[krista1223]

Hi,
We are building a model for a small tributary for the Ohio River. Our trib is perpendicular to the Ohio and has two bridge crossing approximately 100 ft upstream of the Ohio's normal level banks. Our concern is mostly with the high level, 100-500 year events, which puts the Ohio River very high and our trib all in backwater. But, in order to create cross sections that capture the 500-year event, we've found that we need to either cross the roadway or run our downstream cross sections parallel to the contours and never reach the max level. The area downstream of the roadway crossing is much lower than the maximum flood level. Any thoughts on what we should be doing?

I attached a rough drawing that shows our model area. Green lines are our cross section locations, shaded regions are the roadways, the blue lines are the 500-year floodlevels for the Ohio.

Thanks
Krista