Environmental Protection in Lake Tahoe

Environmental Protection in Lake Tahoe: Until recently, construction on the banks of the Lake had been largely under the control of wealthy real estate developers. Construction activities have resulted in a clouding of the lake's blue waters. Currently, the Tahoe Regional Planning Agency is regulating construction along the shoreline. (and has won two Federal Supreme Court battles over recent decisions). These regulations are unpopular with many residents, especially those in the Tahoe Lakefront Homeowners Association.

The League to Save Lake Tahoe (Keep Tahoe Blue) has been an environmental watchdog in the Lake Tahoe Basin for 50 years. Founded when a proposal to build a four-lane highway around the lake—with a bridge over the entrance to Emerald Bay—was proposed in 1957, the League has thwarted poorly designed development projects and environmentally unsound planning. The League embraces responsible and diversified use of the Lake's resources while protecting and restoring its natural attributes.

Since 1980, the Lake Tahoe Interagency Monitoring Program (LTIMP) has been measuring stream discharge and concentrations of nutrients and sediment in up to 10 tributary streams in the Lake Tahoe Basin, California-Nevada. The objectives of the LTIMP are to acquire and disseminate the water quality information necessary to support science-based environmental planning and decision making in the basin. The LTIMP is a cooperative program with support from 12 federal and state agencies with interests in the Tahoe Basin. This data set, together with more recently acquired data on urban runoff water quality, is being used by the Lahontan Regional Water Quality Control Board to develop a program (mandated by the Clean Water Act) to limit the flux of nutrients and fine sediment to the Lake.

UC Davis remains a primary steward of the lake. The UC Davis Tahoe Environmental Research Center is dedicated to research, education and public outreach, and to providing objective scientific information for restoration and sustainable use of the Lake Tahoe Basin. Each year, it produces a well publicized “State of the Lake” assessment report.

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Water Quality in Lake Tahoe

Water Quality in Lake Tahoe: In spite of land-use planning and export of treated sewage effluent from the basin, the lake is becoming increasingly eutrophic (having an excessive richness of nutrients), with primary productivity increasing by more than 5% annually, and clarity decreasing at an average rate of 0.25 meters per year. Until the early 1980s, nutrient-limitation studies showed that primary productivity in the lake was nitrogen-limited. Now, after a half-century of accelerated nitrogen input (much of it from direct atmospheric deposition), the lake is phosphorus-limited.

Test results over the last eight years have shown a stabilization in lake clarity, announced the Lake Tahoe Research Group in March 2009. Fine sediment, much of it resulting from land disturbance in the basin, accounts for about half of the loss in clarity.

Lake Tahoe is a tributary watershed drainage element within the Truckee River Basin, and its sole outlet is the Truckee River, which continues on to discharge to Pyramid Lake. Because of the sensitivity of Truckee River water quality (involving two protected species, the cui-ui sucker fish and the Lahontan cutthroat trout), this drainage basin has been studied extensively. The primary investigations were stimulated by the U.S. Environmental Protection Agency, who funded the development of the DSSAM model to analyze water quality below Lake Tahoe.

Lake Tahoe never freezes. Since 1970, it has mixed to a depth of at least 1,300 ft (400 m) a total of 6 or 7 times. Dissolved oxygen is relatively high from top to bottom. Analysis of the temperature records in Lake Tahoe has shown that the lake warmed (between 1969 and 2002) at an average rate of 0.015 °C per year. The warming is caused primarily by increasing air temperatures, and secondarily by increasing downward long-wave radiation. The warming trend is reducing the frequency of deep mixing in the lake, and may have important effects on water clarity and nutrient cycling.

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Lake Tahoe Human History

Native people

The area around Lake Tahoe was originally inhabited by the Washoe tribe of Native Americans. Lake Tahoe was the center and heart of Washoe Indian territory, including the upper valleys of the Walker, Carson and Truckee Rivers. The English name for Lake Tahoe derives from the Washo dá’o' a ga, "edge of the lake".

