Water quality from SWM pond
Water quality from SWM pond
(OP)
Good Day,
I'm working on a project in which a stormwater management pond is being utilized for both quantity (100 year) and quality control. Quality control is based on "Level 1" criteria (most stringent in the Province of Ontario). However, a concern has been raised by an ecologist working for the reviewing agency with respect to gas/oils (from parking lot runoff) that might spill out and over the pond during severe events (like the 100 year storm will happen every day !!).
My Question: Has anybody ever had to address such a problem as this ? Is there any data available that might relate the removal of oils and petroleum products to the type of vegetation that is in the pond ? The stormwater pond that has been proposed will be built with a forebay as well as a 1.0m deep permanent pool. I don't see what else can be done with respect to oils that might be floating on the ponds surface. Perhaps some sort of filtration device on the overflow weir of the pond ?? Any thoughts on this would be greatly appreciated.
Regards,
John
I'm working on a project in which a stormwater management pond is being utilized for both quantity (100 year) and quality control. Quality control is based on "Level 1" criteria (most stringent in the Province of Ontario). However, a concern has been raised by an ecologist working for the reviewing agency with respect to gas/oils (from parking lot runoff) that might spill out and over the pond during severe events (like the 100 year storm will happen every day !!).
My Question: Has anybody ever had to address such a problem as this ? Is there any data available that might relate the removal of oils and petroleum products to the type of vegetation that is in the pond ? The stormwater pond that has been proposed will be built with a forebay as well as a 1.0m deep permanent pool. I don't see what else can be done with respect to oils that might be floating on the ponds surface. Perhaps some sort of filtration device on the overflow weir of the pond ?? Any thoughts on this would be greatly appreciated.
Regards,
John





RE: Water quality from SWM pond
RE: Water quality from SWM pond
RE: Water quality from SWM pond
RE: Water quality from SWM pond
Try this URL:
http://www.goprincegeorgescounty.com/government/der/ppd/pgcounty/pdf/bioplant2.doc
There are some particular constraints regarding width, depth, and soils which affect the applicability of bioretention, but I find it an elegant solution for water quality where it can be applied.
A simpler mechanical solution to separate volatiles may be to attach a sheet metal baffle to your outlet control structure (assuming a riser-type OCS). It is essentially a 3-sided box enclosing the discharge orifice(s) of the structure. It requires some additional depth of your pond below the discharge invert. The sheet metal extends from below the discharge invert to the elevation of your emergncy overflow, with approximately a foot or so of clearance to the OCS. It works by forcing the design discharge of the rising pool to be drawn from below the free water surface. Any volatiles float on the surface of the water, and are withheld in the pond, allowing UV breakdown, or removal by regular maintenance.
Hope these help.