FLOOD04329

• Designation Number: 534
• County: San Miguel
• Community: Unincorporated San Miguel County
• Basin: San Juan/Dolores
• Title: Flood Insurance Study - San Miguel County and Incorporated Areas
• Date: 9/1/1992
• Designation Date: 11/1/2000
• Floodplain - Doc Type: Floodplain Report/Masterplan

TABLB 2. SUMMARY OF DISCHARGBS (cont'd)

Flooding Source
and Location

San Miguel River
(cont'd)
At confluence of
Mi 11 Creek
At Telluride western
corporate limit
At confluence of
Comet Creek
At Telluride eastern
corporate limit

Leopard Creek

Fall Creek

Cornet Creek
At confluence with
San Miguel River

*Mudflow Discharge

Drainage Area
(sQuare miles)

Peak Discharges (cubic feet per second)
10-Year 50-Year 100-Year 500-Year

27.68 580 1,040 1,360 2,460
26.48 560 1,010 1,320 2,420
25.25 540 980 1,280 2,330
15.63 380 710 940 1,770
62.4 1,050 1,810- 2,300 3,930
42.0 780 1,390 1,780 3,130

2.38

415

210

590
1,500*

1,300

3.2 Hydraulic Analyses

Analyses of the hydraulic characteristics of flooding from
sources studied were carried out to provide estimates of
elevations of floods of the selected recurrence intervals.

the
the

Cross section data for streams in the area _were obtained
aerial photographs (Reference 12); the below-water sections
obtained by field measurement. All bridges and culverts
measured to obtain elevation data and structural geometry.

from
were
were

Locations of selected cross sections used in the hydraulic analyses
are shown on the Flood Profiles (Bxhibit 1). For stream segments
for- which a floodway was computed (Section 4.2), selected cross
section locations are also shown on the Flood Insurance Rate Map
(Bxhibit 2).

Roughness coefficients (Manning's "n") were estimated by field
inspection at each cross section and checked for reasonableness
against a recognized standard text (Reference 13). Roughness
values for the main channel range from 0.025 to 0.060; the overbank
values range from 0.025 to 0.10.

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