Madawaska Lake is listed as targeted (high priority) on the 303(d) list and the Madawaska Lake TMDL has been developed for total phosphorus, which has been determined to be the major limiting nutrient to algae growth in this system. According to ME-DEP (1994), Madawaska Lake experienced a nuisance algae bloom for the first time in early to mid-July through early September 1987. The existing phosphorus load was estimated and allocated among the combined-basin Madawaska Lake watershed land-use classes and atmospheric deposition. The relative contribution of alternative sources of phosphorus loading (e.g., internal recycling, waterfowl droppings) were addressed (ME-DEP 1994) and dismissed as being insignificant (however, not assumed to be negligible Mattson and Isaac 1999) to the overall phosphorus budget of the Madawaska Lake watershed.