Restore Hetch Hetchy is a US non-profit organization seeking to restore the Hetch Hetchy Valley in Yosemite National Park to its original condition.
152-414: The Hetch Hetchy Valley was sculpted by glaciers as recently as 10,000 years ago (like nearby Yosemite Valley ). It has an elevation of 3,800 feet (1,200 m) above sea level and is 3 miles (5 km) long in an east to west orientation. The Hetch Hetchy Valley is in the northwest corner of Yosemite National Park , which was established in 1890. Even before the establishment of Yosemite National Park,
304-478: A "recreational value" of up to $ 178 million per year, or possibly an overall economic value of up to $ 100 billion. Those in opposition of dam removal state that demolishing O'Shaughnessy Dam would take away a valuable source of clean, renewable hydroelectric power in the Kirkwood and Moccasin powerhouses; even if measures such as seasonal water diversion into the powerhouses were employed, it would only make up for
456-803: A 1500-ounce nugget, the fourth largest ever discovered in California. (The largest was found in Carson Hill in Calaveras County, just north of the Tuolumne River watershed along the Stanislaus River , in 1854. ) The prosperity in the region prompted a search for a new crossing of the Sierra Nevada that would provide more direct access to the camps from the east. The Clark-Skidmore Party made this crossing in 1852 via
608-620: A Miwok word earlier anglicized as hatchhatchie , which means "edible grasses" or "magpie". It is likely that the edible grass was blue dicks . Chief Tenaya of the Yosemite Valley's Ahwaneechee tribe claimed that Hetch Hetchy was Miwok for "Valley of the Two Trees", referring to a pair of yellow pines that once stood at the head of Hetch Hetchy. Miwok names are still used for features, including Tueeulala Fall, Wapama Fall, and Kolana Rock. While its cousin Yosemite Valley to
760-602: A Native American village on the nearby Stanislaus River. The suffix -umne , which appears in the names of two other California rivers, the Mokelumne and Cosumnes , is thought to have meant "place of" or "people of" in the native language. The Tuolumne River was the scene of significant gold mining activity during the California Gold Rush . The first known discovery of gold in the area was made by Benjamin Wood,
912-746: A New Moccasin Powerhouse in 1969 when the Old Moccasin Powerhouse was taken out of service. Finally, in 1988, a third generator was added to the Kirkwood Powerhouse. Hetch Hetchy Valley serves as the primary water source for the City and County of San Francisco and several surrounding municipalities in the greater San Francisco Bay Area . The dam and reservoir, combined with a series of aqueducts, tunnels, and hydroelectric plants as well as eight other storage dams, comprise
1064-548: A V-shaped river canyon cut out by the ancestral Tuolumne River. About one million years ago, the extensive Sherwin glaciation widened, deepened and straightened river valleys along the western slope of the Sierra Nevada, including Hetch Hetchy, Yosemite Valley, and Kings Canyon farther to the south. During the last glacial period , the Tioga Glacier formed from extensive icefields in the upper Tuolumne River watershed; between 110,000 and 10,000 years ago Hetch Hetchy Valley
1216-471: A broad, fertile and extensively cultivated alluvial plain . Like most other central California rivers, the Tuolumne is dammed multiple times for irrigation and the generation of hydroelectricity . Humans have inhabited the Tuolumne River area for up to 10,000 years. Prior to the arrival of Europeans, the river canyon provided an important summer hunting ground and a trade route between Native Americans in
1368-612: A fraction of the original power production. The remaining deficit would likely have to be replaced by polluting fossil fuel generation. The removal of the dam would be extremely costly, at least $ 3–10 billion, and the transport of the demolished material away from the dam site along the narrow, winding Hetch Hetchy Road would be a logistical nightmare with possible environmental impacts. Most importantly, San Francisco would lose its source of high-quality mountain water, and would have to depend on lower-quality water from other reservoirs – which would require costly filtration and re-engineering of
1520-531: A hot, dry climate, including chamise (greasewood), California lilac , manzanita , blue oak , interior live oak (Sierra live oak), and gray pine . Further east and higher in elevation are the lower and upper montane forests, which lie between 3,000 to 6,000 feet (910 to 1,830 m) and 6,000 to 8,000 feet (1,800 to 2,400 m) elevation, respectively. The lower montane forests include black oak , ponderosa pine , incense cedar and white fir ; higher up Jeffrey pine and western juniper appear. Higher still
1672-558: A major earthquake and subsequent fire that devastated San Francisco, the inadequacy of the city's water system was made tragically clear. San Francisco applied to the United States Department of the Interior to gain water rights to Hetch Hetchy, and in 1908 President Theodore Roosevelt's Secretary of the Interior, James R. Garfield , granted San Francisco the rights to development of the Tuolumne River. This provoked
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#17327801459951824-724: A man's blue shirt and turn it brown, and were voracious as mosquitoes would be." People have lived in Hetch Hetchy Valley for over 6,000 years. Native American cultures were prominent before the 1850s when the first settlers from the United States arrived in the Sierra Nevada. During summer, people of the Miwok and Paiute came to Hetch Hetchy from the Central Valley in the west and the Great Basin in
1976-472: A million recreational visits each year, primarily to the protected wilderness areas of Yosemite National Park and to the difficult but popular whitewater on the Main Tuolumne and Cherry Creek. The Tuolumne is considered a classic California whitewater run, and has been used recreationally since the 1960s. Most rafters put in at Meral's Pool, located about 2 miles (3.2 km) below Cherry Creek, for
2128-663: A permit before floating the Tuolumne. Running the Tuolumne within Yosemite National Park was also in a legal gray zone until 2015, when the park opened the Tuolumne and Merced Rivers to limited paddling and rafting. In 2013, the Rim Fire burned 257,314 acres. This megafire was, at the time, California's third largest wildfire on record. This wildfire devastated habitat for many native and/or endangered species, and has impacted recreational opportunities, communities and economies alike. The Tuolumne River received
2280-495: A private power company, Pacific Gas & Electric (PG&E). San Francisco was able to accomplish this in 1925 by claiming it had run out of funds to extend the Hetch Hetchy transmission line all the way to the city. The terminus of the incomplete line was "conveniently located next to a PG&E substation", which connected to PG&E's private line which in turn bridged the gap to San Francisco. The city justified this as
2432-432: A prospector from Oregon, in the summer of 1848. During the latter part of that year and early 1849, mining camps were established along the Tuolumne, including Jamestown, Tuttletown, Melones, Don Pedros Bar, and Shaws Flat. The following spring a party of Mexican miners from Sonora discovered an even richer deposit farther upstream, establishing Sonoranian Camp, predecessor of the present-day town of Sonora, California . By
2584-453: A record 72 inches (1,800 mm) of rain fell in the Tuolumne River basin between November 11, 1861, and January 14, 1862, as recorded at Sonora . The gage was not in place during this time. Further downstream, the USGS gage at Modesto – about 10 miles (16 km) above the mouth – recorded an annual mean of 1,326 cubic feet per second (37.5 m /s) between 1940 and 2013. The highest peak
2736-402: A reservoir", with pristine water, lack of development or private property, a steep-sided and flat-floored profile that would maximize the amount of water stored, and a narrow outlet ideal for placement of a dam. They claimed the valley was not unique and would be even more beautiful with a lake. Muir predicted that this lake would create an unsightly "bathtub ring" around its perimeter, caused by
