Former Auburn Mayor Jonathan LaBonte speaks Thursday during the celebration marking 50 years of the Clean Water Act at Simard-Payne Memorial Park in Lewiston.

"Clean Water Champions" gather Thursday for a photo at Simard-Payne Memorial Park in Lewiston to celebrate 50 years since the passage of the federal Clean Water Act. The 100 professionals and volunteers across the state were recognized for their efforts to protect Maine's waters.

Gov. Janet Mills speaks Thursday on the history of the federal Clean Water Act at Simard-Payne Memorial Park in Lewiston. Roughly 200 people gathered to celebrate 50 years since the landmark law was passed.

Alan Haley speaks Thursday on the history of the federal Clean Water Act at Simard-Payne Memorial Park in Lewiston. Haley is Maine's first registered whitewater guide.

Pat Webber speaks Thursday on the history of the federal Clean Water Act at Simard-Payne Memorial Park in Lewiston to celebrate 50 years since its passage. Webber is the director of the Edmund Muskie Archives at Bates College. The landmark law is thanks to the work of the U.S. senator from Rumford.

Guests listen Thursday at Simard-Payne Memorial Park in Lewiston during the celebration marking 50 years since the passage of the federal Clean Water Act.

Former Auburn Mayor Jonathan LaBonte, right, arrives by kayak Thursday at Simard-Payne Memorial Park in Lewiston to celebrate the 50th anniversary of the federal Clean Water Act.  LaBonte, a longtime advocate of the Androscoggin River, was a guest speaker.