Tips on constructing an Agricultural or Soakage Drain, the graphics are hand drawn and as I am not an artist please accept my apologies for any lack of artistic quality.

If you are thinking of putting in an agricultural drain, you have probably by now determined where your water is coming from, so you will have some idea which direction the drain will flow and where to. So I will talk about actual construction as I will not be able to work out your site, or actual depth of drain.

You can either hire a ditch witch and then dispose of the earth that is removed from the trench, or you could employ the use of a local contractor with a dump truck and Bobcat or similar piece of equipment, this will save you a lot of extra toil, as he can load the earth into his truck and take it away for you, there may be an extra charge unless you find somewhere for him to dump the solid fill.

Ideally the trench should be 8 inches (200mm) wide and on the average around 2 foot to 3 foot (600mm to 900mm) deep, the length will be determined by the area you need to collect the water from.

As per the above diagram lay newspaper (about 6 to 10 pages thick) along the bottom of the trench, the paper acts as a barrier to collect water before it soaks through the bottom of the trench and it will take quite a long time to decompose that far down.

Lay in the 4 inch (100mm) PVC Agricultural pipe (the type with elongated slits along the length)[see bottom diagram].

Backfill with 3/4 inch (20mm) screened gravel fill to approximately 4 inches (100mm) from the top.

Lay a double layer of old shade cloth or shade cloth off cuts over the gravel the length of the trench, in some cases your landscape nursery may have old cloth for free or very cheap. The cloth is needed to prevent the drain from silting up too quickly.

Over the top of the shade cloth lay your new soil/sand and re-seed or turf as needed.

The reason that it is best to use PVC pipe is that in years to come when the pipe clogs, you are able to then use and electric drainer's eel to clean it out, and rejuvenate the drains capabilities. You have the option of using the black flexible pipe but it is pretty hard to ever clean it out, unless you dig up the drain.

If the lay of your ground does not allow you to run the water off into a culvert or storm water drain or open land. Then you will need to run it into a soakage trench or pit.

You will probably need to work out the soakage rate of the ground to determine the actual dimensions of this trench or pit.

After the trench/pit is dug back fill with the 20mm gravel top with old shade cloth, soil/sand and re-seed or turf as required.