FoundSF

Historical Essay

by David D. Schmidt, 2026

An excerpt from the book, San Francisco Bay Area: An Environmental History, by David D. Schmidt (Backcountry Press, 2025).

Black Point (now Fort Mason), 1870. A new company formed by John Bensley and Antoine (aka Anthony) Chabot brought water through the flume that skirts the cliffs. Small farms run down to the shore. Alcatraz is in the distance.

Photo: Private Collection, San Francisco, CA

From Mule Carts to Crystal Springs

In the Gold Rush boomtown of 1849, enterprising water purveyors in San Francisco set out by boat to collect water from the sources that had been supplying sailing ships with drinking water before their months-long ocean voyages: Sausalito (Spanish for “little willow grove”) in Marin, and Hunters Point, a narrow peninsula extending into the bay three miles south of the growing city, where a sparkling stream emerged from a cave just a stone's throw from the water's edge.

By 1851, the Saucelito Water and Steam Tug Company was pulling barges filled with water into San Francisco's harbor. The water was lifted in barrels onto 65 mule-drawn carts that circulated on the city's streets. Residents bought this precious water for up to $20 a bucket (in today’s dollars). Bathing was a luxury reserved for the wealthy, and the city was devastated by wildfires that spread rapidly without a water supply to put them out (see Fires and Floods Chapter). The first attempt to build a piped water system began in May 1853, when the Mountain Lake Water Company broke ground on an ambitious brick tunnel beneath the Presidio, with the goal of delivering water from the Presidio’s Mountain Lake,(1) through the tunnel and into a wooden flume to the city.

Two years later, the company had burned through its initial funding, and was unable to raise the money needed to finish the project.(2) So in 1857 the city government granted the water franchise, a legal monopoly, to a new company formed by John Bensley and Antoine (aka Anthony) Chabot, in return for providing water for firefighting and other "municipal purposes."

Bensley, a New Yorker who had gotten rich by consolidating Sacramento River steamboats into a monopoly, and Chabot, a French Canadian who had invented hydraulic mining for gold, invited Latvian-born hydraulic mining engineer Alexei Waldemar von Schmidt to join their company. Within a year, they had built a winding 7-mile redwood flume from Lobos Creek, at the west end of the Presidio, to a pumping station at today's Ghirardelli Square. The company also laid 14 miles of pipe and installed 100 fire hydrants. The first piped water reached customers on September 27, 1858.

The new system supplied two million gallons per day—not enough for the fast-growing city. A competing company, Spring Valley Water Works, had begun selling water from a spring at Mason and Washington Streets (where the Cable Car Barn is today) in 1856. Its production was miniscule by comparison—only 20,000 gallons per day—but it soon acquired the Bensley Company's most important asset: von Schmidt. In 1860 he became chief engineer and a major stockholder in Spring Valley.(3)

Under von Schmidt's dynamic direction, Spring Valley acquired another small water supplier, the Islais and Salinas Water Company, which had dammed a stream in Glen Canyon (today Glen Park), and flumed the water to their reservoir at Potrero Ave. and 16th Street. This brought Spring Valley's capacity up to 200,000 gallons per day—still much smaller than Bensley's, but von Schmidt had bigger plans. In 1861 he began building a diversion tunnel on San Mateo County’s Pilarcitos Creek, northeast of Half Moon Bay. This location had the county’s highest average annual rainfall—49 inches. The creek drained westward into the ocean, but von Schmidt's laborers used picks and shovels to dig their way eastward through Cahill Ridge, to divert the water to the San Mateo Creek watershed. From there, it flowed through a 32-mile wooden flume to San Francisco, arriving for the first time with great fanfare, as von Schmidt had planned for maximum publicity, on the Fourth of July, 1862.

Pilarcitos Dam and Reservoir, built in 1863 in the Crystal Springs Watershed in San Mateo County, was the first dam to supply water to San Francisco.

Photo: Christy Shake, 1997

During the drought of 1862-63, these water systems proved inadequate. To store water for dry years, Von Schmidt completed the first dam on Pilarcitos Creek in 1863, and converted one of San Francisco's small natural lakes, Laguna Honda (Spanish for "Deep Lake"), into a concrete-lined reservoir for Pilarcitos water.

Von Schmidt predicted that San Francisco would soon outgrow San Mateo County’s water sources, so in 1864 he quit Spring Valley to study the feasibility of transporting water from Lake Tahoe. Spring Valley bought out the Bensley Company in 1865, making Spring Valley the citywide monopoly. Hermann Schussler took over as chief engineer, designing and building five dams over the next 30 years on the company's land in San Mateo County.

Lower Crystal Springs Dam, completed in 1888, was the world's largest concrete dam when it was built by San Francisco's Spring Valley Water Co. Today it lies under the Doran Bridge on I-280.

