The long debate over Poseidon Water’s proposed ocean desalination plant in Huntington Beach continued this week as the California State Lands Commission released a draft of a supplemental environmental impact report analyzing planned additions to the facility that are meant to reduce potential harm to marine life and increase the plant’s efficiency. The supplement to a 2010 EIR addresses the possible environmental effects of a screen and diffuser added to the intake and outflow pipes, respectively, that would be used by the $1-billion desalination facility proposed at Newland Street and Pacific Coast Highway.