Landscape Architecture, Ecological Restoration and Planning

The Greening Series

Rain Gardens

Rain Gardens

Look Great and Great for the Environment

By S. Edgar David, RLA


Trail Systems (coming soon)

A Rain Garden is a landscaped area planted with flowers and native plants that collects and soaks up rain water and filters pollutants. Rain gardens have come into popularity as a means to manage rainfall and runoff in a ‘green’ way.  Not only are rain gardens great for filtering pollutants and protecting our natural eco-systems, they also create wonderful habitats and are an opportunity for gardeners to grow wet tolerant species.  Whether your rain garden is for personal gratification, to meet ordinance requirements for storm water management or for LEED Certification in the creation of healthy sites, SED Design brings beautiful form and function to your project through creative design of rain gardens and green infrastructure.


Landscape Features

Rain gardens are vegetated depressions in the landscape designed to capture, detain and release, and/or infiltrate where feasible, stormwater runoff from roofs, parking lots or other  adjacent areas. Rain gardens capture water that will slowly infiltrate into the ground or return to the atmosphere through evapotranspiration from plants.  Both of these processes have beneficial qualities for cleansing rain water of pollutants.  Rain gardens are also referred to as ‘Bio-infiltration Basins and ‘Bio-retention Basins’


Rain Garden and bridge

Creative Solutions

Rain gardens, when integrated with boulders and rounded cobbles and even walkways with bridges, become true artist compositions in the landscape.   When placed outside windows these beautiful rain gardens provide a wonderful means for observing birds since many bird species are attracted to the plants and flowers used to populate the best rain gardens.


Integration with Buildings

Rain chains are a wonderful opportunity to connect roof drains to the rain garden and architecture to the landscape.  In a beautiful and engaging way rain chains allow you to see water cascading into your rain garden.



When designing a rain garden it is important to understand the sources and volume of water to properly size the rain garden.  We start by trying to allocate around 7% of the drainage area for the rain garden.  If the drainage area contributing to the rain garden is too large there is greater potential for the rain garden to be eroded or detrimentally impacted by larger flows.


Designing the outfall from your rain garden is also essential.   Rain gardens, when properly designed, are able to manage 90 percent of the annual rainfall that occurs through smaller more regular storm events.  However, larger storm events will fill and overflow any rain garden.  It is critical that your design manages the excess water from the rain garden in appropriate ways that will not cause detrimental impact to the surrounding environment.




To learn more about Rain Gardens visit these other helpful sites:

by the Wisconsin Department of Natural Resources

What are Rain Gardens?

The Philadelphia Water Department

Temple Arboretum Rain Garden at

the Sustainable Wetland Garden

Hillside Rain Garden Spillway and Pond

Neptune LEED School

Rain Garden and Bioswale

Rain Garden rain chain - Image from the internet