Belhavel LoughBelhavel Lough is a freshwater lake in the northwest of Ireland. It is located in north County Leitrim near the village of Killarga.Geography and hydrologyBelhavel Lough is about south of Killarga and north of Drumkeeran. It covers an area of. The lake drains east into the Diffagher River, which eventually reaches Lough Allen.EcologyThe water quality was reported to be satisfactory with a mesotrophic rating, but had a "" ecological status indicating pollution, though Zebra mussel infestation was not reported. The ecology of Belhavel Lough, and other county waterways, is threatened by curly waterweed, zebra mussel, and freshwater clam invasive species.