George Zeman’s willow wattle solution to control erosion in Saanich is another great example of working with nature to solve a human problem. This kind of thinking has the potential to solve some or all of the sewage problem too, at low cost, while adapting to climate change. See Regenerative Design for Sustainable Development by John Tilman Lyle.
This principle is simple: “Let nature do the work,” and once in place nature will do the work for free. I have advocated this principle in forestry for years, but old paradigms are hard to give up. John Maynard Keynes once wrote: “The difficulty lies not so much in developing new ideas, as in escaping from old ones.” For more on Lyle’s 11 principles, see http://www.ecotecture.com/reviews/lyle2.html.