Small Scale LID Retrofits

Posted by on Jul 30, 2015

Over the last year we have been working with the Northern Rhode Island Conservation District (NRICD) and their Education and Outreach Coordinator, Molly Allard on the design of  stormwater management retrofits at homes and small businesses located in the village of North Scituate, RI.  The steering committee for this project  included the Rhode Island Department of Environmental Management, US EPA Region 1, Providence Water Supply Board, and the Town of Scituate, RI.

The primary goal of the project was to reduce the discharge of non-point source pollutants, particularly phosphorous, to the Scituate Reservoir and the groundwater in the surrounding area by  installing a variety of low impact development (LID) retrofits, also known as best management practices (BMPs), in the village of North Scituate. A second important goal of the project was to educate the North Scituate community about stormwater management through the creation of visually attractive retrofits, educational signage at retrofit locations, and through the involvement of community volunteers in the installation and maintenance process.

N. Scituate DiagramWhile we had the option of designing dry wells, tree filters, vegetated swales or rain gardens for each site, we found that all of the program participants preferred rain gardens for their aesthetic appeal and the function they provide. Most of the homeowners we worked with also seemed excited at the prospect of creating additional wildlife food sources and habitat within their home landscapes. All of the rain gardens were designed in compliance with  the document State of Rhode Island Stormwater Management Guidance for Individual Single-Family Residential Lot Development, .

At each site we calculated the total runoff area to be be infiltrated and sized each rain garden accordingly. Most of the sites were small single family house lots with  building roofs and driveways making up the majority of impervious surface.

In most cases we were able to infiltrate more than half of the roof or driveway run-off into a rain garden custom designed to fit each site. While Scituate in general is pretty rural, the village of N. Scituate is quite dense. We had to get pretty creative with the siting of  the rain gardens to be sure they met the various setback regulations required by the stormwater management guide, while also integrating them into the existing landscape present on each property.

In several cases we were able to work with the existing topography in order to minimize digging and seamlessly fit the rain gardens into the landscape. Using only plants native to Rhode Island, we designed each rain garden taking into account  property owner preferences for specific plants based on bloom time, flower color, form and maintenance requirements.Pages from Christine Hall Properties

Once the designs were complete the NRICD provided all materials for the construction of the rain gardens and working with volunteers, built each retrofit. As part of the agreement with landowners the NRICD wil also provide maintenance of the rain gardens for the next two years at no cost to owners.

This project is a great example of multiple agencies working together and the interface of private and public interests in a way that benefits everyone involved. Over the years to come these retrofits will divert millions of gallons of untreated stormwater from entering a public water supply and will add to the curb appeal and value of the properties involved. If  more neighborhoods were to adopt LID retrofits as way of dealing with stormwater, we could see a significant improvement in the health and quality of our groundwater and water bodies.

23 silk lane

Birchwood Design Group is happy to have been involved in this important project. Projects like this support our mission of improving the built environment while having a positive impact upon the environmental, social and cultural lives of our clients and communities.

23 silk lane 2Images courtesy Molly Allard – NRICD


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