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Winnicut River Watershed restoration
Winnicut River Watershed restoration

Winnicut River Watershed restoration

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Notes from the Winnicut Raingarden: gardening for water quality

Sally Soule, Secretary, Board of Directors

This year marks the second full growing season for the Greenland Central School raingarden. The New Hampshire Rivers Council installed the garden in 2023 in partnership with the school and the New Hampshire Department of Environmental Services.  Important annual maintenance activities were conducted this spring and summer to ensure the raingarden continues to flourish and function as designed to remove pollutants from stormwater runoff.

Spring maintenance activities included raking accumulated debris from the garden, trimming old plant growth, inspecting plants to determine viability, and setting up a cistern to provide water for summer irrigation in the event of dry weather. Much of the important maintenance work was organized and led by Greenland resident Jean Eno, raingarden volunteer extraordinaire.

After spring maintenance raingarden
A view of the garden following spring maintenance activities
Raingarden volunteer Jean Eno sets up a cistern which will provide irrigation water for the plants

Volunteers returned to the garden during the summer to add more plants to fill gaps in the planted area and increase plant diversity. Pollinator-friendly native plants including hyssop, Joe Pye Weed, and rudbeckia were incorporated into the garden. Many pollinators were seen enjoying these new additions!  In July, Jean invited members of the Greenland Conservation Commission for a garden tour to learn about the raingarden’s purpose and the unique partnership that led to its installation.

Happy plants

During maintenance visits, it was noted that the blue flag irises planted at the garden’s inlet and outlet areas had grown quite large during the past two growing seasons. This enthusiastic growth clogged important stormwater drainage design features of the garden. A “divide and conquer” volunteer maintenance event was held to reduce the plant growth so that water could once again flow freely in and out of the garden.

Volunteers divide irises to restore drainage feature functions

Overall, the garden functions as designed and provides much needed treatment of stormwater runoff.  Next steps for the garden include installation of a kiosk which will provide educational information about the raingarden project and its role in improving water quality in the Winnicut River.

Garden performs as designed to infiltrate stormwater and remove pollutants
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Rain, rain, you don’t have to go away; this little rain garden will handle your flow every day! 

Cardinal flowers and other native plants doing their job to soak up the rain at the Greenland Central School (photo credit: Sally Soule)

Spring brought the first year of snowmelt and spring rains to put this little rain garden to its first big test. Right after planting in late August 2023, there were significant storms that showed runoff going where it needed to go: to the plants, soil, and structures beneath doing what they were designed to do—remove pollutants from stormwater runoff. 

Sally Soule, Rivers Council board officer, and Jean Eno, long-time Winnicut River advocate and Greenland resident, put the garden to bed in the fall and gave it a gentle wake-up in the spring.  

“Projects like this go a long way toward reducing nutrient loading in our waterways. Plus, they provide important co-benefits such as habitat and food for pollinators,” said Sally Soule, board officer, New Hampshire Rivers Council.

Since then, last year’s performance has continued through the 2024 growing season. This little rain garden is having a big effect in the Winnicut River watershed. It is removing 1.3 pounds of phosphorus and 13.2 pounds of nitrogen from the watershed each year. When the kiosk is completed, visitors will see the rain garden, read about what it is doing, and how they can do the same in their own backyards. 

“It has been a pleasure watching this raingarden grow and adapt to the stormwater runoff imposed upon it. The resiliency of the all the plants, particularly the thriving Cardinal flower, is remarkable,” said Eno.

“Gigantic kudos to Jean and Paul Eno of Greenland for their amazing work taking care of the rain garden through some extreme summer and fall weather,” added Michele L. Tremblay, President, Board of Directors of the New Hampshire Rivers Council.

When the kiosk is completed, a ribbon cutting event will be announced. 

Want to learn more about rain gardens? Please read on. 

What is a rain garden? 

A rain garden is a depressed area in the landscape that collects rainwater from a roof, driveway, parking lot, or road and allows it to soak into the ground. Planted with grasses and flowering perennials, rain gardens can be a cost-effective and beautiful way to reduce runoff. Rain gardens can filter pollutants and provide food and shelter for butterflies, songbirds, and other wildlife. This garden is filled with plants native to our area. 

Why is it here? 

Runoff from impervious surfaces, including roads, parking lots, and building roofs can carry fine soils, nutrients, and pollutants. The water can also become very warm, which has negative effects on fish and other animals, who depend on our brooks and rivers. This little rain garden has big, positive effects by absorbing these materials and keeping unnaturally warm water from flowing directly into the Winnicut River. 

Should I have one? 

Rain gardens are a wonderful way to absorb runoff to brooks and rivers and to keep water from pooling around houses. Depending on the plantings, they can provide food for pollinators and color year ‘round. 

This rain garden went to work the day it was installed 

From its first day in August 2023, this rain garden absorbed water that flowed from the road and parking lot. It was absorbed quickly and did not runoff into the storm drains, which lead to the Winnicut River. Since then, it has stood strong against heavy rains and snow melt. Each year, the plants will grow, expand, and reproduce to provide increased water absorption, filtration of pollutants, and habitat for butterflies, birds, and other wildlife.  

Funding for this project was provided in part by a Watershed Assistance Grant from the NH Department of Environmental Services with Clean Water Act Section 319 funds from the U.S. Environmental Protection Agency and generous gifts from New Hampshire Rivers Council members.