2888-460: A result, the rivers feeding Hetch Hetchy Reservoir have extremely low loads of sediments and nutrients. The watershed is also strictly protected, so swimming and boating are prohibited at the reservoir (although fishing is permitted at the reservoir and in the rivers which feed it), a measure which is considered unusual for US lakes outside the region. In 2018, the Department of the Interior of
3040-405: A seven-year environmental struggle with the environmental group Sierra Club , led by John Muir . Muir observed: Dam Hetch Hetchy! As well dam for water-tanks the people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man. Proponents of the dam replied that out of multiple sites considered by San Francisco, Hetch Hetchy had the "perfect architecture for
3192-736: A system known as the Hetch Hetchy Project , which provides 80% of the water supply for 2.6 million people. The project is operated by the San Francisco Public Utilities Commission . The city must pay a lease of $ 30,000 per year for the use of Hetch Hetchy, which sits on federal land. The aqueduct delivers an average of 265,000 acre⋅ft (327,000,000 m ) of water each year, or 31,900,000 cu ft (900,000 m ) per day, to residents of San Francisco and San Mateo , Santa Clara and Alameda Counties. As completed, O'Shaughnessy Dam
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#17327801459953344-456: A temporary measure, but no attempt to follow through with completing the municipal grid was ever made. Peter Byrne of SF Weekly has stated that "the plain language of the Raker Act itself and experts who are familiar with the act (and have no stake in city politics) all agree: The city of San Francisco is not in violation of the Raker Act." Harold L. Ickes , Secretary of the Interior in
3496-450: A total cost of over $ 110 million. It would be eleven years before the new reservoir of 2,030,000 acre-feet (2.50 km ) – ten times the size of Old Don Pedro – filled completely in June 1982. The reservoir submerged 25 miles (40 km) of the middle Tuolumne River and 12,000 acres (4,900 ha) of surrounding land, including the historic Gold Rush town of Jacksonville. Since the 1970s,
3648-597: A village called Tautamne. This village is situated on some steep precipices, inaccessible on account of their rough rocks. The Indians live in their sótanos [cellars or caves]". At this time, the Native American population along the lower Tuolumne and Stanislaus Rivers is believed to have been approximately two thousand. Another possible origin of the name Tuolumne is the Central Sierra Miwok word taawalïmi , meaning "squirrel place", referring to
3800-713: A width ranging from 1 ⁄ 8 to 1 ⁄ 2 mile (660 to 2,640 ft; 200 to 800 m). The valley floor consisted of roughly 1,200 acres (490 ha) of meadows fringed by pine forest, through which meandered the Tuolumne River and numerous tributary streams. Kolana Rock , at 5,772 ft (1,759 m), is a massive rock spire on the south side of the Hetch Hetchy Valley. Hetch Hetchy Dome , at 6,197 ft (1,889 m), lies directly north of it. The locations of these two formations roughly correspond with those of Cathedral Rocks and El Capitan seen from Tunnel View in Yosemite Valley. A broad, low rocky outcrop situated between Kolana Rock and Hetch Hetchy Dome divided
3952-434: Is "that the best paddling in is the upper miles while the middle section is better for hikers and canyoneers." The Clavey River, not being located in the national park, is open to public access, but due to its remoteness and difficulty (Class V+), and the short window of boatable spring runoff, it is only run by a handful of kayakers each year. To protect the river, the U.S. Forest Service requires private trips to obtain
4104-782: Is 910 feet (280 m) long, spanning the valley at its narrow outlet. The dam contains 675,000 cu yd (516,000 m ) of concrete. The Hetch Hetchy Reservoir created by the dam has a capacity of 360,400 acre⋅ft (0.4445 km ), with a maximum area of 1,972 acres (798 ha) and a maximum depth of 306 feet (93 m). From Hetch Hetchy Reservoir, the water flows through the Canyon and Mountain Tunnels to Kirkwood and Moccasin Powerhouses , which have capacities of 124 and 110 megawatts , respectively. An additional hydroelectric system comprising Cherry Lake , Lake Eleanor and
4256-479: Is agriculture, but there are also significant urbanized areas. Although only about 68,000 acres (28,000 ha) (5.4 percent) of the watershed itself are farmed, river water is used to irrigate almost five times that area outside the watershed boundaries. About 16,500 acres (6,700 ha) (1.3 percent) of the watershed are urbanized, mostly in the Greater Modesto area. About 550,000 people inhabit
4408-613: Is also part of the San Francisco hydroelectric system. Cherry Creek is dammed at the Cherry Valley Dam, which creates 274,000-acre-foot (338,000,000 m ) Cherry Lake . A major tributary, Eleanor Creek, is dammed to form Lake Eleanor , and diverted into Cherry Lake through a tunnel. The combined flow is channeled into a penstock and returns to the river at the Holm Powerhouse. Unlike the Hetch Hetchy system,
4560-437: Is located farther southeast, on Rancheria Creek. Formerly, a "small but noisy" waterfall and natural pool existed on the Tuolumne River marked the upper entrance to Hetch Hetchy Valley, informally known as Tuolumne Fall (not to be confused with a similarly named waterfall several miles upriver near Tuolumne Meadows ). The waterfall on the Tuolumne is now submerged under Hetch Hetchy Reservoir. The Hetch Hetchy Valley began as
4712-500: Is relatively small compared to other reservoirs in California. As a result, Don Pedro frequently fills and spills during winter storms, causing damage downstream. The La Grange Dam, a much smaller masonry diversion dam, is the last one on the Tuolumne before it joins with the San Joaquin. Modesto Canal, on the north side of the river, and Turlock Canal, on the south side, are both large irrigation diversions. The Modesto Canal feeds
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4864-469: Is the subalpine forest zone between 8,000 to 9,500 feet (2,400 to 2,900 m), which is dominated by Western white pine , mountain hemlock and lodgepole pine . Above 9500 feet, only small shrubs, flowering plants and occasional whitebark pine populate the alpine zone, which is limited to the peaks around Tuolumne Meadows and along the Sierra Crest. Humans have influenced natural conditions in
5016-652: The California Gold Rush . Miners did not stay in the area for long, however, as richer deposits occurred further south along the Merced River and in the Big Oak Flat area. After the valley's native inhabitants were driven out by the newcomers, it was used by ranchers, many of whom were former miners, to graze livestock. Animals were principally driven along Joseph Screech's trail from Big Oak Flat to Hetch Hetchy. Its meadows provided abundant feed for "thousands of head of sheep and cattle that entered lean and lank in
5168-598: The Federal Energy Regulatory Commission (FERC) on the 2015 relicensing of Don Pedro Reservoir. In 2011, Restore Hetch Hetchy announced their plans to put the issue to the voters of San Francisco through a referendum. Proposition F, which would've allocated money to identify other sources of water with a stated goal of restoring the valley went before San Francisco voters in November 2012. The proposition had extensive opposition, including
5320-527: The Great Flood of 1862 . Water releases from Don Pedro Dam peaked at 60,000 cubic feet per second (1,700 m /s); while this vastly reduced potential damage from the flood, it still exceeded the channel capacity by six times, causing extensive property damage along the river. The Tuolumne once supported large spring and fall runs of chinook salmon (king salmon, Oncorhynchus tshawytscha ) and steelhead trout ( Oncorhynchus mykiss ). In its native state
5472-759: The Hayward fault . Pipelines 1 and 2 cross the San Francisco Bay to the south of the Dumbarton Bridge , while pipelines 3 and 4 run to the south of the bay. In the Bay Area, Hetch Hetchy water is stored in local facilities including Calaveras Reservoir , Crystal Springs Reservoir , and San Antonio Reservoir . Pipelines 3 and 4 end at the Pulgas Water Temple , a small park that contains classical architectural elements which celebrate
5624-413: The Hetch Hetchy Project , which in 1934 began to deliver water 167 miles (269 km) west to San Francisco and its client municipalities in the greater San Francisco Bay Area . Before damming, the high granite formations produced a valley with an average depth of 1,800 ft (550 m) and a maximum depth of over 3,000 ft (910 m); the length of the valley was 3 mi (4.8 km) with
