Scour

General
Scour is the result of the erosive action of flowing water excavating and carrying away material from the bed and banks of streams. Potential scour can be a significant factor in the analysis of a stream crossing system. The design of a crossing system involves an acceptable balance between a crossing that is economical and provides the required traffic service and one that provides a sufficient water opening that will not cause upstream damage due to backwater nor damage at the crossing from scour. TxDOT practices are contained in TxDOT’s
Geotechnical Manual
.
Federal Requirement
  1. 23 CFR Part 650, Subpart C
    – Sets national standards for the proper safety inspection and evaluation of all highway bridges. Some bridges are identified as scour-critical.
State Requirement
  1. 43 TAC §§5.59
    ,
    15.56
    ,
    26.33
    and
    27.56
    – Requires projects to be designed in accordance with TxDOT manuals, procedures, standards and guidelines. For RMA, toll and pass-through financed projects, the preliminary design information must be sent to TxDOT for review and approval when the design is approximately 30 percent complete.
Required Practices
The LG is responsible for performing scour analyses in accordance with TxDOT guidelines. The required practices are included in the
LGPM Guide
.