Flow Control Manhole to Basin to Pond

[acsimpson]

I am working on a project where a previous phases pond's outflow is controlled by a flow control manhole, which outlets into an existing basin. I am now designing a new pond further downstream and need to account for the runoff of the existing basin upstream as well as the flow that is released from the flow control manhole. Basically I want to model it like this: Flow Control Manhole flows into Basin "A" then Basin "A" Flows into the Proposed Pond. Please let me know if you have any ideas of how to model this.

 

[psmart]

If "basin A" is a catchment area (subcatchemnt), then you would need to use a reach to model the manhole flow across this area. Please see

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

 

[acsimpson]

Sorry, but I still don't understand.

The flow from the flow control manhole will most likely infiltrate into Basin "A" and never reach the downstream pond. Is there anyway to create a reach that has the same characteristics as Basin "A" to accuratly replicate what will happen with the runoff before reaching the downstream pond.

 

[psmart]

It's hard to predict this behaviour with any real accuracy. Since the ground will generally become saturated during the rainfall event, there may not be any infliltration (loss) of the overland flow.

You can use a reach to specify a fixed inflow loss, but you'll have to determine the exact value on your own. Another option is to use the exfiltration option for a pond, but your case doesn't seem to fit the behaviour of a pond. Or you can use a link to scale the flow or set a flow threshold. It all depends how you expect the system to behave...

 

[Quest101]

Hello,

Hoping someone can help me with hgl analysis up the pipe storm drain. I’m designing my storm drain for the 25 yr storm.

If one has the flexibility of starting the hgl computations from anywhere in the basin or pipe ( crown or half way ), which would be the best place to start ? I have been starting from the peak elevation for the 25 yr storm in the basin given to me by hydrocad and inserting that number into hydraflow, but my pipe is submerged and my water surface level is well about the crown of pipe.

It seems that because of the submergence of my pipe additional water coming through the pipes will not make it into the basin because there seems to be no head difference ( flat hgl ) to push the water from the pipes into the basin, resulting in water going up the inlets and spilling out.
Does hydraflow understand that my basin pipe is submerged?


Am I understanding this correctly?
Hope you can help me

Thank you!

 

[psmart]

If you're asking about modeling a pipe system in HydrCAD please see

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

If this is a general (non-HydroCAD) question you'll get a better response by starting a new thread in the general Stormwater forum.