Novel rain garden keeps water on site

When it rains, the newly planted trees, shrubs and perennials at the Flathead Youth Home will help prevent river pollution, thanks to a rain garden planted last week.

A rain garden is a way to keep storm water from running off a property and into the drains, possibly sending pollutants into local rivers.

Instead, the water is diverted into a specially designed garden.

"The whole idea is that the water on the site stays on the site," said Dan O'Neill, a landscape contractor.

O'Neill is implementing the garden design by Tom Weller, who specializes in storm drainage design and sustainable engineering.

Rain gardens "provide an inconspicuous and visually appealing way to deal with storm water," Weller said. "Here in Flathead Valley, it's the first of its kind."

Pipes attached to down spouts on the youth home are buried under the soil and drain into a 30-inch deep garden bed that has been filled with a special water-absorbent soil mix made of compost and sandy loam.

The garden is planted with hardy native trees, shrubs and perennials including maple, ash, birch, snowberry, sumac, dogwood, day lily and aster. A three-inch layer of bark mulch will be laid on top to hold in moisture.

The rain garden was built to comply with a 2004 state mandate for cities with populations greater than 10,000 that requires all developed land sites greater than 10,000 square feet to detain storm runoff with small storm-sewer systems. A rain garden is one such system.

Rain gardens don't require additional watering, so cities don't have to provide potable water for lawns.

There will also be a vegetable garden on the youth home site to allow children staying there to become involved in horticulture.

Weller said that he came up with the rain garden after living in the Seattle area, where such gardens are a common solution to capturing storm water. Weller also noted that such gardens are increasingly common throughout the United States.

"Storm water more and more is getting dirtier and dirtier," Weller said, citing the example of metals from automobiles getting swept into rivers from storm drains. "Rain gardens remove or keep trapped pollutants at the location so they don't pollute waterways. It's an attractive way to keep our streams clean."

Reporter K.J. Hascall may be reached at 758-4439 or by e-mail at kjhascall@dailyinterlake.com