 To reduce phosphorus runoff to this part of the lake, Vermont and Quebec agreed to reduce their inputs by 60% and 40%, respectively, by an agreement signed in 2002.While agricultural sources (manure and fertilizers) are the primary sources of phosphorus (about 70%) in the Missisquoi basin, runoff from developed land and suburbs is estimated to contribute about 46% of the phosphorus runoff basin-wide to Lake Champlain, and agricultural lands contributed about 38%.In 2002, the cleanup plan noted that the lake had the capacity to absorb of phosphorus each year.