Ecological planning for urban sustainability: Manifestation of Ian McHarg’s ecological wisdom
Ian McHarg's influential book Design with Nature (1969) synthesizes and generalizes his ecological wisdom in informing landscape planning and design. In this paper, we suggest that his design process leads to the expression and application of his ecological wisdom as actionable and practical knowledge. Key features of his design process include: (1) multidiscipline integration to provide holistic design strategies, (2) ability to tackle wicked design problems residing in a wide range of scales, and (3) targeting landscape performance in a quantitative manner. We review the development of McHarg's ecological wisdom in the context of his education, teaching, and practice, as well as the influence from scientific theories of Charles Darwin and Lawrence Henderson. Then, we illustrate McHarg's design process using The Woodlands, Texas, a 117-km2 town development that McHarg considered to be the most ecologically based in the United States in the 1970s.
Four decades of empirical examinations reveal the outstanding performance of The Woodlands, highlighting the credibility of McHarg's ecological wisdom. Compared with adjacent Houston communities, The Woodlands shows significantly less stormwater runoff during 100-year storms, substantially lower pollutant loadings (e.g., NO3-N, NH3-N, and TP), lower levels of forest fragmentation, an average of 2 °C lower land surface temperature, and higher walkability and pedestrian access to open space. We conclude that McHarg's design process fosters the application of his ecological wisdom in an actionable and practical manner in The Woodlands case.