sentences:  On the opposite side of the lake the mountains form the beginning of the Corni di Nibbio chain which divides the Val d’Ossola from the Valgrande and its National Park.The lake is fed by the waters of a number of clean mountain streams, the two most important being the Rio Bracchio and the Rio Rescina.Its sole outlet is the 2.7 km canal which links it to Lago Maggiore near Fondotoce.