FLOOD06640

• Designation Number: 100
• County: Otero
• Community: La Junta
• Stream Name: Arkansas River, Anderson & King Arroyos
• Basin: Arkansas
• Title: Special Flood Hazard Information Report - Arkansas River, Anderson and King Arroyos, La Junta, Otero County, CO
• Date: 8/1/1977
• Designation Date: 3/1/1978
• Floodplain - Doc Type: Floodplain Report/Masterplan

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BACKGROUND

In the study area, the flood plains north of the Arkansas
River are approximately one mile in width, very flat and bordered
on the north by low bluffs or hills. The flood plains south of
the river vary from one-fourth to one-half mile in width. Hills
on the south side rise more gradually than on the north, with an
average rate of rise of about 125 feet per mile. Land along t~
north side of the river is largely agricultural although approx-
imately one mile, through North La Junta and La Junta Gardens,
is fairly densely developed as a residential area. The city
of La Junta occupies approximately two miles of the land on the
south side of the river while the land east and west of the
city is used for agricultural purposes. either grazing or
cultivated.
Arkansas River tributaries considered in this study
are King and Anderson Arroyos. 80th arroyos are right bank
tributaries and originate south of La Junta, flow through the
edges of the city and enter the Arkansas River about 1.3 miles
apart. King Arroyo flows almost due north along the east side
of La Junta and has a well-defined flaw channel for the entire
lenqth in the study area. rt is about ten feet deep through-
out with some widened areas providing small flood plains within
the banks. The lower portion, from the Arkansas Riv<)r to 3r<.l
Street, has been partially shaped and riprapped. The ramdin-
der is ina natural state, with the exception of large all1ount..
of junk and debris wn.icn. have been dumped into it in thevidnT
ity of 14th Street, causing some Choking of the channel. The
arroyo channel has an average slope of 24 feet per mile within
the study area. King Arroyo drains an area of about 25 square
miles.

settl.,.,,,nt

La Junta is located in the fertile Arkansas River Valley
in tILe southeastern section of Colorado. It is the county seat of
Otero County and is located in east-oentral Otero County. This seC-
tion of the Arkansas River Valley is a rich agricultural and stock
raising territory, which is the basic econornyof th..area. This
economy has been fairly stable through the years.
Touris~ is also a source of income. Eight miles east of
La Junta is Bent's Old fort National Historic Site. The fort waS

once important as a fur-trading post, Indian rendezvous, advance
ba~o in ~~" war with Mexico and way station 0n the Santa Fe Trail.
La Junta is also the homo of the nationally known Koshare Indian
Explorer Scouts, a group of Boy Scouts who give exhibitions of
authentic ~erican Indian dances.

The Streams and Their Valleys
The Arkansas River above canon City is a typical mountain
stream which descends over 6,000 feet in elevation in a dist..nc" of

less than 130 miles, at gradients often exceeding 50 feet per mile.
Between Canon City and Pueblo, the valley is generally narrow and
the streambed WOll-defined with a gradient ranging from 10 to 23
feet per mile. The river valley widens below Fueblo and varies in
width from one to three miles throughout eastarn COlorado. In this
reach, the gradient fluctuates between five and nine feet per mile,
with an average of about 6.7 feet per mile in the study reach of
La Junta. The land immediately adjacent to the river has heavy
growths of trees and brush. The Arkansas drainage area above River
Mile 1,198.1 at La Junta is 12,210 square miles.

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