We’ve touched on the topic of development density and stormwater a few times in the magazine. Although it seems counterintuitive to many people that high-density development is good for stormwater management, it begins to make sense when you look at it from a watershed perspective rather than lot by lot. An article by Randel Lemoine a few years ago compared the amount of impervious surface per residence in higher- and lower-density developments; although the high-density neighborhoods have more impervious cover per acre, they allow more people to live and work within a smaller space—and therefore not to spread out over many acres in one- or two-story homes with the roads, sidewalks, and driveways necessary to get to them—resulting in significant overall savings in imperviousness.
More recently, Paul Crabtree wrote about smart growth and its implications for stormwater. Smart growth—the term has been around at least since the early ’90s—involves much more than just stormwater management, such as creating walkable neighborhoods with a mix of land uses, access to public transportation, and preservation of open space. Several presentations at StormCon also examined the concepts of smart growth, light imprint, and their relationship to low-impact development.
But, someone always asks during discussions of higher-density urban neighborhoods, who really wants to live there?
Quite a lot of people do, apparently. A recent Reuters article looks at the trend in many cities for people—especially empty-nesters—to move away from suburban neighborhoods, with their big lawns and two-car garages, in favor of homes closer to the city center, neighborhoods where shops and restaurants and other amenities are within walking distance and where proximity to public transit might eliminate or greatly reduced the need for a car.
There are many excellent resources for those who want more information. One is The Smart Growth Manual that Paul Crabtree mentions in his article, by Andres Duany, Jeff Speck, and Mike Lydon. Another is the Light Imprint Handbook: Integrating Sustainability and Community Design by Thomas E. Low, another of the speakers at StormCon. His book includes the very useful concept of the rural-to-urban transect—zones ranging from natural and rural areas to the urban core, something I hope to cover more in upcoming issues—along with a tool box of dozens of stormwater techniques and matrixes showing which tools and techniques work better at different points along the transect, as well as numerous case studies.