We had some very high winds in the last storm in the mountains and apparently at Lake Tahoe, too. (BTW, the storm didn’t do diddly squat here in Reno and not much for the Truckee River either as far as I can tell, but more on that later).
High winds actually brought out surfers to Lake Tahoe and a photo in the RGJ showed them on their boards during the high winds (you’ll have to look around in the current story a bit to find the photo).
I’m wondering if those strong winds aren’t responsible for the interesting graph of Tahoe’s water elevation that the USGS collects near Tahoe City, CA. First you see a very big increase in the level of the water level (2.4″ rise), followed by a sharp decrease of the water level by an even greater amount, then followed by a slower rise of more than an inch and then a gradual decrease. Could it be that water is being pushed by the wind? Then rolling back as the wind slacks off? I’d be interested to hear from experts on this topic.
Lake Tahoe ‘bathtub’ effect from strong winds on December 11, 2014?
The Truckee River flows are up again through Reno, right? So that water is going to Pryamid Lake, you’re thinking? Of course, those giant cutthroat trout that folks try to catch at Pyramid Lake are getting the benefit of the water finally flowing in the river?
In reality, as the river comes up, the Truckee River is tapped by the Newlands Project. The water diversion 15 miles east of Sparks at Derby Dam sends the Truckee’s increased flows of water through a canal to fill the reservoir on the Carson River. Lahontan Reservoir stores water to be used by farmers in the Fallon area. Lahontan sits outside of the Truckee River watershed and Truckee River water only reaches it through the man-made canal built 110 years ago.
The graphic which follows shows what happened between November 1st and today, December 11, 2014. As the river flows increased starting around November 28, more and more water was taken out of the Truckee River and sent through the canal to Lahontan Reservoir. So instead of 350 CFS flowing into Pyramid Lake today, the majority of the water is diverted to Lahontan. Pyramid Lake receives just about 110 CFS while about 240 CFS heads to the reservoir (December 11, 2014). [Click on the graph to see a larger version.] No wonder that Pyramid Lake has fallen more than 25 feet during the past 14 year drought. [See post “Just 14 years ago”]
Graphic of Truckee River flows: Pyramid Lake doesn’t benefit from increasing flows in River
The blue symbols represent Truckee River flows just below Reno at Vista, the yellow symbols flows near Pyramid Lake, and the red symbols flows in the diversion canal. (Diversions from the Truckee River have taken the lion’s share of water during the 3 year drought.)
So rivers do flow on – except when they aren’t allowed to.
As I write this, it is raining from Monterey, CA to Redding, CA. Rain has moved into the northern Sierra and even sprinkles of rain with strong winds in Reno. It is 58º F, too, so it is likely to be raining in the mountains rather than snowing. Has the weather shifted to a wet pattern that will bring significant amounts of rain and snow to benefit the Truckee River? Has the high pressure that has come to dominate our weather gone bye-bye? If it comes back again to dominate the weather for the far west and southwest, then what?
Winter Storm Approach on December 11, 2014 at 11:21 AM (National Weather Service Radar)
The warm and wet storm of the past 3 days has reversed Tahoe’s water decline – at least for now. Tahoe has risen over an inch with an upward trend and now stands 4.8″ below its rim (12/4/14). Still no water will flow into the Truckee River from the Lake, but it is better than a continual decline. Much of the rise is likely due to water falling directly on the surface of the lake. (See my last post regarding this phenomenon.) If wet weather continues, then we can expect a much improved water situation, but whether or not we’ll see an end to the long-term drought remains in doubt.
Tahoe Elevation (6223.0 is the rim elevation and no water flows to the Truckee River if water level drops below) – current reading is between 6,222.6 and 6,222.7.
Truckee River view downstream of Center Street in Reno on 12/4/2014.
Truckee River looking upstream from Lake Street Bridge in Reno on 9/16/2014