We will discuss pattern formation resulting from the interaction of sand and water in various contexts ranging from formation of channel networks to building sand castles. The study is motivated not only by the beauty and complexity of the structures associated with these two basic ingredients, but also by implications to extraction and remediation of hydrocarbons and 3-D printing. We will advance the understanding of the observed phenomena by discussing a series of physical experiments performed to develop the erosion and sedimentation laws important to each system.