Watershed

What it is

Short: Make it rain anywhere on Earth and watch where the water goes. Watershed is a rain and flood simulation sandbox on real terrain.

Watershed asks a simple question: what if it rains here? Pick any place on real Earth terrain and make it rain. Water runs downhill, gathers into rivers, fills valleys into lakes and sends flash floods down dry canyons, live on the graphics card. Rain can be continuous, an hourly burst or a daily storm, for hours, days or weeks. The longer it rains, the bigger the floods, and vegetation greens along rivers and lakes over time. It is a simplified illustration for exploring landscapes, not an engineering model.

Every layer is real, public data with its source shown. Every number has a reason. Nothing is a calibrated engineering model, and the app says so.

Key features

• Rain anywhere on real Earth elevation data
• Continuous, hourly burst or daily storm rain, for hours, days or weeks
• Turn the rainfall up for flash floods
• Rivers, lakes and floods form live on the GPU
• Vegetation greens along rivers and lakes over time
• Four simulation detail levels: Fast, Balanced, Detailed, Extreme
• Share links reproduce a whole scenario
• Extras: sea level and historical atlas layers
• Built with WebGPU, Tauri and MapLibre; imagery by Mapbox; elevation from AWS Terrain Tiles; coastline from Natural Earth