South Lahontan hydrologic region

The South Lahonton is a hydrologic region defined by the State of California that encompasses several interior basins east of the Sierra Nevada and the Transverse Ranges, with an area of 17 million acres (69,000 km2).

The ecoregion has an arid to semi-arid climate, with average annual rainfall of 7.9 inches (200 mm).

They instead empty into lake beds from which the water evaporates, leaving deposits of salts and other minerals.

There are some year-round mountain streams and springs, but most of the large rivers are intermittent, and the lakes vary in extent based on variations in rainfall and runoff.

[3] There are 77 state-recognized alluvial groundwater basins and subbasins in the South Lahontan hydrologic region, underlying approximately 55 percent of the land area.