Jaap Graaf runs Aannemingsbedrijf Graaf from De Cocksdorp. He specializes in the construction of ground, hydraulic and road construction. From basement to swimming pool Do you have a job in the ground, in relation to water or a new road? Aannemingsbedrijf Graaf specializes in well dewatering. This means that they have the experience and machines to pump up and advance groundwater through a pipeline, in order to locally lower the water table. This often happens during the preparations for a basement, foundation or construction of a swimming pool. Lots of experience on the island Did you know that Aannemingsbedrijf Graaf collaborated on the Kaap Skil building? Here Graaf provided the well-draining of the cellar. There are also many dairy barns on the island for which this contracting company has built the cellars.