FLOOD04689

• County: Statewide
• Basin: Statewide
• Title: 2001 Colorado Flood Documentation Report: Table of Contents and Sections 1 - 8
• Date: 3/1/2002
• Prepared For: CWCB
• Prepared By: URS
• Floodplain - Doc Type: Flood Documentation Report

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ExecutIVe SumlDanr

. The Town of New Castle reported approximately 1.5 inches in 15 minutes, and a NOAA
event record reported one inch in less than 20 minutes, This precipitation event is
equivalent to approximately a lOO.year frequency event locally,

. No flow data was collected due to the fact that no gauged streams or creeks were directly
affected by the rainfall events,

· The heavy rain triggered a massive mudslide that flooded several homes and businesses in New
Castle. Total damages were estimated to be $32,000.

· Clearing debris from local roads and stonn sewers was the majority of work that resulted from
the stann. The storm closed U.S. Highway 6 through town as well as several other local streets,
Up to 2 feet of mud and rocks were left behind after the flooding, and it took several days to clear
the debris; the cost of these efforts amounted to approximately $85,000.

Palisade/Grand Valley

· On September 13,2001 a slow moving thunderstorm dropped rainfall on the western portion
of Mesa County near the Town of Palisade. A NOAA Event Record characterized the
rainfall as "heavy," however, the local newspaper reported that 0.07 inch of rain fell within
a 12-hour period, less than a 2-year frequency event.

· No flow data was collected due to the fact that no gauged streams or creeks were directly
affected by the rainfall events,

· No public or private property damages or expenditures were reported, However, several
cleanup activities were required after the storm, including debris removal from the Interstate
70-Palisade exchange, reshaping drainage ditches, and cleaning stonn sewer structures,
CDOT reported no serious traffic delays and 1-70 remained open throughout the entire time
period. Flood related damages incurred by COOT were estimated to total approximately
$30,000,

Telluride to Placerville (San Miguel County)

· On August 8,2001 slow moving thunderstorms over eastern San Miguel County dropped up
to 5 inches of rain in a 2-hour period, equivalent to approximately a 1S0-year frequency
event locaDy,

. The majority of the effects of the event were in the southeastern portion of San Miguel
County between the Towns of Telluride and Placerville, The two watersheds most affected
by these flood events were the San Miguel River basin and the Upper Dolores River basin.
Several small streams to the north and south of the San Miguel River were also affected,

. According to USGS data, the San Miguel River discharge peaked at approximately 430 cfs,
approximately equivalent to a I-year frequency event. However, according to "The
Watershed Connection" the San Miguel River peaked well over 2,000 cfs, approximately
equivalent to a 5-'Y~aT {Tequen~'Y ~vent,

. Several smaller streams were more seriously affected, namely Bear Creek, Fall Creek, and
Deep Creek. San Miguel County reported that Bear Creek was flowing outside its banks and

URS

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