River Erosion
Drop rain on a rough landscape and physics does the landscaping. In mountain mode, thousands of simulated water drops run downhill across a procedural heightmap, accelerating on steep slopes, picking up sediment while they speed up and dropping it where they slow — and out of nothing but that rule, branching valley networks and ridgelines emerge in a hillshaded relief view with the busiest channels tinted blue. In meandering mode a lowland river migrates sideways: the fast outer bank erodes while the slow inner bank builds point bars, so bends grow, wander downstream and finally pinch off into oxbow lakes. Sliders control rainfall, erosion strength, deposition and terrain roughness, and every new seed grows a different landscape.
Runs 100% in your browser — simulations are computed locally on your device.
Read the full guide to this tool
Notes
- The drop rule is local and simple — carry capacity proportional to speed, slope and water volume — yet the emergent drainage networks show the branching statistics of real river basins: erosion is a self-organizing process.
- Meanders are an instability, not an accident: any slight bend speeds up the outer flow, which erodes the outer bank, which deepens the bend. Growth continues until two loops touch and the river shortcuts, stranding an oxbow lake.
- Uplift is missing on purpose: with rain only, mountains can only wear down. Real landscapes are the tug-of-war between tectonic uplift and this erosion — the sim shows the second half.
- The models are classic computer-graphics/geomorphology approximations: particle-based hydraulic erosion on a grid, and curvature-driven bank migration for the meanders — tuned for insight and looks, not for engineering-grade sediment transport.
- Runs 100% in your browser — simulations are computed locally on your device.
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