Brooklyn Grange Rooftop Farm

LOCATION: Brooklyn, New York, USA

SUMMARY: In an effort to make our rooftop farms as ecological as possible, the Brooklyn Grange team will design and build a water capture system that collects and stores rain and irrigation water on the roof surface, rather than letting it go down the drain.

PROBLEM SPACE: Stormwater runoff is a critical environmental and public health issue in New York City and all cities worldwide that use a combined sewer system (CSS) to manage rainfall. When heavy rainfalls occur in cities like New York, water runs off of rooftops and other impermeable surfaces into the CSS, which is then overwhelmed, discharging millions of gallons of untreated water into our open waterways äóñ this is called a Combined Sewer Overflow (CSO). Green infrastructure, including green roofs, help to alleviate this problem, as is absorbs rainfall before it can run into storm drains. Brooklyn Grangeäó»s rooftop farms help to keep over a million gallons of rainfall out of New Yorkäó»s combined sewer system every year, but we still observe a runoff going down the drains during heavy rains. We also have witnessed some of our irrigation water, which we use regularly during the hot summer months, running down the drain. Keeping this water on the farm, where we can store and recycle it into our irrigation system, will help New York Cityäó»s combined sewer overflow problem, help to reduce irrigation costs for our green business, and additionally enable us to capture and recycle dissolved nutrients in the runoff.

SOLUTION: Our team has been experimenting with a drain pump system that catches and stores rain and irrigation water before it has a chance to run off of the roof. We have proven that this simple system is effective, but in order to deploy it across our farm we will need an infusion of capital, manpower, and technology. Our vision is to pump water from each of our roof’s 8 drains, capturing all of the rain and irrigation-related runoff in central tanks that will then supply our irrigation system. The tanks would be mounted on an existing de-commissioned water tower structure. The system works like this: low overflow dams are installed around each drain, and when the dams fill with water, a pump automatically kicks on and sends the water through a hose to the central storage tank. In order to reduce electrical needs, our goal is to build a solar panel and battery unit for each pump. The outcome is a äóìpump station at each drain, including an overflow dam, an automatic DC powered pump, a battery and a solar panel, all packaged in a tight, weatherproof box that can fit over any drain on any roof.