On August 31, 2011, the United States District Court for the Eastern District of California enjoined the federal government from implementing the so-called “Fall X2” measure, which, absent the injunction, would have restricted California
’s water supply by hundreds of thousands of acre feet.
In his 140-page Findings of Fact and Conclusions of Law, Judge Oliver W. Wanger granted a motion filed by State Water Contractors, Metropolitan Water District of Southern California, Kern County Water Agency, Coalition for a Sustainable Delta, San Luis & Delta-Mendota Water Authority, and Westlands Water District to enjoin implementation of the Fall X2 Action. The Fall X2 Action is part of the Reasonable and Prudent Alternative set forth in the United States Fish and Wildlife Service's December 15, 2008, biological opinion, which addressed impacts of the coordinated operations of the federal Central Valley Project and the State Water Project on the threatened Delta smelt.
Intended as a measure to improve fall habitat for Delta smelt growth and rearing, the Fall X2 Action would require sufficient Delta outflow to maintain a monthly average location of two parts per thousand salinity (X2) at or more westward than 74 kilometers from the Golden Gate Bridge
in 2011, a "wet" water year.
Absent an injunction, "[t]he estimated cost to water users [of implementing Component 3] is 670,000 acre feet ('AF') of water if 2012 is a critically dry or dry year, or 300,000 AF if  is a below normal or above normal year."
(Findings at p. 3.)
The court held that "the record reveals no support for a direct link between X2 and smelt abundance." (Findings at p. 134.) The court further explained:
The scientific evidence in support of imposing any Fall X2 action is manifestly equivocal. There is essentially no biological evidence to support the necessity of the specific 74 km requirement set to be triggered in this 'wet' water year. The agencies still 'don't get it.' They continue to believe their 'right to be mistaken' excuses precise and competent scientific analysis for actions they know will wreak havoc on California's water supply.
(Findings at p. 139.) "Balancing the imperiled status of the species, the equivocal and highly disputed support for the X2 action, and the even weaker and unjustified support for position X2 at 74 km, against the substantial and damaging water supply impact of doing so," the court enjoined the Fall X2 Action or any other attempt by Federal Defendants to set Fall X2 westward of 79km. The court held held that "limiting the X2 position to 80 km or 79 km achieves equity." (Findings at p. 140.)
This latest ruling in the Consolidated Delta Smelt Cases follows a December 2010 decision by the court, in which it found that restrictions on Delta pumping under the biological opinion were not adequately justified, and a May 2011 final judgment that remanded the biological opinion and required issuance of a new biological opinion by December 1, 2013.
A complete copy of the court's Findings of Fact and Conclusions of Law
can be found here
The biological opinion for Delta smelt may be found here