FLOOD03173

• County: Statewide
• Community: All
• Basin: Statewide
• Title: State of Colorado 2002 Flood Documentation Report
• Date: 1/1/2003
• Prepared For: CWCB
• Prepared By: ICON Engineering, Inc.
• Floodplain - Doc Type: Flood Documentation Report

I
I
I
I
I
I
I
I
I
I
II
I
I
I
I
I
I
I
I

- ...
a;:
po

... -. .... - ___ rr

(.#~
. t4f"....;:
.. .-
"., .' :.1". ..f'
....
....i~ ..

r

i .j
. .....r'.

.. '

.. -
- .-

Figure 4.15 - State of Colorado NEXRAD
Radar Image August 3"', 2002 at 5:00PM.

Net:
~

~~
51 ;;1
"' III
.:.."'
o III
Oldahom

Figure 4.16 -Map of the Town of Durango In
Relation to the State of Colorado.
Map courtesy of Mapquest webslte.

Hvdrolol!ic and Hvdraulic Conclusions

There was no flooding associated with any streams or rivers in the studied area Any
damage was due to the increased intensity of mudslides and overland flow from the effects
of the Missionary Ridge fire.

According to information obtained from Mapquest, the Animas River runs through the city
of Durango at an elevation of approximately 6550 feet. Vallecito and Lemon Reservoirs are
located to the northeast of Durango at elevations of7671 and 8143 respectively. The
Vallecito Reservoir empties to the south into the Los Pmos River and the Lemon Reservoir
makes use of the Florida River as a discharge point.

Hydrologic analyses were performed using available baseline data from NOAA Atlas 2 in
order to generate Intensity Duration Frequency, or IDF, curves for rainfall events within the
Durango area Using the varying amounts of rainfall mentioned in the Storm
Characteristics section of this report, and the estimated duration ofthe storm, one could
estimate the frequency of the specific events. The results of this analysis are shown in
Table 4.1 below.

Table 4.1 - Hydrologic Analysis Summary
J ulv 23, 2002 Storm AUl!ust 3, 2002 Storm
Estimated Duration (hours) 3.0 3.0
l.' YR Total Precipitation (in.) 0.81 0.81
.YR Total Precipitation (in.). 8.HOUR DURATION 1.10
5.YR Total Precipitation (in.) 1.71
5. YR Total Precipitation (in.). t.HOUR DURATION 1.42
Total Event Precipitations As Reported (in.) 1.4 (t-HOUR DURATION) 0.75 (8-HOUR DURATION)
0.57 0.80
0.52 0.27
1.48 0.42
0.30 0.30
0.20
Est. Event Freauenev (vr) Less Than 2 to Less Than 25 Less Than 2

ICON Engineering, Inc

January 2003

32