What is a Raingarden?

Image of a Raingarden

A raingarden, as seen above, is a shallow depression that is designed to capture rainwater and allow it to soak into the ground within a 24-48 hour period.  Most gardens are best designed with plants that are well adapted to the unique conditions of the garden and your region (such as local native plants or cultivars of those same plants).    

What is a raingarden?

A raingarden is designed and planted to capture rainwater so it can penetrate deep into the soil to help protect and restore water quality.  This helps to reduce the amount of stormwater runoff that would otherwise take pollutants from the air, our yards, and the streets and carry them into our lakes, rivers, and wetlands.  A raingarden is a great way for homeowners or business owners to reduce the amount of runoff flowing from our properties.  By capturing this polluted water and allowing it to slowly soak into the ground, we can mimic natural systems that have historically purified our waters through a process of filtering underground. Raingardens are also a way to beautify your property.  Using perennial plants that require little maintenance and can thrive without fertilizer or pesticides, we enhance the value and attractiveness of our neighborhood and community.

What causes rainwater pollution?

Catchbasin Road Gunk

Rainwater pollution comes from various sources such as road salts, leaking oil, and road sediment.  It also comes from your yard in the form of fertilizers, herbicides, leaf litter, grass clippings and pet waste.  There are two general categories of pollution: pollution that comes from a direct or a known source and pollution that comes from indirect contaminant sources. Direct sources (point source pollution) like factories or waste treatment plants emit contaminated fluids directly into water supplies (usually through a direct line like a pipe). In the United States and other countries, these practices are regulated, but this doesn't mean that pollutants can't be found in our waters.

Indirect sources (or non-point source pollution) enter our water supply from soils and groundwater that contain the residue of fertilizers or pesticides, and improperly disposed industrial wastes.  Pollution in our rain water comes from atmospheric contaminants from human practices like the gaseous carbon emissions from our cars and trucks, and industrial air emissions from facilities like coal plants, for example. This air pollution is gathered in rain water as it falls.  It is this polluted water that flows off our roofs, lawns and sidewalks carrying residue of fertilizer, pesticide, pet waste, gas and oil into the city storm sewer, that ultimately pollutes our lakes, rivers, and streams.  This is the problem raingardens help solve: raingardening is a cost-effective and beautiful way to reduce the effects of this "nonpoint source pollution" in our watersheds, and to beautify our city and neighborhoods.

What plants should I use?

Native Roots

Most gardens are best designed with plants that are well adapted to the unique conditions of the garden and your region (such as local native plants or cultivars of those same plants).  Raingardens rely on the ground’s ability to absorb and infiltrate water.  In using native plants, or cultivated varieties of these plants, you utilize their deep root systems and help to deliver water deep into the ground so that it can be cleaned naturally.  Native plants are highly adapted plants that have grown in Minnesota for thousands of years.   This adaptation has resulted in deep and thick root systems and special leaf structures that are well-suited to endure our long winters and our variable periods of drought and heavy rain.  Within raingardens, as these plants shed the dead portions of their root systems from last year’s growth they leave behind empty channels in the soil that act as "pipes" to help funnel water deeper into the ground rather than run off into the storm sewer.  This ground-filtering process helps to clean our precious water resource and helps to limit the amount of pollutants that would reach a water body through the stormsewer system.

How can I build a raingarden?

Attend a Workshop through Metro Blooms.  Metro Blooms offers seasonal workshops across the metro area in which you can come to learn, in depth, about how to install a raingarden, how to choose your plants, and how to maintain your garden in the future. 

See this link for more information:   http://metroblooms.org/workshops.php