How much will this screen impede water?

Heres the situation:

Culvert is vertical, extending into the ground.
2 1/2" PVC pipe extends into the side of a culvert (a natural spring that has been tapped). Covering the end of the pipe is a standard 2.5" coupler with a cylindrical cage consisting of 1/2" hardware cloth wrapped in plastic mesh (about 1/8" holes).

The water in the culvert is backing up (culvert overflowing), and one of my theories about the cause is that this screening cylinder (meant to keep contaminants out of the line) is blocking the flow of water. The water is backed up about 3’ over the level of this pipe.

My other theory is that the line is partially clogged or blocked farther in.

So… how much could this screen be impeding the water flow?

Some other things which it would be helpful to know about this:

How big is the culvert? And do you know the rate of flow which feeds into it? Has the PVC pipe historically been able to keep up with the flow rate? Can you estimate the percentage of area which is blocked by the screen?

The culvert is about 3’ across. The screen was replaced last year because the old one had holes, and the new one is of my own design, so I cannot compare. However, the new one has a greater surface area to (hopefully) compensate for the smaller holes in the mesh.

I fail to understand.

You have a 3 foot diameter vertical culvert which is supposed to drain away water. You have a 2-1/2 inch pipe with a screen across the end which feeds water (probably at low pressure/flow) into the culvert. You report the drain culvert isn’t draining quick enough. You wonder if the screen across the input pipe is the cause.

What have I missed here? It seems to me your screen should reduce the input flow & hence improve the draining.

If the drain isn’t draining with the same or less input flow than before your modifications, then it must be (at least partly) clogged.

No no no, LSL guy, here’s the deal:

A 36" (estimated) diameter culvert is inserted vertically into the ground. This is to tap into the natural spring; it functions as a “wet well” of sorts. A small PVC pipe is connected horizontally to the larger one; its purpose is to draw water out of the “wet well”.

Did I get that right Gabe?

You may be right, the new screen may be more restrictive. One easy way to figure that out would be to remove it entirely and observe what happens. Can you use a different type of filter?

Right on the money.

Tomorrow I will be excavating (by hand!!) this pipe to check for breaks. I am also going to dig a ditch to help drain the standing water away.

There is nothing quite as fun as trying to dig in forest duff.

I’d be interested to know what you found out. And hey, don’t forget your axe for those pesky roots. :wink:

Didn’t need the axe - I just hacked at them with the shovel. In between using it to fend off the hordes of mosquitos that were breeding in the standing water.

What I found was disturbing. The 2 1/2" PVC that I mentioned, after I dug up about 3’ of the downhill side, turns into a 60-year old iron pipe. The PVC was just jammed onto the end of it (when that pipe was laid about 20 years ago). The iron pipe was predictably rusted and was putting out a very poor flow, causing the backup. Next weekend when I have a crew of 5 or 6 guys working for me, I’m going to excavate that 20’ or so of iron bullshit and replace it with PVC. Should solve the problem.