Imperial Irrigation District general manager Kevin Kelley will retire at year’s end, capping an often tumultuous and challenging eight years at the helm. Kelley, 60, submitted a letter to the board of directors in a closed session on Monday, and his offer was accepted. “This has actually been in the works for some time,” said Kelley in an interview with The Desert Sun. “I think at this point IID could benefit from fresh thinking and new ideas, and by someone who hasn’t been doing this for eight years.”