Catch Basin Downspout/Liner/Insert

[elminer]

One of the Towns where we do work is requiring that all catch basins be constructed with a "polyethylene liner downspout". Of course they want me to provide a detail on my plans. Does anyone know what these are called, who makes them, or where I can get my hands on a detail?

Ed

 

[waterguy]

I'm not exactly sure what "polyethylene liner downspout" means either, but could they be referring to a GOSS TRAP ? It's not a liner, but simply a device on the catchbasin outlet.

 

[elminer]

Thanks for your response. I think they are refering to a device that fits under the catch basin grate and extends down into the basin. I think its purpose is to protect the riser structure from the effects of road salt, etc.

I know there are devices that fit under the grate and catch sediment, but I don't think that's what they are refering to.

 

[jugglerbri]

ADS (Advanced Drainage System) has a PVC riser for their systm. In fact, it's an entire catch basin, not just an insert. You may want to look at that.

Brian

 

[dicksewerrat]

The city of Mpls. water Dept. used this type of insert for the protection of the concrete adjustment rings. Call them 612-673-3410 is the number for the Admin. office. They can direct yoou to the Engineers.
Or you could try to use the HDPE adjusting rings.

 

[n3rei]

Hi!
Now let me get this straight. You are required by a town to provide a detail for a device that they require and do not know what it should look like. You may have a misunderstanding of what they are saying to you. First ask them if they have a sample drawing of a previous project so you can get an idea!!! of what they are requiring. If they say they can not give you that detail, request the engineers firm and name and contact them. Any good engineering firm, out of professional courstey will help you out.

 

[elminer]

Thanks n3rei for your response. I've known for a while now what the Town thinks they want, a sheet plastic insert that is held by and extends downward from the frame into the structure throat for about two feet. The detail itself is simple to draw.

However, being an old construction engineer, I was looking for a manufactured solution rather than leaving it up to the Contractor to fabricate each and every one. To date, however, I have found no one who makes such an item.

 

[bltseattle]

The way you describe the item is similar to a catch basin insert, a device used for Temporary Erosion and Sediment Control. The concept is that a sack or bag made of geotextile fabric is secured beneath the grate so that flow entering the structure percolates throught the sack. These are temporary devices, because they can clog quickly, and typically get replaced several times if grading is occuring in the vicinity.

There are a number of vendors. I've included a link that has some of the devices, check out StreamGuard and AquaGuard. Also, there is something called Snout on this page that might also match the description of what you are looking for. In any case, make sure you understand the potential debris/sediment loading so that you don't create maintenance headaches. Source control measures should be developed since removing gunk from stormwater is never completely effective, and good source control can reduce the amount of maintenance required for storm conveyances. Good luck!

http://www.epa.gov/region1/steward/ceitts/stormwater/techs.html

 

[n3rei]

elminer,
I am wondering if the liner is more for the elimination of ice at the inlet throat rather than salt protection.

 

[layfieldman]

Does it have to be PE? Is this a curb inlet? If neither then PVC is much more flexable and can be vacumm formed into the shape that you need. Kind of like a top hat with the top cut off then placed inside the drain upside down?

 

[daddymem]

Hi. I just ran into this exact same issue, and voila! here is what I found:

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

Hope this helps someone else in the future.

 

[rd78]

I apologize for being off topic, but I see bltseattle on the list and I wonder if you could help me out.

I'm helping a friend with an oddball residential drainage issue and I haven't done this in detail for many years. In trying to implement the spirit of the DOE stormwater requirements for bioswales, I'm having trouble coming up with a Water Quality Design Flow without doing way more work than the project requires (no detention, no routing). We did a gross rational method approach to oversize the pipes (25 year design), but don't want the swale to be so big. Is there a "rule of thumb" for obtaining the WQ Design Flow from the isopluvials and trib area? We're away from King County, in the North Sound area. If you want to respond away from this thread that's fine. My yahoo.com handle is the same as this board. Thanks.

rd78

 

[DARPA]

The city is requiring the developer to replace a catch basin with an outfall to a canal. The client is required to maintain it. Would placing an exfiltration trench between the CB and the Outfall create a maintenance nightmare or is it an acceptable retention strategy?