Eyeing Drying

The Trinity River system feeds the Klamath River and, through diversions, the Sacramento River system.  Some folks were trying to sidestep the rules and boost the amount of water headed south this year.  Not any more.

The U.S. Bureau of Reclamation has backed away from a proposal to take more water from the Trinity River this year, citing a 2000 Interior Secretary decision on fisheries restoration.

Reclamation was considering a shift from a normal year to a dry year, which would have stifled releases from Lewiston Dam to the river. Water managers were looking to possibly adjust the seasonal forecast used to craft the flows to reflect conditions in May, instead of the April 1 date called for in the 2000 record of decision.

”It's what the record of decision calls for,” said bureau spokesman Jeff McCracken.

Much of the state is headed for drought, and snowpack in the Sierra Nevada is poor. Conditions have been dry in the northern part of the state as well, after substantial precipitation earlier in the year. Trinity River advocates protested the possible decision by reclamation, saying the river should not suffer because of what they called mismanagement of the Sacramento River delta water system in recent years.

Half of the Trinity River's water is diverted to the Sacramento, then pumped from the delta to farms and cities to the south. Flows meant to aid fisheries restoration are released beginning in April. A shift in the water year type would have crimped releases to the river.

The Shasta Reservoir is below two-thirds capacity.  And downstream, the Sacramento River can't expect major contributions from the Sierras...runoff is expected to be just 55 percent of normal.  Switching links:

Just two months ago, it appeared that Northern California was in store for a nice wet year--or at least a year of normal rain and snow levels--following a dry 2007.

But March and April were the driest months in the Sierra Nevada since records were first kept in 1922, state water officials announced Thursday (May 1).

As a result, the Sierra Nevada snowpack averaged 67 percent of normal for May 1 in the state's final snowpack measurement of the year, down from 95 percent April 1.

...

...this April and May, only 2.3 inches of rain fell in the Northern Sierra between Lake Tahoe and Mount Lassen - the lowest since 1922.

Last year, the snowpack in the Sierras was even lower.

Notice how few years the snowpack is near normal.  Volatility is normal.

Comments

[Jeff]

So... where is this imaginary line where we go from a truly excellent snowpack in the Oregon Cascades, to drought conditions somewhere south of Eugene?

[RoguePundit]

The most recent measurements (end of April) showed the snowpack in Rogue drainage averaging 173% of its normal water content and the Klamath at 155%. South of that, things are below normal.

[trotsky]

I thought I was familiar with the basics of the ROD, but now I'm confused. Was the "dry-year" plan to hold water in Trinity Lake? Or to divert it over into the Sacramento?

[RoguePundit]

The ROD covers the amount (and timing) of the water that's released from the Trinity River Diversion into the Trinity River.

Critically dry: 369,000 acre-feet
Dry: 453,000
Normal: 647,000
Wet: 701,000
Extremely wet: 815,000

Thus, keeping the conditions defined as normal versus dry means a difference of 194,000 acre-feet going down the Trinity River rather than being available for diversion to users further south. Unless I'm missing something, the ROD doesn't cover how the diverted water is managed.

[Mike]

But Calif wants us to blow up the Klamath dams on the same river. From which they get the power. And which will put warm water in the river (bad for salmon), whereas the Trinity is cold water.

More than snowpack drops off south of the OR/CA border. Sanity dries up too.