Almost every city has the same thing in common. That is the love/hate relationship with water… specifically storm water. We all love water because it is such a precious resource that we are dependent upon.
However, it is storm water that our civilization has grown to hate. Why is it that we hate storm water so much? It wasn’t nearly the issue in the early 20th century than it is today. The answer is seemingly due to our liberal ways of covering the planet with impervious surfaces. If you think about the downtown of a city, it is almost completely covered with impervious surfaces, whether it is the buildings themselves, the streets, sidewalks, parking lots, etc. We love our impervious surfaces, and even cover our drainage ways with impervious surfaces. Engineers have become so good at their jobs of getting storm water off of the site, that they have inadvertently caused flash flood situations with dire consequences to those who live downstream.
A concrete drainage swale between lanes on an urban highway. Credit: Bing.com
The image to the right is an engineering solution to move the water as quickly as possible out of town. When I drove past this particular eyesore, ironically on a highway which the location will remain anonymous, it was interesting that people/vehicles and water were treated the same way—that is to get them in and out of town as quickly as possible.
As a way to “fix” this storm water problem, the government began its quest to require all developed sites to do their own storm water management, either on site or downstream in another location. Little did they know, this began to cause additional problems? One such problem is the burdensome costs associated with providing and maintaining the infrastructure to quickly move storm water and manage it with detention basins or retention basins.
The other problem was, and still is, not as obvious-that is an increased suburban landscape with low densities due to all of the unnecessary storm water bmp ponds, or storm water best-management practice ponds. Results include a wasteland portion of each site dedicated to managing storm water and greater need for parking lots, roads, etc. This seems like a problematic contradiction, right? So it is “managed” in one place, yet increasing the need for management elsewhere.
There are many documented techniques available and innovative technologies available to better manage storm water, or better yet rainwater. Many of these are referred to today as LID (low-impact development), Green Infrastructure and my favorite of the three, Light Imprint. Light Imprint stands out for me because it addresses the difficulties with density and context with reference to the rural-to-urban transect. Technologies are not as important with Light Imprint, it is more about common sense and infiltrating at the point of impact rather than waiting until it is storm water.
The following image is a diagram of the same impervious drainage corridor referenced above, with suggested modifications as an incremental approach to tackling the larger issue. The corridor does not have to appear so bleak; the water should be used and celebrated rather than forced downstream to become someone else’s problem.
water should be used and celebrated rather than forced downstream to become someone else’s problem. Original image from Bing.com
The diagram illustrates incrementally deconstructing portions of the impervious surfaces, reusing the wasted concrete as rip rap upstream to slow the water down for better infiltration, and beautifying portions directly after the water is slowed with vegetation. Even this will require engineering, and technologies such as structural soils and careful plant selection, but it is an incremental step to utilizing some of the water and creating a more tolerable environment.