FLOOD04571

• County: Douglas
• Community: Castle Rock
• Stream Name: Unnamed Tributary to Sellers Gulch
• Basin: South Platte
• Title: LOMR - Affected Panel 080050 0302 C - Case No. 94-08-115P
• Date: 11/21/1994
• Prepared For: Castle Rock
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

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Federal Emergency Management Agency
Washington, D.C. 204-72

CERTIFIED MAIL
RETURN RECEIPT REQUESTED

IN REPLY REFER TO:
Case No.: 94iii.O'S-U5P

The Honorable Mark Williams
Mayor, Town of Castle Rock
6SD North Wilcox Street
Castle Rock, Colorado SD1D4

Community: Town of Castle
.colorado
Community No.: DSDD5D
Panel Affected: 0'30'2 C
Effective Date of
This Revision:

Rock,

NOV 211994

lD2-D-A

Dear Mayor Williams:

This is in response to a request for a revision to the effective Flood
Insurance Study (FIS) and National Flood Insurance Program (NFIP) map for
your community. Specifically, this responds to a letter dated August 3D,
1994, from Mr. Daniel P. Giroux, P.E., Project Engineer, Tuttle Applegate,
Inc., regarding the effective FIS report and Flood Insurance Rate Map (FIRM)
for the Town of Castle Rock, Colorado. Mr. Giroux requested that we revise
the effective FIRM to show the effects of updated topographic information and
channel improvements constructed along Unnamed Tributary to Sellers Gulch
from approximately 10'0' feet downstream to approximately 50'0' feet upstream of
South Valley Drive.

All data required to complete our review of this request were submitted with
Mr. Giroux's August 3D letter and with letters dated April Sand
September 22, 1994, from Mr. Daniel W. Bare II, P.E., Engineer III, Town of
Castle Rock. All fees necessary to process this Letter of Map Revision
(LOMB), a total of $2,0'90', have been received.

We have completed our review of the submitted data and the flood data shown
on the effective FIRM, and have revised the FIRM to modify the elevations,
floodplain and floodway boundary delineations, and zone designations of a
flood having a l-percent probability of being equaled or exceeded in any
given year (base flood) along Unnamed Tributary to Sellers Gu~ch from
approximately 10'0' feet downstream to approximately SOD feet upstream of South
Valley Drive. As a result of the revision, the Special Flood Hazard Area has
been relocated and is now contained in the right-of-way for Unnamed Tributary
to Sellers Gulch. At the downstream limit of this revision, there is a
discrepancy between the updated topographic information and the topographic
information reflected on the effective FIRM. This causes a mismatch in the
base (lDD-year) flood elevation (BFE) of 2.5 feet at the downstream limit of
the revision. Because of this discrepancy, and because the lDD-year flood is
now contained in the right-of-way for Unnamed Tributary to Sellers Gulch, the
area previously designated as Zone AE is now designated as approximate
Zone A. For the area now designated as Zone A, BFEs are no longer indicated
and the floodway has been removed. Therefore, those portions of Flood