Tracking progress toward total phosphorus load metric: how it’s calculated

The U.S. and Canada adopted targets to reduce annual phosphorus loading to the western and central Lake Erie basins by 40 percent to control hypoxia in the central Lake Erie basin. This load includes all tributaries (including unmonitored areas), atmospheric deposition, and input from Lake Huron. Progress is calculated by comparing the average reduction over the last five years toward the 6,000 metric ton target – approximately a 40% reduction from the 2008 load.

A gauge indicator all the way to the left would indicate no reduction in average annual phosphorus loading, while an indicator gauge pointed all the way to the right would represent an average 40% reduction in annual phosphorus loading over the last five years.

Sample gauges showing progress toward 40% reduction goal

Progress is being tracked at the basin-wide scale, looking at the total load from all sources.