BOARD02035

• Board Meeting Date: 5/16/2006
• Description: ISF Section - Arkansas River Instream Flow Appropriation
• Board Meetings - Doc Type: Memo

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The urbanization of the riparian corridor has an affect on the natural characteristics of the stream
environment and the stream hydraulics, The resulting modification of the stream hydraulics and
natural hydrology has had an affect on the natural streambed composition. The existing stream
channel must be able to convey large volumes of water efficiently without flooding. This
segment functions as an urban corridor stream, and must be able to handle a higher frequency of
greater magnitude storm events due to the large amount of impervious areas located within the
watershed, To accomplish this task, urban streams generally have a limited number of
obstructions located within the channel that provide cover or holding areas for fish, In general,
to improve the fisheries in these urban corridor streams more holding areas or fish habitat must
be created without adding too much of an obstruction to cause flooding problems.

This reach of the Arkansas River has been significantly improved as part of the Pueblo Arkansas
River Corridor Legacy Project (Project). The original stream channel was modified after the
1921 flood to minimize the chance of future flood damage, This resulted in a sterile
environment, in areas, providing little potential for fish habitat or recreational opportunities.

The Project's goals were to change this corridor from a rarely used flood channel to a highly
valued recreational amenity to the community, The Project included approximately 7.5 million
dollars for fish habitat improvement work. The City of Pueblo, Pueblo County, V,S. Army
Corps of Engineers, Great Outdoors Colorado and the DOW all provided funding and expertise
for the Project. To provide the needed additional habitat for fish without diminishing the ability
of the channel to convey high flows, numerous channel modifications, including J, V and W-
shaped weirs were added within the upper segment of this reach. Strategically placed boulders
were positioned between the weirs as well as within the kayaking area. The combination of such
structures and boulders has created a series of drop pools and eddies, allowing for fish passage
and holding areas during high flows. These same structures also provide important pool habitat
during periods of low flow. As documented in the attached article "Extreme Makeover"!, this
project has taken a broad flat river which provided little habitat or cover for fish at the extreme
ends of the flow regime and modified the channel to provide velocity shelters during the high
flows and deeper pools during low flows,

This river segment along with the associated river corridor provides substantial recreational
opportunities including fishing, wildlife watching, boating, walking and biking. A bike path runs
the length of the segment connecting Lake Pueblo State Park, located at the upper end of the
study reach, and DOW's RunyanlFountain Lakes State Wildlife Area, located near the lower end
of the study reach at the confluence of the Arkansas River and Fountain Creek. This river
corridor is a significant asset to the City of Pueblo and to the local economy of the region. All
recreation activities at Pueblo Reservoir and along the Arkansas River for several miles
downstream of the dam are managed by the Department of Parks and Outdoor Recreation
(DPOR) under an agreement with the Bureau of Reclamation (BoR). The DPOR estimates that
1.7 million people use the recreation aspects of Lake Pueblo State Park annually, The land
ownership in these reaches is almost entirely public with the exception of a few parcels. All of
the lands, whether owned by the City, Bureau of Reclamation, State Parks, Pueblo Board of

1 Colorado Outdoors September-October 2005 Issue written by Karl Licis

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