Lake Tahoe rose to about a foot above its rim during the spring, but has now dropped below its rim elevation of 6,223 feet. Flow from Lake Tahoe to the Truckee River is now effectively zero, but was also minimal through much of August as well. Most of the water in the Truckee River is now coming from tributaries to the river below Lake Tahoe both from natural flow and releases from reservoirs.
Water releases from Donner Lake into Donner Creek enter the Truckee River just above the town of Truckee. Water from Prosser Reservoir enters Prosser Creek and comes into the Truckee River several river miles below Truckee. Releases from Stampede and Boca reservoirs into the Little Truckee enter the Truckee River from the north just above the Hirschdale Road.
Other small tributaries to the Truckee come in from Alpine Meadows and Squaw Valley upstream of Donner Creek along with several other streams from the west off the crest of the Sierra Nevada. Downstream of the town of Truckee (in addition to Prosser Creek and Little Truckee River mentioned above) Martis Creek comes in from the south from Mt Pluto and Martis Peak to the south. Further down two creeks – Gray and Bronco Creeks – come in from the Carson Range from the west side of Relay Ridge and Mt Rose.
Together these tributaries make up the majority of the current flow of the river at Farad of 182 cubic-feet per second (CFS), but additional tributaries enter the Truckee River below Farad as well. Truckee River flow below Farad gets confusing because there are significant withdrawals of water from the Truckee River into a canal system designed in the 19th century for irrigation and a modern diversion of water from the river at Chalk Bluff and again at Glendale Bridge by the Truckee Meadows Water Authority for municipal and industrial use (most of the water consumed goes to watering residential and commercial landscapes.)
At Verdi, Dog Creek comes in from the Crystal Peak area to the northwest. In west Reno where the Mayberry foot bridge crosses the Truckee River, Hunter Creek comes into the Truckee River from the southwestern end of the Carson Range.
Steamboat Creek enters the Truckee River just at the Reno-Sparks Water Reclamation Facility at the end of Clean Water Way. Steamboat Creek flows from Washoe Valley (from Little Washoe Lake and from ‘big’ Washoe Lake when it has water). Steamboat Creek picks up additional water from its tributaries – Galena, Whites, and Thomas Creeks being the largest, but there are several other small streams flowing year-round or seasonally that can add to the flow. Steamboat Creek also receives water from the Steamboat Ditch – which is actually a diversion from the Truckee River above the town of Verdi that flows around the west side of the Truckee Meadows.
Downstream of where Steamboat Creek comes into the Truckee River, the only significant tributary to the Truckee River is Long Valley Creek which enters the river from the Virginia Range to the south at Lockwood in Storey County.
Flow in the Truckee River is determined by the amount of water entering from the entire watershed, of course, but as the Truckee River winds its way through its 110 mile length once past Lockwood the amount gain from additional stream flow becomes less and less all the way to Pyramid lake.
The issue for the Truckee River then becomes how much water is taken out of the river for municipal, industrial, and agricultural use that never returns.