I made this plot upon the request of my facultly mentor- he 
had been using an outdated version of this plot when he gave
talks at various conferences and wanted a new one that went
up through 2020, but lost the code for the old plot. 
So, I recreated it for him. The light blue dots represent
the monthly water level data for each lake, the dark blue dots
represent the yearly average water level, and the horizontal red 
line is the overall average water level.