Exploration

Lt. John C. Frémont was the first person of European descent to see Lake Tahoe, during Fremont's second exploratory expedition on February 14, 1844. John Calhoun Johnson, Sierra explorer and founder of "Johnson's Cutoff" (now U.S. Route 50), was the first white man to see Meeks Bay and from a peak above the lake he named Fallen Leaf Lake after his Indian guide. His first job in the west was in the government service, carrying the mail on snowshoes from Placerville to Nevada City, during which time he named the lake "Lake Bigler" in honor of California’s third governor John Bigler. In 1853 William Eddy, the surveyor general of California, identified Tahoe as Lake Bigler. In 1862 the U.S. Department of the Interior first introduced the name Tahoe. Both names were used until well into the next century. The lake didn't receive its official and final designation as Lake Tahoe until 1945.

California and Nevada reached the compromise to partition Tahoe between the two when Nevada became a state in 1864. With the state line east of the approximate centerline of the lake and then at 39 degrees north latitude, the state border runs southeasterly towards the Colorado River.

Mining era

Upon discovery of gold in the South Fork of the American River in 1848, thousands of gold seekers going west passed near the basin on their way to the gold fields. European civilization first made its mark in the Lake Tahoe basin with the 1858 discovery of the Comstock Lode, a silver deposit just 15 miles (24 km) to the east in Virginia City, Nevada. From 1858 until about 1890, logging in the basin supplied large timbers to shore up the underground workings of the Comstock mines. The logging was so extensive that loggers cut down almost all of the native forest. In 1864, Tahoe City was founded as a resort community for Virginia City, the first recognition of the basin’s potential as a destination resort area.

Development

Public appreciation of the Tahoe basin grew, and during the 1912, 1913 and 1918 congressional sessions, congressmen tried unsuccessfully to designate the basin as a national park.

While Lake Tahoe is a natural lake, it is also used for water storage by the Truckee-Carson Irrigation District (TCID). The lake level is controlled by a dam built in 1913 at the lake's only outlet, the Truckee River, at Tahoe City. The 18-foot (5.5 m) high dam can increase the lake's capacity by 744,600 acre·ft (0.9185 km³).

During the first half of the 20th century, development around the lake consisted of a few vacation homes. The post-World War II population and building boom, followed by construction of gambling casinos in the Nevada part of the basin during the mid-1950s, and completion of the interstate highway links for the 1960 Winter Olympics held at Squaw Valley, resulted in a dramatic increase in development within the basin. From 1960 to 1980, the permanent residential population increased from about 10,000 to greater than 50,000, and the summer population grew from about 10,000 to about 90,000. Since the 1980s, development has slowed due to controls on land use.

Government and politics

Lake Tahoe lies within the borders of both California and Nevada, and as such is not governed by any single entity. In California, Lake Tahoe is divided between Placer County and El Dorado County. In Nevada, Lake Tahoe is divided among Washoe County, Douglas County and Carson City (an independent city).

The Tahoe Regional Planning Agency (TRPA) is a bi-state compact between California and Nevada, that is charged with environmental protection of the Lake Tahoe Basin through land-use regulation and planning.

Mansions

Lake Tahoe is also the location of several 19th and 20th century palatial homes of historical significance. The Thunderbird Lodge built by George Whittel Jr once included nearly 27 miles (43 km) of the Nevada shoreline. Vikingsholm was the original settlement on Emerald Bay and included an island teahouse and a 38 room home. The Ehrman Mansion is a summer home built by a former Wells Fargo president in Sugar Pine Point and is now a state park.

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Lake Tahoe Ecology

Lake Tahoe Ecology: Vegetation in the basin is dominated by a mixed conifer forest of Jeffrey pine (Pinus jeffreyi), lodgepole pine (P. contorta), white fir (Abies concolor), and red fir (A. magnifica). The basin also contains significant areas of wet meadows and riparian areas, dry meadows, brush fields (with Arctostaphylos and Ceanothus) and rock outcrop areas, especially at higher elevations. Ceanothus is capable of fixing nitrogen, but mountain alder (Alnus tenuifolia), which grows along many of the basin’s streams, springs and seeps, fixes far greater quantities, and contributes measurably to nitrate-N concentrations in some small streams. The beaches of Lake Tahoe are the only known habitat for the rare Lake Tahoe yellowcress (Rorippa subumbellata), a plant which grows in the wet sand between low- and high-water marks.

