Many lakes in Himmerland have developed in holes like that – “Madum” lake is one of them. “Madum” lake is the largest lake in Himmerland. It covers about 200 hectares and is 8 meters deep at its deepest point.

The lake is surrounded by forest and heath, and the only inlet to the lake is from a couple of forest swamps. The water in the lake is groundwater and the water level changes according to the surrounding ground water level and the amount of rain- and snowfall in the area.
The water leaks from the lake through the gravelly and the sandy bottom. In periods with a very high water level the lake has its outlet through the “Asp” brook.

There are not many fish in the “Madum” lake. But a few pikes and perches are found. During the breeding season golden eyes are found in and around the lake but there is no evidence that they are actually breeding here. Another frequent guest near the lake is the fish eagle and there is a population of grebes found around the lake. You’ll also find swans, coots and mallards at “Madum” lake.

“Madum” lake and the surroundings is a preserved area.
You’ll find nice places to swim around the lake. At the eastern side nudists have a spot where they meet and swim.