 This letter started the chain of events in working that eventually led to a plan presented to the United Provinces to create a water defence plan in 1727.It was this unified water plan that in turn led to the creation of Haarlemmermeer bij pumping the Haarlem lake dry more than a century later.In 1733 he became a member of the 'Hoogheemraadschap Rijnland', the Dutch Waterboard Agency, and worked as a Waterboard inspector in Spaarndam.