Incorporating Potential Climate Change Impacts in Bridge and Culvert Design

About the report:

This project examined the potential impact of changing climatic conditions on structural designs in Virginia. A methodology was developed for producing intensity-duration-frequency (IDF) curves verified against the standard Atlas 14 values. The results suggest increases in rainfall depth for a 24-hour rainfall event. The second objective used a 2-dimensional hydrodynamic model to assess increased rainfall volumes on peak runoff volumes, suggesting smaller watersheds have a constant relationship between peak runoff and watershed size, while larger watersheds have less than 1% increase in peak runoff as the watershed size increases. The third objective illustrated average annual risk over the lifespan of a culvert and a bridge. Finally, the IDF approach showed significant variability across individual stations, but no obvious spatial trend.  It is recommended that VDOT use the findings from this study to update the design standards involving storm water runoff and stream flows.  When VDOT assets are designed using rainfall data, the values should be increased to account for the greater rainfall predicted and reported in this study.  When VDOT assets are designed using discharge data not derived from rainfall, the values should be increased to account for the greater discharges predicted and reported in this study.

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