The Gowanus Canal in Brooklyn, N.Y., has inspired urban legends from the forensic to the ecotopian. In the year and a half since the Environmental Protection Agency bestowed its Superfund designation, the canal has become a site of even more intense re-imagination by several groups, some of whom are customizing Public Laboratory tools for deepening their work.

Designers, developers, researchers and hackers are undertaking their own parallel efforts on issues that even a Superfund clean-up can’t fix: the restoration of original watercourses and the mitigation of 330 million gallons of sewer overflow that continue to enter the canal annually.

Newtown Creek, a second Superfund site in New York City featuring an oil spill twice the size of the Exxon Valdez deep below ground, faces similar issues and community attention. Together, these two urban watercourses offer examples of how democratizing tools for rigorous inquiry can support fresh approaches to community environmental research and action.

What do flying cameras have to do with pollution?

In the worst-polluted spots, 4.5 percent by weight of the sediments at the bottom of Brooklyn’s Gowanus Canal are polyaromatic hydrocarbons (PAH), oily residues from manufactured gas works and oil refineries. Many other heavy industries, including coal yards, cement makers, soap makers, tanneries, paint and ink factories, machine shops, and chemical plants, left a wide range of other toxic chemicals. The former tidal inlet surrounded by wetlands was bulkheaded in the 1860s, resulting in dead-end channels so stagnant a massive tunnel was engineered to move water from the East river underneath downtown Brooklyn to “flush” the toxic waters out to the harbor.

But cleaning up the contamination at the bottom of the canal and under former heavy industrial sites will not make the Gowanus Canal safe to swim and fish. Similar to many urban watersheds in cities with combined sewer systems, the canal is inundated with diluted sewage every time it rains more than the sewer plants can handle, to the tune of 330 million gallons annually. Little to nothing is known about surviving sources of groundwater, which could inform strategies for designing the sub-watershed to yield improvements in water quality.

The Public Laboratory for Open Technology and Science (PLOTS) is an organization and membership community which develops and applies open-source tools to environmental exploration and investigation. Investigation is key to both official and unofficial studies of the Gowanus Canal: Of the marked pipes on the survey by CH2M Hill, blue dots indicate pipes that have “no correlation, require additional investigation,” meaning that these outfalls have no known origin and may lack permits. Red dots indicate pipes that have “no correlation — newly Identified during Phase 2 Survey (approximate location),” meaning these outfalls were not even known to exist before this survey was conducted. Only green dots “correlate with NYC pipe, no further investigation required.”

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Clearly, the official surveys indicate a lack of environmental information here. Using Public Laboratory tools and methods, grassroots investigators have documented not only active pipes missed in the official survey but also flows where no pipes are visible. Georeferenced aerial imagery stitched in January of this year by the Gowanus Arctic Explorers captured evidence of additional unknown flows melting the ice next to a filled-in basin where Vechte’s Brook and its original spring are buried — or perhaps it is merely evidence of illegal industrial dumping of liquids with a lower freezing point than water.

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Note the melted ice under 3rd Avenue bridge — and the filled-in basin just beyond on other side of bridge.

The image below was also captured in January, where an unknown inflow into the canal was revealed in the thinning of the ice. The community’s search for incoming fresh groundwater continues and is aided by “thermal” imagery that takes advantage of seasonal weather patterns. This image also shows frozen floatables from Combined Sewage Overflow (CSO) events trapped in the ice.

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Flow revealed in ice thinning, at right.

The cameras continued flying over Brooklyn this summer, when aerial infrared and visible imagery captured this summer revealed a plume from a pipe that escaped the official survey effort.

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Infrared revealing plume.

The infrared analysis is still tentative, as the infrared technique may have just picked up a “plume” of floating sewer waste temporarily formed by tidal currents, rather than differences in fresh versus sewer-contaminated water. But it is precisely these debates that lead to a better understanding of the canal’s fresh water inflows and opportunities.

Community members canoed over to the source of the plume and discovered a large flowing outfall that had been concealed behind corrugated metal.

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At right: metal plate tacked bulkhead to conceal the flowing pipe exiting Whole Foods property.

The environmental inquiry was performed by the Gowanus Low Altitude Mappers (GLAM) — a project of the Gowanus Canal Conservancy — with canoes borrowed from the Gowanus Dredgers Canoe Club, and with support from Public Laboratory. These local investigators brought their experiential knowledge of the canal to inform their investigation and documentation. They discovered certain phenomena that even well-funded experts had overlooked, notably illegal discharges and long forgotten groundwater flows.

What’s next

By continuing their mapping through winter, spring, summer, and fall (end of October), the designers of experimental green infrastructure can better track the performance of their installations. By flying a second near-infrared camera and combining the two images, photosynthesizing areas are clearly highlighted. There is a Community Advisory Group as part of the Superfund clean-up process at Gowanus which will be the next stop for these high-resolution (both spatial and temporal) images and maps.

Newtown Creek is an example of a community investigation using Public Laboratory aerial mapping tools that is just getting started. Captured a few weeks ago, this image shows particulate matter in the water near a site where in the past the owner was fined for discharging concrete [pH 12] into the water.

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Particles being discharged into water.

The S.W.I.M. coalition instigated this research in collaboration with dontflush.me and Public Laboratory. Many groups including local community colleges and the Hudson Riverkeeper have expressed interest in continued monitoring and investigation of the ways that Newtown Creek continues to be used by industry and for waste processing.

Expect to see more from this site, and more broadly from the community of investigators here and elsewhere as site investigations progress to analysis and advocacy with support from the global Public Laboratory community.