Figure 1
Set-up:
This bar graph shows historic phosphorus releases from Springfield’s Southwest Treatment Plant. Each bar represents the total amount of phosphorus (in pounds) released into Wilson’s Creek during an individual month. The dashed vertical line represents March 2001, when the treatment plant upgrade was completed. Median values are shown for the period prior to and after the upgrade. The median value is simply the middle value when data are ordered from lowest to highest. |

**Data provided by Springfield City Utilities
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