The dam itself is located in the middle of a city. I am having some problems modeling a dam break currently. In general, if you receive 'Volume-Elevation relationship does not have increasing elevation' (or storage) for what seems to be a perfectly increasing table, this could be the problem. When I did this for what I thought was a 3 row storage table, I found the culprit was an entry in row 23, well below what is immediately visible without scrolling in the HEC-RAS application. If you were to select all cells in your problematic Elevation Volume Curve using the select all button (top left cell exterior to the value containing cells) and paste the table into a spreadsheet, I believe you would have found a row of data below the perceived end of your storage table. If that is the case, filling all 100 rows incidentally solves the problem, but the underlying problem doesn't require you to fill the entire table to make it work. I believe there was a rogue row of stage-storage data in your HEC-RAS table. Scott, I believe you and I experienced the same problem. Do I need to make another reach from the storage pond to my main stream (as a second reach)? Then input the lateral structure on that reach? Then I think I need XS of that reach as well? Little confused, need help! Thanks in Advance - Sharif Reply Delete If I input a lateral structure at my stream (close to the stream station where my pond is situated), Now how the water flows from the stream to the pond area? It seems like its not connected. So I added a storage area and tried to connect to the stream but seems I have to use a lateral structure.
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The pond is not directly on the stream, its just beside the stream but there is a connection to it. Now there is a small pond area at the side of the stream which I like to include in my model. So, I have a small stream and I have modeled the stream with XS and culverts and its working fine. This post seems pretty close what I am doing, I think! Hi there, I am new to HEC-RAS and having some problem with the connection between a reservoir and my stream. This is set in the Options menu item in the Unsteady Flow Editor. Initial Stage” for one of the dummy cross sections to set up your starting pool elevation. If you’re providing pilot flow, you must enter in an “Internal R.S. This can be done by coding in gates, or by providing pilot flow. Make sure you provide some outlet flow, or your dam will overtop at the beginning of the simulation. It should look something like this when done: Make sure to uncheck “Move Object” in the menu once you’re finished. RAS should then automatically recognize the connection. Once in “move” mode, click and drag the upstream end point inside the storage area. To do this, go to Edit…Move Object, in the main geometry window. To make RAS recognize the connection between the upper dummy cross section and the storage area, you have to “move” the upper end point of the reach inside the storage area. That’s okay and it doesn’t affect the computations either way.
![hec ras boundary conditions hec ras boundary conditions](https://image.slideserve.com/219153/boundary-condition-editor-l.jpg)
It’s not uncommon to have the two cross sections reside within the storage area’s boundaries. Next draw (or import) your storage area upstream of the inline structure and it’s two dummy cross sections. These can be copies of the cross section downstream of the dam, but should be as close as possible to the upstream toe of the dam and close enough to each other to minimize the associated volume (relative to the reservoir’s total volume). You’ll need to place two dummy cross sections upstream of your inline structure (and downstream of your storage area). Next, place your inline structure (dam) at the upstream end of the reach. Once you’re happy with the level pool assumption, draw in (or import)your downstream reach in the geometric editor. Check this post first to make sure it’s okay. This is even more important if you are modeling a dam breach on this reservoir. “How do use a Storage Area to define my reservoir in RAS?” First of all, make sure using a Storage Area and level pool routing is an appropriate way to model your reservoir.
#Hec ras boundary conditions manuals
It’s a little confusing, and not really directly covered in the manuals anywhere.