Every three seconds the weight of a modern locomotive in water is being released from Lewiston Dam into the Trinity River.

This week's flows are the biggest from the dam since it was built in the 1960s, except for water spilled in flood years. The water is cold and dangerous and the releases come as recent storms pumped water into tributaries.

Tribes, fishermen and agencies are hoping the river and its salmon and steelhead will begin to experience a partial rebirth with the big water. Fine sediment should be flushed from spawning gravels, while vegetation creeping toward the channel is stripped away.

Mike Orcutt, senior biologist with the Hoopa Tribe, called Tuesday historic.

"The missing element has always been the flows," Orcutt said. "That's something to be proud of."

Orcutt said major hurdles -- including decades of scientific study and years in court -- have been cleared. More restoration work remains to be done, he said.

The Trinity River Restoration Program has about 20 people in several locations taking water and sediment samples to help figure out just how the river channels during the big pulse. Other crews are measuring the high water mark with stakes in about 150 spots, and watching to see if any properties are at risk.

Seven thousand cubic feet of water per second marks the highest flow planned for this year, and that will begin to slowly decrease Friday toward typical summer releases of only 450 cfs by July 22.

Now that water-constricting bridges on the river have been replaced, 7,000 cfs could be small potatoes compared to wetter years. In the wettest of years, nearly 11,000 cfs could be released.

Nita Rowley has lived in Willow Creek since 1954, and remembers the river before the dams. She said people took big spring water in stride then, and didn't let their kids swim until July. But after the dams, Rowley saw paltry winter flows she described as sad.

Tuesday, it looked like something out of the past.

"I like to see the river bank-full," Rowley said. "I know it's cleaning it out."

Public safety officials are warning anyone near the river to be particularly careful and mindful of their children, who should be wearing life jackets in the vicinity of the torrent at all times.

A full flow schedule can be found at www.usbr.gov/mp/cvo/vungvari/trinsch.pdf