FLOOD07670

• Designation Number: 479
• County: Park
• Community: Unincorporated Park County
• Basin: South Platte
• Title: Flood Insurance Rate Map - Park County, CO, Unincorporated Areas
• Date: 4/1/1987
• Designation Date: 3/1/1999
• Floodplain - Doc Type: Correspondence

Table 2 (Continued)
Definitions for regulating approximate Zone A floodplains

Regional Regression Equations: Any current publication by the CWCB or U.S. Geological Survey that
provides regional regression equations for estimating 1 DO-year peak flows for streams in the area of
interest
Limited Development: Development involving parks, open space, golf courses, agriculture, bridges and
culverts that serve a single farmlhome/cabin, pole barns, and individual single family structures,
Significant Development: All development that does not fall under one of the categories listed under lhe '
Limited Development definition. A special case of significant development is a development that
involves more than 5 acres or more than 50 units (whichever is more restrictive). This special case is
important because federal regulations require that a detailed study be submitted to the community by the
developer. Failure of the community to require a detailed study will result in a violation of the National
Flood Insurance Program, which can have negative impacts on floodplain property owners within the
community.
Approximate hydrology: 1 DO-year peak flow values estimated for the hydrologic point of interest using
CWCB regression equations or other acceptable approximate hydrologic method approved by the
CWCB.
Detailed hydrology: 100-year (and 10-, 50-, and SOD-year when applicable) peak flow values computed
for the hydrologic point of interest using an acceptable detailed methodology, other than approximate
regression equations, such as an at-site stream gage analysis, a regional stream gage analysis, or a
rainfall-runoff modeL
Approximate hydraulics: Water surface elevations or flow depths computed for the location or reach of
interest using normal depth flow calculations (i.e. Manning's equation/slope-area method). Computer
programs such as QUlCK_2 and FlowMaster are exc~llent tools for this purpose.
Detailed hydraulics: Water surface elevations (base flood elevations) computed for the stream reach of
interest using a step-backwater computer m<Jdel, or other acceptable one-dimensional or two dimensional
computer model, such as HEC-2 or HEC-RAS.

WHEREAS, the approximate floodplain iIlformation on said floodplain maps with said new
report for stream reaches in Park County as listed in Table I meet the requirements for approximate
floodplain information as listed in the Board's "Rules and Regulations for the Designation and
Approval of Floodplains and of Storm or Floodwater Runoff Channels in Colorado" (2 CCR 408-
I), contingent upon the understanding by Park County of the need for a case-by-case review of all
development proposals within the cOtporate limits; and

DESIGNATION AND APPROVAL ACTION
NOW, THEREFORE, BE IT RESOL YEP by the Colorado Water Conservation Board in
regular meeting assembled in Castle Rock, Colorado, this 29th day of March 1999, that it does
hereby designate and approve as approximate floodplain information the storm or floodwater runoff
channels and basins, as listed in Table I and as described by approximate floodplain information on
said Park County Flood Hazard Boundary Maps dated November 22, 1977, with included
Floodplain Information Report dated January 1999, that meet the criteria for the "Board's Rules and
Regulations for the Designation and Approval of Floodplains and of Storm or Floodwater Runoff
Channels in Colorado" (2 CCR 408-1); and