The PBS&J Scour Spreadsheet: A Tool for Stream Restoration, Utility Crossings, and Streambank Protection Projects

Scour analyses are required for stream projects such as stream restoration, utility crossings, bridges, streambank. protection, levees and floodwalls. In lieu of sophisticated numerical models, simplified approaches are often utilized, especially for reconnaissance and feasibility studies. Neglecting local scour such as scour at bridges, the total scour using these simplified techniques is comprised of long term, general, bend, dune formation, and thalweg formation. There are several methods within each of these scour components and calculations are often tedious and repetitive. This presentation provides information on a free spreadsheet developed by PBS&J that computes the most commonly use scour methods. The power of the spreadsheet is in the use of inputting the variables once and computing the results using numerous methods. These scour methods are: 1. General scour, based upon 7 methods, 2. Bend scour, based upon 4 methods, 3. Equilibrium Slope, based upon 4 methods, 4. Incipient motion, based upon Shield's diagram, 5. Bedform scour, based upon 2 methods. The spreadsheet also includes a suggested matrix that aids in assuring that there is no "double counting" of scour components when computing the total scour.