A boundary Condition problem activated the Precipitation BC

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A boundary Condition problem activated the Precipitation BC

Jose A.
Hi,

I have been having problems with a model I'm working so I was checking all the possibilities and when I was going through the unsteady flow data I noticed that a BC that I've deleted in the geometry was still there.  The phony part is that when I selected it the Precipitation Boundary Condition was activated.  I thought that this option was still not available.  Have any of you have experienced something similar?

Unsteady Flow Data window

Precipitation BC Window
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Re: A boundary Condition problem activated the Precipitation BC

Lonnie A
The precipitation BC works on the 2d areas in the March release. But there is a bug in that if you use precipitation and have internal storage area connectors nothing will be computed.

Your screen shot though looks like it was an option for a BC line....which should not be.

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Re: A boundary Condition problem activated the Precipitation BC

Jose A.
I have the march release, how to you activate the precipitation BC? I haven't found anything about it in the literature.
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Re: A boundary Condition problem activated the Precipitation BC

Lonnie A
You add your 2D storage area as a boundary location then when you click on it only the precipitation option is available. The precipitation condition type can only be applied to 2d areas
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Re: A boundary Condition problem activated the Precipitation BC

Jose A.
Is there any information about how HECRAS transforms the precipitation into runoff?
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Re: A boundary Condition problem activated the Precipitation BC

Lonnie A
There is no transformation occurring directly. It is purely a volume in for each cell per time step calculation right now (area x depth).  I use HMS to compute the losses and then take the resulting excess precipitation for the precipitation record in RAS.
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Re: A boundary Condition problem activated the Precipitation BC

Prince
Hi,
Excess precipitation turns into volume via cell area x depth, make sense to me. How it connect/merge with volume generated through stream hydro-graph in overlapping 2D area?
If we combined both the cases i.e. volume due to excess precip and volume through stream discharge, it will end up with large volume with hign flood depth. Please correct me if I am wrong.
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Re: A boundary Condition problem activated the Precipitation BC

Mohsin
In reply to this post by Jose A.
I am a beginner in HEC-RAS, I need some help regarding adding the precipitation in the HEC-RAS.

1- What does the actual mean of time series of precipitation? Is it mean the accumulated rainfall?
for example

Date                                 Simulation time                             Precipitation (mm)
11-01-2019 07:00                   00:00                                               30
11-01-2019 08:00                   01:00                                               30
11-01-2019 09:00                   02:00                                               30

Does it mean the total rainfall added on the 2D flow area during the whole simulation time is 90 mm? Please elaborate?

Thanks