EngQuest, an initiative of Engineers Australia, provides an exciting, non-competitive way for students to participate in free, fun and educational engineering activities involving mathematics, science and technology. This article describes a project designed to teach middle school students how to construct a water catchment system. Water catchments are areas of the land in which the natural landscape is used to collect rainfall. The project requires students design and build a working model, design the topography of their land surface, learn about dams, and test the working model.