lower minnesota river watershed district

Eaton Corp. hosts raingarden workshop

In late June, Eaton Corp. of Eden Prairie became the first business to host a Metro Blooms–run raingarden workshop for its employees. (The District has helped fund Metro Blooms workshops in various District municipalities for the past three years.)

Green initiative

As part of Eaton’s “green initiative,” the workshops celebrated Earth Day (April 22) and World Environment Day (June 5). As such, they are a small part of the United Nations’ effort to make us “active agents of sustainable and equitable development” and parts of communities that must work together to change attitudes towards the environment.

Specifically, the workshops oriented Eaton employees to the environmental effects of rainwater on impervious surfaces. And they suggested simple ways to begin re-engineering home sites (and possibly corporate sites) to be more environmentally friendly. (Karen Radford, the Eaton employee who coordinated the workshops, has a raingarden at her Minneapolis home, thanks to a Metro Blooms workshop held last summer in the Como area.)

Michael Keenan, Metro Blooms’ presenter and designer, took Eaton through a series of thought-provoking and action-oriented PowerPoint slides. From consideration of causes to a look at fixes, Keenan steered employees through the process of becoming greener citizens, home owners, and corporations.

Green concrete — and alternatives

Our much praised lawns, he let us know, are really “green concrete.” Roots are so short and soils so compacted that a typical one-inch rain storm on a 5,000 SF city lot results in a runoff of over 5,400 gallons (an estimated 170,000 gallons per year). The same home uses some 140,000 gallons of water annually (for all needs, including lawn watering).

So why waste the rainwater? Recycling and filtering rainwater can be a remarkably easy way to absorb us once again in the natural process — even the engineers among us — and save money and environment at the same time.

Installing rain barrels at the end of our downspouts can save a lot of water and allow us to apply it, at will, to lawn and garden. (Catching and storing water in conjunction with a pumping system, aka "harvesting" rainwater, can distribute it through house and garden.)

Installing a raingarden can save more water — and direct it in purer form into our water bodies.

How so? As Keenan put it, unfiltered rainwater soaks right through the lawn and pours through gutters into our storm systems, carrying an unsavory mess of chemically coated grasses, dirt, paper wrappers, and other gunk. Through storm drains in the street, this mess gets deposited in our lakes and streams, and pollutes them.

Grass clippings may account for the worst part of the damage. Once the clippings sweep through storm drains into our water bodies, they become a super-nutrient for algae, which bloom and consume so much oxygen that they threaten fish and other desirable aquatic life.

Native plants' root systems

Why a raingarden in yards and corporate campuses? Compared with grass, many native plants in raingardens have long root systems that soak up rainwater and scrub it up. (See "Roots of Native Prairie Plants" slide at right.) Consider the biomass of the humble and hairy compass plant, which can shoot down roots 15 feet; the bearded switch grass; and the familiar purple cone flower.

With the right hydrology, soil preparation, and plant selection [MK slide], just about any site can become a be an efficient raingarden, aka water-pumping and -cleaning machine. For more facts about these prerequisites, see Rusty Schmidt's fine book The Blue Thumb Guide to Raingardens, available from Metro Blooms.

More information about raingardens

Keenan’s show-and-tell focused audience attention on many attractive native plants and on specimens of local raingardens. (See photos at right. Also see our longer article, from 2008, on raingardens; it contains more photos, cost-sharing sponsors, and a select bibliography.)

Especially at this time of devastating water pollution, the District wishes to thank Eaton Corp. and Metro Blooms for doing their part to keep our waters clean.

Showing & telling the way to cleaner water

Michael Keenan, of Metro Blooms, shows how capturing rainwater helps clean up water bodies.

This slide demonstrates the environmentally insensitive process of engineering drainage from our roofs and lawns. (Credit: M Keenan.)

Eaton's Karen Radford and Metro Blooms' Michael Keenan discuss how a raingarden on campus could capture water flow from an eroding grove of trees.

A successful raingarden depends on getting the correct water, soil, and plants (M Keenan).

Roots of native plants used in raingardens plunge way down, cleaning and absorbing rainwater (NRCS and Heidi Natura).

This successful raingarden, in the Mpls. suburb of Columbia Heights, solved a huge flooding problem in the back yard (photo: Shawn Tracy).

Another successful raingarden, this one in Minneapolis, shows how such construction can beautify and cleanse at the same time (photo: M Keenan).