FLOOD05425

• County: Delta
• Community: Delta
• Stream Name: Gunnison, Uncompahgre River
• Basin: Gunnison
• Title: City of Delta Confluence Park Project
• Date: 10/1/1989
• Prepared For: Delta
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

extension of th~ hard-point, however, carriE's the risk of
altering the imnediate river hydraulics, and its effects
should be considered, especially on bank stcLbility on the
other side of t::le river. The bank and overbank appear
relatively free of vegetation, and excavation for the
facility appear.;; to offer no difficulty. This site is
closest to the parking area, and ingress and egress appear
to be easily accommodated. Excavated material could easily
be placed to expand and elevate the parking area.

This launch facility would require excavation of the
riverbank from 3.bout elevation 4,926 to about elevation
4,921, about 2 feet below the 10-year flood elevation. The
river channel bottom would not be disturbed. The length of
the launch would be determined during final design.
Assuming about 3. 10 percent grade, the total ingress and
egress length would be about 100 feet. The width of the
egress and laun::h area should allow for comfortable passage
of two motorized vehicles. stabilization of the riverbank
at each end of the launch facility as well as along cut
slopes should be considered. The hard-point: immediately
upstream of the site should be properly armored since it
provides the hy:l.raulic characteristics which make this
launch site desirable. Bank stabilization t:echniques are
covered in Section 12 of this study. The surface of the
travel way should also be stabilized. Assuming about a
100-foot-Iong launch and another 100 feet for ingress and
egress, it is e.;;timated that about 1,500 to 2,000 cubic
yards of bank excavation may be required, and about 600
cubic yards of .dprap stabilization may be required.
Alternative sta,oilization methods may also be considered.
Due to the erosive nature of the soil, riprap stabilization
would also require a filter material under t:he riprap.
Stabilizing mat,~rial assumes a 2-foot layer of riprap on a 1
vertical to 2 h,::>rizontal slope for a 300-foot length; it may
be modified or .~liminated to a large extent if greater
maintenance and risk is acceptable. Typical details of
other launch fa.::ility features that may be desirable to
incorporate are shown on a set of blueprints provided to the
City of Delta,:itled Elkhorn Regional Park, Yolo County,
California, by ':he Sacramento District, Corps of Engineers.

11. Lime Fill ]1ateria]~.

Lime waste produced as a result of the sugar beet
processing is l,)cated north, northeast, and east of the fish
pond. Lime was':e fill extends eastward with.in 200 feet of
U.S. Highway 50. The lime material is conta.minated by
organic waste Wllich alters the expected engineering
properties of tlle lime. The organic waste makes the lime
material highly compressive and reduces its strength. Lime
uncontaminated by organic matter can be added to soil to
improve the engineering characteristics of t.he soil.
Depending on thr~ soil types, lime admixtures can improve
workability, decrease plasticity and swell, and in some

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