what did sinclair called bubbly creek

"Bubbly Creek" was the name given to the Chicago River.

The packers had wanted a bridge at Ashland Avenue, but they had not been able to get it till they had seen Scully; and it was the same with “Bubbly Creek,” which the city had threatened to make the packers cover over, till Scully had come to their aid. “Bubbly Creek” is an arm of the Chicago River, and forms the southern boundary of the yards: all the drainage of the square mile of packing houses empties into it, so that it is really a great open sewer a hundred or two feet wide. One long arm of it is blind, and the filth stays there forever and a day. The grease and chemicals that are poured into it undergo all sorts of strange transformations, which are the cause of its name; it is constantly in motion, as if huge fish were feeding in it, or great leviathans disporting themselves in its depths. Bubbles of carbonic acid gas will rise to the surface and burst, and make rings two or three feet wide.