5776-705: The New Don Pedro Dam was built to provide hydroelectricity and irrigation water storage. Directly below Don Pedro Dam is the La Grange Dam , where about half the river's natural flow is diverted into the Turlock and Modesto Main Canals to irrigate over 200,000 acres (81,000 ha) in the Central Valley. Leaving the foothills, the Tuolumne flows approximately 50 miles (80 km) west across
5928-741: The Pinchot-Ballinger Controversy caused both Richard A. Ballinger and Gifford Pinchot to resign and be fired respectively. The openings in the Taft administration led to the eventual success of the Raker Act. Work on the Hetch Hetchy Project began in 1914. The 68 mi (109 km) Hetch Hetchy Railroad was constructed to link the Sierra Railway with Hetch Hetchy Valley, allowing for direct rail shipment of construction materials from San Francisco to
6080-463: The Sierra Club , spearheaded a legal battle against the proposed O'Shaughnessy Dam , famously stating – "Dam Hetch Hetchy! As well dam for water-tanks the peoples' cathedrals and churches, for no holier temple has ever been consecrated by the heart of man." The Hetch Hetchy debacle is often credited with birthing modern environmentalism, sharply dividing the conservation movement – which favored
6232-610: The United States . The glacial Hetch Hetchy Valley lies in the northwestern part of Yosemite National Park and is drained by the Tuolumne River . For thousands of years before the arrival of settlers from the United States in the 1850s, the valley was inhabited by Native Americans who practiced subsistence hunting-gathering. During the late 19th century, the valley was renowned for its natural beauty – often compared to that of Yosemite Valley – but also targeted for
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6384-403: The mayor of San Francisco at the time, said in a Los Angeles Times story in 1987: "All this is for an expanded campground? ... It's dumb, dumb, dumb." Hodel, now retired, remains a strong proponent of restoring Hetch Hetchy Valley and Senator Feinstein remained strongly against restoration. The George W. Bush administration proposed allocating $ 7 million to studying the removal of
6536-537: The "use it or lose it" rule, so storage had to be developed to enable the full beneficial use of river water. Named for the Gold Rush mining camp its reservoir submerged, the Don Pedro dam was completed in 1923, holding back 289,000 acre-feet (0.356 km ) of water. In 1923 and 1924 both Don Pedro and La Grange dams were fitted for hydroelectric generation. San Francisco did not move forward with plans to divert
6688-473: The 18-mile (29 km) run to Lake Don Pedro. Several rafting companies serve the main Tuolumne, a Class IV+ (advanced) river with many rapids changing to Class V when the flow exceeds 4,000 cubic feet per second (110 m /s). The most difficult single rapids is Clavey Falls, located just above the Clavey River; the longest is Grey's Grindstone, at nearly a mile (1.6 km). Between these two rapids
6840-415: The 1880s, San Francisco was looking to Hetch Hetchy water as a fix for its outdated and unreliable water system. The city would repeatedly try to acquire water rights to Hetch Hetchy, including in 1901, 1903 and 1905, but was continually rebuffed because of conflicts with irrigation districts that had senior water rights on the Tuolumne River, and because of the valley's national park status. In 1906, after
6992-400: The 19th century, the first white visitors to the valley did not realize that Hetch Hetchy's extensive meadows were the product of millennia of management by Native Americans; instead they believed "the valley was purely a product of ancient geological forces (or divine intervention) ... this was fundamental to its allure as a destination and subject." The valley's name may be derived from
7144-423: The 29,000-acre-foot (36,000,000 m ) off-stream Modesto Reservoir, which regulates the water for distribution to farmers. The Turlock Lake is regulated by the similar but much larger Turlock Lake, which has a capacity of 49,000-acre-foot (60,000,000 m ). The estimated annual diversion for irrigation is 867,000 acre-feet (1.069 × 10 m ), about half of the Tuolumne River's natural flow. Below La Grange,
7296-534: The 9th St. Bridge in Modesto – significantly smaller than the river's maximum flood potential. The valley is dependent on flood control storage at Lake Don Pedro to prevent flows from exceeding the channel capacity. However, this has happened many times, most infamously during the New Year's Flood of 1997 , during which inflows to Don Pedro hit 120,000 cubic feet per second (3,400 m /s), the largest recorded since
7448-502: The Bay Area, it passes through the Irvington tunnel near the city of Fremont , and the aqueduct splits into four pipelines at 37°32′53″N 121°55′55″W / 37.548104°N 121.932041°W / 37.548104; -121.932041 . These are called Bay Division Pipelines (BDPL) 1, 2, 3, and 4, with nominal pipeline diameters of 60, 66, 78, and 96 inches (1.5, 1.7, 2.0 and 2.4 m, respectively). All four pipelines cross
7600-627: The Central Valley to its confluence with the San Joaquin River, passing Waterford , Hughson , Empire , Ceres and Modesto . The lower Tuolumne is wide and slow-flowing, dropping just 230 feet (70 m) from the base of La Grange Dam to its mouth at 26 feet (7.9 m). Highway 99 and the Southern Pacific Railroad tracks both cross the river in Modesto, and the Modesto Airport is located adjacent to
7752-411: The Central Valley to the west and the Great Basin to the east. First named in 1806 by a Spanish explorer after a nearby indigenous village, the Tuolumne was heavily prospected during the California Gold Rush in the 1850s, and the lower valley was cultivated by American settlers over the next few decades. The city of Modesto grew up on the Tuolumne as a railroad hub, absorbing most of the population of
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#17327801459957904-496: The Central Valley's seasonal rainfall patterns made it unsuitable for dryland farming , farmers organized to build irrigation infrastructure along the Tuolumne River. Turlock Irrigation District (TID), established in 1887, was the first irrigation district in California, and the Modesto Irrigation District (MID) was established soon after in the same year. The two districts serve the south and north sides of
8056-478: The Cherry Creek system is used exclusively for hydropower, not water supply, because the water quality is not quite as good. However, there is a connecting aqueduct that allows Cherry Lake to be tapped to supply the Hetch Hetchy system during severe droughts. This backup water supply was last used during late 2015, as a test to ensure its functionality should drought conditions become worse. The previous time it
8208-636: The Hetch Hetchy Restoration Task Force. In 1999, the Club created a separate non-profit organization called Restore Hetch Hetchy (RHH). Because the reservoir in Hetch Hetchy is part of a water-diversion and electric-generating system on the Tuolumne River that includes the much larger downstream reservoir, Don Pedro (51% funded by the San Francisco Public Utilities Commission ), as well as SFPUC's own Cherry and Eleanor Reservoirs near Hetch Hetchy, RHH filed comments in 2011 before
8360-422: The Hetch Hetchy Valley. Bierstadt described the valley as "smaller than the more famous valley ... but it presents many of the same features in his scenery and is quite as beautiful." When Yosemite Valley became part of a state park in 1864, Hetch Hetchy received no such designation. As the grazing of livestock damaged native plants in the Hetch Hetchy Valley, mountaineer and naturalist John Muir pressed for
8512-474: The Hetch Hetchy area, including the largest North American bat, the western mastiff . Before damming, the valley floor contained abundant stands of black oaks, live oak , Ponderosa pine , Douglas fir , and silver fir bordering the meadows, with alder , willow , poplar and dogwood in the riparian zone along the Tuolumne River. The valley's abundant plants provided nourishment for mule deer , black bears and bighorn sheep . Due to large cataracts on
