What Is A Rain Garden?

. . . . and how does it work?

Excerpted from: Green Infrastructure

  As water runs down roofs, driveways and patios and off other impervious surfaces, it picks up pollutants as it flows directly into streams, wetlands, lakes and groundwater aquifers.

Stormwater runoff has become the number 1 source of residential pollution for waterways. It increases potential flooding. Some municipalities have responded, installing rain gardens, a type of green infrastructure, in public and commercial spaces to slow down and treat the water before it enters streams, wetlands, lakes and groundwater aquifers.

  Rain Garden Basics

Rain Garden Rain gardens are a type of water capture feature in landscaping that helps slow and absorb runoff from storms. Other types of naturalized bio-retention methods include storm water planters, green gutters, downspout planters, storm water trees, and tree trenches. The word “bio-retention” speaks to the process of filtering contaminants and sedimentation from storm water runoff.

Rain gardens, as well as other bio-retention systems, capture rainwater before it can flood your property or flow into a storm drain, eventually reaching swollen streams. They range in scope from an industrial size of several thousand-square-feet to a residential size of one hundred-square-feet or less.

Rain gardens recreate the natural function of the land, which includes; capturing rainwater, filtering out pollutants, and recharging groundwater. They can be constructed as simply as digging a shallow depression and filling it with native plants and soil amended with sand.

Graphic showing basic rain garden design.

Reasons To Create A Rain Garden?

Rain gardens are an easy way to capture rainwater that otherwise may lead to flooding and increased pollution. This is because as rainwater flows across our yards, patios, parking lots, and other hard surfaces, the water picks up oil, pet waste, fertilizer, sediments, and other pollutants. This polluted storm water runoff courses into storm drains and eventually dumps into our stream, rivers and other waterways.

No mowing needed. Rain gardens should be trimmed, mulched, and maintained to prevent clogging, but you’ll never have to mow.

Pollinator friendly. Native plants in rain gardens will bring birds, butterflies, and bees fluttering into your lawn. .

Groundwater recharge. Rain gardens help recharge depleted groundwater sources. Water captured by a rain garden drains back into the soil, which replenishes local aquifers.

No fertilizer, herbicide, or pesticide required. Native plants are adapted to your region and soil type, so they won’t need fertilizers or harsh chemicals.

Water pollution protection. Rain gardens divert rainwater away from storm sewers, reducing the load on the sewer system. Less contaminated water gushes into rivers and lakes and harms aquatic wildlife. .

  Benefits of a Rain Garden

Benefits of rain gardens can include a healthier and happier landscape in addition to its bio-retention properties. Utilizing native plants in a rain garden creates essential habitat for beneficial animals and insects. Local pollinators make use of plants that can be found in many rain gardens, which in turn helps the natural food chain and local agriculture.

Retaining water in the ground also helps to build soil health with microbes and mycorrhizae. Healthy soil can capture and retain carbon more effectively than dry or monocultured land can. A diversity of plants with healthy soils will do wonders for water quality and unseen natural life that takes place in your landscape.

Not only do rain gardens reduce pollution and flooding while contributing to groundwater resources, but they can also be a visually attractive feature. One of the best reasons to install a rain garden is that, unlike some other methods, this cost-effective bio-retention powerhouse looks great while providing a wide variety of other untold benefits.

Reference Material On Rain Gardens

 University of Wisconsin: Rain Gardens-Homeownes Guide
 Dane County: How To Build A Rain Garden
 UW-Extension: Rain Gardens-A Way To Improve Water Quality
 Rain Garden Plant List

Beneficial Species
Fertilize & Mulch
Garden Plans
Garden Pests
Lawn Management
Quick Tips
Soil Management
Specialty Gardens
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