Lake Tahoe Basin Watershed Map

Work conducted at the UC Davis Tahoe Environmental Research Center uses this imagery to detect and differentiate vegetation, communities on land, temperature changes across the lake, and document subtle changes in the regional landscape over time. This map is an artificially colored infrared IKONOS image. The IKONOS satellite sees objects as small as 3 feet!

Taken in July 2002, we placed the image over a digital elevation model that represents the actual shape or topography of the ground. The bright green color has been artificially enhanced to highlight features of the watershed. The map consists of two separate digital elevation models (DEMs) one of the Topography of the watershed and surrounding areas from the USGS.

Bathymetry under the lake was obtained in 1998 using high resolution multibeam-SONAR by the USGS. The IKONOS satellite image draped over watershed is false color. Learn more about the different features highlighted on the watershed map. 

Water Movement in the Lake Tahoe Basin

The colored area represents Lake Tahoe’s watershed. Any precipitation that falls within the colored area on the map will end up in Lake Tahoe, unless it evaporates or is taken up by plants first. One reason Lake Tahoe has remained so clear is the small size of its watershed in relation to the lake’s size. There are 63 different rivers and streams that flow into Lake Tahoe. Lake Tahoe’s only outlet, the Truckee River, is located in Tahoe City. From here, water flows down through Reno and to Pyramid Lake. Pyramid Lake is known as a terminal lake because there is no outlet to carry the water further. Water from Lake Tahoe does not flow to the ocean but ends its journey in a desert lake. The Upper Truckee River flows through South Lake Tahoe and is the most urbanized part of the basin. It is responsible for 1/3 of the inflow into Lake Tahoe.

Formation of the Tahoe Basin

Lake Tahoe and the surrounding mountains, streams, meadows, and cliffs offer a fascinating glimpse of geologic history. Our region was morphed by plate tectonics and sculpted by volcanoes and glaciers. New research continues re-writing that story and the exact timeline is still hotly debated by scientists. Approximately one hundred million years ago, all the materials that would become the Lake Tahoe Basin and surrounding mountains, valleys, and formations sat at the bottom of a vast inland sea in a subduction zone. That sediment and a series of volcanoes sat on top of a massive magma chamber that would form the Sierra Nevada Batholith. Eventually, the batholith rose up from underneath the volcanoes and sediment, exposing the granite rock for which the Sierra Nevada is now famous in places like Yosemite, Desolation Wilderness, and Donner Summit.

The Tahoe Basin began forming about 2 to 3 million years ago through fault movements of Tahoe’s 3 main faults – the West Tahoe Fault, from modern day Emerald Bay to Dollar Point, the Stateline Fault running south from Crystal Bay, and the Incline Village Fault running south from Incline Village. Normal faulting lifted the Carson Range on the east and the Sierra Nevada on the west. Between these two ranges, other blocks also dropped down forming a valley that would eventually become the Tahoe Basin. Volcanic uplifting events in the basin from Mt. Pluto to Mt. Rose also occurred. Glaciers sculpted the modern Tahoe’s shape by cutting valleys and glacier moraine lakes.

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