8664-431: The Holm Powerhouse is also part of the Hetch Hetchy Project, adding another 169 megawatts of generating capacity. The entire system produces about 1.7 billion kilowatt hours per year, enough to meet 20% of San Francisco's electricity needs. After passing through the powerhouses, Hetch Hetchy water flows into the 167 mi (269 km) Hetch Hetchy Aqueduct which travels across the Central Valley. Just before reaching
8816-464: The Kirkwood and the Moccasin. The power system is efficient because of the Tuolumne's great drop, over 2,750 feet (840 m), between Hetch Hetchy and the outlet of Moccasin Powerhouse. However, it also causes dewatering of significant portions of the Tuolumne River, especially during low water summers when all but a minimal fish release is diverted through the power plants. Not all of the flow used by
8968-532: The Mayor and entire Board of Supervisors, and Senator Dianne Feinstein. It was soundly rejected, with 76.9% of voters against the proposition. In 2015, Restore Hetch Hetchy sued San Francisco, arguing that the continuing existence of the dam and reservoir is a violation of the California Constitution's prohibition against any "unreasonable method of diversion". The Tuolumne County Courts dismissed
9120-654: The San Joaquin Valley are irrigated using Tuolumne water. About 669 square miles (1,730 km ), or 34 percent, of the Tuolumne River watershed is inside Yosemite National Park. The rivers whose watersheds border that of the Tuolumne are the Stanislaus River and West Walker River in the north, the Merced River in the south, the East Walker River to the northeast, the Mono Lake basin ( Mill Creek , Lee Vining Creek and Rush Creek ) to
9272-539: The Sierra Club and Restore Hetch Hetchy state that draining Hetch Hetchy would open the valley back up to recreation, a right that should be provided to the American people because the reservoir is within the legal boundaries of a national park. They acknowledge that a concerted effort would have to be made to control the introduction of wildlife and tourism back into the valley in order to prevent destabilization of
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#17327801459959424-465: The Sierra Nevada, as two streams. The 7-mile (11 km) Lyell Fork rises at the Lyell Glacier below 13,114-foot (3,997 m) Mount Lyell , the highest peak in Yosemite National Park, and flows north through Lyell Canyon . The 5-mile (8.0 km) Dana Fork originates between Mount Dana (13,044-foot (3,976 m) ) and Mount Gibbs (12,772-foot (3,893 m) ) and flows west. After
9576-585: The South Fork of the Tuolumne to supply the diggings at Groveland and Big Oak Flat ; their most notable achievement was the construction of a 2,200-foot (670 m) long, 265-foot (81 m) high aqueduct (the Big Gap Flume) over Buck Meadows . The first dam on the Tuolumne River proper, near La Grange , was built in 1852 to divert water for hydraulic mining. Sediment and rocks washed down by hydraulic mining and sluicing operations accumulated along
9728-564: The Trump administration began to consider a proposal to allow limited boating on the Hetch Hetchy Reservoir for the first time, supported by the advocacy group Restore Hetch Hetchy which argued that "San Francisco received [Hetch Hetchy's] benefits long ago, but the American people have not." The battle over Hetch Hetchy Valley continues today between those who wish to retain the dam and reservoir, and those who wish to drain
9880-436: The Tuolumne (from Tuolumne Meadows to Hetch Hetchy Reservoir) was first kayaked in 1983. This 32-mile (51 km) segment is rated Class IV-V+, with many waterfalls requiring a portage. In addition to being extremely difficult (if not borderline impossible at the aforementioned waterfalls) the water flow depends entirely on rain and snow melt, and the whitewater season can be extremely short during dry years. The general consensus
10032-483: The Tuolumne River Canyon to provide access to the remote construction site. Hydroelectric power reached San Francisco by 1925, but the first water was not delivered until 1934. Today, San Francisco diverts about 33 percent of the flow of the Tuolumne at Hetch Hetchy, or 14 percent of the river's total flow. By the mid 20th century it was clear that storage capacity in Tuolumne River reservoirs
10184-711: The Tuolumne River basin during the summer. The Yokuts lived along the lower Tuolumne River and were not known to venture up into the Sierra during summer. The chief meeting point of the Paiute and Miwok was the Hetch Hetchy Valley, rich in edible plants and game. The origin of the name "Hetch Hetchy" may have been a type of edible grass that grew in the valley, which native peoples made into grain and ground in stone mortars for meal. They set controlled fires to clear out old vegetation in their gathering areas, allowing for more efficient harvesting of new growth. This would also increase
10336-500: The Tuolumne River by raising the New Don Pedro Dam 30 ft (9.1 m). Water could be diverted into the Kirkwood and Moccasin Powerhouses using lower-impact diversion dams , providing power generation on a seasonal basis, and the increased height, and thus hydraulic head , at Don Pedro would also increase power generation there. Furthermore, the removal of O'Shaughnessy Dam would not require costly sediment control measures, as would be typical on most dam removal projects, because of
10488-434: The Tuolumne River upstream, Hetch Hetchy Valley may have been in the uppermost range for native rainbow trout in the river. Due to its abundant wetlands and stream pools, Hetch Hetchy was notorious among early travelers for becoming infested with mosquitoes in the summertime. Said San Francisco resident William Denman in 1918, "The first time I went into the Hetch Hetchy the mosquitoes were intolerable. They would light upon
10640-585: The Tuolumne River watershed as a whole, with approximately 210,000 living in Modesto. Like most other Sierra Nevada rivers, the Tuolumne has been extensively dammed to provide flood control , water supply, and hydroelectric power. The uppermost dam is the O'Shaughnessy, which impounds the 360,000-acre-foot (440,000,000 m ) Hetch Hetchy Reservoir, providing water and power to the City of San Francisco. The Hetch Hetchy hydroelectric system diverts large volumes of water into tunnels that feed two hydroelectric plants,
10792-471: The Tuolumne River watershed for centuries. Native Americans set controlled fires in grassland to clear out dead foliage, providing room for new growth which in turn attracted game animals to forage. They also periodically burned out oak woodland areas in the foothills to control pests, which otherwise would have affected their main food supply, acorns. During the Spanish and Mexican periods, the Central Valley
10944-780: The Tuolumne River watershed. The San Joaquin River and the Sacramento–San Joaquin River Delta , which link the Tuolumne salmon runs to the Pacific, have also been affected by flow reduction and pollution. In addition, introduced species such as striped bass prey on juvenile salmon, consuming as much as 93 percent of smolt before they can migrate to the sea. A controversial proposal by the State Water Resources Control Board from around 2013 would require increased spring and summer flows on
11096-441: The Tuolumne River which would benefit native anadromous fish populations, but greatly reduce the water supply available for farms and cities. This has been countered by irrigation districts who maintain that the aforementioned predation, not low flows, are the primary cause of salmon smolt deaths. Forests in the watershed are divided between several distinct zones. The foothill region is characterized by trees and plants adapted to
11248-418: The Tuolumne River's name is unclear. The first recorded use of the name "Tuolumne" was by the Spanish explorer Gabriel Moraga in 1806, who may have named the river for the nearby Native American village of Tualamne or Tautamne . This may in turn refer to the native word talmalamne , or "a group of stone huts or caves". Father Pedro Muñoz, a member of the 1806 expedition, noted in his diary that "we came upon
11400-449: The Tuolumne at the mouth is greatly reduced by diversions to both San Francisco's Hetch Hetchy municipal water system and the canals of the Modesto and Turlock irrigation districts. The United States Geological Survey (USGS) operates, or has operated, several stream gages along the Tuolumne River. Today, average annual river flows reach a maximum in the short stretch between Don Pedro Dam and La Grange Dam, about 50 miles (80 km) above
