Low Impact Development

Recently, I listened to a webinar (a seminar on the Internet) about Low Impact Development (LID for short). It was put on by JFNew and the Delta Institute. JFNew is a native landscaping company, and the Delta Institute is a group that works towards creating a sustainable Great Lakes Region.

So, what is LID? It is all about working with the natural features and qualities of the land to manage stormwater in a non-structural way.

The stormwater management paradigm has long been to build systems to collect and transport away all of the rainwater that falls in a given area. Storm sewers, concrete lined swales, even traditional lawns, are essentially ways to keep water moving away from wherever it fell.

LID means capturing and using or infitrating water closer to where it lands through green infrastructure systems that are actually disconnected.

Try to picture this yard:

1. Rain hits the home's roof, and runs into the gutters, then through the downspout. At the end of the downspout is a rain barrel that collects the first 60 gallons of water for later use watering plants in the garden.

2. Once the rain barrel is full, water then flows out into the yard, where it encounters native plants that absorb some of the water, and slow the flow of the water (unlike a turf lawn that tends to move water quickly).

3. Eventually, some of the water reaches a rain garden - an area of native plants whose deep roots help absorb the water into the ground, and whose leaves help transpire water back into the atmosphere.

4. The yard also has several large trees whose leaves and branches intercept hundreds of gallons of water each time it rains, keeping that water from becoming run-off.

In this scenario, no water ever needs to reach the street and the public stormsewer system.

LID means doing this on a larger scale, and even though it saves money (today and in the future), it is still a very misunderstood, and little used method of handling rain water.

Why? A couple of reasons:

1. It isn't what most public works or consulting engineers learned in school. It is new, and perhaps seen as untested. Let's face it, stormsewers have been around for a long, long time. Builders, engineers, even the average person on the street, have a pretty good idea of how they work.

2. LID involves green stuff, not concrete. How can living things perform as well as -- or better than -- the concrete things we build? I think there is a suspicion of natural systems, because they are harder to quantify and predict. Fortunately, that is changing!

3. Our culture likes control. LID means turning over control of the rainwater to natural systems - to trees and rain gardens. LID means trusting living, growing green things to do their jobs. Yep, they will do what they are made to do whether we tell them to or not!

4. Local ordinances make it harder. Since LID is newer, many local governments do not yet have standards in place to facilitate these systems. Developers often have to fight for the right to use less -- or no -- stormwater piping!

It is time to embrace our natural systems, and to help them do what they are meant to do! It is a peculiar hubris that leads people to believe that they can design something that will operate better than the systems that Mother Earth provided! Call me a savage, but that seems very naive!