catchment area oer-ij
The river catchment of the Oer-IJ is the more limited area where the northern branch of the Vecht actually flowed, including the former estuary. The Oer-IJ basin now consists of two very different landscapes. Firstly, it is the northern part: the former estuary landscape with the tidal channels. Here the sea flowed into the hinterland twice a day with the rhythm of the tide and out again. The northern branch of the river Vecht also flowed through this area, helping to keep the trench open. Secondly, this is the Oer-IJ river that was located outside the estuary area. From the Middle Ages the influence of the tide from the Zuiderzee expanded the peat landscape into inland sea: the IJ and the Wijkermeer. These lakes were reclaimed at the end of the nineteenth century for the construction of the North Sea Canal.