The sun rises against a coal-fired power plant in Glenrock, Wyoming, July 27, 2018. Credit: J. David Ake | AP

Two environmental groups have sued two utilities over a coal-fired power plant in New Hampshire, saying they are violating the Clean Water Act.

The Sierra Club and the Conservation Law Foundation sued in federal court Monday regarding the Merrimack Station power plant in Bow.

The plant was owned by Eversource until last year, when it was sold to Connecticut-based Granite Shore Power. Both are named as defendants.

The environmental groups said the plant draws about 287 million gallons of water per day from the Merrimack River, heats that water as a result of its cooling process, and then discharges the water back into the river at temperatures that often exceed 90 degrees Fahrenheit.

Messages seeking comment were left with both utilities Monday afternoon.