Tidal Hydraulics

[Crystalct1]

Does anyone have any ideas about how to estimate flow in a tidally-affected stream? I have topography and land use info and can estimate the fluvial flow using TR-55, but there is a tidal influence present. If I consult the NOAA site, I can get tidal predictions and elevations for a gaging station that is about 1-2 miles away (closer to ocean). Is there someway to "propagate" that tide info up the estuary for a tidal flow estimate at my bridge?

 

[TerryScan]

I would probably be inclined to perform some tidal observations at the bridge and make a correlation to the guage you mentioned.

This would be then use my estimates as tailwater elevations in my model (I have two products that will allow tidal tailwater: HydroCad and ICPR).

 

[Crystalct1]

Thanks. Good idea. Now I have to figure out how to get elevations at the bridge - by obervation or maybe a gage at the site. Is is possible to put a fluctuating downstream tailwater into HECRAS unsteady flow?

 

[blueoak]

If you are working near a city or highway the city or DOT will have the info.

You can do a quick fluctuations by using a gate, but that might be more for management strategies. But for flow studies normally it is worst case and best case, so just two runs. How large is your stream though? Typically TR-55 is for small sites. If this is like a delta you may be able to use similar nearby streams and absolute elevations.