Case Study
City Of Billings: Complex Floodplain Issues
Click Here To Download:
•Case Study: City Of Billings: Complex Floodplain Issues
By XP Software
The City of Billings. The floodplain in the vicinity of Billings, however, is not a typical situation. First, the prevalence of manmade structures like ditches, bridges, and canals complicated the hydraulic model. Second, Billings lies on extremely flat terrain without distinct channels, making it very challenging to determine where or how far flood water will spread. This lack of a distinct natural flow pattern and the frequent splitting of flows by manmade structures eliminated HEC-RAS as an option. It was immediately clear to the PBS&J engineers and hydrologists that HEC-RAS would not be capable of accurately characterizing the reality of the situation.
Rather than considering only the maximum peak flow for all channels like one-dimensional modeling, xpswmm routes flow input from each sub-basin through the flow network. This accounts for factors like temporary storage within a channel or along the channel sides that decrease peak flow. Also, routing in xpswmm reflects the time required for flood waters from each sub-basin to reach a particular point, resulting in off-set flow peaks. With these factors and complexities built into the model, PBS&J could create a far more realistic picture of the floodplain.
Click Here To Download:•Case Study: City Of Billings: Complex Floodplain Issues
