Richland Ranchettes

Project Highlight: Richland Ranchettes Floodplain Study


Cochise County, Arizona


Cochise County Highway & Floodplain

Project Leads

John Wallace, FLO-2D Modeling & Floodplain Mapping
Jon Fuller, Alluvial Fan Mapping


  • Existing approximate Zone A FIRM mapping was outdated and inaccurate.
  • Lack of detailed floodplain information made permitting in the area difficult.


  • JEF utilized FLO-2D to perform hydrologic modeling of upstream contributing watersheds and hydrologic and hydraulic modeling of flow in the study area.
  • JEF also utilized the FEMA three-stage approach to alluvial fan identification and mapping for the Cochise Stronghold Canyon Wash.


  • JEF prepared revised FIRM mapping with Zones A, AO2, AO1 and Shaded X zones for the Richland Ranchettes study area.
  • The revised FIRM mapping included AO mapping with velocities for the Cochise Stronghold Canyon alluvial fan.
  • The revised mapping was approved by FEMA on January 17, 2011