_REVISION - M1981302 ‎(117)‎

• Permit No: M1981302
• IBM Index Class Name: Revision
• Doc Name: FLOOD HAZARD AREA DELINEATION SOUTH BOULDER CREEK JULY 1986
• Type & Sequence: AM2
• Media Type: D
• Archive: No

SOUTH BOULDER CREEK information and conducted a preliminary hydraulic analysis of the study reach.
FLOOD HAZARD AREA DELINEATION The information developed by the COE was utilized to complete this Flood Hazard
Area Delineation Report. The following is a brief summary of the scope of work
- AUTHORIZATION - for this project.
This report was authorized and contracted through the Urban Drainage and Flood 1. Calculation of water surface profiles for the 10- , 50-, 100- , and 500-year
Control District (UDFCD) as part of a program of identifying floodprone areas flood events;
within the District's jurisdiction. The study was jointly funded by the UDFCD 2. Delineation of the 100-year floodplain boundary on Flood Hazard Area Maps;
and Boulder County. 3. Development of discharge profiles indicating the relative magnitudes of the
10- , 50- , 100- , and 500-year flood events;
This study identifies floodprone areas along South Boulder Creek within portions 4. Determination of floodways based on encroachment resulting in a maximum
.of the City of Boulder and unincorporated Boulder County. The study reach increase in the energy grade line of 0.5 feet and 1 .0 feet;
extends from the Colorado and Southern Railroad (C&S R.R.) crossing, located 5. Preparation of a report describing characteristics of the study area, flood
approximately 1100 feet north of Arapahoe Road, upstream to the town of Eldorado history of South Boulder Creek, various hazards associated with areas in or
Springs , Colorado. The floodplain information included in this report is near the 100-year floodplain, tabulations indicating pertinent floodplain
provided by the Urban Drainage and Flood Control District to enable Boulder and floodway information, and reduced copies of floodplain maps and flood
County to adopt and administer comprehensive floodplain management regulations. profiles.
Upon acceptance of this report by the Urban Drainage and Flood Control District With the exception of planned improvements to the South Boulder Road crossing of
and designation of the flood hazard areas by the Colorado Water Conservation South Boulder Creek, which were incorporated in this study, the flood profiles
' Board, this study can be used by Boulder County to regulate future floodplain and floodplain delineations presented in this report are based on existing flood-
construction , to guide future drainageway improvements and to plan flood plain and channel conditions. Flood elevations and the corresponding floodplain
protection measures along the channel and floodplain of South Boulder Creek. are often altered by road and bridge construction, floodplain development, flood
control improvements, or natural processes. Prior to utilization of this report
- PURPOSE AND SCOPE - for planning or design purposes, the user is advised to contact the Urban
Drainage and Flood Control District or Boulder County to determine if the
This report was prepared to guide county officials in planning the use and information in this report has been amended.
regulation of the 100-year floodplain. The report includes information on past
floods and the nature and extent of probable future floods along an 8.4 mile - ACKNOWLEDGEMENTS -
study reach of South Boulder Creek.
This report was prepared by Greenhorne and O'Mara, Inc. , Consulting Engineers of
Hydrologic analysis of the South Boulder Creek basin was completed by the Omaha Denver, Colorado, under contract with the Urban Drainage and Flood Control
District, U.S. Army Corps of Engineers (COE). The COE also compiled hydraulic District (Agreement No.84-12.02).
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