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

impacts to any federally listed threatened and/or endangered plant or animal
species would be expected.

ALTERNATIVE 4 - CHANNEL SPILLWAY IN LEFT ABUTMENT

This alternative would include a lined spillway channel located as far into

the left abutment as it could be reasonably situated. The construction of the

spillway channel would involve the removal of a portion of the existing dam

embankment, including its vegetative cover of grasses. These grasses are

nonnative species, however, and represent low quality habitat from a species and

locational perspective. Therefore, their removal should noC result in any

significant negative ecological impacts. Approximately 8 acres of land which are

presently owned by Greenwood Village need to be acquired to accommodate the

proposed structure. This parcel presently has a vegetative cover of nonnative

grasses and various weedy species and is used for recreation. While construction

of the proposed structure could possibly impact the habitat used by some

surface-dwelling and burrowing animal species, the overall habitat quality is

poor and greatly disturbed. Therefore, acquisition of these few acres should not

represent a significant negative ecological impact. Likewise, removal of these

acres from recreational usage should vot have a significant negative impact to

local recreation since other open spaces exist close by for these activities.

Construction of the left abutment channel spillway would direct overflow

waters toward the 1-225 highway berm which could possibly result in the breaching

of this berm and the severance of this transportation corridor.. Overflow waters

could then continue on to threaten the proposed Galleria mall complex and this

could possibly result in significant property damage. Waters would then fan out

to cover the adjacent soccer fields near JFK golf course. Measures should be

included in any left abutment channel plans to protect these structural features,

if possible. Also, no additional structures should be built in this emergency

floodway in the area of the soccer fields or golf course which could impede the

quick evacuation of these flood waters.

Given the location of the proposed construction, no federally listed

threatened or endangered species should be affected. Noise, fumes, and fugitive

dust would be associated with the construction and may pose an adverse impact to

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