The Hydraulic Design Section is responsible for the hydraulic design of stream encroachments (bridges, culverts, channels, etc.) whose 50 year discharge is greater than 500 cubic feet per second (14.15 cubic meters per second) (by the United States Geological Survey (USGS) regression equations) at the most downstream portion of the encroachment.
Additionally, the replacement or rehabilitation of any existing structure twenty feet (six meters) long or longer will be reviewed by the Hydraulic Design Section to determine if hydraulic criteria govern the site.
The Hydraulic Design Section performs the deck drain analysis of all grade separations designed in the Structures Division.
All hydraulic design notes bear the seal of a licensed engineer.
For information about TDOTs hydraulic design standard policies and procedures see the Tennessee Hydraulic Design Memoranda downloadable on our home page.
The Hydraulic Design Section ensures that Grant Bridges and FEMA Bridge Replacements meet current hydraulic design policies of the department. Permit requirements are the responsibility of the sponsoring agency.
The Grant Bridge Program began in 1982. It provides partial funds to local governments (county, city, etc.) for replacement or refurbishing of deficient bridges. The program has continued to provide replacement funds for deficient structures since its inception.
To be eligible to participate in the Grant Bridge program the Local Government must be in compliance with the National Bridge Inspection Standards at the time the contract between the State and the Local Government is executed. These standards require that all bridges with a load rating less than 15 tons be properly closed or posted with appropriate load rating signs. TDOT approves all plans before funding is provided to the Local Government.
The Federal Emergency Management Agency (FEMA) provides funding to replace bridges damaged due to storm events. TDOT approves all plans before funding is provided to the Local Government.