Stream beds and banks etc must be completely sealed before using resin. I can’t make it out clearly from the picture but it doesn’t look as if yours was.
Often polystyrene would be coated in plaster bandage or papier-mâché then painted before the resin pour.
No wasn't sealed just added the small stones and painted them I've ordered extruded polystyrene foam board now hopefully they will work just abit gutted spent hours creating the rivers just glad that was only a small part i did first
It’s a shame as those beds looked very convincing. I think you put the cart before the horse in the sequence for your scenery. I would always do the resin after all the scenery ie scatter or static grass is complete. This avoids the surplus sticking to the resin.
As I said before this all has to be completely sealed so that no resin can get through.