Natural pools in cold climate?

What should I think about when building a natural pool in Scandinavia? I live in south Sweden and it gets below -20C sometimes during Jan-Feb. My groundwater is almost at surface in spring and dropps 2 meters in late summer. Will the system still work here?

Johan

Hi Johan,
The low temperatures are not a problem in terms of the ecology of the pool. However, the rising winter groundwater will pose problems if the liner is laid directly on the pool floor. The ground water will make it "balloon" up. The liner will have to be trapped within an outer layer of concrete or stone flags on the floor and an external wall within the swimming zone.

living in a very cold winter area and having a pond, I can tell you there are things you really do have to think about. Your pumps and filters will have to be drained, removed and stored in a dry area to keep them from breaking, you should remove them before the water surface freezes..if you have elec for your pump, you CAN replace it with a bubbler of some kind which will help the health of the system over winter.

You will have to be careful when purchasing plants and animals and fish for your water feature to make sure they are hardy for your temperatures. MOST things you buy for a pond by mail order are not hardy and will not survive, so make sure you check your hardiness before spending money on things that might only live one year.

Even some hardy plants will be killed by animals, birds, etc. getting into your pond. I have hardy water liilies and water lotus that are damaged each year by critters.

also ICE itself can damage pond liners.. I do not use pond liners here, I use a natural clay bottom. Other structures can be damaged by ice as well.

Also deeper the better, as shallow water will go dry if there isn't a steady water inflow during the summer droughts, and make sure you have proper overflow, so that when you have spring thaws and heavy rains there is a proper place for the excess water to go and drain away.

Also if the pond goes dry you may lose your fish ..water plants can be potted up inside to live through a serious drought

Many hundreds of Natural Swimming Pools have be made in Austria and Switzerland with synthetic liners. They endure pretty cold winters perfectly well.

No animals should be bought and introduced into a Natural Swimming Pool. The only animals in the pool are ones that have made there own way in there so they will be adapted to the pool conditions. The same rule of thumb should apply to the plants. Species native to the locality are going to be the best survivors and be most beneficial the local ecology.

There is no need to circulate the water during the winter in a Natural Swimming Pool. The native animals will look after themselves under the ice cap.