This film shows two contrasting rivers catchments and their different responses to rainfall. On the left, there is a managed catchment with straight river channels, extensive upland drainage and housing built in the floodplain (blue bricks). The lack of upland water storage means that rainfall runs off very quickly, flooding the downstream catchment. Housing on the right hand side is protected by engineered flood defences (orange bricks). On the right, there is a more natural catchment with a meandering river channel, upland water storage (run-off attenuation features) and leaky dams all slowing the flow of water. With the same amount of rainfall, the water takes longer to reach the lower catchment and more water is retained in the upper catchment compared to the other catchment. For further details, please see https://www.jbatrust.org/how-we-help/physical-models/ar-sandbox/. Please use, share and adapt this resource with attribution to JBA Trust. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.