Pumps on, pumps off. Pumps on, pumps off.

Four days after Judge Oliver Wanger issued an order allowing state and federal pumps to really start churning because salmon weren’t in danger, the U.S. Fish and Wildlife Service has decided that Delta smelt are in danger, triggering a mandatory shutdown of one of five pumps at the federal plant.

The pumping shutdown will begin after 5 p.m. Wednesday, according to court documents filed by Ignacia S. Moreno, U.S. assistant attorney general.

This is “necessary for the Central Valley Project and State Water Project operations to avoid jeopardizing the continued existence of the delta smelt and adversely modifying its critical habitat,” the document says.

Attorneys for the water users promptly requested a restraining order and asked that a hearing be held in Judge Wanger’s courtroom on Wednesday. The water users say they are in “immediate danger of irreparable harm.” Their request says that less than one week ago, a U.S. Fish and Wildlife attorney told the court that the smelt had turned left into the north part of the Delta and were out of the influence of the south-Delta pumps.

The complaint goes on: “New data available… do not indicate that the distribution of delta smelt has changed. They show that delta smelt remain in the north, west section of the Delta.”

“The FWS-imposed restrictions upon Old and Middle River flows under the BiOp (biological opinion) threaten to substantially restrict the ability of Reclamation to pump available, desperately-needed water. This water must be pumped now, or be forever lost.”

Unless a restraining order is granted, the reductions to protect smelt would remain in effect until spawning begins, typically about March. Total water loss for the feds: 2,900 acre-feet of water per day, or about 115,000 acre-feet for the course of the reduction. Could be more if conditions are wet.

It’s like watching tennis.