Details of the deal between Westlands and the federal Bureau of Reclamation have not been revealed to members of Congress, who would have to approve it. But according to a short “principles of agreement” document that has been made public, the deal would forgive $342 million in federal debt that Westlands owes for construction of the 1960s extension of the Central Valley Project to deliver water to the San Joaquin Valley farms. In return, taxpayers would be relieved of an estimated $2.7 billion obligation to remove the contaminated water that results from the irrigation. Resolution of the drainage problem would...