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Green Infrastructure in New Haven

New Haven's Sewage & Stormwater Challenges

About 22 outflow pipes, like this one that empties into the West River, carry combined sewage into New Haven area waterways after rain events.

A majority of New Haven’s land area is covered with impermeable surfaces like roads, parking lots, sidewalks, and roofs, which generate a lot of stormwater run-off. New Haven’s existing combined sewage and stormwater system puts local rivers (Mill River, Quinnipiac River and West River), New Haven Harbor and Long Island Sound at environmental harm during every substantial rain event. Because the system capacity cannot meet the combined demand of sewage and stormwater, approximately 257 million gallons of mixed sewage overflows directly into New Haven area waterways, on average, every year. As a result, harmful bacteria levels cause frequent closures of shellfish beds and beaches after rainstorms, and marine life in Long Island Sound suffers.

Map showing New Haven area beaches and shellfish beds affected by stormwater New Haven CSO Map
After heavy rains, stormwater runoff combines with sewage causing beach and shellfish closures in the New Haven harbor area.
The yellow dots on the map above show the locations of active combined sewage overflow (CSO) pipes into New Haven area waterways.

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Green Infrastructure Scan by Hazen and Sawyer and Save the Sound

A feasibility scan was conducted for New Haven to evaluate the potential of green infrastructure to reduce wet-weather sewage overflows in New Haven. Specifically, the study was intended to address green infrastructure source controls available for implementation, an implementation framework, small-scale and neighborhood demonstration projects, green infrastructure costs and benefits, funding mechanisms, and opportunities for job creation. Results of the feasibility scan conclude that green infrastructure can serve as an effective approach to managing and reducing combined sewage overflows within the New Haven area.

You can read more about New Haven’s Green Infrastructure Feasibility Scan by downloading the full report here.

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Proposed New Haven Urban Neighborhood Green Infrastructure Project

Within the East Rock region of New Haven, there is a combined sewer area largely surrounded by streets where the sewer has been separated through projects dating back to the early 1980s. This area is generally bound by Willow Street, Mechanic Street, Hines Place, and Nash Street. Due to the somewhat isolated combined sewer region in this area, there are no plans in the near future for separating these sewers.

This area does contribute to combined sewer overflows, with the closest downstream CSO outfall discharging into the Mill River in the general vicinity of Interstate 91. Evaluation results suggest that the nature of this localized combined sewer area makes it a good candidate for a green infrastructure demonstration project.

There are a variety of impervious surfaces within this demonstration area, including streets, driveways, sidewalks, and rooftops, which combined cover approximately 55% of the demonstration area. Sidewalks and streets are of particular interest for green infrastructure implementation as they are located within the publicly owned right-of-way, facilitating construction and maintenance logistics, and cover more than 25% of the demonstration area.

The northern portion of the demonstration area, labeled as “on-site demo boundary”, consists primarily of rooftops and parking lots associated with the East Rock Global Studies Magnet School. There may be opportunities for on-site green infrastructure implementation at this location, utilizing controls such as blue roofs, green roofs, and permeable pavement.

Conceptual schematic of a street-side bioswale

Potential area in New Haven for green infrastructure projects
The highlighted area in the East Rock neighborhood of New Haven has been identified as a potential area for the implementation of green infrastructure demonstration projects.

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How Can I Build a Rain Garden in New Haven?

An example of a residential rain garden
An example of a residential rain garden.
One way New Haven residents can help reduce the harmful effects of stormwater runoff is by building a rain garden on their property. If you would like to learn how to construct a residential rain garden in your yard, please visit the informative rain garden section of our website as developed by UConn’s NEMO program.

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New Haven Rain Garden Permitting Guidance

In New Haven, most rain gardens will not need special permitting, but in certain instances there could be permits required, as well as certain regulations that need to be followed.  Here is some applicable guidance:

1) Zoning: Unless you are planning to remove equal to or more than 800 yards of soil, there is not a need to apply for a Soil Erosion and Sediment Control Permit. If you are on a corner lot, your rain garden construction will need to comply with section 28 of the zoning code:

On a corner lot in any residence district no planting shall be placed or maintained, and no fence, building, wall or other structure other than necessary retaining walls shall be constructed after the effective date of these regulations, if such planting or structure thereby obstructs vision at any point between a height of two and one-half feet and a height of ten feet above the upper face of the nearest curb and within the triangular area bounded on two sides by two street lines, or by projection of such lines to their point of intersection, and on the third side by a straight line connecting points of such street lines (or their projections) each of which points is 25 feet distant from the point of intersection of the two street lines. Poles, posts, and guys for street lights and for other utility services, and tree trunks exclusive of leaves and branches, shall not be considered obstructions to vision within the meaning of this provision.

For questions regarding this requirement, please call your city/town’s Zoning Enforcement Officer. For those living In New Haven, you can call the City Plan Department at (203) 946-6378.

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How Do I install a Rain Barrel in New Haven?

One of the rain barrels made by The Sound School

Another way that New Haven residents can help reduce the harmful effects of stormwater runoff is by installing a rain barrel on their property. A rain barrel that is hooked up to the downspout of a house will collect rain water that can be conserved for later use or diverted back into the landscape. To learn how to buy, make or install a rain barrel, please visit that section of our website here.

There is an opportunity to purchase locally-made rain barrels thanks to a partnership between New Haven's The Sound School and the Greater New Haven Water Pollution Control Authority (GNHWPCA). This partnership is in its 4th year and helped produce 300 rain barrels to date! Another 100 rain bain barrels will be available on April 1, 2013. Interested customers can purchase a rain barrel by emailing The Sound School's Steve Joseph.

The rain barrels are sold as an easy to assemble kit. For $50, customers will receive a 55-gallon plastic drum, a gutter adaptor and flexible downspout, an overflow elbow, and a bottom spigot. Proceeds from sales will benefit The Sound School's student entrepreneurship group.

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New Haven Green Infrastructure Atlas

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