A proposed $300 million plant to desalt seawater--slated to be the largest facility of its kind in the Western hemisphere--won the support of a Superior Court judge and regional water board this week. The developer plans to use the aging intake infrastructure of a once-through cooled power plant in Carlsbad. Over the objections of environmentalists, developer Poseidon Resources--which plans to turn seawater into up to 50 million gallons of potable water a day for the San Diego area--received May 13 a requisite wastewater discharge permit from the San Diego Regional Water Quality Board. The day before, a San Diego Superior Court judge rejected opponents\u2019 assertions. Instead, she held the California Coastal Commission\u2019s conditional approval of the desalination project that would use NRG Energy\u2019s Carlsbad power plant intake satisfied state law. After \u201cfive years in the state\u2019s permitting process, the Carlsbad Desalination Plant has now received final approvals from every required regulatory and permitting agency in the state,\u201d claims Poseidon\u2019s website. That is not quite true. The Coastal Commission recently asked the developer, as part of its conditional permit, for more information because of questions about earlier data on the facility\u2019s impacts on fish and other aquatic species. The main project opponent, Surfrider Foundation, which sued the water board and California Coastal and State Lands Commissions over their approvals of the project, is not dropping its fight. \u201cThey blew it on a lot of fronts,\u201d said Marco Gonzales, representing Surfrider. The environmental organization challenged the Coastal Commission\u2019s permit on grounds it violated the state water code for allowing offsite mitigation instead of requiring onsite technology that reduces the plant\u2019s impact to the marine ecosystem. That suit goes to trial May 22. In addition, Surfriders\u2019 lawsuit against the lands agency claims its lease of tidelands for the project requires a supplemental environmental impact statement. According to Poseidon, construction of the desalination plant is expected soon so the plant can begin operating by the end of 2011. However, in the economic downturn financing is expected to be a challenge.