Build a Pond
If you don´t have a pond, you can build one. First start with the licenses. (Finnish Environment Institute in Finland).
After the construction permit arrived the trees inside the pond area were cut. As the ground was very wet it was let to dry for one year after the skin soil was removed. After the winter the pit was finished.
At the deepest the soil was very hard clay, so no water insulating film or plastic was needed.
A 20 cm diameter duct was installed through the 15 meters thick dam bank. This was the pipe which later on raised because of the ground frost next March. The water started to drain below the duct and slowly there was a 20 cm wide, 4 meters deep hole from the top of the bank to the bottom. And the pond had dried.
In the next summer, 2009, the pond was rebuilt without the pipe. Overfill was conducted through a bottom/base/bed dam. Where the bank is strengthened from the top with stones.
Bed dam was made by digging a moat which circulates the dam bank. Its slope is 3 meters / 200 meters. Over the dam, there is a place for the sauna.
A strainer fabric was installed at the bottom of the raising bank. Rocks and stones were put on it with sand and clay between them.
It has been working now perfectly for 5 years without any problems.
The ecosystem of the pond
This kind of artificial pond is like a big 10 million liters aquarium. In the beginning it started to seek the natural balance. According to my observation:
1) soon after digging when the clay was dry the pond surroundings were crowded by small spiders
2) the pond was crowded with water fleas
3) in the next year frogs found out this paradise
4) which after I put 200 European perch and a couple of crayfish into the pond
Now it seems to be working very well. There are newborn baby fish and a good amount of water fleas. After leaves have been falling 5 times to the pond. There is a thickening biological filtering layer at the bottom of the pond with micro organism and the crayfish are doing the mortician work with dead fish.
In the beginning, there was thin slime,alga or kelp in the water. After water plants came there has not been nutrient for them any more, fortunately.
The water is coming to the pond from 5 different fountains. The water is very cold in the fountains (+4 degrees centigrade) and it is very clear.
It may take years before my pond is thoroughly “naturilized”.
Bed dam examples
Material taken from Finnish Environment Institute:: http://www.ymparisto.fi/download.asp?contentid=76282
Next pictures are taken from: http://www.karhoismajanvesireitit.com/haavistonkeitaanojien_pohjapadot.pdf
22.3.2012 Copyright Jouni Finnilä © / Kexin oy (ltd) / www.kexin.fi
Note! These instructions are only for “nice-to-know”-information. Me nor Kexin oy (ltd) does not give any guarantee or has any responsibility of your construction work. Try and build with your own risk. You may use these instructions and guides for a non-commercial purposes, but remember to reference this source.