Who has experience with cisterns?

Hello garfunkel

that's exactly how it is.
I saw it with a pond builder. They make the concrete ponds watertight.

Steven

Is there a rule of thumb for how much rainwater one should be able to store temporarily? Somehow, what the roof supplies during a heavy rain and what is consumed in the weeks before and after must be in a reasonable proportion. Otherwise, the cistern empties too quickly or it constantly overflows and the surplus has to infiltrate.

I would like to install a drip hose at my place, both under the lawn and in mulched areas. 100 meters probably wouldn’t be enough, rather 200 meters. It has an outlet every 30 cm, from which 1.6 liters drip per hour. That would mean: With 200 meters of drip hose, I bring one cubic meter of water into the garden in an hour. To avoid forgetting to turn off the pump again, I would probably install a push button with a timer that switches off after one hour.

If you water for one hour three times a week and have a 10-cubic-meter cistern, it would be empty after three weeks. That could be tight with the current weather conditions...

Another question: What kind of pump would one use that is capable of delivering the corresponding amount of water but also building sufficient pressure for 200 meters of drip hose? And is there a way to install something somewhere where you can see directly that there is pressure in the system?

Matthias

There are maps that show the amount of precipitation and various calculators that then immediately calculate the appropriate cistern size. The yield that is possible for you is logically also what is available to you. 10m³ cistern... I don't know anyone who has such a monster in the garden. Most are in the 1-3m³ range and that is already quite decent, some have 5m³. The lawn is not watered by anyone here... I imagine 200m hose and drip irrigation to be difficult. The pressure must be there until the last meter, which means there is more pressure at the very beginning than at the end. The hole at the beginning will therefore bring much more water into the soil than the hole at the very end. I believe it will not work easily like that. I also consider that too much of a good thing. We do have drought here and there this year, but with simple surface irrigation that runs in the evening, at night or in the morning, one should still be able to bring more than enough water into the soil here in DE so that nothing dries out.

I have since read that the Netafim drip hose may only be up to 170 meters long. By the way, it is pressure-compensated, so it is supposedly ensured that the same amount of water drips from every hole, regardless of the pressure.

In my opinion, the lawn absolutely must be watered because otherwise it suffers too much from the dryness. In addition, it is gradually taken over by ants that eat the roots and thus completely destroy it. So far, I have been watering the lawn with pop-up sprinklers, but after ten years they also seem to be reaching their mechanical lifespan.

With the drip hose, the water goes exactly where it is needed, and there are no losses due to wind and evaporation. At least, that is what the manufacturers claim. So far, I have no experience with it.

Matthias

Now I have recalculated everything and keep coming to the conclusion that all expenses for using rainwater in the garden will never pay off. The tap water is simply too cheap here in Berlin. Especially if you have a second meter and don’t have to pay wastewater charges for the water that seeps into the ground in the garden. Also, due to our geology and our deep wells, we do not have any water problems in Berlin even in a summer like this.

Therefore, I wonder if it is even worth all the effort when the water simply comes from the tap...

Matthias

On our property (in NRW), rainwater must infiltrate on our own ground. Since I have to install a soakaway or similar anyway, I can directly integrate a cistern with overflow. Then the additional costs don't look that bad at all.