Each autumn, from late September through mid-October, mature kokanee salmon (Oncorhyncus nerka), transform from silver-blue color to a fiery vermilion, and run up Taylor Creek, near South Lake Tahoe. As spawning season approaches the fish acquire a humpback and protuberant jaw. After spawning they die and their carcasses provide a feast for gatherings of mink (Neovison vison), bears (Ursus americanus), and Bald eagles (Haliaeetus leucocephalus). These salmon were transplanted from the North Pacific to Lake Tahoe in 1944.

North American Beaver (Castor canadensis) were re-introduced to the Tahoe Basin by the California Department of Fish and Game (CDFG) and the U. S. Forest Service between 1934 and 1949. Descended from no more than nine individuals, 1987 beaver populations on the upper and lower Truckee River had reached a density of 0.72 colonies (3.5 beavers) per kilometer. At the present time beaver have been seen in Tahoe Keys, Meeks Creek at Meeks Bay on the western shore, and King's Beach on the north shore, so the descendants of the original nine beavers have apparently migrated around most of Lake Tahoe. That beaver were once native to the area is supported by the fact that the Washo have a word for beaver, c'imhélhel and the northern Paiute of Walker Lake, Honey Lake and Pyramid Lake have a word for beaver su-i'-tu-ti-kut'-teh. When Stephen Powers visited the northern Paiute to collect Indian materials for the Smithsonian Institution in preparation for the Centennial Exhibition of 1876, he reported that the northern Paiute wrapped their hair in strips of beaver fur, made medicine from parts of beaver and that their creation legend included beaver.

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Lake Tahoe Climate

Lake Tahoe Climate: Mean annual precipitation ranges from over 55 in (1,400 mm) in watersheds on the west side of the basin to about 26 inches (660 mm) near the lake on the east side of the basin. Most of the precipitation falls as snow between November and April, although rainstorms combined with rapid snow melt account for the largest floods. There is a pronounced annual runoff of snowmelt in late spring and early summer, the timing of which varies from year to year. In some years, summertime monsoon storms from the Great Basin bring intense rainfall, especially to high elevations on the east side of the basin.

August is normally the warmest month at the Lake Tahoe Airport (elevation 6,254 ft (1,906 m)) with an average maximum of 78.7 °F (25.9 °C) and an average minimum of 39.8 °F (4.3 °C). January is the coolest month with an average maximum of 41.0 °F (5.0 °C) and an average minimum of 15.1 °F (-9.4 °C). The all-time maximum of 99 °F (37.2 °C) was recorded on July 22, 1988. The all-time minimum of -29 °F (-33.9 °C) was recorded on December 9, 1972, and February 7, 1989. Temperatures exceed 90 °F (32.2 °C) on an average of 2.0 days annually. Minimum temperatures of 32 °F (0 °C) or lower occur on an average of 231.8 days annually, and minimum temperatures of 0 °F (-17.8 °C) or lower occur on an average of 7.6 days annually. Freezing temperatures have occurred every month of the year.

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Geology of Lake Tahoe

Geology of Lake Tahoe: The Lake Tahoe Basin was formed by a geologic block (normal) faulting. A geologic block fault is a fracture in the Earth's crust causing blocks of land to move up or down. Uplifted blocks created the Carson Range on the east and the Sierra Nevada on the west. Down-dropped blocks (a graben) created the Lake Tahoe Basin in between.

More technically, Lake Tahoe is the youngest of several extensional basins of the Walker Lane Deformation Belt that accommodates nearly 12 mm/yr of dextral shear between the Sierra Nevada Microplate and North America. The Lake Tahoe basin is formed by a series of large down-to-the-east normal faults, including the West Tahoe—Dollar Point fault, Stateline/North Tahoe fault and the Incline Village fault. These right-stepping en-echelon faults are capable of large magnitude 7 earthquakes, with the most recent M7 paleoquake (~1500 AD) occurring on the Incline Village fault with nearly 9.7 ft (3.0 m) of vertical offset. The West Tahoe-Dollar Point Fault (WTDPF) appears to be the most active and potentially hazardous fault in the basin. A study in Fallen Leaf Lake, just south of Lake Tahoe, used seafloor mapping techniques to image evidence for paleoearthquakes on the WTDPF and revealed the last earthquake occurred between 4,100-4,500 years ago.