Photo: Christy Shake, 1997

Among these was San Andreas Dam, which survived the 1906 Earthquake without leaking, despite sitting directly athwart the San Andreas Fault. The powerful quake moved half the dam eight feet upstream of the other half. Schussler's biggest project was Lower Crystal Springs Dam on San Mateo Creek. Built of interlocking concrete blocks, it was the world's largest concrete dam when completed in 1888. Still in use today, it lies beneath the Doran Bridge on I-280, invisible to thousands of drivers who pass over it daily.

Hard Luck Dam: Calaveras and the Drive for a City-Owned System

Despite Spring Valley's aggressive construction program, many San Franciscans were dissatisfied with the company. In 1873, the city government began its first effort to buy out and expand Spring Valley's system. Two years later, the city identified Calaveras Creek in southern Alameda County as a good location for a major dam, and started moving to buy the needed land and water rights, but Spring Valley moved faster and bought them first, leaving city officials high and dry. Spring Valley sat on the land for the next 38 years, until the State Railroad Commission (today's California Public Utilities Commission) in 1913 ordered the company to build the dam to meet San Francisco's needs.

Before the advent of bulldozers, a common dam-building technique in California was to use a hydraulic mining water cannon to wash away a hillside, channel the resulting slurry of mud and rock to a dam site, and deposit it between two narrow, parallel embankments—like the filling in a Double Stuf Oreo cookie—to create one wide dam. These mud-filled sandwich dams were cheaper to build, since they required less labor, but weaker than dams built of dry material. Spring Valley used this method for the Calaveras Dam.

On March 24, 1918, after the half-built dam had been soaked by winter rains, the upstream embankment partially collapsed, and the mud filling oozed out around it. Spring Valley had to redesign the dam and rebuild it from the ground up, which took another seven years.

Completed in 1925, Calaveras was the world’s highest earth-fill dam, at 215 feet—nearly as high as the concrete Hetch Hetchy Dam built at the same time. To deliver Hetch Hetchy’s water to San Franciscans, the city government needed to buy out Spring Valley's entire system, including pipelines beneath city streets. Voters in 1928 approved a bond proposition to buy out the Spring Valley system (albeit on the fifth try, for the needed 2/3 majority), making the city the new owner of Calaveras and the Crystal Springs Lakes in 1930—57 years after the city's buyout efforts began.

Calaveras Dam again became a concern in the 1960s, after the Calaveras Fault—just 1,500 yards from the dam—was recognized as a hazard. San Francisco’s Water Department strengthened the dam to meet earthquake safety standards in 1975. But after the 1989 Loma Prieta quake, the state government toughened dam safety standards, and Calaveras again failed to make the grade. In 2001, the California Division of Safety of Dams ordered the city to keep the reservoir 60% empty, to prevent a potentially catastrophic wall of water from flattening Fremont if the dam failed. To replace it, San Francisco built an entirely new Calaveras Dam, containing enough rock and soil to fill 330,000 dump trucks.(4) It was completed in 2018 at a cost of $823 million.

San Francisco’s watershed lands around these dams in San Mateo County (about 40 square miles) and Alameda County (62 square miles) made the city the largest absentee landowner in these counties. By 2000, San Francisco also owned 12 reservoirs, two drinking water treatment plants, and 1,191 miles of pipes beneath city streets.

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San Francisco Water Development Chronology

1776 Mission Dolores founded near Mission Creek, Presidio founded near El Polin Spring

1849 Gold Rush "49ers" arrive; water sold by the bucket from mule-drawn carts

1851 Saucelito Water and Steam Tug Co. imports water by barge from Sausalito

1850-1852 San Francisco devastated by fire five times due to lack of water supply

1858 Bensley Company taps Lobos Creek in Presidio, builds flume, pipes, hydrants

1862 Tunnel, 32-mile flume bring Pilarcitos Creek water to San Francisco

1863 First Pilarcitos Dam completed

1865 Spring Valley buys out Bensley, gaining citywide monopoly

1870 Spring Valley completes San Andreas Dam on San Mateo Creek

1875 Spring Valley buys Calaveras Creek land and water rights in SW Alameda County

1876 Spring Valley builds Upper Crystal Springs Dam

1888 Spring Valley completes Lower Crystal Springs Dam, world's largest concrete dam

1898-1900 Spring Valley drills wells in Pleasanton, builds Sunol aqueduct to Crystal Springs

1900 New charter mandates that San Francisco develop its own water supply

1906 Earthquake severs water lines; more than half of homes, businesses destroyed by fire

1908-1910 City voters approve bond propositions to build Hetch Hetchy system

1910-1911 City buys land, water rights in Eleanor, Cherry Creek basins near Hetch Hetchy

1913 Congress approves Raker Act, allowing dam in Yosemite National Park

1918 Spring Valley's Calaveras Dam, under construction, collapses; City completes first dam in Hetch Hetchy area—Eleanor Dam, 70 feet high

1923 City completes 227-foot-high dam, flooding Hetch Hetchy Valley

1925 Spring Valley completes rebuilt 215-foot-high Calaveras Dam

1924-34 City builds tunnels, pipelines to bring Hetch Hetchy water to Crystal Springs

