Big and small lake Wintelre

The Grootmeer and the Kleinmeer were originally natural weakly buffered fens, which are still surrounded by heath on the map of 1900. They arose in the period after the last ice age, about 10,000 years ago. They are located in an area that is slightly higher than the surrounding area. Heather fens are normally filled by rainwater that is retained because the bottom of such a fen is poorly permeable, usually due to a layer of clay or loam. In the past, however, the Grootmeer was also partly fed groundwater, which resulted in special vegetation.
Thousands of toads, frogs and salamanders live in the forest on the other side of the road. They flock to the Grootmeer in the spring to mate and then return again. When crossing the road, they were then flattened in large numbers. In 2009/2010 7 amphibious tunnels were constructed under the Merenweg. The amphibians can now cross on their own.
What is special about the Groot Meer is that there are vegetation from the shore herb association with species such as stemmed glass duckweed and shore weed. The Groot Meer has been designated as one of the most important growing places for this vegetation type, which is very special and not only in the Netherlands but worldwide.