Pyramid Lake, NV

Pyramid Lake is the geographic sink of the Truckee River Basin and is located 40 mi (64 km) northeast of Reno. The inflow is moderately high silt-loaded surface runoff.

Pyramid Lake is fed by the Truckee River after leaving Lake Tahoe upstream and enters the lake from its southern end. There is no outlet, with water leaving only by evaporation, or sub-surface seepage. The lake has about 10% of the area of the Great Salt Lake, but it has about 25% more volume. The salinity is approximately 1/6th that of sea water. Although clear Lake Tahoe forms headwaters that eventually drain to Pyramid Lake, the Truckee River delivers more turbid waters to Pyramid Lake after traversing the steep Sierra terrain and collecting moderately high silt-loaded surface runoff.

Major fish species include the cui-ui lakesucker, which is endemic to Pyramid Lake, the Tui chub and Lahontan cutthroat trout (the world record cutthroat trout was caught in Pyramid Lake). The former is endangered, and the latter is threatened. Both species were of critical importance to the Paiute people in pre-contact times.[3] As they are both obligate freshwater spawners, they rely on sufficient inflow to allow them to run up the Truckee River to spawn, otherwise their eggs will not hatch. Diversion of the Truckee for irrigation since the early 20th century has reduced inflow such that it is rarely sufficient for spawning in modern times. Due to the construction of Derby Dam in 1903 made to divert water to croplands in Fallon, an adjacent town, the Lahontan cutthroat trout (the "salmon-trout" as described by Frémont) became extinct in Pyramid Lake and its tributaries due to the immediate lowered water level, increased water salinity, and lack of fish-ladders on the dam (for upstream spawning runs), and were replaced with Lahontan cutthroat trout from hatcheries. Fish populations are now sustained by several tribally-run fish hatcheries.