Lake Tahoe Water Surface Elevation change from 2-15-17 to 2-22-17.

The recent rain storms in Reno and snow and rain in the central Sierra Nevada including Lake Tahoe have raised the Lake’s water surface elevation from 6226.23 to 6226.73 – an additional increase of 5 inches in just 7 days. A significant portion of that rise likely came from rain and snow falling directly on the surface of the Lake. Lake Tahoe occupies 40% of its own watershed. The 5 inch rise is equivalent of 50,933 acre-feet or 16.6 billion gallons of water.The rise is dramatic especially when coupled with the more than 3.5  foot of rise between October 2016 to just before the storms of the past week. Lake Tahoe now stands just 2.37 feet below its maximum water surface elevation of 6229.1 feet (set by court decree). With a current snowpack of more than 200 percent of average, Tahoe seems likely to approach or reach its maximum surface elevation.

Tiny flows from Tahoe into the Truckee River

Truckee River downstream of the Mayberry foot bridge on 2/10/17.

The dramatic rise in Tahoe’s water surface elevation hasn’t resulted in significant flows to the Truckee River from Lake Tahoe, however.  In fact, very little water is being released into the Truckee River with flows near Tahoe City, California staying close to 50 cubic-feet-per-second (CFS). Compare this to yesterday’s flow in the Truckee River at Reno of 4,500 CFS. Water in the Truckee River is coming from direct runoff from rain and melting snow into tributary streams entering the Truckee River below Lake Tahoe. Lake Tahoe has a dam (built by the US Bureau of Reclamation over 100 years ago) at Tahoe City that controls the release of water into the Truckee River. Under natural conditions flows from Lake Tahoe would be much higher. It is easy to forget that dams control the amount of flow along the river’s entire course. The biggest diversion on the Truckee River is at Derby Dam between Sparks and Wadsworth.  (Want to know more about tributaries to the Truckee? Click here.)

Pyramid Lake rising finally

Pyramid Lake rose at least 1.27 feet although unofficial reports say the actual rise to date is higher. The last official measurement of the water surface elevation of Pyramid Lake shows the first rise in elevation since 2011. The next measurement of Pyramid Lake’s elevation should be on March 1, 2017 (no measurement occurred in January, e.g.). Yesterday, flows of the Truckee River at Pyramid Lake were just under 7,000 CFS. By this morning’s report on the  Truckee River Operating Agreement website the Truckee River flow at Pyramid Lake’s Nixon Gauge was 6,450 CFS.

Pyramid Lake is now accessible on SR 445 although SR 446 between Nixon and Sutcliffe is still closed due to a washout caused by flooding in January 2017. (Click here or the link above for more info).

Drought areas shrinking

In northwest Reno near the University, I recorded approximately 3.75″ of precipitation in the form of mostly rain with slush and snow at the end of the storm. This is a pretty significant amount of rain/snow for just a little over 2 days and may be a record for us at our house. The NOAA California River Forecast Center website reports that since the beginning of the water year on October 1, 2016, Reno has officially received 9.36″ of precipitation – 126 percent of average for an entire year. The Reno precipitation gauge is located at the airport in southeast Truckee Meadows. Precipitation amounts vary widely across the Truckee Meadows.

The Drought Monitor map released on February 14 may change yet again from that shown below when next released. Drought conditions in Nevada and California have consistently shrunk in size and severity as rain pummeled California and western Nevada and snow piled up in higher elevations of the Sierra Nevada Mountains.

Related articles across the web

• Evacuations ordered amid heavy Northern California rainstorm

Rain returned to the eastern Sierra and western Nevada this afternoon bringing the possibility of minor to moderate flood stage again on the Truckee River.  Mid-afternoon, the Truckee was running at 7,000 CFS through downtown Reno, but the flow is currently increasing as rain continues and melts low-elevation snow. Temperatures will be falling over the next 24 hours bringing more snow and an end to the rain. Currently, the National Weather Service has the following forecast for the Truckee River.

