Introduction: Automated Ground Water Garden Irrigation
Dry gardens with many dead plants, typical for the summer of 2018 in the Netherlands. Spraying gardens is a good way to keep plants alive. However, this takes a lot of time, and water is (to a large extent) pricey.
How can we solve this? How do we make water cheaper and can this be linked to the internet? In this instructable you can read how I pump up groundwater, and control the sprinklers with my Apple Watch or phone.
Sprinklers with Homekit integration, who would not like that?
Step 1: What Is a Well Borehole?
By drilling for a well it is possible to discover groundwater from the ground. This can be seen schematically in the picture above.
In the ground a pipe of several meters (in my case 10 meters) is drilled, at the bottom of the pipe are all small holes. Because there is water at the bottom of the ground, this pipe will automatically fill up with water. With a centrifugal pump the water that has run into the pipe can be pumped up. With this water the garden can then be sprinkled.
In the picture above, a submersible pump is used, which is lowered into the pipe. This is optional, and is also a possibility. I did not use this because I see advantages in a centrifugal pump.
Step 2: The Pump
How does a centrifugal pump work?
Centrifugal pumps are the most common type of pump used in industry, agriculture, municipal (water and wastewater plants), power generation plants, petroleum and many other industries.
Centrifugal pumps work by converting a rotational energy from a motor to induce a flow or raise the pressure of water. When water enters from the suction end of the pump, the impeller catches the fluids and then rotates, making the fluid entering the pump rotate as well.
The pump cannot suck air, it is important to fill all the pipes and tubes connected to the pump with water before turning it on. Air is compressible, water is not.
Step 3: Building the Pump
A groundwater pump does not only consist of the pump itself. Underneath the pump is a pressure vessel, which is controlled by a pressure regulator and the pump.
The pump is adjusted to a certain pressure, this pump fills the vessel and when the set pressure is reached the pressure regulator switches the pump off.
These pumps are ready for sale on the internet.
My pump is self assembled, and the connections are made with some high pressure PVC pipes and fittings.
A complete groundwater pump is also called a hydrophore pump.
- The top connection to the pump is often the press side, so the outgoing side.
- The side connection on the pump is often the suction side, so the inlet side.
It is important that the outgoing pipe of the pump is also connected to the pressure vessel.
The pump then fills the pressure vessel. The pressure vessel can therefore provide the sprinklers with a little extra pressure, this to prevent fluctuations.
The green couplings are polyethylene couplings, to easily attach the black sprayer hoses.
The hose on the suction side enters the groundpipe. My groundpipe is 10 meters deep, and the hose that goes in is 9 meters long. This is to avoid sucking rubbish on the bottom.
At the bottom of this suction hose a non-return valve has to be attached.
Step 4: Drilling the Groundpipe
Under high pressure with water a hole is drilled in the ground. The water washes away the excess sand, and makes a hole in the ground. A tractor with slurry tank was used.
The filter tube is then pressed into the soil and automatically fills up with groundwater.
Doing this yourself is difficult, ask a local installer.
Step 5: First Test
By connecting a sprinkler to the pressure pipe and connecting the suction pipe to the suction pipe, the pump can be tested.
The set pressure is 2.5 bar.
Step 6: Building the Housing
I have built a housing around the pump to prevent the pump from being damaged.
For this a concrete putring was used, this was first a cow drinking trough.
With an excavator, the ring was placed above the pump, then a concrete floor was poured into it. This step is fairly simple, as the putring was available.
Step 7: Controll Unit
Now we have a pump that pumps water away, turns off at pressure and a robust housing. The idea for our garden is to create 4 zones, which can be operated separately with Homekit. Each zone consists of 2 sprinklers, to prevent the pressure from falling off, the 4 zones have been created.
The control piece consists of some PVC fittings, pipes and PE couplings. The zones are operated with solenoid valves. - By applying current to a solenoid valve (24VAC / 230VAC), the valve opens and water flows. - No current on it, means pipe closed.
When all solenoid valves are closed, the pump ensures that the vessel is filled and switches off at the set pressure.
In the white boxes on the wooden plate are the electronics. To control the valves we used Sonoff Basic's. This is a WiFi relay, which can be controlled from your phone. This Sonoff is flashed with alternative software, to make it compatible with homekit. A Homekit server runs on a Raspberry Pi to control the Sonoff's.
A good tutorial about the Sonoff's is this one:
A good tutorial for the Homekit server is this one:
Learn here how to communicate between Homebridge and Sonoff
The ball valve on the manifold is used to empty the pipes or to connect a garden hose to them. This has the advantage that no telephone is needed to get water. At the moment this port is connected to a faucet, to get groundwater from a faucet.
PE pipes have been dug to points from where we wanted to spray. Brass sprinklers were used as main sprinklers for the grass.
Step 8: Drip Irrigation
The brass sprinklers throw a lot of water. For a vegetable garden, or young plants this can be fatal. The water jet then comes on too hard, and it destroys the plant. For grass sprinkling this is fine.
An alternative to large sprinklers are drippers. Drippers drip small amounts of water exactly at the root of the plant. This method of sprinkling is much more effective, and softer for the plant. However, longer irrigation is necessary to provide the plant with sufficient water. This has the advantage that the plant does not drown either.
Simple drop installations are for sale from Aliexpress. The drippers are adjustable, in the amount of liters per hour may flow through them
In my garden drip irrigation has been installed in various planters, and in the vegetable garden. By setting up an automation with Homekit, I can provide the vegetable garden with enough water at night. For example, I sprinkle for 2 hours.
Step 9: Does It Work?
The summer of 2018 in the Netherlands was extremely dry. Many grasslands and corn fields were lost because there was no water to be found in the ground. Our filter proved to be active throughout the summer, and was full of water.
On the picture above you can see that our grass is very green, and the meadow is completely withered.
It works! We can spray, and drip water using our phones.
Participated in the