11552-418: The Tuolumne until the 1906 San Francisco earthquake and subsequent fires devastated the city, proving the inadequacy of the existing water system. After exploring fourteen sites throughout Central California, San Francisco had settled on the Tuolumne's Hetch Hetchy Valley as the ideal location to develop storage and hydroelectric power. Because the area had been located inside Yosemite National Park since 1890,
11704-519: The Tuolumne valley around the turn of the century. As agricultural production rose, farmers along the Tuolumne formed California's first two irrigation districts to better control and develop the river. From the 1900s to the 1930s, the river was dammed at Don Pedro and Hetch Hetchy to provide water for Central Valley farmers and the city of San Francisco , respectively. The Hetch Hetchy project, located inside Yosemite National Park , incited national controversy, and has been described as having forged
11856-403: The Tuolumne – much reduced due to irrigation diversions – flows through a fixed channel with a highly restricted floodplain . Before agriculture, the river inundated large areas of seasonal marshland and was free to change course during its frequent floods. Today farms and communities are protected by a levee system with a channel capacity of roughly 9,000 cubic feet per second (250 m /s) at
12008-546: The Turlock Irrigation District has proposed damming the Clavey River, a free-flowing tributary of the Tuolumne, to produce hydroelectricity. The dam would have been 413 feet (126 m) high and dried up most of the lower Clavey, a popular whitewater run. In 1994 the Federal Energy Regulatory Commission studied the project and determined that the benefits would not justify the financial and environmental costs. The Tuolumne River watershed receives over
12160-441: The aqueduct system – to meet its needs. The economic wisdom of removing the dam has been frequently questioned. Some observers, such as Carl Pope (director of the Sierra Club ), stated that Hodel had political motives in proposing the study. The imputed motive was to divide the environmental movement: to see residents of the strongly Democratic city of San Francisco coming out against an environmental issue. Dianne Feinstein ,
12312-654: The arrival of the first Hetch Hetchy water in the city. The Early Intake (Lower Cherry) Powerhouse began commercial operation five years before the O'Shaughnessy Dam was completed. The first Moccasin Powerhouse in Moccasin, California began commercial operation in 1925 followed by the Holm Powerhouse in 1960 (the same month the Early Intake Powerhouse was taken out of service). In 1967 the Robert C. Kirkwood Powerhouse started commercial operation followed by
12464-588: The case, saying California Courts have no jurisdiction, as the dam was allowed by federal law. Restore Hetch Hetchy appealed, and the California Attorney General opined that the matter should be tried on the technical, not legal, merits. In July 2018, the appeals court threw out the lawsuit, declaring that Congress had overruled the state. The case was taken to the California Supreme Court which, in mid-October 2018, rejected
12616-535: The catchment area of the Merced River above Yosemite, allowing a greater volume of ice to form. Hetch Hetchy is home to a diverse array of plants and animals. Gray pine , incense-cedar , and California black oak grow in abundance. Many examples of red-barked manzanita can be seen along the Hetch Hetchy Road. Spring and early summer bring wildflowers including lupine , wallflower , monkey flower , and buttercup . Seventeen species of bats inhabit
12768-427: The city of San Francisco began considering the Tuolumne River and Hetch Hetchy Valley as a possible location for a reliable water source. This sparked a social and political debate which lasted until the issue was brought before Congress. John Muir , a naturalist and president of the Sierra Club , fought vigorously against the proposition of flooding the valley, stating, "Dam Hetch Hetchy! As well dam for water-tanks
12920-513: The city petitioned for Congress to pass the Raker Act . Signed in 1913 by President Woodrow Wilson , the Act allowed San Francisco to dam the Tuolumne River, as long as the water and power provided would be reserved exclusively for public utility, not private sale. The Hetch Hetchy Valley became the center of the first major environmental controversy in the United States. John Muir , the leader of
13072-446: The city to conduct an $ 8 million study on how the flooded valley could be drained and restored to its former state. The proposed study would also have been required to identify potential replacements for the water storage capacity and hydroelectric power production. Tuolumne River The Tuolumne River / t u ˈ ɒ l əm i / ( Yokutsan : Tawalimnu ) flows for 149 miles (240 km) through Central California , from
13224-541: The confluence of the forks in Tuolumne Meadows , the river meanders northwest, passing under Tioga Road . Although calm for the first few miles, this quickly changes as the river drops over Tuolumne Falls and White Cascades. After briefly passing through Glen Aulin , the river enters the spectacular 20-mile (32 km) Grand Canyon of the Tuolumne , where it forms three more major waterfalls – California, LeConte and Waterwheel Falls . Return and Piute Creeks join
13376-447: The dam in the 2007 National Park Service budget. Dianne Feinstein opposed this allocation, saying, "I will do all I can to make sure it isn't included in the final bill. We're not going to remove this dam, and the funding is unnecessary." Opponents of dam removal have pointed out that the flooding of the Hetch Hetchy Valley has also deterred the crowds that overrun other areas of Yosemite National Park. Indeed, Hetch Hetchy today remains
13528-469: The dam site. Construction of O'Shaughnessy Dam began in 1919 and was finished in 1923, with the reservoir first filling in May of that year. The dam was then 227 feet (69 m) high; its present height of 312 feet (95 m) was achieved only later, in 1938. On October 28, 1934 – twenty years after the beginning of construction on the Hetch Hetchy project – a crowd of 20,000 San Franciscans gathered to celebrate
13680-430: The development of natural resources for public benefit – and the preservationists, who believed that sites of scenic value like Hetch Hetchy were better left for public recreation and enjoyment. Despite the controversy, the city of San Francisco pushed through, beginning construction in early 1914 and filling the reservoir for the first time in May 1923. The Hetch Hetchy Railroad was built along 68 miles (109 km) of
13832-480: The development of water supply for irrigation and municipal interests. The controversy over damming Hetch Hetchy became mired in the political issues of the day. The law authorizing the dam passed Congress on December 7, 1913. In 1923, the O'Shaughnessy Dam was completed on the Tuolumne River, flooding the entire valley under the Hetch Hetchy Reservoir . The dam and reservoir are the centerpiece of
13984-405: The dominant tribe. About 1853, his brother, Joseph Screech (credited in some accounts for the original discovery of the valley) blazed the first trail from Big Oak Flat , a mining camp near present-day Lake Don Pedro , for 38 mi (61 km) northeast to Hetch Hetchy Valley. During this time, the upper Tuolumne River, including Hetch Hetchy Valley, was visited by prospectors attracted by
14136-425: The east, and the headwaters of the San Joaquin River proper to the southeast. Major tributaries of the Tuolumne and pertinent data are listed in the below table. Order is from the headwaters downstream. Almost 80 percent of the Tuolumne River watershed lies above New Don Pedro Dam and is primarily forested with some alpine, meadow and grassland zones. The primary land use in the lower Tuolumne River watershed
14288-431: The east. The valley provided an escape from the summer heat of the lowlands. They hunted, and gathered seeds and edible plants to furnish themselves winter food, trade items, and materials for art and ceremonial objects. Today, descendants of these people still use milkweed , deergrass , bracken fern , willow , and other plants for a variety of uses including baskets, medicines, and string. Meadow plants unavailable in
14440-481: The ecosystem, and that it might be decades or even centuries before the valley could be returned to natural conditions. In 1987, the idea of razing the O'Shaughnessy Dam gained an adherent in Don Hodel , Secretary of the Department of the Interior under President Ronald Reagan . Hodel called for a study of the effect of tearing down the dam. The National Park Service concluded that two years after draining
