Numbered series of drawings (including floor plans indicating heaters, baths, toilets; design drawings of toilet, bath and basin; technical and construction drawings for the installation of water pipes in the reservoir tower) for the purpose of heating and hot and cold water supply in the castle, châtelet, garden and parks, with stamps of 'Eisenwerk Kaiserslautern' and Huijgen, signed by C.A. Huijgen, engineer, 1892, 1893, 1894, 1897, 1911, scale 1 in 5, 1 in 20, 1 in 50, 1 in 100, 1 in 250;

Technical drawings found separately including:
- Transit pipes, with stamps by Groeneveld & v/d Poll, Amsterdam, C.A. Huijgen, Rotterdam, 1893;
- 'Machine á vapeur,' stamped by Groeneveld & v/d Poll, Amsterdam, signed by C.A. Huijgen, 1892, 1893;
- Models for sinks in the reservoir tower;
- Plan of basement floor with piping;
- Steam pumping machine [drawing for inspiration or example] for the Werkendam municipal waterworks, scale 1 to 10;
- Wall trenches for steam and condensation water and for hot cold and drain water;
- Condensate pump, stamped by Groeneveld & v/d Poll, Amsterdam, signed by C.A. Huijgen, 1892.