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.
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.
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.