14592-582: The end of 1849, there were over 10,000 miners in the Tuolumne River area, half of them in Sonora, which became the Tuolumne County seat in 1850. Mining activity increased dramatically in the early 1850s, with prospectors pushing up into the foothills beyond Soulsbyville . In March 1850, an "enormously rich" deposit was discovered at Columbia. The same year, the Bonanza Mine near Sonora yielded
14744-531: The fall Chinook run alone may have numbered as high as 130,000. With the exception of the Merced River immediately south, this is the southernmost existing population of Chinook salmon in North America. Massive irrigation diversions and river channelization projects have led to the extinction of the spring Chinook run and greatly reduced the fall run. Dams have blocked more than half of the original 99 miles (159 km) of migratory fish spawning habitat in
14896-419: The former meadow in two distinct sections. The valley is fed by the Tuolumne River , Falls Creek , Tiltill Creek , Rancheria Creek , and numerous smaller streams which collectively drain a watershed of 459 sq mi (1,190 km ). In its natural state, the valley floor was marshy and often flooded in the spring when snow melt in the high Sierra cascaded down the Tuolumne River and backed up behind
15048-545: The high Sierra Nevada to join the San Joaquin River in the Central Valley . Originating at over 8,000 feet (2,400 m) above sea level in Yosemite National Park , the Tuolumne drains a rugged watershed of 1,958 square miles (5,070 km ), carving a series of canyons through the western slope of the Sierra. While the upper Tuolumne is a fast-flowing mountain stream, the lower river crosses
15200-500: The high quality of the Tuolumne River water – in the first 90 years since its construction, only around 2 in (5.1 cm) of sediment had been deposited in Hetch Hetchy Reservoir, much less than most other dams. A 2019 study commissioned by Restore Hetch Hetchy argued that draining the reservoir and equipping the valley with a tourism infrastructure comparable to that of Yosemite Valley (which receives around 100 times as many visitors annually as Hetch Hetchy's 44,000) could result in
15352-412: The irrigation season and to provide water during dry years. A secondary purpose for the construction of the dam was that TID and MID were aware that the city of San Francisco, 160 miles (260 km) west of the river, coveted water from the Tuolumne. Although the irrigation districts had the primary rights to the Tuolumne under the doctrine of prior appropriation , those rights could be relinquished under
15504-470: The largest in Yosemite National Park. Melting ice feeds the upper reaches of the Tuolumne River, maintaining water flow in the late summer when many other streams in the region are dry. The Lyell Glacier is the second largest in the Sierra Nevada, after Palisade Glacier at the headwaters of Big Pine Creek a tributary of the Owens River . Both Lyell and Maclure glaciers have shrunk significantly since
15656-483: The largest regional Native American group immediately prior to European contact, first established themselves in the area around 1200 CE. The Miwok lived in the Sierra foothills and Central Valley lowlands during winter and traveled into the upper Tuolumne River in summer to hunt, as well as seek refuge from the summer heat. The Paiute , who inhabited the Great Basin on the east side of the Sierra, also ventured into
15808-539: The late 1800s when measurements were first made. Between Hetch Hetchy Reservoir and the upper end of Lake Don Pedro the Tuolumne flows through the Sierra foothills, where it has a lower gradient but continues to maintain a fast current. Stream pools and gravel bars figure more prominently in the channel, allowing the growth of riparian habitat. By the time the river reaches Lake Don Pedro it has accumulated almost 90 percent of its total flow as precipitation run-off, snowmelt and groundwater base flow . Below Don Pedro Dam
15960-489: The late 1930s, said there was a violation of the Raker Act, but he and the city reached an agreement in 1945. In 2015, Restore Hetch Hetchy filed a complaint arguing that the construction of the dam had violated a provision in the constitution of California about water use, but the lawsuit was rejected by an appeals court and later the California State Supreme Court. Preservation groups including
16112-481: The lawsuit in a 3–0 ruling. Beginning in 2018, the Department of the Interior of the Trump administration began to consider a proposal initiated by RHH and California Trout to allow limited boating on the Hetch Hetchy Reservoir for the first time, with representatives of the two organizations arguing that "San Francisco received [Hetch Hetchy's] benefits long ago, but the American people have not." A 2019 study commissioned by Restore Hetch Hetchy argued that draining
16264-455: The least visited developed area of the park. Karin Klein has described Yosemite Valley as "so crammed ... that it looks more like a ripstop ghetto than the site of a nature experience." However, she does support breaching the dam once it has reached the end of its lifespan, and not replacing it. In November 2012, San Francisco voters soundly rejected Proposition F, which would have required
16416-429: The lower Tuolumne, destroying native floodplain habitat and making much of the river unnavigable. After the gold rush many miners settled along the lower Tuolumne River as farmers. Ferry sites grew into lively towns, such as at Waterford, where a crossing had been established in 1866. The town of Tuolumne City was founded near the mouth of the Tuolumne as a port, but it soon became apparent that mining debris had made
16568-453: The lower river were navigable, from the mouth to above Waterford . The unpredictable nature of the river made both navigating and crossing difficult, so starting in the Gold Rush era many ferries were established, one of the first at Dickenson's Ferry in the early 1850s. This particular location was the crossing of Fort Miller Road (Millerton Road), a major land trade route that connected Stockton with Millerton near present-day Fresno (today
16720-401: The lowlands were particularly valuable resources to these tribes. For thousands of years, Native Americans subjected the valley to controlled bushfires, which prevented forest from taking over the valley meadows. Periodic clearing of the valley provided ample space for the growth of the grasses and shrubs they relied on, as well as additional room for large game animals such as deer to browse. In
16872-445: The modern environmental movement in the United States. As the mid-20th century progressed, demands on the Tuolumne continued to increase, culminating in the completion of New Don Pedro Dam in the early 1970s. These projects halved the amount of water flowing from the Tuolumne into the San Joaquin, greatly reducing the once-abundant runs of salmon and steelhead in both rivers. The Tuolumne originates in Yosemite National Park, high in
17024-488: The modern name Hetch Hetchy to Screech's initial arrival in the valley, during which he observed the Native Americans "cooking a variety of grass covered with edible seeds", which they called "hatch hatchy" or "hatchhatchie". Screech reported that the valley was bitterly disputed between the "Pah Utah Indians" (Paiute) and "Big Creek Indians" (Miwok), and witnessed several fights in which the Paiute appeared to be
17176-551: The mouth, before the start of large irrigation diversions. A USGS gage recorded an average annual flow of 2,343 cubic feet per second (66.3 m /s) here between 1911 and 1970, with a maximum peak of 60,300 cubic feet per second (1,710 m /s) on January 31, 1911, and a minimum monthly mean of 57.5 cubic feet per second (1.63 m /s) in October 1912. During the Great Flood of 1862 , the river reached an estimated peak of 130,000 cubic feet per second (3,700 m /s) here, after
17328-486: The narrow gorge which is now spanned by O'Shaughnessy Dam. The entire valley is now flooded under an average 300 ft (91 m) of water behind the dam, although it occasionally reemerges in droughts, as it did in 1955, 1977, and 1991. Upstream from the valley lies the Grand Canyon of the Tuolumne , while the smaller Poopenaut Valley is directly downstream from O'Shaughnessy Dam. The Hetch Hetchy Road drops into
