Procedural River Generator.

Works with Blender 3.3 and above.

Created using Geometry Nodes.

Works in EEVEE and Cycles.

Check out a tutorial by The CG Essentials:
https://www.youtube.com/watch?v=0SIVT5qm3UA

Update

Version 1.1:

  - More control over modifier;

  - Better ground displacement algorithm;

  - Small optimizations.