Large and small lake Wintelre

The Grootmeer and the Kleinmeer are originally natural weakly buffered fens, which are still surrounded by heathland on the map of 1900. They were created in the period after the last ice age, about 10,000 years ago. They are located in an area that is somewhat higher than the surrounding area. Heathland fens are normally filled by rainwater that is retained because the soil of such a fen is poorly permeable, usually by a clay or loam layer. In the past, however, the Grootmeer was also partly fed by groundwater, which resulted in special vegetation.
Thousands of toads, frogs and salamanders live in the forest on the other side of the road. In the spring they migrate en masse to the Grootmeer to mate and then return. When crossing the road they were run over in large numbers. In 2009/2010, 7 amphibian tunnels were constructed under the Merenweg. The amphibians can now cross by themselves.
What is special about the Groot meer is that there is vegetation from the bankweed association with species such as stalked glassweed and bankweed. The Groot meer has been designated as one of the most important growth areas of this vegetation type, which is very special and not only in the Netherlands but worldwide.