Lake Veluwemeer and Lake Wolderwijd are located in the Netherlands between the provinces Gelderland and Flevoland. They were created in 1957 (Veluwemeer) and 1969 (Wolderwijd) for the purpose of serving as flood polders. Both lakes are shallow and have an average water depth of 1.5 meters. They have been eutrophic since 1957 and 1969. This case study deals with the regime shift from a submerged plant dominated system of Potamogeton pectinatus and Potamogeton perfoliatus to 'meadows' of Charophytes, (especially Chara spp.) in Lake Veluwemeer and Lake Wolderwijd that happened between 1987 and 1993. Potamogeton pectinatus, better known as fennel pondweed, is a submerged plant that has 2 mm wide, dense, long and linear leaves. Potamogeton perfoliatus, also known as clasping-leaf pondweed, is a submerged plant with oval, translucent leaves with no stalk that can be up to 8 cm long. Charophytes are a division of green freshwater algaes that have large thalli (which means they have no organized and distinct parts such as leafs, roots or stems) which can grow up to 120 cm. Chara spp., also known as Stonewort, is a rapidly growing submerged plant, which grows on the bottom of a lake with its roots attached to the sediment. Water depth and turbidity, which affect the availability of in situ light, seem to be the main drivers for the shift from the regime dominated by Potamogeton pectinatus and Potamogeton perfoliatus to the Chara spp. dominated regime. However, this is speculative because it is not clear whether luxuriant air plant growth, high turbulence, nutrients and grazing by herbivorous birds had an impact on the shift, too.