FLOOD11630 ‎(2)‎

• County: Statewide
• Basin: Arkansas
• Title: Post Flood Assessment Report - Arkansas River
• Date: 9/15/1999
• Floodplain - Doc Type: Flood Documentation Report

The Pueblo Floodway Levee Extension was completed in 1952. The Ievee extends the
lower end of the 10,000-foot long Pueblo Floodway on the Arkansas River in th~e city of Pueblo.
The floodway is part of a major flood control improvement that was constructed by local
interests between 1924-1925 after a disastrous flood in 1921. Rock Canyon Bar.rier Dam, a
concrete gravity and earthfill retarding structure on the Arkansas Rider 6 miles upstream of
Pueblo, was also constructed by local interests to regulate major floods on the Ackansas River to
the capacity of the floodway. Barrier Dam was later engulfed by the lazger Pueblo Dam project
completed by the Bureau of Reclamation in 1975 at the same site. The Pueblo floodway is a
concrete trapezoidal channel with a capacity of about 110,000 cubic feet per second (c.f.s.). The
purpose of the levee extension is to prevent inundation of an urban area of impoitant industrial
and transportation facilities by backwater from floods on the Arkansas River.
The Fountain Creek Levees and Channelization project was completed in July 1~89 and consists
of two levees and channel excavation work. The west levee begins just upstream of the 8`~ Street
bridge and extends 600 feet downstream. A concrete floodwall extends upstreana from west
levee another 787 feet. The east levee is comprised of both earth an~ soil cement sections. The
east levee begins approxunately 1,500 feet upstream of the 8t° Street bridge past I3`h Street and
extends 8,316 feet downstream to the Ivlissouri Pacific Railroad bridge, just past <~n existing
grade control structure. A recreational trail extends another 1,200 feet downstream past a
recreational area built within the east floodplain. The trail ends with a pedestrian bridge
traversing over Fountain Creek to the west overhank. Channel excavation work was conducted
primarily along the west river channel over a distance of 10,500 feet io obtai.n suf~icient flow
capacity to pass the 200-year flood.
The Corps af Engineers completed Pinon Canyon Dam in 1954. The dam protects a highly
developed urban area of about 40 acres in the northwestern and central sections oi~ Trinidad from
floods that originate in the watershed of Pinon Canyon Arroyo. The arroyo has a drainage area
of about 1.4 square miles. Pinon Canyon Dam is an eazth dam with a reservoir stc~rage capacity
of 406 acre-feet.
In February 1977, the Corps completed the large multiple purpose Trinidad Reservoir project on
the Purgatoire River, about four nules upstream from the city of Trinidad. Trinida~d Reservoir
provides a high degree of protection to the city of Trinidad and the agricultural areas above and
below the ciTy. The project also regulates the available water supply for more effective
agricultural use. A permanent pool is also maintained for fish, wildlif~ and recrea~ion. The dam
is a 200-foot high earthf 11 structure with a crest length of 6,610 feet. 'I'he capacity of the
reservoir is 114,500 acre-feet, with 51,000 acre-feet allocated to flood control, 20,000 acre-feet to
irrigation, 4,500 acre-feet for the permanent fishery pool, and 39,000 acre-feet for sediment
retention. The project can regulate flood discharges of 125,000 c.f.s. down 14,500 c.f.s.; the safe
channel capacity through the city of Trinidad. However, the dam does not signuficantly affect the
flood peaks at the mouth of the Purgatoire River downstream of Las Animas.
Chapter 2- History of Flooding and Flood Protection
Post Flood Assessment Report 10 Draft Revised 09/09/99