HECRAS Controller for Hydraulic Design Function

[Anonymous]

I am trying to use Hydraulic Design function within HEC-RAS for computing normal depth for a large river system with lots of tributaries. Currently, I can only do this one cross section at a time by pasting cross section station/elevation/Manning’s n data from Excel to Hydraulic Design Function, then compute H based on certain Q and S. Does anyone know how to use HEC-RAS VBA Controller to automate this process and obtain the results? Since I may need to deal with thousands of cross sections along river. I really appreciate your help!

[Anonymous]

Trevor-

There are no procedures in the RASController that work with the hydraulic design interface. While the hydraulic design input file (*h##) is an ascii text file, and you can automate reading/writing to it, station/elevation data is not stored there. It uses the geometry file. If you fill in the table yourself, that data is not saved anywhere, unless you export it to a geometry file. I would suggest first getting all that data into a geometry file. Then you can just scroll through the XS’s in the Uniform Depth editor to get all the normal depths. For a 1000 cross sections, it’ll probably take you a 1/2 or so, but that would be much faster than writing your own code to compute normal depth.

Why do you want to get normal depth anyway? Wouldn’t the real computed depth be more useful?

[Anonymous]

Chris:

Thank you very much for your answer. I was planning to use HEC-RAS to compute real depth. But I figure out to get a very basic model to run, you still need to set up Bank Stations, Downstream Reach Length, etc. in order for HEC-RAS to run. In order to achieve that, I still need to manually create the bank line features, flow path features etc. within HEC-GeoRAS to get those information, which would require huge efforts for thousands of miles of streams. Currently, I only have a huge spreadsheet with thousands of XS profile, with only Station/Elevation/Manning n, no bank station, no downstream reach length, etc.

I will try your idea of writing all those XS information to a Geometry File and then use Hydraulic Design Function to compute normal depth. Could you advise is there a tool that can create bank lines/flow path/XS automatically, so that the level of manual effort can be reduced. Thanks again!

Trevor

[Anonymous]

Trevor, it would be some work, but I don’t think it’s as bad as you might think. Your bank stations and overbank flow lines won’t be all that critical since normal depth will presumably be well within the channel confines. You can quickly digitize those-even for thousands of miles. Even the stream centerline, which you want to get pretty precise shouldn’t take you more than 10 minutes or so to draw in. The hard part will be getting all of those cross sections into GIS. If you have end point coordinates for each cross section, it shouldn’t be too hard to get those into GIS, especially if you or someone you know has some GIS skill. But if you keep the River Stationing consistent between the GIS-created import file and the geometry file you create with the XS station elevation data, you should be able to easily merge them together.

Chris

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