Decades ago, the biggest threats to America's waterways were industrial waste and untreated sewage. Factories and outdated utility systems became targets for protest and regulation - their waste products being visible, smelly and dangerous to public health.

Decades ago, the biggest threats to America's waterways were industrial waste and untreated sewage. Factories and outdated utility systems became targets for protest and regulation - their waste products being visible, smelly and dangerous to public health.

Today, the roughly 40,000 miles of streams in Ohio face a hazard that's less obvious but nearly as threatening to aquatic ecosystems: stormwater.

"It's kind of out of sight, out of mind," said Stephanie Suter, a habitat conservationist with the Franklin Soil & Water Conservation District. "You don't think stormwater ends up getting into our streams. A curb-and-gutter system is how we have always done things."

Instead of filtering into the soil, rain that falls onto landscapes hardened by asphalt and concrete is collected and dumped untreated into nearby waterways. The danger comes from the volume and speed of runoff, which erodes banks and stirs up sediment, and the harmful chemicals carried along for the ride.

"Stormwater and urban impact is one of the largest contributors to the degradation of streams," said Harry Kallipolitis, a stormwater coordinator for the Ohio Environmental Protection Agency.

But it doesn't have to be.

You can stop runoff in your own backyard with a simple landscape feature known as a rain garden.

These green zones act as miniature treatment facilities - collecting water from downspouts or parking lots and letting hearty native greenery soak up the flow. Soil and organic matter eventually break down chemicals, and excess fluid recharges the water table.

As you dig in this weekend, those with the Central Ohio Rain Garden Initiative hope you'll consider planting one of the beautiful and beneficial plots.

"There are people you can hire, but the average homeowner can do this pretty easily," said Suter, who's coordinating the local rain garden push. "It's really caught on."

Good rain gardens require minimal upkeep, because recommended plants can handle both flooding and drought. In fact, they become more useful over time, as deep roots and bigger plants are capable of processing more water and pollutants.

Since the 1990s, rain gardens have protected watersheds across the country.

Seattle, for example, implemented the Street Edge Alternatives Project in 2001 to provide drainage that mimics the natural landscape. After two years of monitoring, the project reduced the volume of stormwater runoff by 99 percent.

Currently, 35 rain gardens in Franklin County collect 1.1 million gallons of stormwater each year. The organization's goal is to collect one billion gallons annually.

Rain Drain

Here are some basic tips for plotting a rain garden. The Central Ohio Rain Garden Initiative offers specific advice to individuals at CentralOhioRainGardens.org.

Size it up. Before you start, you'll need to know the size of your drainage area, how quickly your soil drains and where excess water will go.

Place matters. Gardens should be constructed away from your house's foundation, so excess water doesn't damage the structure. A pipe extension or grass channel can funnel runoff away from downspouts.

Dig it, safely. Before breaking ground, call the Ohio Public Utilities Protection Service at 800-362-2764.

Make the grade. Gardens should be depressed from surroundings and graded evenly, so water enters the space and distributes equally.

Use native plants. Native wildflowers, ornamental grasses, ferns and shrubs also provide resources for birds, insects and butterflies.

Mulch wisely. To spread cover between plants, use double- or triple-shredded hardwood mulch, which won't float away in heavy rain.

Barreled Over

Another great way to reduce runoff is with rain barrels - large containers that collect downspout water to be used for gardening. Most are food-grade plastic barrels with a screened top opening (to keep out debris) and a spout at the bottom (to connect a hose). They retail starting at $55 at many hardware and gardening stores.

For more outdoor adventures, click to the Venture blog at ColumbusAlive.com/venture