Hydraulics

Bridge scour

Some bridges are vulnerable to damage and failure during flooding. Scour may undermine bridge foundations or remove the protection from the abutment slopes, as in these bridge scour examples (PDF). To protect the public, bridges determined to be scour critical are monitored during flooding. Monitoring generally requires measuring the riverbed elevation at the bridge to determine whether:

• The bridge should be closed
• Corrective action should be taken immediately (i.e. remove debris)
• Protection should be installed as soon as practical

Forms and procedures

• Bridge Office flood response plan (PDF)
• Bridge scour code definitions (PDF)
• Bridge scour evaluation procedure (PDF)
• Bridge scour plan of action templates
  • Bridge Scour Plan of Action Check Sheet (PDF)
  • Bridge Scour Plan of Action - Template G (Word)
  • Bridge Scour Plan of Action - Template K (Word) 
  • Bridge Scour Plan of Action - Template O (Word) 
  • Bridge Scour Plan of Action - Template P (Word) 
  • Bridge Scour Plan of Action - Template R (Word) 
  • Bridge Scour Plan of Action - Template U (Word) 
• Water alert signup for high water emails from USGS
• Bridge cross section tools
  • Single Span Monitoring Form (Word) 
  • Double Span Monitoring Form (Word)
  • Bridge Cross Section Spreadsheet (Excel) 

Flooding

• Elev benchmarks
• Stream gages - USGS
• River gage info (Excel)
• NWS Twin Cities Hydro Page Area Rivers
• NWS Twin Cities AHPS Page - Rivers and Creeks Stages and Forecasts
• 7-Day Precipitation Forecast
  

New Bridge Monitoring Technology

• Multi-Beam Sonar Infrastructure Mapping- MnDOT Research (PDF)
• 3D sonar scan Luverne I-90 (YouTube) - video has sound and closed captioning
• 3D sonar scan of the old Stillwater Lift Bridge pier 8 (YouTube) - video has sound and close captioning