by James Laughlin
I’ve been reading a lot about Low Impact Development recently, in part because of my involvement in the Urban Water Management Conference that’s being sponsored by WaterWorld (see article on the cover). The concept certainly appeals to me. I like to think I’m a low impact kind of guy and like to see natural systems used in place of concrete and steel.
On a personal level, how to control stormwater runoff through my back yard is becoming an issue. Whenever we get a heavy rain, what appears to be a fully-functional stream flows through my yard. It’s funny to see the volume and speed of the water, given my neighborhood is relatively flat. But it’s more than a little annoying to see the impact on my vegetable garden.
Last spring I built a garden in a sunny corner of my yard, with wide walkways running between four raised beds. To control weeds, I put down landscaping fabric in the walkways and covered it with what the manufacturer called “No Float” Cyprus mulch.
After the first heavy rain, I found all the mulch piled against my neighbor’s privacy fence on the “downstream” side of the garden.
Since a certain portion of the mulch escaped through the fence during every good rain, I had to remulch the walkways a couple times during the growing season. Now, mid-way through winter, most of it is gone.
Since a concrete and steel flood control system for my backyard is out of the question, I decided to research low impact methods of stormwater flow control.
EPA hosts a website that offers tips and instructions, including a document on Low Impact Development Design Strategies. According to the document, to develop an integrated management plan I need to define the hydrologic controls required, evaluate site opportunities and constraints, screen candidate practices, evaluate the candidate practices in various configurations, and then select the preferred candidate and design.
Of course, one of the first steps in low impact development is to avoid developing in natural drainage areas. “Where possible, natural drainage ways should be used to convey runoff over and off the site to avoid the expense and problems of constructing an artificial drainage system,” the guide warns. Little late for that.
I initially considered developing a bioswale to gently direct flow away from the garden, but that involved digging and seemed like too much work. Another plan to let the grass grow tall enough to block flow through the yard was nixed by the wife. I’m currently considering designs for vegetative buffers and decorative planters strategically placed in the yard to slow and disperse flow.
I’ve also considered just going next door and asking my neighbor if I could retrieve my mulch.
If you’re interested in Low Impact Development and its use is stormwater flow control and water management, EPA’s web page is a good place to start. The address is www.epa.gov/nps/lid. Featured on the page is a new report highlighting 17 case studies from across North America: “Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices.” The site also includes fact sheets, design guides and links to other informative sites.
James Laughlin, Editor
