FLOOD04959

• County: Garfield
• Community: Rifle
• Stream Name: Rifle Creek
• Basin: Colorado Mainstem
• Title: City of Rifle Flood Hazard Mitigation Plan - The May 15, 1993 Flood
• Date: 9/1/1993
• Prepared For: Rifle
• Prepared By: Rifle, Colorado Office of Emergency Management
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

City af Rilk Flood Haa:ard Mitigation Plan

The May 15th. 1993 Flood

Based on the observations of local residents, it
was determined that a major thunderstorm cell
passed north of Rille on the evening of Saturday
May 15th. The flash flooding that inundated
areas along the two creeks was caused by this
intense storm, which was situated over the upper
half of the Government Creek Basin. The storm
was estimated to last approximately four hours,
from 5:30 to 9:30 p.m. Another thunderstorm
cell also passed through the area during the early
morning hours of the 16th. This second cell
caused flooding conditions to linger, however it
was the first cell which was primarily responsi-
ble for releasing the torrents of water which
flowed down Government Creek.

A rain gauge located at the Department of En-
ergy's Estes Gulch uranium clean-up site indi-
cated a peak rainfall of 2.5 inches over the four
hour period. Estes Gulch is a small side-tributary
to Government Creek north of Rille. Hydrologic
data on peak discharges was not obtained by any
federal agency. Using eyewitness accounts, the
Estes Gulch rainfall information and by measur-
ing the high water mark, the Colorado Water
Conservation Board (CWCB) determined the
peak flows ofthe flash flood to be 2,950 cubic feet
per second (cfs) for Government Creek and 2,970
cfs for Rifle Creek (below the confluence with
Government Creek). It was estimated that some
areas along the creek were inundated by a wall
of water nearly 10 feet high. Other areas re-
ported depths ranging from 2.5 feet to 5 feet. The
CWCB estimated the flash flood to be a 125-year
flood event.

A 100-year flood event is defined as
the degree offlooding which has a 1%
chance of occurring each year.

Communities nationwide are urged to partici-
pate in the National Flood Insurance Program

(NFIP), which requires adoption of floodplain
regulations. These regulations guide develop-
ment within the 100-year floodplain, that area
subjected to flooding in the event of a 100-year
flood. By adopting and administering these regu-
lations, flood insurance can be purchased by
home and business owners in the co=unity.
The City of Rifle participates in the NFIP, and is
a member in good standing.

The flood impacted several homes and busi-
nesses adjacent to Rille Creek where the creek
winds through the city. There was some damage
on Government Creek upstream of the conflu-
ence with Rifle Creek, but the damage was minor
because of the sparse development found at the
northern end of town.

Emergency Response

Agencies Responding to Flood

. City of Rifle
. Rifle Fire Protection District
. Colorado State Patrol
. Garfield Road & Bridge
. Garfield CountylEmergency Mgt.
. State Highway Department

Ageneu,s Respondill/f to Rifle FkJod

Emergency personnel from the Rille Police De-
partment and the Rille Fire Protection District
responded i=ediately to the situation. How-
ever, the initial warning was received too late to
conduct an emergency flood fight. All that could
be done was to begin warning residents along the
stream that flooding was imminent.

The initial warning came from a motorist travel-
inginto town on Highway 13 from the north. The
highway runs adjacent to Government Creek
and the motorist reported water flowing over the

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