Category Archives: Keep it flowing

Cities, towns, development, farms, ranches take water from the Truckee River – some years taking nearly its entire flow

Snow drought in an average year of precipitation for Truckee River

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

The Truckee River watershed saw more rain than snow this year. So, this year appears to continue the trend of at least the last decade as rain replaces snow – especially at lower elevations. The maps show just how significant the effect is as we approach the end of the first month of spring. Many sites in the Truckee River basin (including the Tahoe basin) are reporting 101% of the longterm average for precipitation. The picture is different for snow water equivalent, however. Snow water equivalent (the amount of water in the snow pack) is almost or well below the longterm average for this date for sites at lower elevations. You have to go to the highest elevation sites to see average snow water equivalent conditions.

In the graphic below, the blue dots on the left represent sites where total precipitation is 101% and the white sites represent 100% of the long-term average. On the right the 3 sites (between 6400′-7700′) in red have 0% of snow water left; the orange sites have 50% of snow water left compared to the long-term average. Only the site at Big Meadow (8235′) shows 101% of snow water left and one site at Heavenly Valley (8500′) shows 100% of snow water left – both high elevation sites. Click on the graphic to see full size. Or check out the site yourself here.

NRCS 4-24-2018 - Total Precipitation vs. Snow Water Equivalent for water year to date

NRCS 4-24-2018 – Total Precipitation vs. Snow Water Equivalent for water year to date

If the trend continues as expected, there will be very little snow left to melt in the late spring and early summer. When snow disappears earlier, natural stream flow of tributaries and the Truckee River itself decrease. Less natural stream flow often results in additional releases from reservoirs or increased ground water pumping because of our long, dry summers.  Ultimately, it will negatively affect recreation and fish and wildlife that depend on water in the Truckee River.

One Truckee River Month: May 1 through May 31

One Truckee River kicks off its inaugural OTR Month with river events for each day this May. Activities include river tours, yoga on the river, learning about the river, river and park clean-ups, vendors offering food and more. Below is a schedule of some of the events. The One Truckee River website (onetruckeeriver.org) will have the details so be sure to visit to plan how to join in.

Truckee River escapes drought designation

Drought Map for 3-29-2018 - On the edge of the drought the map appears to exclude the Truckee River and Tahoe Basins - at least for now.

Southern California, Arizona, Utah, Colorado, and New Mexico are experiencing severe drought conditions, but far western Nevada and parts of northern California are not. In fact, the map on the US Drought Monitor website currently shows that the Truckee River and Lake Tahoe basins are in the “none” category. We are however, surrounded by “abnormally dry”. Perhaps it would be safer to say we are on the cusp of drought conditions later this year. Dry conditions usually persist here from late spring into early fall. Being dry for half of the year is the norm for western Nevada – actually, most of the far western states. Nevada has the distinction of having the lowest average annual precipitation statewide – less than 10″. Much of western Nevada is even lower at 7.4″ or less average annual precipitation.

Drought Map for 3-29-2018 - On the edge of the drought the map appears to exclude the Truckee River and Tahoe Basins - at least for now.

Drought Map for 3-29-2018 – On the edge of the drought the map appears to exclude the Truckee River and Tahoe Basins – at least for now.

Truckee River in Reno with flows at 2,000 CFS during the last weekend in March 2018.

For the moment, however, we can enjoy the high flows in both the Truckee River – currently above 2,500 cubic-feet-per-second (CFS). The snowpack is already melting and won’t provide runoff for anywhere near as long as we saw last year. A storm is forecast for the end of the week.

As we mentioned in our earlier post, the Federal Water Master is releasing water from Lake Tahoe today at more than 1,300 CFS (and rising as this as I write this). Lake Tahoe stands just below 6,228.6 feet in elevation. Pyramid Lake may actually be rising due to increased inflows and may now be higher than the last official reading reported at 3,802.37 feet surface elevation on February 28, 2018.

Snow is melting fast on the north-facing slopes of the Carson Range shown here at about 6,400 feet.

Most low elevation areas – below 7,000 ft – are already snow free such as here on the Jones-White’s Creek Trail.

The Carson River is currently flowing at nearly 1,000 CFS (April 2, 2018). Diversions from the Carson River for agriculture have already begun. Diversions to agriculture place a huge burden on the Carson River and cause it to be dry by early summer most years before it gets to Lahontan Reservoir. When flows are low on the Carson River and Lahontan Reservoir has storage available, then the Truckee-Carson Irrigation District (TCID) diverts water from the Truckee River (it uses the entire flow of the Carson River that is available). Diverted Truckee River water flows through the “Truckee Canal” and dumped out at Lahontan Reservoir just upstream of the Dam. Water diverted by TCID never gets to Pyramid Lake; the loss of water caused Pyramid to fall 80 feet in elevation since diversions began 113 years ago.

Carson River at Mexican Dam at Silver Saddle Park March 28, 2018.

Carson River at Mexican Dam at Silver Saddle Park in Carson City,  March 28, 2018.

