As has been mentioned earlier, Lake Nedre Kalven is part of a larger FVO some 20 km NW of Åmål. Its catchment area is to the west, mainly from Lake Övre or Upper Kalven. After passing a power station, the waterway empties into Lake Nedre or Lower Kalven.
The lake empties to the south, passing another power station and the Korsbydammen pond and on through the Åmålsån River. Lake Nedre Kalven is a eutrophic lake with may reed areas along the shoreline. There is a lot of humus in the water, which explains why a Secchi measurement stops at or before one metre. As the lakes northern part is rather shallow, it’s best reached with a bellyboat of canoe. The southern section is somewhat deeper.
The lake is surrounded by a golf course limiting spin-fishing to the southern end. Thus the land along the shore is open, with rather large grass areas and some few deciduous trees. Spruce begins to dominate at 70-100 metres from the shore and serving as the beginning of the true forest.