The plot of the Yahara lakes was created using data from https://data-cityofmadison.opendata.arcgis.com/datasets/lakes-and-rivers. To grab the data, run wget https://opendata.arcgis.com/datasets/c46082b091a941f8b2ded1dd115a1a05_8.zip.
Data for the plots that used measurements from the lakes was taken from https://data-cityofmadison.opendata.arcgis.com/datasets/public-health-surface-water-quality-monitoring-data-1935-present. The columns of this dataset include a sample number, the site where the water sample was collected, the date the sample was collected, the analyte being measured, the result of that measurement, and the units for that measurement. To grab the data, run wget https://opendata.arcgis.com/datasets/ae2a8f3dd26f4e5d829d51cf4c6f81a9_9.csv