Boulder Creek Floodplain Study

Boulder Creek Civic Area

Boulder Creek Mapping

Boulder Creek at Broadway

Arapahoe Underpass

Fishing Pond

Project Summary

Completed in 2013, the primary purpose of the Boulder Creek Floodplain Study was to define various flood hazards for Boulder Creek over a 6.2-mile reach through the City of Boulder and a portion of unincorporated Boulder County, including 7.5 miles of 30 distributary flow paths along adjacent drainage corridors and city streets. This project would be classified as a hydraulic study with flood hazard mapping and a Physical Map Revision (PMR).


  • Client/Owner: City of Boulder
  • Project Location: City of Boulder, Colorado
  • Approximate Project Cost: $911,000
  • Project Completion Date: September 2013
  • Project Components:
    • Field reconnaissance efforts
    • Field surveying
    • Hydrologic evaluation and modeling for the Boulder Creek watershed
    • Development of six hydraulic (HEC-RAS) models for Boulder Creek
    • Hydraulic modeling for Boulder Creek included the 10-, 25-, 50-, 100- and 500-year events, the City-defined conveyance zone (½-foot rise floodway), and high hazard zone (Product 4 Corridor)
    • Flood hazard mapping along Boulder Creek
    • Two-dimensional modeling (using FLO-2D)
    • Development of the graphical flood profiles, tables, and text providing detailed documentation of the study for incorporation into the Boulder County Flood Insurance Study (FIS)
    • Preparation of floodplain and floodway information in support of a Letter of Map Revision (LOMR)/Physical Map Revision (PMR) submittal to FEMA
    • Supporting City of Boulder staff through the public education and review process

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