Before revision: On land This swale concept has also been popularized as a rainwater harvesting and soil conservation strategy by Bill Mollison , David Holmgren , and other advocates of permaculture.
After revision: On land The use of swales has been popularized as a rainwater-harvesting and soil-conservation(1928-2016)(1955- ) strategy by Bill Mollison , David Holmgren , and other advocates of permaculture.