Well, making something anew or restored is always more expensive than allowing nature to bring things in. If we allow the streams and rivers to function on their own, they'll bring in their own wood and their own gravel, rather than you and I having to hump it in on a four-by-four. If we allow the fish to do their thing, they will actually keep the infrastructure clean. Chum salmon are wonderful about cleaning out an area, so they will provide a great service for us, providing we do it correctly.
I would like to note that a lot of the things that were done under the emergency works were not fish friendly and were being done with the infrastructure that was available. MoTI, I understand, ran out of culverts. Maybe the culverts are not the correct ones. When we do things and we do them greener, maybe we can pull out those old culverts and reuse them in a more appropriate place.