Meet your Chicagoland Stormwater Storage Requirements with a rain garden!

Rain Gardens: Hydrology is back, baby!

Old time rain water harvestingRain gardens are one of the hottest gardening trends of the 21st century.

Which isn’t that surprising when you consider it was the only gardening trend prior to the 20th century.

That’s right.

The modern rain garden, with it’s concept of designing a garden around rain, was just a garden to anyone older than our great-grandparents.

It was the development of our modern stormwater systems and the introduction of low-cost, abundant, running water that our need to understand and use rain in the garden was lost around the turn of the 20th century.

Garden Design Elements of the 20th Century

Now, after over 100 years of resource draining (literally) landscapes that are drying up our wells and streams while at the same time causing increasingly widespread flooding, we are reevaluating our impacts on the hydrologic cycle and are seeing the return of rain into our garden designs.

As we do so, it is important that we remember to see the big hydrological picture, especially with the use of soil mixes.

Rain Garden with Soil Mix or Existing Soil

Although rain gardens with deep soil mixes are on the right path by converting our rainwater into groundwater, they are taking a hydrologic shortcut in their design.

Rather than developing the skill set needed to estimate the soil moisture conditions after this rain is reintroduced and then designing to these conditions with the appropriate plants, we are in essence creating a soil dry well that will always have Medium to Dry soils.

Dry well compared to Rain Garden

I go into more detail in my post about why soil mixes should not be the standard, but in short, this practice is not an environmentally holistic, nor scalable, way to meet the groundwater challenges we are facing.

The real solution is that we need to relearn hydrology as gardeners. We need to teach how to effectively use rain in the landscape to landscape architect students. We need to have courses on rain gardens at the local community colleges. We need more books devoted to the creative ways in which we can garden with rain, as opposed to our current practices of gardening without rain.

We need to be able to make educated guesses on what the soil moisture of a certain location will be by observing the surrounding terrain, and then have the plant palette available commercially to design to these Medium-Wet to Wet soils.

Wet Plant Availability

Note: This is one of my favorite nurseries. If you recognize them, you probably know that they are one of the leaders in getting native plants to more store locations. I use them as an example here because of their wide selection of “traditional” plant choices that is very representative of the nursery industry as a whole.

Hydrology has moved to the forefront of city planning as we’ve realized that we can’t push all our incoming rain water off our lawns and out to the Gulf of Mexico while we also pull up our finite drinking water supply to water our lawns, AND expect this groundwater to always be there.

Stormwater and Sprinkler System

Villages recognize this and have changed their stormwater guidelines and ordinances. They are currently figuring out ways to increase fees and taxes for our stormwater runoff and our drinking water use to pay for the unplanned consequences of these 20th century practices.

These changes have already impacted how the landscape industry approaches projects, forcing rain back into the design discussion.

Gardeners, hydrology is back to stay.

This upcoming season is your time to get back in the classroom.

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Image Sources:
Rain Barrel – http://www.rainbarrelguide.com/wp-content/themes/thesis_17b3/custom/rotator/old-rain-barrel.jpg
Dry well – http://www.customgardens.com/cms/wp-content/uploads/drywell_cross-section.gif
Rain Garden – http://www.betterground.org/rain-gardens/
Sprinkler System – http://www.hydrotechirrigationsystems.com/

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