Good day!
The ongoing dry spell has brought up a topic again that I have postponed several times: Where should the water for garden irrigation come from? Until now, I have been using water from the public supply: always available, consistently good pressure, and fairly cost-effective thanks to separate metering. But it probably isn’t sensible to let high-quality drinking water soak into the garden soil.
Is there a general rule of thumb about which form of garden irrigation is best from both financial and ecological perspectives? Essentially, there are three options: water from the public supply, collecting rainwater from roofs in cisterns, or drilling a well (if permitted).
To make the use of rainwater worthwhile, you would need to store a large volume, at least 20 to 30 cubic meters (700 to 1,060 cubic feet) to cover dry periods. The costs for cisterns and the associated earthworks would accordingly be high. Then there are ongoing expenses, such as electricity and maintenance for the pump. Drilling a well also involves costs, plus electricity and pump maintenance. The advantage of a well is that you don’t have to worry about storage capacity.
My garden irrigation system (drip hoses under mulch) consists of four zones, each of which requires one cubic meter (35 cubic feet) per hour. During prolonged dryness, I would ideally run each zone for one hour every two to three days. That adds up to about ten cubic meters (350 cubic feet) per week. With 30 cubic meters (1,060 cubic feet) of storage, this would last just about three weeks. We are increasingly facing situations in Berlin where it doesn’t rain for well over three weeks.
Has anyone here already worked through this in detail?
Matthias
The ongoing dry spell has brought up a topic again that I have postponed several times: Where should the water for garden irrigation come from? Until now, I have been using water from the public supply: always available, consistently good pressure, and fairly cost-effective thanks to separate metering. But it probably isn’t sensible to let high-quality drinking water soak into the garden soil.
Is there a general rule of thumb about which form of garden irrigation is best from both financial and ecological perspectives? Essentially, there are three options: water from the public supply, collecting rainwater from roofs in cisterns, or drilling a well (if permitted).
To make the use of rainwater worthwhile, you would need to store a large volume, at least 20 to 30 cubic meters (700 to 1,060 cubic feet) to cover dry periods. The costs for cisterns and the associated earthworks would accordingly be high. Then there are ongoing expenses, such as electricity and maintenance for the pump. Drilling a well also involves costs, plus electricity and pump maintenance. The advantage of a well is that you don’t have to worry about storage capacity.
My garden irrigation system (drip hoses under mulch) consists of four zones, each of which requires one cubic meter (35 cubic feet) per hour. During prolonged dryness, I would ideally run each zone for one hour every two to three days. That adds up to about ten cubic meters (350 cubic feet) per week. With 30 cubic meters (1,060 cubic feet) of storage, this would last just about three weeks. We are increasingly facing situations in Berlin where it doesn’t rain for well over three weeks.
Has anyone here already worked through this in detail?
Matthias
S
Steffen809 Apr 2020 08:29Please keep in mind: For automatic lawn irrigation, a cistern is usually necessary to increase pressure. The pressure from the main water supply is generally not sufficient for pop-up sprinklers!
Steffen80 schrieb:
Water pressure from the supply line is usually not enough for pop-up sprinklers!I cannot confirm that. The pumps at the water utility produce about eight bar (116 psi), and I still get more than four bar (58 psi) at my place. So, I have never had problems with pop-up sprinklers. Although I never had as many as ten in one zone—more like four—they have always operated properly.My current drip irrigation tubes are pressure-compensated anyway, so they work correctly even at very low pressure. Besides, I always connect them from both ends because they are quite long.
Oh, I see now. The amount of water is definitely something you need to pay attention to. You can easily figure it out by timing how long it takes to fill a 10-liter (2.6-gallon) bucket from the tap. Then you compare that to the flow rate of the nozzles built into the pop-up sprinklers, since there are always several of them. That way, you know if it’s sufficient. In my case, four sprinklers per zone were no problem; eight would definitely have been too many.