Making a nature mandala is a great activity to tune into the colours, shapes and textures of natural objects at your waterway.  Collect some treasures, plan a design and create a masterpiece.  Ideally, this is done by the waterway where collected materials can stay on site.  If collecting from your waterway and completing the activity back at school, try to return the materials later.

Extension: find objects in nature that are mandalas in themselves.  See this article for examples.