For each bridge, A&O used survey data from FDHV and LiDAR data to create a hydraulic model using Geographic Information System (GIS) tools. We used step backwater hydraulic model HEC-RAS version 4.1.0 to create a one-dimensional steady flow hydraulic model. We developed hydraulic a variable for use in the HEC-18 scour equation, performed scour calculations,  prepared bridge profile scour drawings, and prepared a scour analysis report.

For third-party QA/QC of scour analysis, A&O reviewed the hydraulic model provided by FDHV and verified that the model was created using appropriate survey data and processes. We conducted a preliminary report QA/QC, verifying that the model was running accurately, scour variables developed properly, scour calculations performed properly, and that the report contained all the required elements. For the final report QA/QC, we reviewed the final draft of the report which contained the bridge profile scour drawing, verifying that all changes were made and that calculations were appropriate.