17480-611: The new park continued their use of Hetch Hetchy Valley – a "sheep-grazing free-for-all [that] threatened to denude the High Sierra meadows" – before disputes over state and private properties in respect to national park boundaries were finally settled in the early 1900s. Interest in using the valley as a water source or reservoir dates back as far as the 1850s, when the Tuolumne Valley Water Company proposed developing water storage there for irrigation. By
17632-418: The north and southwest. When the glacier retreated for the final time, sediment-laden meltwater deposited thick layers of silt , forming the flat alluvial floodplain of the valley floor. Compared with Yosemite Valley, the walls of Hetch Hetchy are smoother and rounder because it was glaciated to a greater extent. This is because the Tuolumne catchment basin above Hetch Hetchy is almost three times as large as
17784-534: The north just below the intake of the Hetch Hetchy Aqueduct , which delivers water to San Francisco. The South Fork of the Tuolumne joins from the south a few miles downstream, near Groveland-Big Oak Flat , followed by the Clavey River from the north a few miles after that. The North Fork of the Tuolumne joins from the north near the upper end of Lake Don Pedro , which was formed in 1971 when
17936-499: The people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man." The construction of the O'Shaughnessy Dam (built 1915–1923) flooded the valley, creating the Hetch Hetchy Reservoir . In the late 1980s, in response to an initiative by the Reagan Administration, the national Sierra Club created a group dedicated to restoring Hetch Hetchy Valley in Yosemite National Park called
18088-400: The population of the area grew, the Tuolumne River districts soon began to experience seasonal water shortages. The Dallas-Warner Reservoir (today's Modesto Reservoir) was completed in 1912 on the north side of the river, but was only considered a temporary solution. Construction on the first Don Pedro Dam began in 1921 to store floodwaters of the Tuolumne proper, allowing for the extension of
18240-419: The power plants is returned to the river. About 244,000 acre-feet (301,000,000 m ) per year flows through the gravity fed Hetch Hetchy Aqueduct to serve San Francisco and its customer municipalities. Due to the pristine quality of the water, the Hetch Hetchy system is one of only a few serving major cities in the United States that does not require filtration. Cherry Creek, the Tuolumne's biggest tributary,
18392-417: The prevalence of grasses and ferns, attracting game animals such as deer, and made the landscape more easily navigable. Many of the landscapes in the Tuolumne River area encountered by the first European explorers were thus not pristine but the result of hundreds of years of management; indeed, the famous meadows of Hetch Hetchy Valley prior to its damming only existed because of the annual burn. The origin of
18544-577: The project. However, it took until 1966 for the Federal Power Commission (now FERC ) to greenlight the project. Concerns that the new dam would impact king salmon populations were the primary cause of the delay. Construction of the dam began in 1967 and the river was diverted in September 1968. The embankment was topped out on May 28, 1970, and the project was formally dedicated on May 22, 1971, after four years of construction and
18696-498: The protection of both valleys under a single national park. Muir, who himself had briefly worked as a shepherd in Hetch Hetchy, was known for calling sheep "hoofed locusts" because of their environmental impact. Muir's friend Robert Underwood Johnson of the politically influential Century Magazine and several other prominent figures were inspired by Muir's work and helped to get Yosemite National Park established by October 1, 1890. However, ranchers who had previously owned land in
18848-503: The reservoir and equipping the valley with a tourism infrastructure comparable to that of Yosemite Valley (which receives around 100 times as many visitors annually compared to Hetch Hetchy's 44,000) could result in a "recreational value" of up to $ 178 million per year, or possibly an overall economic value of up to $ 100 billion. Hetch Hetchy Valley Hetch Hetchy is a valley, reservoir, and water system in California in
19000-408: The reservoir and return Hetch Hetchy Valley to its former state. Those in favor of dam removal have pointed out that many actions by San Francisco since 1913 have been in violation of the Raker Act, which explicitly stated that power and water from Hetch Hetchy could not be sold to private interests. Hydroelectric power generated from the Hetch Hetchy project is largely sold to Bay Area customers through
19152-472: The reservoir" is feasible. The dam would not have to be completely removed; rather, it would only be necessary to cut a hole through the base in order to drain the water and restore natural flows of the Tuolumne River. Most of the dam would remain in place, both to avoid the enormous costs of demolition and removal, and to serve as a monument for the workers who built it. The water storage provided at Hetch Hetchy could be transferred into Lake Don Pedro lower on
19304-488: The river could only be used for public interests. Ultimately, San Francisco sold hydropower from the dam to the Pacific Gas and Electric Company (PG&E), which led to decades of legal wrangling and controversy over terms in the Raker Act. The controversy over Hetch Hetchy was in the context of other political scandals and controversies, especially prevalent in the Taft administration. The Great Alaskan Land Fraud and
19456-537: The river drops nearly a mile (1.6 km) to the Hetch Hetchy reservoir at 3,800 feet (1,200 m). Below the O'Shaughnessy Dam the Tuolumne passes Poopenaut Valley and enters a series of continuous canyons as it flows through the Sierra foothills, leaving the western boundary of Yosemite National Park and entering the Stanislaus National Forest . Most of the Tuolumne's main tributaries join within this reach, beginning with Cherry Creek from
19608-479: The river flows across the large alluvial plain of the San Joaquin Valley, formed by millions of years of sediment deposits eroded from the Sierra. Historically this section of the river was subject to frequent course changes and formed thousands of acres of seasonal wetlands during the spring floods. Since the introduction of large-scale agriculture the Tuolumne River course has been fixed between an extensive system of levees. More than 300,000 acres (120,000 ha) in
19760-643: The river from the north within the Tuolumne Canyon. At the end of the canyon the river widens into Hetch Hetchy Reservoir, formed by a dam built in 1923 to provide water to the city of San Francisco , in the scenic Hetch Hetchy Valley . Falls Creek forms Wapama Falls and Tueeulala Falls , two of the highest in Yosemite, as it enters the reservoir from the north. From its source at 8,589 feet (2,618 m) above sea level in Tuolumne Meadows,
19912-673: The river shortly upstream. Dry Creek joins the Tuolumne from the north between the airport and the railroad. The confluence of the Tuolumne and San Joaquin is located in the San Joaquin River National Wildlife Refuge , about 2 miles (3.2 km) north of Grayson in Stanislaus County . By volume, the Tuolumne is the largest river draining the southern Sierra, with an estimated virgin flow of 1,850,000 acre-feet (2.28 km ) per year – over 2,550 cubic feet per second (72 m /s). Near
20064-485: The river unsuitable for navigation, and the area was abandoned. In the mid-1860s Tuolumne City and Paradise (located about 5 miles (8.0 km) further up the river) were reestablished as farming communities. The founding of Modesto in 1870, along a new railroad through the San Joaquin Valley, drew most of the population away from these towns and others along the Tuolumne. By the early 1900s Modesto's population numbered more than four thousand. As it became apparent that
20216-430: The river's mouth, the highest recorded annual volume was 3,995,000 acre-feet (4.928 km ) or 5,518 cubic feet per second (156.3 m /s) in 1983, and the lowest was 134,000 acre-feet (0.165 km ) or 185 cubic feet per second (5.2 m /s) in 1977 – a 30:1 difference. Although most of the flow in the river originates from summer snowmelt, massive floods can occur following heavy winter storms. The natural flow of
