Green Infrastructure: Rain Gardens

June 11th, 2019

What is a rain garden?

Diagram of Rain Garden (Rutgers University)

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

Rain gardens, as well as other bioretention 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.

Why do we need rain gardens?

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 stormwater runoff courses into storm drains and eventually dumps into our stream, rivers and other waterways.

Often homeowners are unaware of the effect that their stormwater runoff has on neighbors downhill. These systems are an important concept to consider when trying to alleviate flooding and erosion problems because they are a simple, environmentally friendly way to capture and treat rainwater.

By installing a rain garden, you redirect the water from flooding your neighbor’s property into a garden that is both an attractive landscape feature that also allows for water to naturally soak into the ground.

What are the benefits of a rain garden?

Benefits of rain gardens can include a healthier and happier landscape in addition to its bioretention 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 bioretention powerhouse looks great while providing a wide variety of other untold benefits.

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