Natural and artificially recharged groundwater

One glance at a map reveals that Finland is a country with a lot of water. A large part of our fresh water is hidden under the ground, however, and not shown on the map.

The volume in lakes, ponds and rivers is enough to provide 40 million litres of water for each person in Finland. Nevertheless, this visible water is only the tip of the iceberg compared to the groundwater reserves, which are three times larger.

Groundwater is a real treasure, as it usually is very clean and also contains suitable amounts of minerals dissolved from soil. Water utilities also prefer to use groundwater as their raw water source, and it comprises two thirds of the water they supply. More than a quarter of this amount is artificially recharged.

Artificially recharged groundwater is abstracted from the ground through wells exactly like ordinary groundwater. The difference is that its volume has been increased artificially by infiltrating lake or river water into the ground. Once this surface water has been filtered through the soil layers, it is almost as good as natural groundwater.

The longest-standing infiltration method is special seepage pits or basins. Alternatively, water can be sprayed onto the ground surface from where it infiltrates into the soil. In highly permeable shore areas, so-called shore infiltration of surface water is used, or water is simply allowed to infiltrate into the soil naturally.