>>New London is in Waupaca County<<
yes, and is also in Outagamie Country. See a map for the line of delineation.
The issue of the Wolf River and flooding in the spring time was discussed intensely in the early 1920's. If you can access the Appleton Post Crescent on-line (ACOM and newspaperarchive), there's an front page article on a flood in New London, 10 Apr 1922.