Public Lab Research note

Water quality testing with a robot in the Gowanus Canal

by jeff | September 05, 2014 02:04 05 Sep 02:04 | #11105 | #11105

This is one of the robots used in the Brooklyn Atlantis project. We've recently fit it with YSI 600r water quality sonde, which gives us a few measures of water quality, such as pH, dissolved oxygen, conductivity, etc. Both the water quality data and the GPS are logged as the robot moves throughout the canal. We've also put a DSLR camera with an automated pan-tilt mechanism on top to get some interesting photos.

My attempt and results

Overlaying the water quality data with the position data, we can see some interesting trends;


Noting that the flushing tunnel was on at the time, we see a higher dissolved oxygen as we travel towards it (located at the top-most part). The water from the flushing tunnel is also a bit saltier and cooler when compared to the rest of the canal (as expected)

As Eymund has pointed out, there is a somewhat unexpected spike in the dissolved oxygen right around where the Union St. bridge is. We'll be trying to figure out what is going on there.

Below is an example of six photos stitched together into a single panorama.


With the correct viewer, one can pan the view, similar to google street view. We've posted the image on 360cities, but as I check it now, it doesn't seem to be loading.

Questions and next steps

What's with that anomalous spike in dissolved oxygen? We'll be doing more water quality testing in the coming days and analyzing the data.


Thanks to Ben High for helping to develop the camera rig and Angela Chen for helping with the water quality testing. This project was developed at New York University Polytechnic School of Engineering with the support of the National Science Foundation.


Excited to meet Yellow Robot tomorrow!

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Yes! I can't wait to see more.

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Those dissolved oxygen maps are super intriguing.

Weird spike in oxygen readings just north of Union Street Bridge should be investigated further. Could that be the long lost Bergen Stream outflow ? The Gowanus Dredgers Canoe Club, working with NYC Department of Environmental Protection during the 2013 City of Water Day, found that traditionally the stream seepage has LOWER oxygen readings (eg less chance to mix with oxygen underground), so there is some data weirdness here. These oxygen spikes may also be caused by City water main breaks such as those caused by the recent Lightstone Apartment Complex pile driving.

These are some July 2014 views of what we have tongue in cheek nicknamed "Catskill Spring" - thousands of gallons of tax payer funded clean water pouring into the Canal at 2nd Street. Because of political pressure from local fish, I've been asked to keep this water quality improvement quiet.



I have access to some neighborhood sump pumps were underground streams are visible and accessible. We can get oxygen calibration readings from them to help answer these questions.

Your spatial fluctuations in Canal water quality matches the data from our Citizen Science water quality tests with the Water Trail Association, ( where the outflows on the east Canal side of 2nd Street were shown to lower sewer bacteria counts. The Fresh water inflows from the historic springs would lower salinity readings.

This is area of Canal where your robot data is showing unusual water chemistry fluctuations (2014, 4 September photo, looking torwards the Denton's Spring and Pond outflows)


Looking forward to testing our "Greening the Gowanus" concept with your Yellow Robot. We can use environmentally friendly food colorings to test the patterns of fresh water inflows in the Gowanus Basin.


(from Peter Tsai's Greening the Chicago River stop motion video :)

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And to maintain keep citizen science fun and light hearted, another intriguing question about Jeff's Data:

Do Fish Fart ?

A 2 year old explains:

Is the improved water quality from the NYCDEP Flushing Tunnel leading to spikes of Gowanus Fish Farts ?

Oh, the philosophical questions that Robots raise..

Intrigued by this potential scientific Gowanus research topic ? (The Spatial Prevalence of Fast Repetitive Tick (FRT) among Gowanus Fundulus) See:

This tongue in cheek research raises a more serious topic:

How can water quality data spatial fluctuations help EPA Ecosystem Rehabilitation experts prioritize parts of the Canal for wetland and marine habitat improvements ?

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@jeff , this was an incredible event!!! It was great to steer the water quality boats with joystick and kinnect!

I made a bitsync folder for photos from our dye tracing experiments, the name is 20140907gowanus and the secret is A3JMF3QV7V42MNXHRKEDDJH75FJ443Z34

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Christopher Swain, the first person to swim the entire length of the Gowanus Canal in over a century is also getting similar Canal length sensor fluctuation results in October 2015.


His body suit data is also showing a very slight unusual Ph and Temperature fluctuation at the Bayside Fuel depot area of the Union Street Bridge. Note that the map shows two different swim date readings (April and October), which should not be confused as temperature differences.


We can only continue speculating and researching what may be causing these fluctuations. Besides floatable pollutant or bathymetric causes, this could also be a freshwater seepage point for the long lost Sassian Brook which can be currently heard flowing in the sewers at Wyckoff and Hoyt Street. It may also be Bergen Creek, which frequently floods basements on Sackett Street.

2011 - 28 August; Hurricane Irene - Bergen Creek being pumped out of basements on Sackett Street


Circa 1770's map of Gowanus Creek and Sassian Brook, from the Fort Green Map, Office of Chief of Engineers, War Department, US Library of Congress

The Brouwer's Mill Bridge shown on the map is about a 100 feet north of where Union Street Bridge is today.


The temperature fluctuations we are seeing may be surviving fragments of the streams shown on the map.

A 8 July 2012 balloon aerial of the data fluctuation site, showing the Bayside Fuel Depot Canal site edge just north of the Union Street Bridge:


This data clue justifies further research on Union Bridge area to pinpoint what is causing the data fluctuation. Should an actual fresh water inflow be found, opportunities for diverting those streams out of the City's overloaded combined Bond Street sewer system should be explored.

Some rough field research notes of the area from a 1782 Military Map


The map below shows a balloon aerial of the Brouwer's Bridge area in 2011.


The 8 July 2012 Balloon Union Street Bridge Mapping Team


Accidental data pieces - community generated grains of sand, which accumulating together, start creating a broader beach of knowledge.

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