Robert F. Kennedy Jr. has served as a board member and chief prosecuting attorney for the environmental group Riverkeeper, based in the Hudson Valley. Kennedy, though, submitted a letter of resignation to the organization’s chairman earlier this week.

"I now live on the West Coast, and the weekly commute has been hard on my family, to say nothing of my carbon footprint," Kennedy said. "Furthermore, keeping up with the exploding growth at Waterkeeper Alliance and my work with World Mercury Project have been consuming, increasing bandwidth, leaving me little time to give Riverkeeper the attention it deserves."

Riverkeeper officials said they are thankful for his dedication to the organization over the past 33 years.

"Nobody has been more important to Riverkeeper than Bobby Kennedy, and we're going to do our best to continue his work. We're fortunate to have a lot of folks in communities up and down the Hudson River from one end to the other who see us as important partners,” said Riverkeeper President Paul Gallay.

Kennedy was an influential part in working to shut down Indian Point by 2021.

"The agreement to close Indian Point is sort of a capstone for his career here at Riverkeeper,” Gallay said. "He has put in a tremendous amount of effort on behalf of closing Indian Point and supporting Riverkeeper. So I think having achieved this, he thought that perhaps this was a good time to focus on other matters."

Kennedy said the win to close Indian Point was an important milestone for his career. Riverkeeper officals said they will continue to their work and do their best to move forward without Kennedy.

"We're going to make sure that we remain very relevant on issues having to deal with water quality, renewable energy, recreation, restoring the fishery, so I think that we have a good future ahead," Gallay said.