The EPA put a stop to that.
It's pollution if it's been on the ground in the city. You cannot dump such hazardous waste in the ocean.
Boston dumped it in the harbor in 2011.
The middle of Manhattan where Fifth and Sixth Avenue run north and south is about forty feet higher in elevation than the east or west side highways. So, to some extent once it starts to melt the water runs downhill towards the Hudson river eventually. They have open lots where they do end up dumping much of the snow. However, they have to load it in dump trucks and haul it away.
My coworker Tom will be pumped. He sells rock salt by the truckload. His main supplier is American Rock Salt just south of Rochester, NY. He sold ten trucks of salt on Friday. I bet the phone will be ringing off the hook tomorrow and Tuesday.