UNIVERSITY CITY • A half dozen homeowners are guinea pigs in an experiment to learn how well rain gardens protect property from storm water.
If the gardens — a combination of special soil, deep-rooting plants and stone designed to suck up and channel rainwater — work, MSD plans to expand them with the help of municipalities and the public.
They could help homeowners avoid flooded basements and provide MSD with an alternative to costly drainage systems.
DJM Ecological Services of Hazelwood, a contractor of MSD, recently completed installing rain gardens on six properties in the west end of the 8300 blocks of Cornell and Gannon avenues. (The owner of a seventh property decided against a rain garden but modified landscaping in his backyard using ideas from the project.)
Officials had decided the sloping topography of the neighborhood made it a good place to experiment with rain gardens.
Engineers terraced the gardens, making the ones on higher ground the largest.
The backyards are partly excavated, and the dirt is replaced with a specially engineered, highly absorbent mix of sand, compost and micro-organisms.
Vegetation includes native Missouri plants such as beautyberry, prairie root alum and zigzag goldenrod.
Natives can penetrate as far as 15 feet below ground, compared with the 18-inch range of typical ornamental plants, and their ability to absorb water is commensurate.
The goal of the gardens is to absorb the first inch of rain in a heavy storm, said Karla Wilson, a consultant who helped organize the project.
Because the native plants will need three years to mature, MSD and property owners won't know fully how effective the rain gardens will be until then.
One of the University City homeowners, Ed Mass, called the rain gardens "a terrific idea." Mass, president of Yes It's Organic clothing and furniture company and a lifelong conservationist, became a believer in the ability of plants to absorb rainwater after the death of two big oak trees near his home. Water then began showing up in his basement.
He said the gardens allow "people and nature to work together."
Lance LeComb, spokesman for MSD, could not provide a total cost for the project. DJM Ecological Services' contract is for about $35,000.
MORE RAIN GARDENS PLANNED
The rain garden projects are one of three done by the Deer Creek Watershed Alliance, which includes MSD, the Missouri Botanical Garden and Washington University.
The other rain gardens will be installed next spring on Chalet Court, off Graeser Road in Creve Coeur, and near the Mount Calvary Lutheran Church of Brentwood, in the 9300 block of Litzsinger Road, Brentwood, east of Tilles Park.
The rain garden behind Mount Calvary will test how well gardens can slow storm water from business or institutional places.
The efforts are aimed at curbing urban stream syndrome — flash flooding, highly contaminated stream water, bank erosion and elimination of certain plant species.
Kathleen Logan-Smith, executive director of the Missouri Coalition for the Environment, has taken a slide show around the region to illustrate the syndrome. Her slides show streams in good health with shallow banks, vegetation in their flood plains and few sharp drops in the stream's path.
Distressed streams have trees and bushes with exposed roots, steep banks, severe erosion and gravel deposits. Utility pipes are sometimes exposed, and bridge foundations can be damaged.
She said that Fishpot Creek in southwest St. Louis County was depositing gravel into the Meramec River to the point that it could block that waterway.
The bad-tasting water that upset residents of the Meramec River watershed in south St. Louis County last weekend is an example of the pollution problem officials are trying to stop with rain gardens and other measures.
The federal Environmental Protection Agency has pushed local agencies into action. In 2003, the sewer district, St. Louis County and 59 municipalities signed a five-year agreement with the agency to act to reduce storm-water flows and pollution.
The agreement was extended for an additional five years in 2008 and included new activities.
MSD spends about $3 million a year for this effort.
The traditional approach has been storm sewers and retaining walls. Bruce Litzsinger, MSD's director of environmental compliance, listed some of the new efforts:
• Expanded cleanup of the Meramec River, Deer Creek and creeks downstream from the confluence of the Missouri and Mississippi rivers.
• The sale of about 1,000 55-gallon rain barrels for $65 each. They can be linked to downspouts to store water that could later evaporate or used in gardens.
• Passage by St. Louis County and 58 of the district's municipal partners of ordinances that require stream buffers, areas along stream banks where developers cannot touch existing vegetation in new construction.
• Strict enforcement of regulations to require developers to include ways to reduce runoff and improve water quality in their construction plans.
As an example of the increased vigilance to storm water, the staff of the St. Louis County Planning Commission recently held up a housing proposal at the Jewish Community Center because of runoff concerns.
The organization had requested permission for a builder to construct 157 single-family houses on 47 acres on the northwest side of center property.
The planning department staff discovered the site contained a small creek that the developer planned to cover by grading.
The center has come back with a new plan that contained stream buffers, and several rain gardens and a detention pond. On Monday, the planning commission will consider making a recommendation on the project to the County Council.