20368-442: The river, respectively. The present-day La Grange Dam , completed in 1893, replaced the older mining dam at the same site; at 122 feet (37 m), it was the highest overflow dam in the United States. The dam diverted the river into canals that water most of the lower valley. The first TID farmers received water in 1900. The MID canal took a total of thirteen years to complete, with the first water deliveries on June 27, 1903. As
20520-419: The same site. The Turlock and Modesto Irrigation Districts control the lion's share of water in the reservoir, although the City of San Francisco also has storage rights, which it uses mainly to offset the effects of water diverted upstream at Hetch Hetchy. Because of the desire to increase water storage for other uses, only 340,000 acre-feet (420,000,000 m ) of the reservoir is designated flood control, which
20672-611: The site of the Millerton Lake reservoir). By 1853, most of the easily mined gold had been exhausted, and hydraulic mining operations became the dominant extraction method. The Tuolumne County Water Company, first organized in 1851 to divert water from the Tuolumne River basin to the Stanislaus River, constructed a network of reservoirs, ditches and flumes initially used for mining and later for irrigation. The Golden Rock Water Company, incorporated in 1855, diverted
20824-403: The snowpack that feeds the Tuolumne accumulates in this region. Streams are generally high-gradient, clear and rocky, but large alpine meadows provide riparian and wetland habitat, which contribute sediment to the watershed's runoff. There are also a large number of natural lakes and tarns in the upper watershed. The Sierra crest harbors a number of glaciers, including Lyell and Maclure Glaciers,
20976-423: The south had permanent Miwok settlements, Hetch Hetchy was only seasonally inhabited. This was likely because of Hetch Hetchy's narrow outlet, which in years of heavy snowmelt created a bottleneck in the Tuolumne River and the subsequent flooding of the valley floor. In the early 1850s, a mountain man by the name of Nathan Screech became the first non-Native American to enter the valley. Local legend attributes
21128-528: The spring, but left rolling fat and hardly able to negotiate the precipitous and difficult defiles out of the mountains in the fall." In 1867, Charles F. Hoffman of the California Geological Survey conducted the first survey of the valley. Hoffman observed a meadow "well timbered and affording good grazing", and noted the valley had a milder climate than Yosemite Valley, hence the abundance of ponderosa pine and gray pine. The valley
21280-433: The susceptibility of the watershed to wildfires . In order to protect property and watershed quality, intensive fire suppression began in the early 20th century. However, this led to overgrowth and a disruption of the natural forest succession process that was previously driven by wildfires. Estimates of the first human habitation along the Tuolumne River range from 3000 to 7000 BC. The Plains and Sierra Miwok , who were
21432-521: The swimming holes of the Clavey are a popular camping spot during the summer. The Cherry Creek is also run by commercial trips. It is considered one of the most difficult whitewater rivers in the entire United States, with fifteen Class V rapids. Both runs are dam controlled, which usually extends the rafting season through the dry late summer and fall. In Yosemite National Park, the Grand Canyon of
21584-470: The upper Stanislaus River and the north fork of the Tuolumne. Parts of the route they established eventually formed the Walker River Trail, regarded as one of the more difficult of the main Sierra crossings. For a brief period the lower Tuolumne became a major steamboat route, ferrying prospectors and supplies from Stockton . Depending on water level, approximately 35 miles (56 km) of
21736-545: The valley at the dam, but all points east of there are roadless, and accessible only to hikers and equestrians. The O'Shaughnessy Dam is near Yosemite's western boundary, but the long, narrow, fingerlike reservoir stretches eastward for about 8 miles (13 km). Wapama Falls , at 1,080 ft (330 m), and Tueeulala Falls , at 840 ft (260 m) – both among the tallest waterfalls in North America – are both located in Hetch Hetchy Valley. Rancheria Falls
21888-523: The valley, grasses would cover most of its floor and within 10 years, clumps of cone-bearing trees and some oaks would take root. Within 50 years, vegetative cover would be complete except for exposed rocky areas. In this unmanaged scenario, where nature is left to take hold in the valley, eventually a forest would grow, rather than the meadow being restored. However, the same NPS study also finds that with intensive management, an outcome in which "the entire valley would appear much as it did before construction of
22040-420: The water delivery. Water from Hetch Hetchy is some of the cleanest municipal water in the United States; San Francisco is one of six U.S. cities not required by law to filter its tap water, although the water is disinfected by ozonation and, since 2011, exposure to UV . The water quality is high because of the unique geology of the upper Tuolumne River drainage basin, which consists mostly of bare granite; as
22192-418: The water's destruction of lichen growth on the canyon walls, which would inevitably be visible at low lake levels. Since the valley was within Yosemite National Park , an act of Congress was needed to authorize the project. The U.S. Congress passed and President Woodrow Wilson signed the Raker Act in 1913, which permitted the flooding of the valley under the conditions that power and water derived from
22344-468: Was 57,000 cubic feet per second (1,600 m /s) on December 9, 1950, and the lowest daily mean was 56 cubic feet per second (1.6 m /s) on August 6, 1977. The Tuolumne River watershed can be divided into three distinct physiographic regions. From the headwaters to below Hetch Hetchy Reservoir, the river drains the Sierra highlands, which are characterized by solid, glacier -carved granitic bedrock, thin poor soils and areas of heavy forestation. Most of
22496-419: Was insufficient to meet growing water demands. The irrigation dam at Don Pedro could only store enough water for a single growing season, allowing little carryover for drought years, and on the other hand providing very little flood control. In the late 1950s TID and MID began planning for a high dam on the Tuolumne River several miles below the existing Don Pedro Dam. In 1961 voters approved revenue bonds to fund
22648-488: Was sculpted into its present shape by repeated advance and retreat of the ice, which also removed extensive talus deposits that may have accumulated in the valley since the Sherwin period. At maximum extent, Tioga Glacier may have been 60 mi (97 km) long and up to 4,000 ft (1,200 m) thick, filling Hetch Hetchy Valley to the brim and spilling over the sides, carving out the present rugged plateau country to
22800-494: Was slowly becoming known for its natural beauty, but it was never a popular tourist destination because of extremely poor access and the location of the famous Yosemite Valley just 20 miles (32 km) to the south. Those who did visit it were enchanted by its scenery, but encountered difficulties with the primitive conditions and, in summertime, swarms of mosquitoes. Albert Bierstadt , Charles Dorman Robinson and William Keith were known for their landscapes that drew tourists to
22952-438: Was used for cattle ranching, which quickly decimated natural range grasses. During the 1880s American sheep ranchers brought their herds into the upper Tuolumne River watershed for summer pasture, which further damaged the range in the foothills and Sierras. Hetch Hetchy Valley was one of the main summer grazing areas for sheep. The decline of native perennial grasses caused invasive annual species to flourish, and also increased
23104-599: Was used was 1988. Below the confluence with the North Fork of the Tuolumne the river flows into Lake Don Pedro, the largest in the Tuolumne River system and the sixth-largest man made lake in California at 2,030,000 acre-feet (2.50 × 10 m ). The earth-filled New Don Pedro Dam, 585 feet (178 m) high, is the 10th tallest dam in the United States and was constructed as a multipurpose project, serving irrigation, municipal water supply, hydropower and flood control. It replaced an earlier concrete dam built on approximately
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