Katwijk, Dunea Pompstation Katwijk, the former Duinwaterbedrijf Zuid-Holland (DZH) manages the dunes between Monster and Katwijk and uses them as a natural filter to purify river water from the Afgedamde Maas. The water is first pumped to bergambacht for initial purification after which it is pumped to the dunes which act as a natural filter and storage © 22 juni 2020 Aerophoto-Schiphol