Rethinking Water Runoff Design

  • Rainwater that falls on paved areas is diverted into drains and gutters. If the rainfall is heavy enough, the diverted water can cause flash flooding in nearby rivers and streams. (Photo by Michele L.)

Some planning experts are worried that the rapid development in cities and suburbs is paving over too much land and keeping water from replenishing aquifers below ground. The Great Lakes Radio Consortium’s Lester Graham


Some planning experts are worried that the rapid development in cities and suburbs is
paving over too much land and keeping water from replenishing aquifers below ground.
The Great Lakes Radio Consortium’s Lester Graham reports:

In nature… when it rains… the water slowly soaks into the ground and makes its way
through the soil and rock to eventually be stored as groundwater. Some of it makes its
way underground to be stored in aquifers. And some of it slowly seeps through the rock
for a while and then resurfaces as springs to feed streams during times when there’s not a
lot of rain. It’s a natural storage system and a lot of cities rely on that water.

But when we build buildings and houses and parking lots and roads, a lot of the land
where the rain used to soak into the ground is covered up. Instead the rainwater runs off
the hard surfaces and rushes to stormwater gutters and ditches and then overloads creeks
and rivers. Even where there are big expansive lawns in the suburbs… the rain doesn’t
penetrate the ground in the same way it does in the wild. The grass on lawns has shallow
roots and the surface below is compact… where naturally-occurring plants have deep
roots that help the water on its way into the earth.

Don Chen is the Executive Director of the organization Smart Growth America. His
group tries to persuade communities to avoid urban sprawl by building clustering houses
and business districts closer together and leave more natural open space.

“With denser development you have a much lower impact per household in terms of
polluted runoff.”

Chen says the rain washes across driveways and parking lots, washing engine oil, and
exhaust pollutants straight into streams and rivers instead of letting the water filter across
green space.

Besides washing pollutants into the lakes and streams… the sheer volume of water that
can’t soak into the ground and instead streams across concrete and asphalt and through
pipes can cause creeks to rise and rise quickly.

Andi Cooper is with Conservation Design Forum in Chicago. Her firm designs
landscapes to better handle water…

“Flooding is a big deal. It’s costly. That’s where we start talking about economics. We
spend billions and billions of dollars each year in flood damage control.”

Design firms such as Cooper’s are trying to get developers and city planners to think
about all that water that used to soak into the ground, filtering and being cleaned up a bit
by the natural processes.

Smart Growth America’s Don Chen says those natural processes are called infiltration….
and Smart Growth helps infiltration…

“And the primary way in which it does is to preserve open space to allow for natural
infiltration of water into the land so that there’s not as much pavement and hard surfaces
for water to bounce off of and then create polluted runoff.”

People such as Chen and Cooper are bumping up against a couple of centuries or more of
engineering tradition. Engineers and architects have almost always tried to get water
away from their creations as fast and as far as possible. Trying to slow down the water…
and giving it room to soak into the ground is a relatively new concept.

The U.S. Environmental Protection Agency is trying to get communities to give the idea
some consideration. Geoff Anderson is the Acting Chief of Staff for the EPA’s Office of
Policy, Economics and Innovation.

“Anything you can do to keep that water on site and have it act more like it does in its
natural setting, anything you can do to sort of keep that recharge mechanism working,
that’s helpful.”

The EPA does not require that kind of design. It leaves that to local governments and the
private sector. The Conservation Design Forum’s Andi Cooper says sometimes getting
companies to think about treating water as a resource instead of a nuisance is a hard

“You know, this is risky. People tell us this is risky. ‘I don’t want to do this; it’s not the
norm.’ It’s becoming less risky over time because there are more and more
demonstrations to point to and say ‘Look, this is great. It’s working.’ ”

But… corporate officials are hesitant. Why take a chance on something new? They fear
if something goes wrong the boss will be ticked off every time there’s a heavy rain.
Cooper says, though, it works… and… reminds them that investors like companies that
are not just economically savvy… but also have an environmental conscience.

“A lot of companies are game. They’re open. If we can present our case that yes, it
works; no, it’s not risky; it is the ethical thing to do; it is aesthetically pleasing; there are
studies out there that show you can retain your employees, you can increase their
productivity if you give them open spaces to walk with paths and make it an enjoyable
place to come to work everyday.”

So… doing the right thing for the environment… employees… and making investors
happy… make Wall Street risk takers willing to risk new engineering to help nature
handle some of the rain and get it back into the aquifers and springs that we all value.

For the GLRC… this is Lester Graham.

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