On Aug. 14, the U.S. Environmental Protection Agency (EPA) issued phosphorus Total Maximum Daily Loads (TMDLs) for the 12 Vermont segments of Lake Champlain, the sixth-largest freshwater body in the U.S.
Despite reductions in phosphorus entering the lake from several of its tributaries, phosphorus concentrations have not significantly decreased in any areas of Lake Champlain. In some segments, phosphorus concentrations continue to rise compared to long-term trends.
According to EPA’s TMDL plan, about 631 metric tons of phosphorus flowed into Lake Champlain annually between 2001 and 2010 from Vermont. The TMDL plan calls for an overall 34% reduction in phosphorus.
States normally develop their own TMDLs. However, EPA proposed the Lake Champlain TMDLs following a lawsuit by the Conservation Law Foundation, which claimed EPA erred in originally approving Vermont’s TMDLs. In 2010, EPA withdrew its approval of the state’s plan and began creating the new TMDLs, for which the public comment period ended Sept. 15. Once the TMDLs are finalized, Vermont will submit its water quality plan to EPA for approval. The plan will include an accountability framework that requires Vermont to report in 2.5 years on its progress toward achieving the phosphorus reduction targets. Read more.