 

 

Truckee River snowpack much improved; still below average

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. Slide Mountain as viewed across Washoe Lake from Deadman Canyon in the State Park.

The greatly improved snowpack will improve runoff in the Truckee River and flows to Pyramid Lake this spring. The snow and rain in March did come too little and too late to push us to an average water year, however. How quickly drought conditions on the river will return depends on how rapidly the spring warms up and whether we get additional storms – never to be counted on – during the early spring. Precipitation since October 1 (the beginning of the water year) remains below normal, too, but better than the snowpack. Snow water in the end-of-season snowpack appears to be diminishing year after year, especially the lower elevation snowpack.

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. Slide Mountain as viewed across Washoe Lake from Deadman Canyon in the State Park.

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. (Slide Mountain as viewed across Washoe Lake from Deadman’s Canyon in the State Park.)

The Tahoe and Truckee River basin snowpack water content remains significantly better today than in February. Although the official water content gets counted on April 1, the numbers  won’t change too much. So for March 29, the median water equivalent in the snowpack stands at 78% in the Lake Tahoe basin and 83% in the Truckee River basin. However, total precipitation (rain and snow water equivalent) for this water year is better at  97% and 91% of normal. The Carson River basin has more water in the snowpack at 88% which matches the total precipitation percentage – 88%. Overall, the Carson River’s watershed is higher elevation than the Truckee River’s which may account for the precipitation tracking overall precipitation. 

Lake Tahoe stands at 6228.6 feet – just 6″ below its maximum legal elevation and 5.6 feet above its outlet rim. The Lake Tahoe dam controls flows out of Lake Tahoe into the Truckee River. The Lake will soon see an increase in runoff from the melting snowpack. How fast it rises will be based on flows into the Truckee River by the Federal Water Master’s office – the administrator of the Federal Court decree that governs water in the Truckee River for both California and Nevada – as well as the temperatures this spring that determine how quickly the snowpack melts.  In an average water year, Lake Tahoe sees a rise in elevation of about 3 feet over spring and early summer. Truckee River flows are running above the long-term average now at more than 2,000 cubic-feet-per-second (CFS) at Pyramid Lake.

Truckee River in Reno with flows at 2,000 CFS during the last weekend in March 2018.

Pyramid Lake may see a moderate rise if flows in the Truckee River remain high for most of the spring and diversions to the Newlands Project are small. As of February 28, 2018 Pyramid’s elevation was 3,802.37 feet elevation. Pyramid Lake’s historic elevation before the Newlands Project was built was 3,880 feet in elevation. Last year saw a significant rise in the Lake’s elevation – some 10 feet. With a less than stellar water year for 2017-18, however, Pyramid Lake’s elevation will most likely decline again. The highest elevation for Pyramid Lake in the last 25 years occurred in 1999 when it reached an elevation of 3,817 feet.

Water flows from Lake Tahoe into the Truckee River increased dramatically in the past 7 days. How long these flows from Tahoe last will be based, in part, on how rapidly the snow pack melts.

Flows from Lake Tahoe have jumped from 50 to 900 CFS in the last 7 days.

Spring Equinox Storm brings late surge in Truckee River basin snowpack

Rain over a two day period in Reno is always a rare event. Even less common is a spring equinox atmospheric river storm that drops nearly an inch of rain at the airport in Reno. I recorded 1.75″ of rain in NW Reno from March 20 to 22 while temperatures during the storm never dropped below 42ºF. While the storm was relatively warm and produced mostly rain below 6,000 feet, the snowpack in the Lake Tahoe and the Truckee River basins saw a significant boost. Flows in the Truckee River on Thursday afternoon surged to 4,000 cubic-feet-per-second (CFS) from 500 CFS earlier in the week. If you didn’t get down to the river, check out the video from Whitewater Park at Wingfield Park in downtown Reno yesterday.

The NRCS is now reporting a significant improvement to the area snowpack. In February the snowpack was in the 30 percent of average range. As of today (3/23/18) reports show the snowpack in the Lake Tahoe basin is 77% of the average and the Truckee River basin stands at 80% for snow-water equivalent. The Carson River is at 88%.

The National Weather Service forecasts another colder (but less wet) storm is heading into the Tahoe and Truckee basins late today and continuing into Sunday. It remains to be seen if the new anticipated storm adds significantly to the snowpack. Forecasts for next week show no precipitation with temperatures rising into the mid-60s.

Eastern Pacific circulation as of 3/23/2018 mid-day. (Click for full size)

Lake Tahoe’s water surface elevation rose continuously during the spring equinox storm to stand at 6,228.6 feet. Its legal limit is 6,229.1 feet. Depending on how much runoff results from the snowpack (and any additional snow and rain), there should be good flows from Lake Tahoe into the Truckee River this spring. One thing for sure, the dismal winter up until late February has seen a significant reversal with the late season storms.

Lake Tahoe’s water surface elevation has risen nearly a foot since early in 2018. The recent storms alone resulted in a half-foot rise.