### Appendix A — Temporal Analysis

Examines how water samples are spread across time for the various sites. Some interesting patterns are easy to see, which helps us realize which sites we can reasonable compare to each during a given time period.

### Appendix B — QIP Calculation Methods

We introduce a novel method for comparing different pollutants using their respective water quality standard as a reference. We explain how to calculate the Quality Impact Percentage (QIP) and discuss how the values can be interpreted.

### Appendix C — Geometric Mean Table

The Geometric Mean bar charts can be understood at a glance (Figures 2a-f) and for those who are interested, the values behind the charts are available here. For each bar you can see how many water samples were measured and over how many years.