Maybe you’ve walked along Butler Street or left Public Records, and wondered what that charming red brick building is for. Maybe you’ve stood at the end of Douglass Street, or canoed to the very northern end of the Canal, and noted the water is strangely effervescent. Or perhaps you’ve heard the phrase ‘Flushing Tunnel’ and wondered why people in Gowanus care so much about Queens?
When we’re talking about the Flushing Tunnel, we mean the piece of underground infrastructure that brings water from Buttermilk Channel to the head of the Canal. As Joseph Alexiou described in the comprehensive Gowanus: Brooklyn’s Curious Canal, the story of the Flushing Tunnel is a long fight pitting the powers of engineering against stagnant sewage, drawn out by reluctant funders and technical challenges. The Flushing Tunnel was first proposed as a solution in the 1840’s, but construction didn’t begin until 1904, and the mile-long tunnel wasn’t completed until 1911. At that time, water was pumped from the Canal to Buttermilk channel. The propeller mechanism pushing the water broke in the 1960’s, and it wasn’t repaired until 1999, when the flow was reversed, pulling water from Buttermilk Channel to the Canal.
The tunnel’s pumps have stopped at different points over the past 25 years, including since the EPA began remediation work on the upper third of the Canal (called RTA 1). Now that they’ve moved on to RTA 2, the middle third that starts around the Third Street Bridge, the Flushing Tunnel is back on! We observed a distinct rise in dissolved oxygen on August 8, 2024 at Douglass Street:
And the effect appeared to extend down the Canal:
And the higher dissolved oxygen levels held up into the fall!
Compared to September of 2023 (the earliest point in 2023 for which we have data at Douglass Street), this is a big improvement:
We’re still seeing dips in the dissolved oxygen after rainfall, but starting at higher values of 6-8 mg/L of dissolved oxygen means the dip doesn’t fall below the 4-5mg/L levels that are known to cause problems for fish.
The tunnel doesn’t seem to be operating all the time. At the end of Douglass Street, you can see the effervescence in the water that’s a result of the pump working… or just still water when it’s off. If you know how to explain this behavior, or what determines the rate of the Flushing Tunnel’s flushing action, get in touch!