Community Gardens Mitigate Stormwater

Every year, over 140 million gallons of stormwater do not enter NYC's waterways with untreated sewage because New Yorkers have built and maintain hundreds of community gardens. Almost every time it rains, NYC's sewer system overflows, carrying stormwater and raw sewage together directly into our rivers, bays, and oceans. Community gardens absorb stormwater throughout the city, helping to prevent this, and many are in flood zones - particularly critical to protecting our waterways. And yet, community gardens are still under constant threat of development.

Last month, NYCCGC Board Member Mara Gittleman published a peer-reviewed article in the journal Urban Ecosystems entitled "Estimating stormwater runoff for community gardens in New York City." Download it here. The final article is published here. She and her co-authors found that community gardens absorb 130 million gallons of stormwater annually, with an additional 12-13 million gallons absorbed due to compost-amended raised beds in particular, totaling over 140 million gallons. The study recognizes that community gardeners use a lot of compost in their growing areas, which at a minimum doubles infiltration rates (the metric used in this article), although some studies have recorded an improvement in infiltration rates by up to a factor of 10.5 (EPA Publication No. 600R-00016).

This paper shows just one more reason, on top of many, that we can't afford to lose even one more community garden to development. In fact, the city should be encouraging residents to develop more community gardens, to help achieve its green infrastructure goals for pennies on the dollar. The NYC Department of Environmental Protection is tasked with increasing the amount of green infrastructure in the city to absorb stormwater so that it doesn't become runoff. We have been and will continue to help with that effort, and we will continue to make the case for community gardens as green infrastructure through Gardens Rising. Join us!