FLOOD09590

• County: Arapahoe
• Community: Aurora
• Stream Name: Cherry Creek Lake
• Basin: South Platte
• Title: Hydrologic Improvement Assessment Cherry Creek Lake
• Date: 9/1/1993
• Prepared For: State of Colorado
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Project

aLTERNATIVE 7 - RAISE DAM CREST
This alternative considered a reinforced concrete parapet wall located on
the upstream side of the crest or an earthfUl dam raise. A typical concrete
wall section is shown on plate 30. The dam cn,st raise was included as part of
the other alternatives in some combinations and was also considered by itself,
with raises of 3, 9, 15, and 19 feet. Ni.net~~en feet is the maximum height of
wall or dam raise necessary for complete containment .ofthe PMF with freeboard
without any other modifications to the project under existing developed
conditions.

Raises up to 9 feet (el, 5654) can be accommodated within the Federal

Government boundary at both abutment locations. At t:he right abut:ment, the

embankment raise would be tied into Parker Road, a major four-lane road.

Elevations of the crest higher than 5654 feet m, s. 1. (9 - foot raise) would extend

outside of the Government Boundaries art both right and left: abutments and require

increased costs. At the right abutmeI1t, t:he erest would need to extend across

P,uker Road into an area which is highly o"veloped w:Lth multistory office

complexes I hotels, and residences. A closure structure or road raiSE~ would be

needed for the crossing of Parker Road. For crest raises of 15 feet (e1. 5660)

and 19 feet (e1. 5664), walls would need too be extended an additional 500 feet

and 1,000 feet, respectively, east of Parker Road. This would involve the

additional t"king of land for the wall construction amoun'ting to about 1/2 acre

for the 500 -foot extension to 1 acre for t:he 1,000- foot .,xtens ion,

At the left abutment, dam raises of 15 and 19 feet would require extensions

of the parapet wall across Union Avenue, through a portion of Cherry Creek High

School grounds and also, through a portion of the residential neighborhood south

of the Cherry Creek High School. For each of the above crest raises, two

additional closure structures would be required in the left abutment ar.:a for two

street crossings and up to 2 acres of additional lands would be needed for wall

construction and maintenance.

Preliminary analysis indicates that a dam crest raise in excess of 9 feet

may be at or near the limit of embankment and foundation stability and may

require an increase in cost to buttress or fortify t:he dam for i.mproved

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