Michelle Avis, P.Eng and Rob Avis P.Eng are the authors of Essential Rainwater Harvesting (New Society, 2018). They are also the owners of Adaptive Habitat, a leading-edge property design firm and Verge Permaculture, a globally recognized award-winning education business. They have over 20 years of experience in project management, ecological design, and sustainable technologies. They live in Calgary, Alberta.