The Houtribdijk, between Enkhuizen and Lelystad, has been strengthened. It again protects all surrounding provinces against the effects of high water levels. Part of the dike has been reinforced with quarry stone. Another part is fortified with sandy banks that are overgrown. In addition, Trintelzand has been developed, a large nature reserve that already attracted a lot of birds during construction. All proceedings and particularities of this project are shown in this book that has been sent as a thank you to all 500 collaborators.