Officials fear the rivers could become too shallow and warm, affecting food supply and making salmon easier to catch by predators, the Sacramento Bee reported (http://bit.ly/Oh5dS8).
State and federal officials said Monday they were watching conditions and would be ready to implement the plan next month, barring heavy rains.
Salmon are usually released in April and May from the Coleman National Fish Hatchery on Battle Creek, a tributary of the river.
The hatchery is the largest in the state, producing about 12 million fall-run Chinook salmon.
Such fish are key to West Coast salmon populations, producing most of the wild-caught salmon found in California markets and restaurants. The fish are also key to California's robust salmon sport fishing industry.
"What this means is we'll likely have a much better salmon fishing season in 2016, when these fish reach adulthood, than we would have otherwise gotten," John McManus, executive director of the Golden Gate Salmon Association, told the Bee.
Unless the state sees lots of rain in March, wildlife officials worry the rivers will slow to a trickle in April and May when young salmon migrate to the sea.
The problem is heightened by water diversions from the Sacramento-San Joaquin Delta to farms and cities.
The California Department of Fish and Wildlife is also putting together similar trucking plans for the Feather, American and Mokelumne rivers, which also produce millions of young salmon annually.
Some concerns over trucking the fish have been raised after evidence that the transported fish sometimes swim into the wrong river when they return to spawn as adults, harming the unique genetic traits of the species.
A long-term study is underway to help scientists determine the least disruptive way to transport the salmon.
The trucking plan would be a one-time program meant to protect the fish during the drought. It's similar to one used during the drought of 1991-92.
The state would scrap the plan if heavy rains hit the region.
"We don't want to truck them down if conditions aren't going to be as bad as we think they're going to be," said Bob Clarke, fisheries program supervisor at the U.S. Fish and Wildlife Service.
Information from: The Sacramento Bee, http://www.sacbee.com