Posted 11/25/2012 01:57 (#2715377 - in reply to #2714908) Subject: Re: Irrigation with drain tile?
North Shore, O`ahu
There was some work done on that in Israel several years ago. It only works when the lines are relatively small in diameter and shallow. While it can work it isn't really a good idea. Drain tile usually needs to be large and deep, because it flows at atmosphere and depends on gravity. Irrigation lines need to be shallow to get the water to the root zone, and typically are much smaller than drain tile. Think of the difference in size between a tape emitter and the opening in a drain tile. Now multiply that by all of the openings in a line and you can see why it doesn't work very well. Tape is usually pressurized at about 12 psi at the source end so it can still have working pressure at the end of the run.
The Israel system was designed to maintain a near constant moisture level. If any part of the soil dried out, it was difficult to get the system to deliver water except in the driest area because the drain/irrigation tiles sere only operating at a few pounds.
It's kind of like trying to drive a nail with a shovel. It may eventually work, but having a shovel to dig and a hammer to pound is more efficient in the end.