The phosphorus data shown here represents the estimated annual load of phosphorus to Lake Champlain from the major Vermont tributaries. Phosphorus loading to the lake fluctuates annually due to weather and precipitation patterns. Higher amounts of precipitation, particularly heavy rainfall (as was seen in 2017), move more phosphorus from the land to flowing waters and on downstream to the lake. As a result, annual phosphorus loading patterns closely follow annual stream flow patterns. The target load of 418 metric tons total phosphorus represents the maximum amount of phosphorus the lake can receive each year, as specified by the Phosphorus Total Maximum Daily Loads (TMDLs) for Vermont Segments of Lake Champlain, and continue to meet water quality standards. With the passage of the Vermont Clean Water Act (Act 64) in 2015, we now have additional permitting and funding tools to further reduce phosphorus loads to our rivers, streams, and lakes. Decreased loading should be measurable at a local level (individual smaller rivers and streams) as implementation progresses, however it is likely to take many years to show substantial progress in the larger Champlain tributaries and the lake itself. The DEC utilizes additional metrics to evaluate load reductions over time (see our annual RBA report for more information).