The U.S. Environmental Protection Agency (EPA) has proposed new Clean Water Act section 316(b) regulations for once-through cooling water intake structures. Comments on the proposed rules closed in August, and a final rule is expected mid-2012. The EPA estimates that at least half of the power plants using once-through cooling will be required to implement a best technology available solution in coming years. That typically means barriers and screens, but you may want to consider other options.