In A Stick in the Mud: Evaluating a Landscape, students explore landforms and erosion in the context of geotechnical engineering. The unit begins with the storybook Suman Crosses the Karnali River, in which a boy named Suman living in Nepal explores the field of Geotechnical Engineering in order to convince his father to build a TarPul suspension bridge in the best possible location. Over the course of the unit students build model earthquake-proof structures, analyze soil types, and use evidence to argue for their plan. Like Suman, students then follow the steps of the Engineering Design Process to imagine, plan, create, and improve their own model TarPul and to propose where to place it.