Complex sentence: Because of erosions, numerous cracks, caves and sinkholes which prevail in the limestone, two of the three lakes have no surface drainage: the water of the Fälensees flows by the mountain ridge southwest into the Rhine.
Split into simpler sentences: Because of erosions, numerous cracks, caves and sinkholes which prevail in the limestone. Two of the three lakes have no surface drainage: the water of the Fälensees flows by the mountain ridge southwest into the Rhine.