FLOOD00002

• County: Delta
• County: Gunnison
• Community: Hotchkiss to Somerset
• Stream Name: North Fork Gunnison River
• Title: Flood Hazard Information
• Date: 2/1/1980
• Prepared For: Delta County
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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FLOOD HAZARD INFORMATION

Dam. From its source to jts mouth near Lazear
the stream flows about 30 miles on a southwest~
erly course. Its tributary drainage area (a part of
the Colorado River Basin) is situated in west-
central Colorado on the western slope of the
Rocky Mountains. At Hotchkiss and Somerset,
the stream drains 940 and 530 square miles,
respectively. Elevation ranges from 5400 feet
(NGVD) at Hotchkiss to around 13,000 feet in
the highest headwater regions, and stream
gradients vary from about 30 feet per mile at

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Hotchkiss to 60 feet per mile at Somerset.
Terrain of the basin is mostly mountainous with
some mesa and tableland in the lower portion.
Predominant vegetation consists of pine, fir,
and spruce in the high portions of the drainage
area, while sagebrush and other low-growing
shrubs are characteristic in the lower portions.
Thick stands of cottonwood occur along the
river. A map of the North Fork Gunnison River
Drainage Basin and its tril:iutaries within the
study limits is shown on page 3.

NORTH FORK GUNNISON RIVER.

Hotchkiss to Somerset, Colorado

CONTENTS

Page

NATURE OF FLOOD PROBLEMS

INTRODUCTION .......
NATURE OF FLOOD PROBLEMS
FUTURE FLOODS .......

General frontal-type rainstorms approaching
from the southwest can occur over the North
Fork Gunnison River basin from mid-June
through December, but records show that they
occur most often during September and
October. Convective-type cloudburst storms
occur frequently during the summer in west-
central Colorado. Most of the annual precipita-
tion in this region, however, occurs as snow and
a deep snowpack usually accumulates in the
high areas. Studies show that rapidly melting
snow in the spring and early summer constitutes
the principal source of flooding along the North
Fork Gunnison River. Severe floods result when
rapid snowmelt is augmented by rain. The
largest flood known in the Gunnison River
basin occurred in June 1884. It is probable that
flood conditions along the North Fork were also
severe that year.

Generally, high flows along the North Fork
Gunnison River are contained in-channel, and
extensive overbank flooding is infrequent.
However, newspaper accounts indicate flood
damage. to orchards, roads and road bridges,
railroad facilities, homes, and business estab-
lishments in 1906, 1907, 1912, 1916, 1917, 1920,
and 1927. All flood events occurred in May with
damage specifically mentioned in Bowie,
Paonia, and Hotchkiss. Serious erosion of
farmland, pastureland, and orchards is known
to have OCCurred. In descending order of
magnitude, the highest recorded flows on the.
North Fork occurred in May 1932, June 1957,
May 1929, May 1973, May 1928, and May 1974.
Peak flows of the larger historical floods on the
North Fork Gunnison River in the study area are
shown in the following tabulation.

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APPENDIX

A PEAK FLOWS AND STAGES . . . . . . . . . . . . . . . . . . . . . . . . . . 7

PLATES

PLATES

1 INDEX MAP
2-16 FLOODED AREAS
17-33 FLOOD PROFILES

PEAK FLOWS OF HISTORICAL FLOODS

INTRODUCTION

Peak Flow (cubic feet per second)
Near Paonia CaRe Near Somerset Cage

Date

This report covers the findings of a flood
hazard information study of the North Fork
Gunnison River from Hotchkiss to Somerset, a
distance of 21 miles. Its purpose is to provide a
basis for planning to avoid or reduce damage
from the use of lands subject to inundation by
the 100-year flood. Topographic maps and
channel cross sections needed for the report
were jointly provided by the Colorado Water
Conservation Board and the Commissioners of
Delta and Gunnison Counties. Data on past

floods, as well as other information useful in
making the study, were obtained from local
residents, County Planning Departments, and
State and Federal agencies.

Hotchkiss is in Delta County at the junction
of State Highway 92 and 133, and Somerset
(Gunnison County) is 17 miles northeast from
Hotchkiss along Highway J33. The North Fork
Gunnison River is formed by the confluence of
Muddy and Anthracite Creeks near Paonia

3 May 1928
15 May 1929
12 May 1932
4 Jun 1957
21 May 1973
8 May 1974

6,450
7,310
8,590

7,860
6,580
5,130

'Gage not in operation.

incl1

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