[Vince Moody]

This is a program limitation. Not sure if the same issue exists in version 5.0.1, but give it a shot in the new version. For the older version there is no resolution; as a work around you could save a copy of your model and restart plan numbering in the new model directory.

I’ve never seen an application of HEC-RAS that called for 99 plans, do you mind sharing what you’re working on?

[Vince Moody]

I have used rules quite extensively, and if you have any experience using a programming language or even Excel macros you should be able to get the hang of it. You’ll need to go through the rules line by line and make sure the instructions you’ve included match what you’re trying to do; this can be tedious. If you’re unable to find the problem just by inspecting the rules you can view the results of how the program implements the rules, line by line by time step, in the computation log file (Unsteady Flow Analysis window > Options > View Computation Log File). You’ll likely need to turn on detailed log output under Output Options for Unsteady Flow Analysis.

[Vince Moody]

So it looks like in Joe’s project that the program is filling below the template, only up to the existing bank elevation. As a work around, move the bank stations in your existing geometry out to the end of the cross section, then apply the new channel template. A little tedious to modify bank stations, but that’s what I would do. Not sure if there is a better work around.

[Vince Moody]

Might be an issue with Language/regional settings on your computer. Sometimes RAS has a hard time handling special characters. Try changing your regional settings in Windows to English (US), and re-attributing your project using only standard characters. Also very important is to use a “.” as the decimal point instead of a “,”

[Vince Moody]

Soroush,

Have you tried using RAS Mapper to generate your inundation maps? It’s much more stable and user friendly than the cumbersome export to GeoRAS. You can even export grids to a stand-along raster, which you can open and view in GIS if needed.

[Vince Moody]

Chapter 6 of the new RAS 2D Modeling User’s Manual presents an entire discussion on steady vs unsteady modeling.

I will tell you from my perspective that I would go with a steady model over an unsteady model every time, if the steady model will meet project requirements. Steady models are often much more straightforward to develop and refine compared to unsteady. Besides, if FEMA calls for a steady model that’s what you should use.

[Vince Moody]

Are you asking if HEC-RAS can use gridded rainfall? No, it can’t.

It can use time-series rainfall, a hyetograph, but it is uniformly applied to your 2D area.

[Vince Moody]

A quick pedantic note: 2D simulations are inherently unsteady. You can use a constant inflow hydrograph, but review Chapter 6 of the 2D Modeling manual for additional discussion.

Within RAS Mapper, does your 2D Mesh line up with your Terrain (i.e. same projection)?
Within RAS Mapper, if you right click the 2D Area layer under your geometry and select “Compute 2D Area Hydraulic Tables”, what happens?

[Vince Moody]

You should review Page 16-51 of the User’s Manual, in which User Defined Rules for operation of hydraulic structures are discussed. User rules are incredibly powerful and I think one of the most overlooked features in HEC-RAS. If you have any experience with any type of programming language (even Excel Macros and VBA) you should have not problem picking it up. Even if it is all new to you, you should be able to pick it up pretty easily.

[Vince Moody]

Do you have the “Fill Channel below Template” box checked in the template editor?

Unchecking the box in one of my models seemed to duplicate the behavior you’re seeing. If you do have it checked, you could send me your model and I’ll take a look. Might be something funny going on with the way you built your template.

[Vince Moody]

You probably didn’t get your model to run successfully. Right click in that window and select “Profiles”, make sure that one or more are selected and press OK.

You also have some issues with your cross section direction. See how that green line zig-zags back and forth? That means some of your sections are drawn from left to right, and some right to left. This should consistently be left to right, when looking downstream, and is pretty important.

[Vince Moody]

ensure that your flowpath centerlines, in your case the left overbank, are drawn in the right direction. Generally upstream to downstream. If your numbers are negative, try flipping the direction of the flowpath and recomputing attributes.

[Vince Moody]

You could modify the XS station-elevation points, to stick up like a fence post. Though to be honest I’ve never seen the kind of granularity in a 1D model, where individual fence posts are modeled. I’d probably just use a higher n value at that section if the fence posts are an impediment to flow.

[Vince Moody]

What about the cutlines are negative?

[Vince Moody]

Can you post a screenshot?

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