water supplies h~created economic incentives to sell and transfer agricultural water supplies.
This report, authorized by the Colorado General Assembly as a part of Senate Bill 92-87, documents
a multi-disciplinary study of issues arising out of a possible large-scale transfer of water out of the
Ft. Lyon Canal to alternative uses. It examines changes to be anticipated in such a water transfer
and proposes alternative actions to such a water transfer. This chapter presents introductory
information on the Arkansas River Basin and the area of study.

In Chapter 2, issues associated with water transfers in and around the study area are presented
along with information on historic water transfers. Chapters 3 and 4 present descriptive
information of the Ft. Lyon Canal Company system and the regional socio-economic characteristics.
They include a physical description of the system, operational analysis, historical background, and
characterization of the social, economic and environmental aspects of the study area, Chapter 5
identifies current and future demands for Ft. Lyon water, inside and outside the study area.
Chapter 6 describes the methods employed in alternative analysis and identifies alternatives to
potential water transfers out of the Ft. Lyon system. In Phase 2 of this report the most promising
altemative(s) and proposed plans for implementation will be developed.

Basin Characteristics

The Arkansas River originates upstream from Leadville at an elevation of over 14,000 feet and exits
the state near Holly at 3,400 feet. The basin is illustrated in Figure 1.1. In passing through the
plains east of Pueblo to the state lin~, the river gradient is less than 9 feet per mile. About 25,600
square miles is tributary to the Arkansas River in Colorado. Geologically, in the plains the valley
aquifer rests in a U-shaped trough, cut into cretaceous shale and limestone bedrock.

Climate in the Arkansas River Basin varies widely in both temperature and precipitation, On the
plains, annual precipitation levels increase moving eastward from Pueblo, reaching an average of
about 16 inches per year at the state line. Over the study area, average rainfall is 11 to 15 inches,
with a high degree of areal, daily, seasonal and annual variability.

The basin's water resources consist of snowmelt, rainfall runoff and ground water development.
Most of the surface irrigation systems were constructed between 1874 and 1890. As junior water
rights appropriators realized that remaining natural streamflow was generally too variable to supply
irrigation requirements during many years, they constructed reservoirs to capture flood flows. The
estimated 30-year average annual native streamflow is 283,000 acre feet (af) measured at the
Arkansas River gage below Pueblo Reservoir. An additional net 172,000 af is imported from other
basins by transmountain diversion projects for use in the Arkansas River Valley (USGS and SCS
1992), Total diversions for Colorado ditches between Pueblo and the Kansas state line are

1-1