FLOOD01808

• Designation Number: 451
• County: Logan
• Community: Unincorporated Logan County
• Stream Name: South Platte River
• Title: Special Flood Hazard Information Report - South Platte River, Volume III - Logan and Sedgwick Counties, CO
• Date: 6/1/1977
• Designation Date: 5/1/1997
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Platte River In Logan end Sedgwick Counties would result In the
fnundation of end subsequent damage to prlmer!ly agricultural
propertles,"ndassoclllteddevelopmentseswell aspublTcutllltles
and pUblIc roadways. Deep floodwater flowing at high velocity and
carrying floating debris would create conditions hazardous to persons
and vehIcles llttemptlng to cross flOOded areas. In gene..a), flood-
"ater 3 or more teet deep and tlowlng at " velocity of 3 or more
feet per second could easily sweep an adult person off hIs feet,
thus creating deflnlte danger of Injury or drowning. Rapidly rising
and swiftly flowing floodwater may trap persons In homes that are
ultImately destroyed or In vehIcles that are ultimately submerged
or floated. Isolation of areas by floodwaters could create hazards
In terms of medical, fIre, or law enforcement emergencies.

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StudY Results
The results of this study are presented In the form of flooded
areas, plates 3 through 28; water surface profiles, plates 29 through
32; elevation-discharge curves, plates 33 through 43; and flood plain
reference data, table 6. Water surface elevation deta was computed
through the use of the Corps of Engineers computer program HEC-2
"Water Surface Profiles". These comoutatlons loIere besed Ullonchennel
and flood plain conditions as represented by surveys conducted In the
spring of 1973 and data collected from the South Platte River flood of
May 1973. The location of each cross section Is shown on tho flooded
area plates.
Water surface profiles for the IO-year,50-yoar, l00-year,and
500-year floods were developed for reaChes of the South Platte RIver
locattld in th., viclnityol Sttlriing end JulesDurg, ColoradO. IMse
prof ties elso show high water marks for the May 1973 flOOd and a
computed water surface profile which represents that flood. ThIs
computed 1973 flood profIle Is based upon the Observed high loIater
merks Shown and Isa "best flt"protlle, Elevation-dlschargecurv9S
showl"gthe!O-ye"r,SO-ye",",IOO-ye"r,""dSOO_yearfloods"real"lO

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