Some of the highest peaks of the Lake Tahoe Basin that formed during process of Lake Tahoe creation are Freel Peak at 10,891 feet (3,320 m), Monument Peak at 10,067 feet (3,068 m), Pyramid Peak at 9,983 feet (3,043 m) (in the Desolation Wilderness), and Mount Tallac at 9,735 feet (2,967 m).

Eruptions from the extinct volcano Mount Pluto formed a dam on the north side. Melting snow filled the southern and lowest part of the basin to form the ancestral Lake Tahoe. Rain and runoff added additional water.

Modern Lake Tahoe was shaped and landscaped by scouring glaciers during the Ice Ages, which began a million or more years ago. Lake Tahoe is fed from 63 tributaries with the Truckee River as the only outlet. The Truckee flows northeast through Reno, Nevada and into Pyramid Lake, Nevada which has no outlet.

Soils of the basin come primarily from andesitic volcanic rocks and granodiorite, with minor areas of metamorphic rock. Some of the valley bottoms and lower hill slopes are mantled with glacial moraines, or glacial outwash material derived from the parent rock. Cryopsamments, Cryumbrepts, rockland, rock outcrops and rubble and stony colluvium account for over 70% of the land area in the basin (see USA soil taxonomy). The basin soils (in the < 2 mm fraction) are generally 65-85% sand (0.05–2.0 mm).

Given the great depth of Lake Tahoe, and the locations of the normal faults within the deepest portions of the lake, modeling suggests that earthquakes on these faults can trigger tsunamis. Wave heights of these tsunamis are predicted to be on the order of 10 to 33 ft (3 to 10 m) in height, capable of traversing the lake in just a few minutes. A massive collapse of the western edge of the basin that formed McKinney Bay around 50,000 years ago is thought to have generated tsunami/seiche wave with height approaching 330 ft (100 m).

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Geography of Lake Tahoe

Geography of Lake Tahoe: Lake Tahoe is the second deepest lake in the U.S., with a maximum depth of 1,645 feet (501 m), trailing only Oregon's Crater Lake at 1,949 ft (594 m).^[7] Tahoe is also the 16th deepest lake in the world, and the fifth deepest in average depth. It is about 22 mi (35 km) long and 12 mi (19 km) wide and has 72 mi (116 km) of shoreline and a surface area of 191 square miles (490 km²). Washoe Indians used the lake. Approximately two-thirds of the shoreline is in California. The south shore is dominated by the lake's largest city, South Lake Tahoe, California, which adjoins the town of Stateline, Nevada, while Tahoe City, California, is located on the lake's northwest shore. Although highways run within sight of the lake shore for much of Tahoe's perimeter, many important parts of the shoreline now lie within state parks or are protected by the United States Forest Service. The Lake Tahoe Watershed (USGS Huc 18100200) of 505 sq mi (1,310 km²) includes the land area that drains to the lake and the Lake Tahoe drainage divide traverses the same general area as the Tahoe Rim Trail.

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Lake Tahoe

Lake Tahoe is a large freshwater lake in the Sierra Nevada range of the United States. At a surface elevation of 6,225 ft (1,897 m), Lake Tahoe is located along the border between California and Nevada, west of Carson City, Nevada. Lake Tahoe is the largest alpine lake in North America. Its depth is 1,645 feet (501 m) making it the USA's second-deepest (the deepest is Crater Lake in Oregon, being 300 ft (91 m) deeper, at 1,945 feet (594 m) deep).

The Lake Tahoe was formed about 2 million years ago and is a part of the Lake Tahoe Basin with the modern lake being shaped during the ice ages. It is known for the clarity of its water and the panorama of surrounding mountains on all sides. The area surrounding the lake is also referred to as Lake Tahoe, or simply Tahoe.

Lake Tahoe is a major tourist attraction in both Nevada and California. It is home to a number of ski resorts, summer outdoor recreation, and tourist attractions. Snow and skiing are a significant part of the area's economy and reputation. Mountain and lake scenery are attractions throughout the year. The Nevada side also includes large casinos. Highways provide year-round access from Reno, Carson City and Sacramento.

