This DPW SEWER cover from 1878 is nearly identical to DPW sewer covers found in Manhattan from around that time, except this one was spotted on 50th Ave in Long Island City, then an independent city incorporated in 1870.
The 16 spoke design with the ring of lettering around the center is quite similar to others dated 1875 in New York, with some slight variance; the two pry holes on the outer rim are located between two spokes rather than along a spoke, and the lettering, similar in alignment to the 1875 covers in that all the letters are bottoms out, but the period mania of has subsided and there is no dot after SEWER!
Whatever the source of the cover, it's clear in it's function.
This design dated 1878 can be found on 50th Ave between Vernon Blvd and 5th St. A duplicate cover is at 50th Ave between Vernon Blvd & 5th St. Similar designs are found in Manhattan, specially on the Upper West Side.