Flooding on the Truckee River as of early evening Feb. 9.

Truckee River at Wingfield Park Feb 9, 2017

Meanwhile the spillway at Oroville Dam has been severely damaged by high water flows over the spillway and a dam in northeastern Nevada has collapsed flooding the unincorporated town of Montello, NV.

Nixon – Sutcliffe highway at Pyramid Lake damage.

Most of us have seen the photos of damage to the roads and infrastructure around Pyramid Lake especially between Sutcliffe and Nixon with the wash out of the highway and loss of water supply to Sutcliffe residents and businesses. Current reporting by the Reno Gazette-Journal says that the Pyramid Lake Paiute Tribe is not allowing non-tribal members entrance to the Lake because of the damage. The estimated date quoted in the newspaper was sometime in April. For those of us who travel frequently to Pyramid to fish, boat, and look at the abundant bird life, it is hard to stay away, but certainly no one wants to interfere with the fastest recovery for the residents and businesses during the infrastructure re-construction period.

Pyramid Lake (from the UNR Geology Field Tour Announcement, 2016)

However, the flood of 2017 had a good effect on the water surface elevation of Pyramid Lake. The surface elevation of Pyramid Lake measured on December 1, 2016 was 3792.16. The latest measurement taken on January 31, 2017 was 3793.43. This rise 1.27 feet of the Lake’s water level is very good news for everyone. This is the first rise of water surface elevation at Pyramid Lake in more than 5 years.

Unfortunately, diversions from the Truckee to the Newlands Project took nearly 700,000 acre-feet of water from the Truckee River over the last 6 years. Had those diversions not occurred, Pyramid Lake would be more than 7 feet higher in elevation providing better habitat for fish and recreation for visitors and residents alike. One example are the boat launch facilities: Popcorn Beach and the Marina at Sutcliffe – both of which have been unusable for several years due to low water levels.) While drought does have an impact, the greatest impact to Pyramid Lake is the Newlands Project which diverts water from the Truckee River to the Carson River.

Since 2000, Pyramid Lake fell 27 feet in elevation exposing vast areas of beach and river bottom at Pyramid Lake and impacting tourism, fishing, boating, and the natural environment that supports numerous birds and the Lahontan Cutthroat Trout and endemic Cui-ui fish essential to the cultural identity of the Pyramid Lake Paiute People.

Water from the Truckee River, diverted into the Truckee Canal at Derby Dam, ends in Lahontan Reservoir on the Carson River.

La Niña hasn’t lived up to its reputation for 2016-17 any more than El Niño lived up it its reputation for 2015-16 a year ago. The much-anticipated “super” wet weather for last winter didn’t happen and the “drier” weather seen in early winter this year turned much wetter. The latest drought map from the Drought Monitor folks shows that exceptional  drought has disappeared from the California map entirely and extreme drought has shrunk to a small area of southwest coastal California. Drought has retreated in Nevada as well. [See previous drought posts here and here.]

Drought Monitor map for the Western US last week of January 2017 (click for large version)

Abnormal, moderate and severe drought still dominate southern California. Drought colors have disappeared from northern California and most of northern Nevada. Abnormal and moderate drought show up only in southwestern Nevada and a small part in far northwestern Nevada extending into southeastern Oregon.

Currently snowpack in the central Sierra is running close to 200% (double the 30 year average). The remainder of the winter, however, will determine just how well runoff will help fill lakes and rivers in the coming months. A dry winter from here on out could result in a just “average” runoff year while an average winter through the April 1 final measurement could see much better stream flow and reservoir storage for the remainder of 2017.

The implications of a much above average winter could have many beneficial effects for the Truckee River with enhanced stream flows, improvements to the riparian corridor with new trees and shrubs, and an infusion of much-needed water for Pyramid Lake. The next few weeks of winter will tell us whether we have double average runoff or just run-of-the-mill runoff.

The water surface elevation of Pyramid Lake fell 27 feet since 2000.

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