Fluvial erosion is a "secondary" erosion. It is most useful when applied on top of an already eroded surface, or when you need light erosion where carving is more important than sedimentation.
|Duration||The number of erosion cycles to simulate. Usually 200 is sufficient.|
|Power||The strength of the erosion.|
|Granularity||Whether debris should be fine like dust, or coarse like rocks and even boulders.|
|BasLen||The sub-simulation length of each particle.|
|Radius||The area affected by each particle.|
|Random||The randomness of each particle's motion.|
|Seed||The randomization pattern or seed for the node's process.|
|Enable Parallel Processing||Enable multi-CPU processing of the effect.|
|Chunk Size||The chunk size into which the image is divided for processing.|
|Edge Blending||The percentage of blending between the edges of neighboring chunks. Higher values require more memory and processing time.|
If you see grid-like artifacts in your output, use higher values for Edge Blending. If that does not help, try increasing Chunk Size. If either does not help, you can disable Parallel Processing. This may result in slower builds, but the result will be accurate and error free.