The Truckee–Carson Irrigation District (TCID) is a public enterprise organized in the State of Nevada, which operates dams at Lake Tahoe, diversion dams on the Truckee RiverinWashoe County, and the Lake Lahontan reservoir.
TCD also operates 380 miles (610 km) of canals, and 340 miles (550 km) of drains, in support of agriculture in Lyon County and Churchill County, western Nevada. The excess irrigation water eventually drains into the endorheicLake Lahontan Basin.
Diversion of water by the TCID from the Truckee River has caused a reduction in the level of natural Pyramid Lake, resulting in the endemic species of fish that live in it becoming endangered species.