Saturday, January 20, 2018

How Does Your Raingarden Grow?

March 1, 2016 by · Leave a Comment 


raingarden 1

Created as a way to mimic the natural water retention areas that existed before an area was developed, raingardens have grown in size and popularity over the last decade, expanding to both residential use as well as in the commercial building industry.

Rusty Schmidt, co-author of The Blue Thumb Guide to Raingardens, is a landscape ecologist specializing in managing stormwater runoff in environmentally conscious ways.  He’s designed and constructed hundreds of alternative stormwater runoff solutions for habitat restorations, raingardens, bio-infiltration swales (moist or marshy low tracts of land), bio-retention basins, and stormwater ponds. His expertise is in integrating naturalized ecology systems into our modern lifestyle.

I had the opportunity to interview Schmidt and learn about raingardens.

BT D2 S04-19Raven Peterson: What is a raingarden?

Rusty Schmidt: A raingarden is a shallow depression in the ground, six to 12 inches deep, with a flat bottom. Water from rain events can be directed into this garden, which is planted with deep-rooted plants.  The soil is modified to be more organic, slowing the infiltration of stormwater through sandy soils, or supplemented to increase infiltration in slow draining soils/clay conditions. 

The soil is key to the function of a raingarden, as the soil acts as a filter that helps to capture pollutants carried in stormwater.  Raingardens perform an important function by slowing stormwater runoff and filtering pollutants before they reach our streams, rivers, bays, and groundwater. 

The plants within the raingarden provide beauty; however, they have an important role in maintaining healthy soil necessary to filter the water before it reaches surface waters or groundwater.  Raingardens are designed to allow the rainwater entering the garden to be soaked up in less than one day. 

RP: How do raingardens impact the marine environment on Long Island?

RS: Raingardens help improve water quality by filtering pollutants and debris from stormwater that ultimately flows into nearby streams, lakes, and bays.  The gardens will bind 100 percent of the heavy metals and petroleum products within the top four centimeters of the surface.  The healthy soils will destroy harmful pathogens like E.coli and others which are a cause of beach closures around the Island.  Raingardens also help to absorb nutrients that are carried in stormwater, thus reducing sources of nitrogen entering our streams, bays, and groundwater.

RP: How do raingardens affect the environment as a whole?

RS: Raingardens are beneficial by cleaning water at the source, which mimics natural shorelines. By infiltrating the rainwater at the source, water is filtered through the soil and recharges the groundwater as it would under natural conditions.

native cultivar combinationRP: What types of soil are best for raingardens?

RS: Sandy loam soils are the best for good infiltration and filtering of water into the ground.  Long Island has rich, sandy soils, which are typically fast draining.  It is desirable to add a bit of loam or organic material to the bottom soils of the raingarden, as this will slow infiltration and improve filtering of pollutants.  In some areas of Long Island (much of Huntington for instance) the soils do have clay.  The water will still soak into the ground if the clay is loosened up — however, at a much slower rate.  In these areas, the depth of the gardens are more key to infiltrate the soil in one day and not try to speed up the water with sand.  That is where more mistakes in construction occur.  Make the garden work with the soils that you have instead of trying to amend the soils too much.

RP: What types of plants and flowers are best suited for raingardens?

RS: Most plants will work in a raingarden except the plants that need a lot of water.  Wetland plants will not do well in a raingarden, as they will die during the typically dry conditions of the garden when it’s not raining (a rain garden is dry 90 percent of the time and only wet when it rains).  After creating a list of potential plants, choose plants for sun or shade, height, flower color and timing, aesthetics, habitat for bees, birds and butterflies, or maybe to provide a bit of screening or other reasons. 

RP: What benefits do you see from the use of raingardens on Long Island?

RS: For Long Island, the biggest benefit is to clean the water and reduce the amount of nitrogen and pathogens from getting to our bays and beaches.  Raingardens are an easy way for all homeowners to filter pollutants carried in rainwater and have an aesthetic garden in the yard. 

As the population of Long Island grows, I cringe a little at the loss of the open space and greenery that comes along with it.  I often wonder how it will be possible, on this tiny island of ours to find a happy balance between maintaining our ecosystem and the constant desire to expand.  Raingardens are one of the ways that we can all help keep that balance in check and create a more sustainable environment for generations to come.

By Raven Peterson

More raingarden photos

BT D2 S34-18

native formal_maplewood


was born and raised in Port Jefferson. She has traveled extensively throughout the United States in search of new adventures and culinary delights. Her three favorite things in life are friends, food, and fashion.

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