Complex sentence: The Massena Power Canal, which connects the St. Lawrence River to the lower Grass River, and the powerhouse were built in the early 1900s to provide hydroelectric power to the local community of Massena, New York.
Split into simpler sentences: The Massena Power Canal, which connects the St. Lawrence River to the lower Grass River. A powerhouse were built in the early 1900s to provide hydroelectric power to the local community of Massena, New York.