Lake Tahoe
Lake Tahoe from the east shore (in Nevada)
Location	Nevada and California
Lake type	Geologic block faulting
Primary outflows	Truckee River
Basin countries	United States
Max. length	22 mi (35 km)
Max. width	12 mi (19 km)
Surface area	191.588 sq mi (496.21 km2): Placer Co CA (40.961%) El Dorado Co CA (28.626%) Douglas Co NV (13.207%) Washoe Co NV (10.955%) Carson City NV (6.251%)
Average depth	1,000 ft (300 m)
Max. depth	1,645 ft (501 m)
Water volume	122,160,280 acre·ft (150.68249 km3)
Residence time	650 years
Shore length1	71 mi (114 km)
Surface elevation	6,225 ft (1,897 m)
Frozen	Never
Islands	Fannette Island (only island)
Settlements	South Lake Tahoe, California Stateline, Nevada Tahoe City, California

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List of Largest Lakes In The World

This is a list of largest lakes in the world with a surface area of more than 3,000 square kilometers (1,200 sq mi), ordered by area. This list does not include reservoirs and lagoons; if include reservoirs and lagoons, Garabogazköl in Turkmenistan, Lake Maracaibo in Venezuela, and Lake Volta in Ghana would come in at numbers 15, 17, and 19.

The area of some lakes can vary considerably over time, either seasonally or from year to year. This is especially true of salt lakes in arid climates.

Oceanic 'lakes'

	Name	Countries with shoreline	Area	Length	Maximum depth	Notes
1	Caspian Sea*	Kazakhstan Turkmenistan Iran Azerbaijan Russia	371,000 km2 (143,000 sq mi)	1,199 km (745 mi)	1,025 m (3,363 ft)	Variously considered the world's largest lake or a full-fledged sea. Geologically, the south Caspian is a small ocean. *Not including Garabogazköl Aylagy.

