Rain Gardens & Maintenance

Visitors admire a rain garden at Hunt Hill

Hunt Hill is the permanent site of a green and growing collaboration between LLPA, the Audubon Sanctuary and UW-Extension. With the help of Master Gardeners, and others who attended the free how-to sessions, three impervious surfaces there now drain into rain gardens. The practice of planting native perennials in swales dug out to collect and cleanse storm water and snowmelt is climbing the charts of lake stewardship. In Seattle, Madison and suburban Twin Cites, entire neighborhoods and even some commercial sites have incorporated rain gardens. As an individual effort, anyone with shovel, wheelbarrow and trowel can make a significant difference in preventing fine sediment and pollutants associated with development from entering storm sewers, streams and lakes.

How to build a rain garden – manual

The rain gardens planted at Hunt Hill were designed to trap and filter runoff from the office, barn and a dorm. Each demo plot took into account slope, soil type, sunlight and surface area it would drain—in each case a roof. Downspouts direct storm water to the gardens, where it percolates through the soil and recharges the groundwater instead of racing across the lawn to the lake. Native plants were selected because they require minimal maintenance, no fertilizer and no pesticides. Each garden was mulched to retain moisture and choke out weeds, and down slope berms were seeded for easy mowing. Hunt Hill’s longtime conservation ethic means its slopes are not heavily contaminated by construction debris; automotive fluid leaks; household chemical, paint and wood preservative spills; and bacteria-laden pet waste. Or sedimentation from bare dirt piles, which kills off littoral zone fish and amphibian egg clusters. Or phosphorus from excess fertilizer, which grows whopper algae blooms.

But what’s happening at our homes? Even car-washing suds that pour off pavement and accumulate on lawns carry chemicals harmful to aquatic life. Since no one seeks out lakefront property only to have a dead zone offshore, it behooves each of us to practice lake-friendly living. Rain gardens contain storm water for only a short time, avoiding mosquito breeding. While doing so they create beauty and intensify life. Wouldn’t we all enjoy more blooms and butterflies, dragonflies and ground-nesting songbirds along our shores? The EPA calls polluted runoff “the nation’s greatest threat to clean water.”