The definition of eutrophication is an increase of nutritive substances to a water recipient, and the results of this increase. The most important nutrients coming with the runoff water are nitrate and phosphate. You would think this as a good thing, because more plants and algae will grow and supply oxygen to the water. However, when the plants die and sink to the bottom, bacteria break down the dead plants. During this process the dissolved oxygen in the water can be so low that fish and other animals near the bottom might die.
Additional runoff comes from the grass tanks, excessive use of fertilisers and from milking rooms.
Usually caused by leaks in the sewage pipes. In addition the landfill in Heftingsdalen may cause runoff problems. Normally the runoff from here goes to the wastewater network, but a few smaller overflow accidents have occurred. Reduce the plowing in the fall. Establish protecting zones along the lakes and the rivers.