wich is a word name ending that mean salt works.. so Northwich, and Nanwich, and other UK *wich cities (a number exist near Liverpool) are all historic cities that were (or are) places for salt works.. Wich is old A/S term, but that all i know.

English salt that from the Northwich and other salt works in the Cheshire area passed through Liverpool, and became know as Liverpool salt.. (it was considered to be of exceptional high quality). Most of the salt works date back to QE1.