We are finding that, over time, recaptured sediment in the trio is becoming less structural. This could be due to leaching of topsoil. As such, it is becoming more relevant to bring in fresh material to conduct major erosion repairs. To be effective, this needs to be compacted to mix/bond with the existing surface into a fairly consistent smooth surface. Achieving the right moisture levels can take time (perhaps an overnight soak).
Plate compaction should be performed to re-seal the surface (in the original shape) with no evidence of runnels. If runnels are not completely eliminated, they will return quickly.