The U.S. EPA and the Vermont Agency of Natural Resources (VANR) recently completed a series of public meetings on controlling phosphorus loadings to Lake Champlain. The federal-state effort has evolved over more than 10 years and, to a large extent, is based on EPA’s concern that Vermont has not adequately planned to address additional phosphorus loadings to the lake caused by climate change.
EPA’s disapproval
The current effort goes back to 2002 when the EPA approved the phosphorus total maximum daily load (TMDL) the VANR prepared for its portion of the Lake Champlain basin. In response to a lawsuit attacking the state’s TMDL, the EPA withdrew its approval in January 2011, citing among other reasons the failure of the state plan to consider the potential effects of climate change on phosphorus loadings. Once the EPA disapproves a state TMDL, the Agency must itself undertake development of a new TMDL.
In its disapproval, the Agency expressed the desire to collaborate with the VANR in developing a new plan.
Target reduction
The meetings presented the public with EPA’s preliminary TMDL, which would reduce the phosphorus load to the entire lake from 817 metric tons a year (mt/yr) to 495 mt/yr. The EPA estimates that Vermont is responsible for approximately 553 mt/yr of all phosphorus loadings, and the plan would reduce that by 36 percent to 343 mt/yr. Phosphorus controls focus on its sources, primarily eroded sediment; runoff from farm fields, barnyards, roads, parking lots, and streambanks; and wastewater discharges.
The Agency’s TMDL will be one of the first in a nationwide plan to incorporate the potential impact of climate change into TMDLs. Among the many technical documents the Agency has produced and continues to produce with regard to Lake Champlain is its May 2013 Climate Response Modeling Report. The report explored “the implications of a wide range of plausible alternative futures, or scenarios” to determine where the greatest vulnerabilities lie.
Six scenarios were applied to the entire Lake Champlain watershed and 12 rivers that drain into the lake for the 2040 to 2070 time horizon. Across all the scenarios, the report estimated a 12.7 percent to 45.6 percent increase in the annual flow and load of total phosphorus into the watershed. Projected increases of total phosphorus in several rivers exceeded 60 percent and neared 90 percent in one case.
Aggressive effort needed
In their public presentations, the EPA stated that a “very aggressive level of effort” will be needed to achieve the desired reductions, particularly for nonpoint sources. The Agency says that “with some strengthening,” a package of actions proposed by the VANR can achieve the desired reductions. Released November 20, 2013, VANR’s proposal places an emphasis on improving management of nonpoint sources as opposed to point sources such as wastewater treatment plants that are already tightly regulated.
Actions included in the proposal include inspections of concentrated animal feeding operations (CAFOs), inspections of all large farm operations in the Lake Champlain watershed, strengthening the state’s Accepted Agricultural Practice Rule, and providing technical assistance to small farms in their nutrient management programs.
The EPA says it expects to complete the Lake Champlain TMDL by summer 2014. At that point, it will be delivered to the state of Vermont for implementation.
EPA’s Lake Champlain TMDL home page includes links to technical documents and other information developed by the Agency.
VANR’s proposed control measures