Mijdrecht – Amstel, Gooi and Vecht water board has closed the so-called water quality screen in the river Geer to maintain the water quality of the Vinkeveense Plassen nature reserve. Due to the drought, water from the Groot Mijdrecht polder, which flows to the lakes, is now relatively salty and rich in nutrients. That is bad for the flora and fauna. The screen prevents that from happening.