Continental lakes

	Name	Countries with shoreline	Area	Length	Maximum depth	Notes
2	Michigan-Huron	Canada United States	117,702 km2 (45,445 sq mi)	710 km (440 mi)	282 m (925 ft)	Lake Michigan and Lake Huron are physically a single body of water. If counted separately, Huron and Michigan are the third and fourth largest freshwater lakes, respectively.
3	Superior	Canada United States	82,414 km2 (31,820 sq mi)	616 km (383 mi)	406 m (1,332 ft)	Is the largest freshwater lake in the world if Michigan-Huron is counted as two lakes.
4	Victoria	Uganda Kenya Tanzania	69,485 km2 (26,828 sq mi)	322 km (200 mi)	84 m (276 ft)	The largest lake in Africa; also the second largest freshwater lake in the world if Michigan-Huron is counted as two lakes.
5	Tanganyika	Burundi Tanzania Zambia Democratic Republic of the Congo	32,893 km2 (12,700 sq mi)	676 km (420 mi)	1,470 m (4,820 ft)	Second deepest lake in the world.
6	Baikal	Russia	31,500 km2 (12,200 sq mi)	636 km (395 mi)	1,637 m (5,371 ft)	Deepest lake in the world. Largest volume fresh water lake in the world. Largest lake sharing a shoreline with a single country.
7	Great Bear Lake	Canada	31,080 km2 (12,000 sq mi)	373 km (232 mi)	446 m (1,463 ft)	Largest lake entirely within Canada
8	Malawi	Tanzania Mozambique Malawi	30,044 km2 (11,600 sq mi)	579 km (360 mi)	706 m (2,316 ft)	Second deepest lake in Africa. It has more fish species than any other lake on Earth
9	Great Slave Lake	Canada	28,930 km2 (11,170 sq mi)	480 km (300 mi)	614 m (2,014 ft)	Deepest lake in North America
10	Erie	Canada United States	25,719 km2 (9,930 sq mi)	388 km (241 mi)	64 m (210 ft)	Lake Erie is the shallowest of the Great Lakes
11	Winnipeg	Canada	23,553 km2 (9,094 sq mi)	425 km (264 mi)	36 m (118 ft)	Located in Manitoba, it is the largest lake contained within a single province.
12	Ontario	Canada United States	19,477 km2 (7,520 sq mi)	311 km (193 mi)	244 m (801 ft)
13	Balkhash*	Kazakhstan	18,428 km2 (7,115 sq mi)	605 km (376 mi)	26 m (85 ft)	Largest lake in Central Asia
14	Ladoga	Russia	18,130 km2 (7,000 sq mi)	219 km (136 mi)	230 m (750 ft)	Largest lake in Europe
15	Vostok	Antarctic territory claimed by Australia	15,690 km2 (6,060 sq mi)	250 km (160 mi)	900–1,000 m (3,000–3,300 ft)	Largest lake in Antarctica; also largest subglacial lake in the world.
17	Onega	Russia	9,891 km2 (3,819 sq mi)	248 km (154 mi)	120 m (390 ft)	Second largest lake in Europe
18	Titicaca	Peru Bolivia	8,135 km2 (3,141 sq mi)	177 km (110 mi)	281 m (922 ft)	Largest lake in South America if Lake Maracaibo is discounted; one of the highest commercially navigable lakes in the world.
19	Nicaragua	Nicaragua	8,001 km2 (3,089 sq mi)	177 km (110 mi)	26 m (85 ft)	Largest lake in Central America
20	Athabasca	Canada	7,920 km2 (3,060 sq mi)	335 km (208 mi)	243 m (797 ft)	Largest Lake in Saskatchewan/Alberta
21	Taymyr	Russia	6,990 km2 (2,700 sq mi)	250 km (160 mi)	26 m (85 ft)
22	Turkana*	Ethiopia Kenya	6,405 km2 (2,473 sq mi)	248 km (154 mi)	109 m (358 ft)	It is the world's largest permanent desert lake and the world's largest alkaline lake.
23	Reindeer Lake	Canada	6,330 km2 (2,440 sq mi)	245 km (152 mi)	337 m (1,106 ft)
24	Issyk-Kul*	Kyrgyzstan	6,200 km2 (2,400 sq mi)	182 km (113 mi)	668 m (2,192 ft)
25	Urmia*	Iran	6,001 km2 (2,317 sq mi)	130 km (81 mi)	16 m (52 ft)	Largest lake in the Mid East
26	Vänern	Sweden	5,545 km2 (2,141 sq mi)	140 km (87 mi)	106 m (348 ft)	The largest lake in the EU
27	Winnipegosis	Canada	5,403 km2 (2,086 sq mi)	245 km (152 mi)	18 m (59 ft)
28	Albert	Uganda Democratic Republic of the Congo	5,299 km2 (2,046 sq mi)	161 km (100 mi)	58 m (190 ft)
29	Mweru	Zambia Democratic Republic of the Congo	5,120 km2 (1,980 sq mi)	131 km (81 mi)	27 m (89 ft)
30	Nettilling	Canada	5,066 km2 (1,956 sq mi)	113 km (70 mi)	132 m (433 ft)	On Baffin Island. Largest lake on an island.
31	South Aral Sea*	Kazakhstan Uzbekistan	5,000 km2 (1,900 sq mi)	195 km (121 mi)	45 m (148 ft)	In 1960, the Aral Sea was the world's fourth-largest lake at 68,000 km2. The west basin of the South Aral Sea may be expected to stabilize at approx. 5,000 km2; as of 2009, the east basin had essentially dried up.
32	Nipigon	Canada	4,843 km2 (1,870 sq mi)	116 km (72 mi)	165 m (541 ft)	Largest lake entirely within the Canadian province of Ontario.
33	Manitoba	Canada	4,706 km2 (1,817 sq mi)	225 km (140 mi)	7 m (23 ft)
34	Great Salt Lake*	United States	4,662 km2 (1,800 sq mi)	121 km (75 mi)	10 m (33 ft)	Largest lake entirely within the United States if Michigan-Huron is considered a single lake. Also the largest lake entirely within a single U.S. state.
35	Qinghai Lake*	China	4,489 km2 (1,733 sq mi) (2007)			Largest lake in East Asia
36	Saimaa	Finland	≈ 4,400 km2 (1,700 sq mi)		82 m (269 ft)	Numerous basins; 14,000 islands, shoreline 13,700 km (8,500 mi)
37	Lake of the Woods	Canada United States	4,350 km2 (1,680 sq mi)	110 km (68 mi)	64 m (210 ft)
38	Khanka	China Russia	4,190 km2 (1,620 sq mi)		10.6 m (35 ft)

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