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
My mom says that rainwater is much better for plants than drinking water.
We have a decommissioned oil tank in the garden that we could convert into a cistern. Even that probably won’t pay off financially very quickly. Digging a new one would be considerably more expensive. A well would be great, but unfortunately, I have no idea how to find out how deep the groundwater is. Or rather, I haven’t found any information about it yet.
We have a decommissioned oil tank in the garden that we could convert into a cistern. Even that probably won’t pay off financially very quickly. Digging a new one would be considerably more expensive. A well would be great, but unfortunately, I have no idea how to find out how deep the groundwater is. Or rather, I haven’t found any information about it yet.
Yes, I do have such a barrel, of course, but it empties within a few days. I’ll need to increase the capacity. It’s important to keep it as sealed as possible to prevent mosquito infestations.
Regarding groundwater levels, you can obtain information from the relevant water authority; in Berlin, this would be the Senate Department for Urban Development. It should now also be available in publicly accessible geoportals. Otherwise, you would typically conduct a test drilling first.
Regarding groundwater levels, you can obtain information from the relevant water authority; in Berlin, this would be the Senate Department for Urban Development. It should now also be available in publicly accessible geoportals. Otherwise, you would typically conduct a test drilling first.
Some friends of mine get their water from a well and are not connected to the public water supply. This has worked well since the 1930s, but during the last two summers, showering was sometimes difficult.
Rainwater tank: you need to consider the size based on how much water you can collect. What’s the use of a 30 cubic meter (about 7,900 gallons) tank if it only fills during very rainy winters?
I would partially change the planting to reduce water consumption. Even for lawns, there are seed mixes with roots that grow up to 80cm (31 inches) deep.
Rainwater tank: you need to consider the size based on how much water you can collect. What’s the use of a 30 cubic meter (about 7,900 gallons) tank if it only fills during very rainy winters?
I would partially change the planting to reduce water consumption. Even for lawns, there are seed mixes with roots that grow up to 80cm (31 inches) deep.
Pianist schrieb:
you would first do a test drilling anyway. Hello Pianist
Why would you do that? It probably costs about the same as the well itself.
Find out how deep the groundwater is. Maybe neighbors already have a well. Sometimes the authorities can help.
It would also be useful to know which soil layers exist at what depths. Clay is easy to drill through (goes quickly). Gravel requires drilling with a casing pipe. Or preferably right away with a well casing. Install 3 meters (10 feet) of filter pipe into the groundwater. Up to 10 meters (33 feet) depth, it’s pretty straightforward. My groundwater is at 14 meters (46 feet). I installed the pipes down to 18 meters (59 feet).
Steven
nordanney schrieb:
If there is an option for a well (and you don’t have to drill 30 meters (100 feet) down or only need to irrigate about 100 square meters (1,075 square feet)), the well will always be the better choice. In case of doubt, it can even be installed in an electrical room. You really have to do the math. A fully installed well, including drilling, electrical work, pump, and faucet, in my opinion cannot be done for under 1000€ (euros). With that amount, I can use tap water for 20 years here. That’s why we decided against it.
Same with a rainwater cistern. How big does it need to be so that it doesn’t run dry after 1-2 weeks of drought? Two heavy storms won’t even fill it up again.
How much does it cost, and how long could you just use tap water for that price?
From an ecological perspective, the idea makes sense. Pouring tap water into the garden, well… At the end of the day, tap water is simply too cheap here and therefore not as valuable as people try to make you believe. If you can save on wastewater fees (this factor significantly changes the calculations), wells and cisterns are usually too expensive.
You have expressed my thoughts very well. I also believe that neither a well nor a cistern will be cost-effective, but if you prefer not to let tap water infiltrate the ground, then a well probably makes more sense. Ideally, the pump would be powered by photovoltaic solar panels, but I haven’t tried that yet...
Probably, as a result of all the COVID-19 situation, my mind is somehow totally focused on self-sufficiency right now...
Probably, as a result of all the COVID-19 situation, my mind is somehow totally focused on self-sufficiency right now...
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