Fig. 1. Map of the headwater Catchments 1 to 3 located within the watershed of Lake Greifensee (G). The different colors indicate the spatial distribution of the hydrological soil groups (red, high risk for topsoil water saturation; orange, moderate risk; yellow, low risk; green, forests). Black dots, cornfields connected to the brook (for details see text); black hatching, confields that are not connected; P, Lake Pfäffikon.