It's not true that it all flows downhill, or downstream. Caledonia's Fire Station No. 2 is only the latest example of why it doesn't.

This spring, students from St. Rita's School planted a rain garden at the fire station, one of the latest public projects in a series which the Root-Pike Watershed Initiative Network hopes will inspire people to construct their own.

The idea is to slow the

water that otherwise flows rapidly to Lake Michigan. The slowing has three effects: some water will be absorbed into the ground, some may be released more slowly which will reduce flooding, and what is released will be cleaner.

"Our long-term goal is that this is going to be a good model for municipalities, and ultimately they're going to become more interested in funding gardens in their communities or requiring them in new developments," said Susan Greenfield, the executive director of the network. The group's goal is to promote better water quality in the watersheds of the Root and Pike rivers.

Rain gardens are not just low spots with different-looking plants.

"A rain garden is a specifically engineered structure," said Melissa Warner who is on the Caledonia Storm Sewer Utility District, another partner in the fire station project, and works with the watershed network.

Rain gardens are dug below grade by several inches, and their bottoms must be flat. "The idea is that you want the rain to spread out and fill up the whole things and not just fill up one side of it," Warner said.

Then the gardens are planted with plants suited to sun or shade. Water flows into the garden and stays there while it is absorbed by the plants or the soil. The garden dries out in three to four days, before mosquitoes can begin to hatch.

A 100-square-foot garden is big enough for the common home, Greenfield said, and many people can dig that 10-by-10-foot area by themselves. Large public projects typically require gardens of 300 square feet.

For the last two years the watershed network has received grants that help defray the cost of about 30 gardens. Greenfield said that $75 from a homeowner will buy 100 plants and 24 cubic feet of mulch. For larger installations there are contractors familiar with the techniques needed to create the garden basin, she said.

The state Department of Natural Resources and University of Wisconsin-Extension created a guide for property owners interested in creating a rain garden. It's available online at:

http://dnr.wi.gov/org/water/wm/dsfm/shore/documents/rgmanual.pdf

Effortless

Last year, Dave and Carol Pucely installed a rain garden at their Mount Pleasant home. It's enough to handle 75 to 80 percent of the runoff from the roof, he said. For the remainder he's considering a second garden, not because the first was too small but because of the difficulty of directing all his downspouts into the single garden.

"I tried the sump pump. It got a little overloaded, but I think I'm going to try it again," he said.

He had help from the watershed network, but Pucely said he built the garden himself.

"It sounded like kind of a fun thing, the environmentally correct thing to do. I enjoy doing stuff like that. For me it's a nice release from my desk job."

He said he didn't lose any plants and that the garden is filling in nicely.

"Once it's in it's pretty effortless. It's so thick I don't even see weeds," he said. "I notice we're not pumping stuff down into the ditch like we were."

Take it to the street

The city of Madison has taken the idea a step further and now offers rain gardens as part of its street reconstruction projects: http://www.cityofmadison.com/engineering/stormwater/raingardens/index.cfm

That had its origin in 2002 or 2003, said Genesis Bichanich, a water resources specialist in the city's Engineering Division. Members of a friends group for Lake Wingra approached the city and asked whether it could copy Seattle's installation of street rain gardens to stop or slow storm runoff.

The first two were placed on Adams Street on the city's southwestern side. Because these were the first they were very well engineered, she said, with overflow pipes and other features.

"So they ended up being 20-grand apiece. But they're incredibly popular," Bichanich said.

A state grant of $40,000 defrayed the cost, and since then the cost for each garden has come down considerably, she said. The design has been standardized to a 15-foot-long, 1-foot-deep installation costing about $2,500. Homeowners can pick the plants they want and pay a share of the cost, but because the gardens are taking runoff from road, she said, the state requires that they be filled with a special mix of material to absorb metals. There's also stone on the bottom to help water infiltrate the ground.

There are some limitations to using the gardens, she said. In some cases the topography isn't right. Gardens can't be near an intersection because they may interfere with motorists' lines of sight.

By the end of this year the city will likely have installed 30 gardens, and calculations suggest they're taking out 10 to 15 percent of the sediment flowing toward the lakes.

Even with relatively few projects, Bichanich said that people are taking notice.

"It's definitely getting the interest out, and people understand it comes off their property and goes into the lake."