Daily Environment Repost Urban Environmentalist

The rain garden, an incremental solution

Big problems don’t necessarily demand big solutions. Sometimes a series of smaller incremental solutions work to solve a large problem. The modest, home rain garden is one such incremental solution to a larger problem. The problem is pollution from urban stormwater runoff. Because urban stormwater runoff is a widely distributed problem, it is ripe for incremental solutions.

Stormwater falling from the sky is not polluted.  Water falling on an open field or forest usually sinks through the soil into groundwater systems or runs into local streams. However, stormwater falling on an urban setting takes a different path. Paving and roofs cover up to 50 percent of the land surface in the city. Water falling on the concrete, asphalt, and roofs cannot sink into the ground and must flow into stormwater sewers. As the water flows, it picks up all sorts of debris and pollutants and carries them into local streams and rivers.

Stormwater falling in an urban setting encounters less pavement, but more land covered with green lawn and garden. However, significant amounts of rainwater become runoff from lawns and gardens, and then the water flows into stormwater sewers. Because of the herbicides and fertilizers carried in the lawn runoff, our lawns are net contributors to environmental pollution. Heavy irrigation through sprinkler systems also causes runoff into the stormwater sewers.  

Enter the humble rain garden

Rain gardens are landscaped areas that function to collect and filter surface and near-surface runoff. The system prevents stormwater and irrigation runoff into the sewers by collecting the water in small catchments. The catchments are designed and planted as part of the total garden. When done correctly, they blend into the landscape. So, rain gardens improve water quality through bioretention. This process relies on plants and soil to filter pollutants from the water as it slowly sinks into the ground.

But rain gardens are not ponds since they are dry most of the time. When they do fill, the water drains out over a day or two. Because the functional purpose of the rain garden is water retention and filtration, native plants with deep roots often work best when planting the garden. Also, the soils placed below the garden are usually several feet deep, promoting drainage and preventing soil compaction.

Location is important for the rain garden. Don’t build it too close to your home or your neighbor’s home, because water seepage may damage the foundation structure. Sunny locations are good since solar radiation promotes evaporation and plant growth. Remember, the functional reason for the rain garden is to intercept water runoff. Therefore, placing the garden in locations of maximum runoff is advantageous. 

It’s an incremental solution

An individual rain garden may seem like a small thing, but collectively these gardens produce substantial neighborhood and community environmental benefits. Rain gardens improve water quality – they can reduce the amount of pollution reaching creeks and streams by up to 30%. (Prairienursery.com)

The urban environmentalist should consider rain gardens as a functional part of their home landscape. The gardens serve as incremental solutions to a larger problem. The reduction in pollution from stormwater runoff requires a collective solution involving municipal government, communities, and individuals.


Pavement heat in the concrete jungle (Source: ArcheanWeb) – https://archeanweb.com/2020/04/13/pavement-heat-in-the-concrete-jungle/ Also:

Environmental protection starts with your lawn (Source: ArcheanWeb) – https://archeanweb.com/2020/03/13/environmental-protection-starts-with-your-lawn/ Also:

Lawn Alternatives (Source: ArcheanWeb) – https://archeanweb.com/2020/03/16/lawn-alternatives/ Also:


The Beneficial Beauty of Rain Gardens (Source: PRAIRIENURSERY.COM) – http://nativeplantherald.prairienursery.com/2013/05/the-beneficial-beauty-of-rain-gardens/ Also:

Soak Up the Rain: Rain Gardens (Source: EPA) – https://www.epa.gov/soakuptherain/soak-rain-rain-gardens Also:

Rain and Precipitation (Source: USGS) – https://www.usgs.gov/special-topic/water-science-school/science/rain-and-precipitation?qt-science_center_objects=0#qt-science_center_objects Also:

Rain Gardens: A Way to Improve Water Quality (Source: University of Massachusetts Amherst) – https://ag.umass.edu/landscape/fact-sheets/rain-gardens-way-to-improve-water-quality Also:

Lawn Alternatives (Source: ArcheanWeb) – https://archeanweb.com/2020/03/16/lawn-alternatives/ Also:

Feature Image: Rain garden in the Allen Centennial Gardens on the campus of the University of Wisconsin-Madison (Modified) – By James Steakley – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34061836

William House
William is an earth scientist and writer with an interest in providing the science "backstory" for breaking environmental, earth science, and climate change news.