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<br />Federal Emergency Management Agency
<br />Washington, D.C. 20472
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<br />CERTIFIED MAIL
<br />RETURN RECEIPT REQUESTED
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<br />IN REPLY REFER TO:
<br />Case No.: 96-08-105P
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<br />The Honorable Polly Page
<br />Chairman, Arapahoe County
<br />Board of Commissioners
<br />5334 South Prince Street
<br />Littleton, Colorado 80166-000 I
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<br />Community: Arapahoe County, Colorado
<br />Community No.: 080011
<br />Panels Affected: 0480 J and 0485 J
<br />Effective Date of
<br />This Revision: JUL 15 1996
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<br />102-I-A-C
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<br />Dear Ms, Page:
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<br />This responds to a request for a revision to the effective Flood Insurance Study (FIS) and National Flood
<br />Insurance Program (NFIP) map for your community. Specifically, this responds to a letter dated May 17, '
<br />1996, fromMr. Darrell R, Hogan, P.E., Director of Public Works, City of Aurora, regarding the effective
<br />FIS report and Flood Insurance Rate Map (FIRM) for Arapahoe County, Colorado and Incorporated Areas.
<br />In his letter, Mr. Hogan provided additional information to support a revision request from Mr. David A.
<br />Guetig, P,E" Project Manager, Greenhorne & O'Mara, Inc. In a letter dated January 24, 1996, Mr. Guetig
<br />requested that the Federal Emergency Management Agency (FEMA) revise the effective FIS report and FIRM
<br />to show the effects of more detailed topographic information along Cherry Creek, including a new survey of
<br />the East Arapahoe Road bridge, Mr, Guetig also requested that FEMA correct errors in the hydraulic model
<br />used to develop the effective FIRM and revise the FIRM accordingly,
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<br />All data required to complete our review of this request were submitted with Mr. Guetig' s January 24 letter,
<br />with Mr, Hogan's May 17 letter, and with letters dated February 8, February 20, April 2, and April 18, 1996,
<br />from Mr, Douglas J, Williams, P.E., Department Manager, Greenhorne & O'Mara, Inc. Because this Letter
<br />of Map Revision (LOMR) incorporates more detailed information and corrects errors, fees were not assessed
<br />for the review.
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<br />We have completed our review of the submitted data and the flood data shown on the effective FIRM, and
<br />have revised the FIRM to modifY the elevations and floodplain and floodway boundary delineations of a flood
<br />having a I-percent chance of being equaled or exceeded in any given year (base flOOd) along Cherry Creek
<br />from approximately 600 feet downstream of the confluence of Piney Creek, the downstream limit of detailed
<br />study, to approximately 800 feet upstream of East Arapahoe Road. The updated topographic information
<br />shows that flow overtops East Arapahoe Road and a portion of the base flood discharge splits from the main
<br />channel of Cherry Creek and forms the Cherry Creek Right Overbank Splitflow, An area of high ground
<br />separates the split flow from the main channel from East Arapahoe Road to approximately 1,400 feet
<br />downstream of East Arapahoe Road,
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<br />The base flood elevations (BFEs) increased and decreased along the affected reach of Cherry Creek, with a
<br />maximum increase of 0.7 foot occurring just upstream of East Arapahoe Road and a maximum decrease of
<br />2.4 feet occurring approximately 100 feet downstream of East Arapahoe Road. The width of the Special Flood
<br />Hazard Area (SFHA), the area inundated by the base flood, increased and decreased along the affected reach
<br />of Cherry Creek, with a maximum increase of 400 feet occurring just upstream of East Arapahoe Road and
<br />a maximum decrease of 400 feet occurring approximately 1,600 feet upstream of the confluence of Piney
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<br />-i.'+
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