Thank you for your question.
In Canada right now, grey infrastructure solutions appear to be the usual ones, by default. I'm from the United Kingdom and I've worked extensively in the Netherlands, where several methods that involve natural processes were used. It's also being done in several other countries. For example, at Percé, Quebec, there was the beach rehabilitation project, which was largely based on a natural process.
Erosion is a natural process. The problem with rockfill is that it gets in the way of sediment transport. The sediments that are not eroded are not moved, and hence not deposited on beaches. When you have grey infrastructure, it's important to know what the natural system is in order to decide on a process to adopt to make the changes. It's like functional units, and our grey infrastructures prefer natural systems. That means that it's a good idea to know how it all works.