A coalition of water users filed a notice Thursday stating its intent to file a lawsuit alleging that power plants are harming fish in the troubled Sacramento-San Joaquin Delta. The four water districts allege that Mirant Corp.'s natural gas-fired power plants in Antioch and Pittsburg are harming species including the delta smelt. The smelt's decline triggered a recent federal court decision that was expected to limit the amount of water available from the delta for people and farmers, including those served by the Belridge, Berrenda Mesa, Lost Hills, and Wheeler Ridge-Maricopa water districts. The plaintiffs say that Mirant's power plants...