French Drain or sub soil drainage

[bforr]

I have read the few posts on trench drains and underground storage chambers to act as perforated pipe in Sanitary Storm and Analysis.  I am not understanding how a storage chamber will act as a perforated pipe.  The past posts were from 2012 I believe.  Has there been any developments on this?  I am hoping to model this in SSA.  It is a comercial layout with the islands in the parking lots designed as trench drains with preforated pipes.  Also some larger grassy areas with I see where one can model a perforated riser in Hydrographs.

In SSA, what if i created a storage node, defined as a storage curve-storage chamber using Cultec products ( all their products are perforated top with open bottoms) with 0 exfiltration.  Since the product is listed does SSA take into account the perforated aspect of the pipe as far as infiltration is concerned or is it just an exfiltration calculation?

C3D 2015

[Hidden_Brain]

I may be wrong on this one, but i think choosing a product only helps populate the stage storage data for the storage curve. to account for exfiltration, you will have to set it at the following places to fit your setting:

[bforr]

sorry for all of the mispellings earlier.  So, i would think all exfiltration data is water lost from the rain event as is goes into the soil and not the drainage system.  Any way to model a storage node that is filled with rock or sand with infiltration rates?

[Hidden_Brain]

the rate will be the perc rate of the underlying soil. gravel will be part of your stage-storage if pipes are perforated.

[bforr]

On page 9 of Storm and Sanitary Analysis Help, it states:

Water Quality MOdeling Capabilities

                       Autodesk Storm and Sanitary Analysis provides you with all the tools necessary to perform your urban stormwater quality modeling.

                         - Account for rain gardens, green roofs, rain barrels, bioswales, dry detention ponds, wet ponds, retention ponds, wetlands, and more.

So what I am aiming for is essentially a French Drain with perforated pipes 4' below surface in the end islands of a parking lot with a drain inlet in the middle to take the excess water that backs up once the French Drain is saturated and water ponds.

From what I have read, a rain garden is essentially the set-up comparable to a French Drain.  I haven't found anywhere in the help how to model this.

[bforr]

Understand I am not an Engineer, simply a CAD operator.

[Hidden_Brain]

I think what Pg 9 refers to is the water quality (pollutant loading) for SWMM method. refer to Chapter 10 of the user manual.

SWMM has something called LID controls which calculates reductions in flow volumes by using hundreds of rain gardens, porous pavement etc in a sub area. I do not think that exists in SSA.

For your case, storage node with stage storage may be the approach. the gravel above the perforated pipes will be storage, perforated pipes will be outflow orifices, the top of raised inlet will be a weir, both connecting the storage node to another node (or junction), which has an outflow pipe.

[bforr · Accepted solution]

See this other thread I posted for best solution I have found.  Hidden_Brain gets the Kudo.

http://forums.autodesk.com/t5/autocad-civil-3d-stormwater/riser-in-a-pond-storm-and-sanitary-analysi...