FLOOD11021

• County: Arapahoe
• Community: Greenwood Village
• Stream Name: Big Dry Creek
• Basin: South Platte
• Title: LOMR - Affected Panel 455J - Case No. 99-08-410P
• Date: 2/23/2000
• Prepared For: Greenwood Village
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

CHANGES ARE MADE IN DETERMINATIONS OF BASE FLOOD ELEVATIONS FOR THE CITY
OF GREENWOOD VILLAGE AND THE UNINCORPORATED AREAS OF ARAPAHOE COUNTY,
COLORADO, UNDER THE NATIONAL FLOOD INSURANCE PROGRAM

On August 16, 1995, the Federal Emergency Management Agency identified Special Flood Hazard Areas
(SFHAs) in the City of Greenwood Village and the unincorporated areas of Arapahoe County, Colorado,
through issuance of a Flood Insurance Rate Map (FIRM). The Mitigation Directorate has determined that
modification of the elevations of the flood having a I-percent chance of being equaled or exceeded in any
given year (base flood) for certain locations in these communities is appropriate. The modified base flood
elevations (BFEs) revise the FIRM for the communities.

The changes are being made pursuant to Section 206 of the Flood Disaster Protection Act of 1973 (Public
Law 93-234) and are in accordance with the National Flood Insurance Act of 1968, as amended (Title xm
of the Housing and Urban Development Act of 1968, Public Law 90-448), 42 U.S.C. 4001-4128, and
44 CFR Part 65.

A hydraulic analysis was performed to incorporate the effects of construction along Big Dry Creek of
major drainageway features that consist of bank protection, grade-control structures, crossing structures,
and detention facilities, including Pond 10 just upstream of South University Boulevard, and revised
hydrologic and hydraulic analyses along Big Dry Creek Tributary A. This has resulted in a revised
delineation of the regulatory floodway, increases and decreases in SFHA width, and decreased BFEs for
Big Dry Creek and the establishment of a regulatory floodway, increases and decreases in SFHA width,
and increased BFEs for Big Dry Creek Tributary A. The table below indicates existing and modified BFEs
for selected locations along the affected lengths of the flooding source(s) cited above.

Location

Existing BFE
(feet) *

Modified BFE
(feet) *

Big Dry Creek:
1 Approximately 1,200 feet upstream
of West Littleton Boulevard
2 Approximately 250 feet upstream of
East Arapahoe Road
2 Approximately 150 feet downstream of
County Line Road

5,424

5,423

5,521

5,520

5,678

5,672

Big Dry Creek Tributary A:
2Approximately 300 feet upstream of
East Dry Creek Road
2 Approximately 260 feet upstream of
East Jamison Avenue

5,594

5,596

5,620

5,623

*National Geodetic Vertical Datum, rounded to nearest whole foot
lCity of Greenwood Village
2Unincorporated areas of Arapahoe County

Under the above-mentioned Acts of 1968 and 1973, the Mitigation Directorate must develop criteria for
floodplain management. To participate in the National Flood Insurance Program (NFIP), the community
must use the modified BFEs to administer the floodplain management measures of the NFIP. These