Connecting Pump to Water Tank and Irrigation System

In previous posts, I wrote about sinking wellpoints,  and connecting them to a pump.  So now I could fill a water tank from the wellpoints, but what about pumping water from the tank into the irrigation piping?  I had four irrigation circuits covering the garden and wanted have taps that allowed one or more to be turned on at a time, with perhaps a spare tap or two.  The water also needed to be directed into the tank when required.  How hard could that be?  Quite hard, as it turned out…

Looking back at the initial hand drawn diagram I had made, I decided to use PVC pipe and plastic taps.  I found some adaptors which fitted perfectly into the 45 degree three way junctions and allowed a tap to be screwed on.  I glued them into the adaptors using PVC cement and screwed the taps on tightly.  This will allow the taps to be removed and cleaned or replaced when necessary.

For the input side, I designed and printed (using ABS again) an adaptor which allowed a 20mm pipe to be pushed onto it.  I did the same for two hooks to hold it.  The yellow hooks can be seen at the top of the photo and the white 20mm adaptor is on the left, with a spare one also shown.  It’s quite possible to find standard fittings and adaptors to do the same job if 3d printing is not your thing.

It was hard to find the exact adaptors I needed, so I also designed and printed a few custom ones. One was a 90 degree bend with one end threaded and the other a push fit as you can see in this photo.  Eventually some of these broke, mainly because of inter-layer weakness in ABS and the stress from pushing on pipes and click-on adaptors.  In the end I replaced most of them with standard nylon moulded fittings.  In the photo, the output from the pump enters at the left, and the rightmost tap goes to the water tank.  Four of the remaining taps go to irrigation circuits, with two spare.  One of the spares has a snap on connector to which a hosepipe can easily be connected.

When it was all rigged up, it looked like this.  You can see a dark vertical line in the centre of the tank, which is showing that the tank is about a quarter full.  That’s just a length of thin clear tubing with one end hanging down inside the tank.  It comes out of a small hole drilled into the top of the tank, loops down to below the tap, and then back up again.  It has a bit of dark dye in it, which means I can see how full the tank is from the other end of the garden.

The timer turns on the pump four or five times a day, for 15 minutes at a time.  It takes three or four 15 minute intervals to fill up the tank.  Once a day, or as needed, I turn off the main wellpoint tap, as well as the tap to the water tank.  I turn on the tap which feeds water from the tank to the pump, and also turn on whichever irrigation circuit I want to use.  When the timer kicks in for the next 15 minute slot, it empties the tank.

When that is done, I need to switch off the irrigation circuit and tank-to-pump tap, and turn on the pump-to-tank tap and the main wellpoint tap.

Of course, it would be nice to have all of that automated!  Perhaps with some water level detectors, and even soil moisture detectors to see when and where irrigation is needed.  How hard could that be?