FLOOD08449

• County: Bent
• Community: Bent County
• Basin: Arkansas
• Title: Lower Arkansas River Watershed and Flood Mitigation Plan for Bent County
• Date: 10/1/2000
• Prepared For: Bent County
• Prepared By: CWCB
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

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Section One
Purpo.'ie. and Dt'/ini/;on,\'

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The Lower Arkansas River Watershed Plan is a frame....ork for constructi...ely developing strah..-gies 10
impru\e the river system of the Arkansas and Purgatoire Rivt:f from the west boundary of Bent County to
the Pro"crs Co. linC'. The- focus orthe plan is on flood mitigation. COrTl."Ction of channel evolution
(becall.'>e of the downstream efft.'Ct of dam management), wetland and habitat restoration and protection,
waler quality protection. and enhancing the natural and beneficial functions of the floodplain.

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DefinitiorL~

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ARSC: Arkansas River Sleering Committee

ewes: Colorado Water Conservation Board

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Rj.~k; The phenomena orlhe relationship betwl..-en an um..anted circumstance happening based on the
potential for it 10 actually happen.

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Tool.s: Collective ideas. strateg.ies. and plans to mitigate flood and watershed issues. Tools are classified
as structural and non-structural. The National Flood Insurance and homcowm.'fs in...urance
policics are examples of non.struclural tools, structural tools include: levl.-es. channel
improvement, bank stabilization. vegetation removal. and bank contouring.(See Appendix ^)

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Section Two
C(}mmuni/J'lJnJ Riw!T lli\lfln'

Communitv l>escriptioo

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Bent County is located in the eastern plains of southern Colorado. Las Animas is the county seat and the
population center of Bent Count). and is located approximately 80 miles east of Pueblo. The population
of the county is approximately 3,193 the population of the Las Animas is about 3,o.t8. State Highway 50
is the major east.west highway that passes through the northern part of Bent County and the City of Las
Animas. Bent County is bounded by Kiowa Count)' to the north. Prowers County to the east. Baca and
Las Animas Counties to the south. and Otero County to the west. The section of Bent County covered in
this plan includes all of the Arkansas and part of the Purgatoire Rivers. Stale Highway 101 is a main
artery going south of Las Animas to Highway 160 in Baca Count). ....hich crosses the Purgatoire River
south of Las Animas.

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\\lalenhed llescription

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The Arkansas River rises in the Rocky Mountains. Lt.'3dville. in central Colorado. From its source to
Cannon City. Colorado. the stream is a typical mountain torrent descending from e1e\oation 11.500 feet to
5300 feet. This s~'(:tion is characterized by a succession of narrow valleys separated by short canyon
st..'(:tions. Between Canon City and Pueblo. the vallcy widens slightly and is flanked by foothills as it
descends to elevation 4.700 fet.'l at Pueblo. Here the ri\o'er emerges into a plains section and the stream
course is characterized by low banks and a broad sandy tx,:d. ....hich shifts fr~'quently. Elevation of the
slrcambl.>d at John Manin Dam is 3.765 feet and from there descends gradually to 1800 feet at Great
Bernd. Kansas. Slopes vary from a maximum of about 110 feet per mile in the mountain reaches to about
7 fC1.1 per mile in the plains section. Abo....e John Manin Dam. these slopes result in 1100d flows
characterized by rapid rise. high peak discharge and soon duration. ....hile the more moderate slopes
between the dam and state line tend 10 flatten the peaks and extend the duration of a flood wave. The river

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rpAGE 1_