Gowanus Canal CAG Meeting
Tuesday, January 22, 2019
Mary Star of the Sea Senior Apartments, 41 1st Street
Katia Kelly and Brad Vogel opened the meeting at 6:35 p.m.
Project Updates: Kevin Clarke, New York City Department of Environmental Protection
NYC Department of Environmental Protection: Presentation on Gowanus CSO Storage Tunnel Alternative to Proposed Gowanus CSO Tanks.
In lieu of the Combined Sewer Overflow (CSO) storage tanks. The city has to build two tanks: an 8-million gallon tank at the Head End (RH-34), and a 4-million gallon tank at the Owls Head site to abate OH-007.
DEP has met all the EPA Superfund milestones and will continue to do so.
The tunnel idea came out of a discussion about other water bodies, Flushing Bay and Newtown Creek, where DEP is pursuing tunnels under those bodies for stormwater, so when looking at those, it occurred to DEP to explore the potential to use a tunnel for Gowanus as well. The tunnel would be a 16-million-gallon, soft-ground tunnel to follow the alignment of the canal.
There are assets on the water side, like the pumping station, many built more than a hundred years ago. Very expensive, but built to last. We have to make the right decision when building this kind of thing. At a minimum, the tunnel would hold 16 million gallons – four million more than the capacity of the two tanks – this would give the same solids capture. Reduces CSO RH-34 outfall from about 6 discharges to 4. At Owls Head, it goes from 4 to zero. The tunnel is easier to construct, and has less construction impact. The headhouse would be about the same size as the lot at the RH site. There is no longer above-ground facilities so we can be more flexible with the design of the open space. The cost is estimated at $1.2 billion.
The City has already acquired the necessary parcels The timeline would be a little bit longer and the schedule is more aggressive. The tunnel provides a scalable system – we can extend the tunnel further than the alternatives we looked at, and will continue to look at, including following down Second Ave and fixing drainage in Red Hook and Park Slope.
The timeframe for completion could be 2030. This follows the rezoning; everyone knows the area is ripe for development. This would help plan for population growth and resiliency. There is street flooding, and occasionally sewer backups. As sea level rises, it is harder to get sufficient flow – the tunnel makes that easier and protects against rising sea level.