TxDOT IH 10 Drainage, Ozona, TX

Water Resources | Drainage

Role: Prime

This $3.5 million project consisted of the construction of a new location frontage road and bridge over Johnson’s Draw in Ozona, Texas. Johnson’s Draw, though usually dry, is subject to severe flooding and is a Zone ‘A’ FEMA floodplain. The NRCS (SCS) had channelized the Draw and had constructed seven detention ponds in the watershed. AZ&B modeled the basin using TR-20 methodology, subdividing the 157 sq. mi. watershed into ten subbasins to reflect the detained and unbound areas. Calculations of the peak runoff values for the 25-year design and 100-year check storms were performed. AZ&B created existing and proposed condition models in HEC-RAS to determine the proper size of the proposed bridge to ensure no WSEL rise in the 25- and 100-year floods. AZ&B also provided HEC-18 scour calculations for the proposed bridge, including a scour plot for the bridge layouts.

Construction Estimate

$3.5 million


    • PS&E
    • Roadway Design
    • Bridge Design
    • H&H Design
    • Traffic Signal Design
    • Data Collection
    • Geotechnical