US34 Bypass and Business Permanent Flood Repair

East of Greeley, Colorado

During the flooding of the South Platte River following the September 2013 rains, US34 Business and Bypass in Weld County sustained severe damage including major sections of roadway that were breached and impassable. The goal of the permanent flood repair project is to rebuild the highway to prevent a repeat of the catastrophic damage, and maintain access during a major storm event.

Tsiouvaras Simmons Holderness completed extensive hydraulic analysis to evaluate five permanent repair options on each stretch of highway to meet the goals of the project. The selected permanent repair options include new bridge structures at the breach locations to pass the flood flows across the highway through the floodplain. TSH completed the following hydraulic analysis to support of the selected options:

  • Hydraulic design of new reliever bridge and culvert and guide banks using 2D hydraulic modeling
  • Large-scale two-dimensional modeling South Platte River floodplain of using ADH and SRH-2D
  • One dimensional modeling using HEC-RAS for floodplain administration
  • Weld County Floodplain Development Permit
  • Extensive coordination with FEMA and Weld County Floodplain Administrator
  • CLOMR Preparation and Acceptance