Catch Basin Hanging Trap / Horizontal Orifice Plate 1

[darth051]

Hello,

I am looking for detail drawings for a catch basin "hanging trap" aka "horizontal orifice plate". To be clear, this is an insert which sits just below the catch basin frame & grate and restricts the flow into the catch basin and thereby forces water to pond on the road. It should be somehow removable to allow for the cleaning of the catch basin as required.

While I have been able to find many examples of vertical orifices and goss traps, I am having trouble finding information on this type of horizontal orifice beyond the fact that they exist.

Thank you.

David Dietrich
KMK Consultants Ltd
Windsor, Ontario, Canada

 

[LHA]

The PA, USA Erosion and Sediment Pollution Control Program Manual, available here:

http://164.156.71.80/VWRQ.asp?docid...aspx?fs=0442d740780d00008000084d0000084d&ft=1

On pp 109-110 has an Inlet Protection which sounds like what you want, but it is above the grate.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve

 

[RWF7437]

But WHY would you want to do such a thing ?????

 

[darth051]

Its a lovely thing called "stormwater management". In my area it boils down to "Post-development peak runoff cannot exceed Pre-development peak runoff". When you restrict the rate at which water leaves the site you need to create storage to contain the water that you are detaining for later release. Storing it on the road is one of the cheapest forms of stormwater storage there is.

David Dietrich
KMK Consultants Ltd
Windsor, Ontario, Canada

 

[cvg]

i would recommend an orifice plate on the connector pipe. it can be made hinged to allow for lifting and cleaning

 

[darth051]

Unfortunately, an orifice plate on the connector pipe won't work in this situation.

The minimum orifice I can use is 100mm (4") due to local standards and clogging issues. If the orifice was placed on the connector pipe it won't restrict the flows enough to create road storage.

David Dietrich
KMK Consultants Ltd
Windsor, Ontario, Canada

 

[waterguy]

David,

I too work in Southern Ontario...currently in London, but have worked in Windsor. Anyway, I have been finding recently that more and more municipalities are not accepting the horizontal CB lid orifices for fear that they can be removed too easily. At one time I had information on these but can no longer find it.

Would an orifice plug (such as the ones produced by IPEX) be of any use ?

 

[daddymem]

Maybe you could modify this detail (Polyethylene Liner). The purpose of this one is to keep the salt from running down the sides of the catch basin so the hole is large. You could shrink that hole to whatever size you need.

http://webster.state.nh.us/dot/standardplans/pdf/dr-4-000.pdf

Covered in this topic:

http://www.eng-tips.com/viewthread.cfm?qid=25191&page=2

Just a thought outside the box...

 

[TerryScan]

Interesting. We have a thing called Stormwater Management here too. Yet, getting water OFF the roadways is part of our management (safety). Here, the storage would have to be provided in the drainage system or downstream of the road. We also manage for water quality.

 

[cvg]

I agree with Terryscan that ponding of water on the roadway is at cross purposes with our normal requirements (in the US) to maintain dry lanes for safety. Retention is not allowed on any public roads. Occasionally on parking lots, but even this is generally frowned upon by the owners.

 

[darth051]

In my area the depth of allowable road ponding on public roads ranges from none for sewer design storm event to a maximum of 300mm (1') for 1:100 Year event. (The sewer design storm is the 1:2 or 1:5 year event depending on the Municipality.) Of course, in practical terms you can only generally get to 200mm of ponding before you transition from causing ponding to creating an overland flow route that discharges some of the stormwater.

For private parking lots we are generally allowed 150mm of ponding for a maximum of 1 hour for the 1:2 year storm event up to a maximum of 300mm for the 1:100 year event. In practical terms though, we generally end up with less than the allowable 1:2 year ponding amount if the outlet from the catch basin is sized to only allow 300mm of ponding under the 1:100 year event.

Since ponding is allowed, we take advantage of it to keep construction costs down. In this area the owners would rather put up with a little flooding in their parking lots once in a while rather than pay the increased costs for some other form of detention.



David Dietrich
KMK Consultants Ltd
Windsor, Ontario, Canada

 

[cvg]

in this area (Phoenix, Arizona) new development is generally required to construct 100-year, 2-hour storm retention. This must be fully retained, off the roadways in a basin or ditch of some kind. It can then bleed off through small outlets or into dry wells or evaporate (within 36 hours). This requirement serves fairly well also to limit movement of pollutants, recharge the groundwater and limit increase in peak flows downstream.