I’m looking to put river rock (depending on size) around the shore of my pond to help erosion. Very little waves, pond is in the woods, but I’m looking to avoid erosion and soggy edge. Likely will have some grass planted on top of bank if I can get it to grow in the heavy shade.

Question is how far into the water should I put the rocks to prevent erosion and secure the bank line.

Slope is generally 3:1 throughout, a little steeper on one small side of the pond. Waves will mostly be from light aeration underwater and surface.