Drop Structure Weirs for Storm Water Management Facilities (residential/commercial attenuation purposes)

[Waterpig]

Hi, everyone.

Is it possible for a bleed down weir to be drilled into an existing outlet control structure for a dry retention facility?

For example, let's say there was a multiphase project where two different properties share a pond.
In phase 1, an outlet control structure was constructed for a pond to treat the first property. In phase 2, the pond would be expanded to treat the adjacent property alongside the first. Would it be possible to drill a weir into the structure after its been constructed for the purposes of pollution abatement (typically some jurisdictions require a total drawdown within 48-72 hours)/ attenuation.

Thank you guys!

 

[engineerwillis]

Why not just go ahead and construct the pond and configure the OCS in phase 1 to meet the stormwater treatment requirements of the final development? In my location this would result in cheaper construction cost, only require one hydro study and one as-built.