City of Prescott Risk MAP and Floodplain Mapping Update

 Wilson & Company was contracted by the City of Prescott, Arizona, to work on their floodplain mapping update. The project included:

  • Project management
  • Field survey and new LiDAR QC
  • Development of regulatory, detailed (1- and 2-D) hydrologic and hydraulic models
  • Nine (9) linear miles of Zone AE floodplain/floodway remapping through the center area
  • Development of non-regulatory products
  • Coordination with stakeholders and FEMA RIX
  • FEMA MIP maintenance

Wilson & Company provided submittals to FEMA via the MIP, with floodplain remapping submitted to FEMA as a LOMR. Two-dimensional H&H analyses were performed for total City limits and contributing areas. A detailed HEC-RAS modeling was conducted in Zone AE floodplain and floodway delineations. 


Hydrology submitted to FEMA was conducted using a 2-D modeling approach to best capture the complex timing of numerous tributary flood waves conveyed through the urban area and concentrated within Granite Creek – the primary stream corridor through the city. However, the 2-D modeling results (discharges) were used as input for HEC-RAS (1-D) modeling of subject streams to address potential regulatory floodway delineation issues.