FLOOD04852

• County: San Miguel
• Community: Telluride
• Stream Name: San Miguel River
• Basin: San Juan/Dolores
• Title: CLOMR - Affected Community 080168 - Case No. 96-08-190R
• Date: 6/30/1997
• Prepared For: Telluride
• Prepared By: FEMA
• Floodplain - Doc Type: Historic FEMA Regulatory Floodplain Information

p-

Federal Emergency Management Agency
Washington, D.C. 20472
AUG 091996

CERTIFIED MAIL
RETURN RECEIPT REQUESTED

IN REPLY REFER TO:
Case No.: 96-08-190R

The Honorable Elaine Fischer
Mayor, Town of Telluride
P.O. Box 397
Telluride, Colorado 81435

Community: Town of Telluride, Colorado
Community No.: 080168

104

Dear Mayor Fischer:

This is in response to a letter dated June 21, 1996, from Mr. Eric L. Krch, P.E., Buckhorn Geotech, Inc.,
to the Federal Ernergency Managernent Agency (FEMA) regarding the effective Flood Insurance Rate Map
(FIRM) and Flood Insurance Study (FIS) report for the Town of Telluride, Colorado. With his letter,
Mr. Krch provided additional information to support his January 10, 1996, request for a Conditional Letter
of Map Revision (CLOMR). Mr. Krch requested that FEMA evaluate the effects that rnore detailed
topographic information and existing and proposed fill in the northern overbank area along the San Miguel
River frorn approximately 350 feet downstream of the Fir Street foot bridge to just downstream of Pine
Street would have on the effective FIRM and FIS report.

VAil data required by FEMA to evaluate this request were subrnitted with Mr. Krch's letters dated
January 10, May 22, and June 21, 1996.

We have reviewed the data submitted and the flood data used to prepare the effective FIRM for the Town
of Telluride. We believe that if the proposed project is constructed as shown on Sheet 1 of 1 of the plan
.,/ entitled "Gondola House Assoc., L.L.C., Uncornpahgre Plaza, Floodplain Work Map," prepared by
Buckhorn lSieotech, Inc., dated May 21, 1996, a revision to the.FIRM would be warranted.

In support of his request, Mr. Krch subrnitted a HEC-2 hydraulic computer model that incorporates
additional topographic data and a corrected hydraulic analysis of the Fir Street foot bridge. Because this
corrected model does not reflect any physical changes that occurred since the information presented on the
effective FIRM was developed, it was used as the base conditions model in our review of the proposed
conditions model for this CLOMR request. The corrected model indicates increases in the elevations of
the flood having a I-percent chance of being equaled or exceeded in any given year (base flood) along the
affected portion of the San Miguel River. The maximum increase in the base flood elevations (BFEs),
1.4 feet, occurs just downstream of Pine Street.

A proposed floodway was developed based on the corrected HEC-2 model. The proposed floodway
elevations do not exceed the BFEs determined by the corrected HEC-2 model by more than I foot. The
flood way width will increase compared to the floodway shown on the effective FIRM. The maximum
increase in floodway width, approximately 50 feet, occurs approximately 120 feet downstream of Pine
Street. All property owners affected by the increase in floodway width have been notified, and no
insurable structures are impacted.

As a result of existing and proposed fill outside the proposed floodway, the BFEs will increase a maximum
of 0.7 foot and decrease a maximum of 0.3 foot compared to the BFEs determined from the corrected
model. The post-project model indicates a maximum increase in BPE of 1.2 feet compared to the BFEs

"K