New Plan Seeks To Reduce Phosphorus Loading In Lake Memphremagog

Nov 20, 2017

Phosphorus runoff from farms and other sources is a nuisance for Vermont’s lakes. Phosphorus loading can lead to toxic algae blooms that threaten the health of our waterways. This is a well-known problem for Lake Champlain, but now Vermont’s second-largest body of water, Lake Memphremagog, is in the spotlight for a new plan developed to correct its water pollution issues.

Ben Copans, watershed coordinator for the Vermont Department of Environmental Conservation (DEC), tells Vermont Edition about the cleanup plan that seeks to reduce phosphorus loading by 29 percent.

Similar to Lake Champlain, the majority of Lake Memphremagog’s phosphorus loading comes from farm lands.

Copans said, “We estimate that about 46 percent of the phosphorus pollution comes from farms. But we also estimate that 21 percent come from developed lands — things like roads, lawns, parking lots, and our wastewater treatment facilities. Another 20 percent from stream channel erosion, and 12 percent from forest lands across the watershed.”

In September, the Environmental Protection Agency approved the Total Maximum Daily Load (TMDL), which acts as a phosphorus budget for the lake. This was developed by learning the sources of phosphorus and then creating a “scenario tool.”

Copans said, “This allows us to apply different best management practices across those different land uses and see the effect of that in terms of reducing phosphorus loading.”

Water quality sampling from 160 sites across the watershed has been key to determining where the phosphorus is coming from. In many cases it can be linked to farms, so the DEC will work directly with the farmers to adopt new field practices.

The main source of funding for implementing farm practices comes in the form of a $674,000 grant from the Orleans County Natural Resources Conservation District.

One unique characteristic of Lake Memphremagog is that it straddles the Vermont-Quebec border; only about a quarter of the lake lies in Vermont. The Quebec portion of the lake has lower phosphorus levels and meets the local guidelines. Copans attributes this largely to the increased depth on the northern end.

Although Quebec is not part of the TMDL in an official capacity, the two entities collaborate through the Vermont Quebec Steering Committee For Lake Champlain. They meet twice annually to coordinate efforts and ideas.

Broadcast live Monday, Nov. 20, 2017 at noon, and rebroadcast at 7 p.m.