I am being asked to model an outdoor art piece to provide a “no rise” certification for a project and was wondering if others may be able to provide assistance. My initial run i modeled the 2×2 columns as obstructions and received results in the range of 0.01 to 0.06 rise in the adjacent cross-sections. My first question is does Hec-Ras only apply the obstruction to the cross-section its shown on or does it apply it interpolate to the next cross-sections?
What I would recommend is to place cross-sections at the beginning and ending of the art piece which include the blocked obstructions and then place cross-sections 1 ft away upstream and downstream that do not include blocked obstructions, but you would need to include ineffective areas.