PROJ00273

• Contract/PO #: C153368
• Contractor Name: Cache LaPoudre Water Development Study
• Water District: 0
• County: Larimer
• Bill Number: SB 81-439
• Loan Projects - Doc Type: Feasibility Study

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CHAPTER II
BASIN DBSCRIP'l'IOR

A.

Dl'l'lGlUC'l'ICH

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This chapter contains a general description of the Cache la Poudre River
Basin, including a physical description of the basin and a discussion of the
present water use within the basin. It also discusses the existing power
system. It is intended to provide an understanding of the present day
conditions for comparison to projected future conditions with and without a
potential Cache la Poudre Project.

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B. LOCATIOR ARD PHYSIOGRAPHY

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The Cache la Poudre River Basin lies in north-central Colorado on the
eastern slope of the Continental Divide of the Rocky Mountains. The basin is
shown on Figure II-I. The Laramie and Medicine Bow mountain ranges form the
western boundary of the basin separating it from the Laramie River, Michigan
River and Colorado River basins. The Mummy Range and foothills to the east of
the Mummy Range form the southern boundary of the basin separating it from the
Big Thompson River drainage. The northern boundary develops in the high
plateau region of southern wyoming. The eastern boundary is in the low ridges
common to the transition zone between the foothills and plains. Separate
ridges divide the Cache la Poudre River basin from that of other South Platte
River tributaries, Lone Tree Creek and Owl Creek. The Cache la Poudre River,
a major tributary of the South Platte River, discharges into the South Platte
River near the City of Greeley.

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Elevations in the basin vary from just over 4,600 feet at the confluence
with the South Platte River to 13,560 feet on Hagues Peak in the Rocky
Mountain National Park. Along the southern boundary of the basin there are
five mountain peaks with elevations greater than 13,000 feet.

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The mainstem Cache la Poudre River is fed by two major tributaries, the
North Fork Cache la poudre River and the South Fork Cache la Poudre River
(known locally as the Little South Fork). The North Fork Cache la Poudre
River enters the mainstem at River Mile 60.3; river mileage being measured
upstream from the confluence with the South Platte River. The North Fork
drainage basin ranges in elevation from about 5,550 feet at its confluence to
11,000 feet on South Bald Mountain. The South Fork Cache la Poudre River
enters the mainstem at River Mile 73. Its drainage basin ranges in elevation
from about 6,570 feet at its confluence to 13,400 feet on Rowe Peak.

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As shown on Figure II-I, the Cache la Poudre River Basin is composed of
two distinctly different geographical units. The mountainous upper basin is
primarily the water yielding area. The lower basin, in the Colorado Piedmont
section of the Great Plains Province, is the area of water use. The mouth of
the Cache la poudre River canyon, about 13 miles upstream from the City of
Fort Collins, is roughly the dividing line between the upper and lower

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