Thank you waldronate! That seems to have worked quite well to keep the coastlines intact!

The rivers are also embedding far better when after using Filter>>Fill>>Set Value to zero too. Obviously it isn't completed, but I think that either the heights of the mountains compared with the land needs to be increased, or I should continue to add rivers in order to influence the terrain generation more. Right now, the basins are pretty flat and ordinary so I think that I need to add more rivers, or some extra hills, to make it more interesting.

Screenshot 10.PNG Terrain Generation New 12-02-2022.png