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• Board Meeting Date: 5/20/2009
• Description: WSP Section - Tamarisk Control Cost Sharing Grant Pr9ogram - Transmittal of Grant Applications
• Board Meetings - Doc Type: Memo

Statement of Existing Ecological Condition
Of the South Platte River in Sedgwick County

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The South Platte River flows northeast for approximately 28 miles
across the northwest quadrant of Sedgwick County. The river bottom
riparian area varies from a quarter to three eighths of a mile wide and
has developed a meandering, braided stream channel with
associated sandbars and small islands. '

Native plains cottonwood and native Peach leaf willow are the
overstory dominant species. Riparian ecosystem functions provided
by willows and cottonwoods include the following: 1) Riparian
vegetation traps sediments and nutrients from surface runoff and
prevents them from entering the aquatic system; 2) the dense matrix
of roots in the riparian zone can serve as an effective filter of shallow
groundwater; 3) water quality is improved through filtration and the
trapping of sediment, nutrients (particularly nitrogen dissolved in
groundwater), and pollutants; and 4) riparian areas act as a sponge
by absorbing floodwaters. The water is then slowly released over a
period of time, which minimizes flood damage and sustains higher .
base flows during late summer. These overstory trees are vital to
cavity nesting birds and small mammals. The understory is made up
of grasses, forbs and coyote willows.

The South Platte River is home to and frequented by many species of
birds and animals including deer, beaver, muskrats, turkeys, quail,
songbirds, migratory waterfowl, hawks, bald eagles and many small
mammals.

Decreased flows in recent years have allowed vegetation to increase
on sandbars and encroach on the channels. Where Russian olive has
become established, cottonwood and willow trees have been
displaced. Russian olive does not have the extensive filtering root
system like the willows and cottonwoods and does not provide holes
for cavity nesters.

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