Lake Memphremagog restoration plan released, public meetings Nov 9 & 14

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The Department of Environmental Conservation (DEC) is holding two public meetings to present the Lake Memphremagog, Coaticook and Tomifobia Rivers Tactical Basin Plan, which outlines how the State will achieve new phosphorus pollution targets for the Memphremagog Watershed in Vermont. ​The US Environmental Protection Agency recently approved the Lake Memphremagog phosphorus TMDL or Total Maximum Daily Load, which calls for a 29 percent reduction in phosphorus flowing off the land into the lake. Too much phosphorus causes nuisance plant and algae growth and occasional cyanobacteria blooms that limit recreational use of the lake.

DEC collaborated with local and regional experts to develop the tactical basin plan, with public input throughout the process. The plan outlines watershed-specific actions and projects that reduce phosphorus pollution from farms, roads, developed lands, and forests necessary to achieve the target.   

“Whether you are a landowner, farmer, municipal official, developer, or logger, as Vermonters, we all have a responsibility to ensure a legacy of clean water for this and future generations,” says DEC Commissioner Emily Boedecker. “We are eager to begin implementing this plan, in close coordination with our local and regional partners that have been integral to its development.”

Basin 17 includes the Vermont portions of the St Francis River Watershed encompassing a total of 589 square miles between the Lake Memphremagog drainage and the Tomifobia and Coaticook River watersheds. The Vermont portion of this basin includes the Black, Barton and Clyde Rivers and many lakes and ponds, including Great and Little Hosmer Lakes, Lake Parker, Crystal Lake, Lake Willoughby, Island Pond, Great and Little Averill Ponds, Norton Pond, Holland Pond and Seymour Lake.  

According to the EPA, the largest source of phosphorus from the Vermont watershed is from the agricultural sector, estimated at 46% of the loading to Lake Memphremagog, followed by loading from developed land at 22%, stream channel erosion at 21% and finally forest and water/wetland at 12%. Modeling for the Lake Memphremagog TMDL further breaks down loading across several land uses for each of these major land use sectors as shown in Table 4 and Figure 3. For developed lands the largest sources of loading are buildings/parking lots/lawn areas (developed in the pie chart) at 9% as well as dirt roads with loading of 8% with lesser amounts of loading from paved roads, septic and WWTF loading.

For agricultural lands, loading is most significant from hay land due to the large percentage of the watershed comprised by these lands, 11% of the watershed in Vermont, resulting in an estimated loading of 19%. This is followed by cropland, agricultural production areas and pasture lands. As noted above there is a loading of 21% from stream channel erosion, and 12% from forest/wetland/water due to the large percentage of the watershed these land uses make up at 78% of the watershed in Vermont.

For information on the Memphremagog TMDL and the Lake Memphremagog, Coaticook and Tomifobia Rivers Tactical Basin Plan, visit:

Tuesday, November 14, 2017 - 2:00pm