Debris In A Culvert

ch0mpie

I'm currently working on a jobsite now that has a small stream which dumps into a 30" dia culvert and goes out to the hudson river. The pipe goes underneath a capped landfill and cannot be replaced as excavation of the landfill will not be permitted.

The problem is that the culvert is undersized and flooding occurrs when ever there is heavy rain. I am designing a bypass system, however, it will only partially relieve the problem.

Currently the existing culvert has metal grading over it. When flooding occurrs trash and branches clog grading and make the situation even worse. I was thinking a series of trash screens up-stream with holes getting smaller and smaller as the stream approches the culvert might improve the situation. What do you guys think? Seen anything else used in this situation?

nywoodwizard

I'm no expert but it sounds like you may end up causing a dam? also sound like you are stuck between a rock and a hard place.

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Learning without thought is labor lost; thought without learning is perilous.

firemike

Can the grate be reworked/modified to allow larger debris to flow through, or create a larger surface area (ie "V" shaped inlet or bulbous-shaped inlet) for runoff to drain through?

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-Mike-

ch0mpie

wood wiz, when there is heavy rain a dam does form and thats causing all the problems.

firemike, I can rework the end of the stream and grate any way I please. I only wish I had enough space to build a retention pond. I'm afraid to allow larger debris through because its only a 30" pipe and its a pretty long run if it gets clogged. Creating more grate suface area was the first thing I was thinking. The stream drops down into a chamber where the culvert is, I was think to put chain link netting over the whole chamber so that the water would have to flow through.

tgeb

How much room do you have, to possibly put a small retention pond or maybe some kind of structure?

I am trying to think something up.

Can you move upstream any distance for a solution?

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Tom

www.gebcon.com

ch0mpie

I'm going to take a better look at the area in question in themorning so I'll have a better idea of how much space I actually have. As far as I know I have a pretty good stretch upstream. The other problem with the retention pond is that I have no idea what my runoff area is to even estimate how big it would need to be.

LNG24

You mentioned the Hudson so I am going to say your in NY. Is the DEC working with you on this? How about the Riverkeeper. They usually make a mes of anything they get involved in, but if you don't include them, they can make your life difficult!

I have found that California, Arizona and probably other drought problem states have WAY BETTER means of protecting their storm water than we do. Look into that Storm Water Mag. Same publisher as Excavation and grading contractor.

There are already systems like you are describing for filtering out the debris. Most involve a drop down method not a horizontal screen.

ch0mpie

Since this landfill and culvert have been on the river for a while they already have dec/dep issues ironed out. Stopping the flooding is actually in the environments best interest as the floods ussually damage the land fill liner.

I was actually consider laying the chain link mesh down vertically over the chamber opening so that the water would drop down through it. I found some research articals that say this causes the filter to be self cleaning to an extent.

I went to the site today and I found that there is a good amount of room for a pond, but there are still issues like nearby transmision towers, and a service road would have to be eliminated. I'll have to see what the owner says about this.

LNG24

I understand that it already had approvals, but if the owner goes to modify, maintain or improve it, Even if it is in the Rivers Best Interest, the DEC, RiverKeeper and a bunch of others will be all over it. Since it is not your property, you wont have too much to loose except if the project gets stopped, your not getting paid.

Tread Lighty!

ch0mpie

The owner of the facility has a close relationship with these agencies, and therefore does not include dealing with them in our scope of work. We are only providing preliminary design options for this part of the job, so we get paid weather or not this thing gets built. When it comes to final design, the client will submit our design to the agencies and they will probably have a few things they want added or changed before construction begins.

Being that this is a landfill, dec is so far up there a$$ they know they can't get away with anything.