[Lonnie A]

If you set up a dummy unsteady run and just execute the geoproccesor you’ll get the htab data. If you need the conveyance capacity at a certain elevation you can adjust the xs htab table so you get results at that elevation.

[Lonnie A]

You just need to edit the storage area’s first point to an elevation -3.17 or lower. You can set your -1 elev vol to 0.01 if you want to keep that point

[Lonnie A]

Since there isn’t a rain on surface option…yet…what might work is to set a inflow hydrograph along the upstream side of the catchment for a trial run. Then look at the mapping and determine where the flow concentrates in the surface. Then reassign your upstream inflow hydrograph to generally coincide with the concentration. might get you close to what you want

[Lonnie A]

The 2d is doing storage routings so it needs a volume. You could run a long steady state hydrograph but not sure what the results will be like as you’ll be essentially feeding a infinite volume. If there isn’t a way for the 2d to let the received flow go it’ll fill to it’s maximum.

[Lonnie A]

In regards to Leandro’s post I think the issue might be that you added the connector and then edited the mesh. This renumbers things so you probably have to redfine the connector. It does the same thing with laterals, a quick fix with laterals is just to move the connector to the other side of channel, hit apply and then move it back.

[Lonnie A]

Sounds like a problem with the culvert. Does your unencroached profile look right? My first guess would be you need to add or adjust ineffective flow stations up and downstream?

[Lonnie A]

I never could get it to work in that model. Same exact approach though worked fine in another model so not sure what the deal was with it. I didn’t save it and ended up editing the surface or I’d share it. One thing I found though is that upstream/downstream matters in the current version. I had drawn upstream downstream based on the channel, but the channel in the 2d had no flow assigned and was being backwater fed from the 1D model. So tailwater would continue to rise and no flow would pass through culvert until upstream cell got wet. Once it got wet it would function. If reversed upstream and downstream it would function. Spoke with Gary B at HEC and he said they have it fixed now so it’ll work correctly in the official release version.

[Lonnie A]

The way I’ve done this in the past is to use storage areas and connectors. I’ll connect the large storage area to a “micro” storage area that is defined as an area x depth with a very small area, say 0.01ac. This connector models the weir dropping into the outfall box. Then connect the micro area to another micro area to model the actuall outfall pipe. The downstream micro area can be tied to the outfall channel so you get the tailwater effect. Sometimes you have to increase the area of the micro basin for stability.

[Lonnie A]

I’ve found that you can create rasters of the mapping. This is how I did it:
1)select the floodplain mapping check box in the unsteady flow analysis window
2)After running model open RAS Mapper, tools, manage results map, select the plan results for the plan you want in the view results maps pulldown, select add new map then in that window pick elevation, maximum, the stored raster button and “create this map”, then back at the manage resulst map you may need to select the “elevation (max)” line and then hit “compute/update stored maps”. If the line has a icon by it it should of been created and is stored in your model location folder.

I’ve tried the stored polygon (zero depth boundary) using both depth and elevation along with maximum hoping to get a polygon but didn’t have any luck.

[Lonnie A]

Dana,
If you can accurately define the reaches where the flow leaves the channel and moves downstream you should be able to model it with the optimization. What you described sounds like unsteady would be the tool I’d use and perhaps model the splits using the 5.0 version 2D flow option. If the flow spills out and covers a wide area or travels a significant distance the flow rate returning could be significantly less than what left.

I have seen models compute a peak flow diversion into a overflow area and when you mapped the overflow inundation area the volume required to fill the mapped area was greater than the total volume of runoff. This is where the use of unsteady or detailed storage routings are a must. Anytime you want a confident answer over areas receiving a diverted flow the consideration of volume is a must.
Lonnie

[Lonnie A]

More than likely initial conditions are flawed. Check initial flows, basin starting wsel etc to start with. If your inflow hydrographs start with no flow you’ll want to set a “min flow” on the upper most one and have the same flow on the initial conditions page for each reach. I will usually plot the profile for initial conditions. If it looks good it’s usually where I have a basin coming in and the starting wse if significantly different than the receiving stream, setting the basin close to stream initial wse usually fixes it. Pilot channels also help to greatly improve initial conditions. Theres a lot of other things that could be going wrong though too.

[Lonnie A]

There are a number of ways,
1) create a new geometry file and then in your original geometry file: file>import geometry. Your river and reach names need to be identical in both files. There are options within this that you can select such as what sections to import etc.
2) if replacing just a few sections just copy and paste over the data in the previous or if supplementing them use the “add cross section” under cross section editor.

Outside of full section import there isn’t a way to just import a portion of a cross section if that is what you are inquiring about. You’ll have to just delete the points in the existing section and copy past the new points in.

double check all your reach lengths after you import to verify if they are correct.

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