Modelling a level infiltration system

[eschelle]

I am trying to put an existing stormwater management system into HydroCAD, but am at a loss as to how to begin.

The runoff at the site in question is collected via catch basins. All the catch basins are connected via perforated pipes laid level at 322.17'. Some of the catch basins are also connected at 319' by perforated pipe, but not all. Coming off this loop, there is an infiltration gallery set level at 322.7'. On the other side of the loop, the final overflow pipe is at 323.58'.

I guess I am stumped because there is no obvious direction of flow in the system, except for the final outlet. Therefore, I have found it difficult to split up the system into componenent parts because the routing is not clear. I almost wonder if I would be better off modelling it as one big pond, but I am not quite sure how to do that either.

Thank you in advance

 

[TerryScan]

Forgive me if I am not correctly visualizing your situation, but here is my go at it. I am going to leap to the assumption that the perforated pipes are bedded in stone or gravel.

Storage:
1.all pipe @319 EMBEDDED in trench with appropriate voids....connected to
2.all pipe at @322.17 EMBEDDED in trench with appropriate voids....connected to
3. gallery @322.7

Outlets:
1.Outlet attached to one of the above using a culvert @323.58
2.each storage structure above would have an exfiltration outlet as well.

 

[eschelle]

Thanks TerryScan. Are you suggesting that there be three separate storage nodes then? The only problem with that is that I need to push water uphill to get from node to node and it sends me error messages stating that my water elevation is exceeding previous nodes.

 

[psmart]

If the pipes are large enough so that the water level will equalize at all points in the system, then you can treat this as a level pool, and model it as a single pond. Just use an additional line in the pond storage table to define each volume.

For embeded storage details (perf pipe in stone) please see

http://www.hydrocad.net/chambers.htm