1930 City buys out Spring Valley system

1934 First Hetch Hetchy water reaches San Francisco

1938 Hetch Hetchy Dam raised 85.5 feet

1949 Voters approve bonds to build Cherry Valley Dam near Hetch Hetchy

1952 City completes second pipeline across San Joaquin Valley

1956-1967 City builds additional dams, tunnels, pipeline, hydroelectric power plants

1965 Hetch Hetchy system delivers record 220 million gallons per day (GPD); City completes 195-foot-high Turner Dam in southern Alameda County

1968 San Joaquin Pipeline #3 ups system capacity to 300 million GPD

1967-1971 City, Irrigation Districts build New Don Pedro Dam on Tuolumne River

1972 Bay Crossing Pipeline #4, San Andreas drinking water filtration plant completed

1975 City strengthens Calaveras Dam for earthquake safety

1987-1992 Worst drought of century spurs mandatory rationing: up to 45% reductions

2002 Voters approve $1.6 billion in bonds to repair, replace aging water infrastructure

2018 City completes $4.8 billion seismic safety, rebuild projects

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O'Shaughnessy and the Hetch Hetchy Project

By the time San Francisco bought out Spring Valley in 1930, the company's system could supply 65 million gallons per day (MGD)—more than 32 times as much as the Lobos Creek system in 1858. About 700 wells drilled throughout the city provided another 8.5 MGD. As early as 1900, however, city officials planned to tap a source that would dwarf the Spring Valley system. In 1901, Mayor James D. Phelan and City Engineer Carl Grunsky focused their attention on the Tuolumne River in the Sierra, due to its high volume, clean water, potential reservoir sites, and hydropower potential.

To prevent anyone else from beating the city to the water rights (as Spring Valley had done with Calaveras Creek), Phelan secretly filed for the Tuolumne water rights in his own name, then signed them over to the city in 1903. Opponents of the plan—Spring Valley, the Modesto and Turlock Irrigation Districts (which tapped the Tuolumne downstream in the San Joaquin Valley), and nature lovers led by John Muir—fought the proposed dam for 10 years. Muir famously proclaimed, "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!"

Hetch Hetchy was much like Yosemite Valley, just 20 miles north of its famous twin: It had towering granite walls, waterfalls, a meandering river, meadows, oaks, a warmer climate than the surrounding mountains, and was within Yosemite National Park. Dam promoters contended that they would create a lake just as beautiful, but useful, too. Muir and park supporters throughout the nation vehemently disagreed and wrote more than 5,000 letters to the Secretary of the Interior and Congress, urging them to block the project.

Hetch Hetchy Valley in Yosemite National Park was much like the more famous Yosemite Valley before it was flooded by San Francisco's O'Shaughnessy Dam in 1923.

Photo: unknown provenance, c. 1912

Conservationists were divided between Muir's preservationists, and Progressives led by Mayor Phelan and Marin Congressman William Kent, who put the highest value on using public resources for the public’s benefit: The dam would supply water and electric power (which never reached San Francisco customers).

San Francisco voters approved the dam by a lopsided 20-1 margin on a 1910 bond proposition, thanks to a widespread perception that Spring Valley's water system was to blame for the fire that devastated the city in 1906. In reality, the city’s water mains would have been ruptured by the quake with or without the Hetch Hetchy system.

In 1912, newly-elected San Francisco Mayor "Sunny Jim" Rolph contacted prominent civil engineer Michael M. O'Shaughnessy and made him an offer: If he could live on half the money he was making as a private consultant, O'Shaughnessy could preside over the most massive engineering project in the West—Hetch Hetchy, as well as a new municipal railway system with tracks and tunnels throughout San Francisco. O'Shaughnessy, then 48, an Irish immigrant and graduate of the Royal University of Dublin, leaped at the chance.

The first challenge was to transport workers and supplies to the dam site. For this, O’Shaughnessy built a 68-mile-long railroad, completed in October 1917. Next, the workers needed electric power for lights, drills and machinery. For that, they built a 70-foot-high dam on Eleanor Creek (also in Yosemite National Park), and a three-mile system of flumes, tunnels, and canals to transport the water to a new powerhouse, which began generating electricity in May 1918.

Once construction began, the railroad delivered 2,000 cubic yards of cement per day, operating around the clock for four years. Workers carved a tunnel through granite to divert the Tuolumne River around the dam site. Boulders and gravel up to 91 feet deep in the riverbed had to be removed before concrete could be poured. When Hetch Hetchy (aka O’Shaughnessy) Dam was dedicated on July 7, 1923, it was the largest man-made structure in the West.

Another tunnel, 19 miles long, was carved through solid rock to deliver the water to Priest Reservoir, and from there down a steep drop to the Moccasin Powerhouse, completed in 1925. Moccasin not only generated power, but also money from selling it (to PG&E), to fund construction of the aqueduct to bring the water to the Bay Area.

Then came three years of work on a tunnel to move the water 16 miles beneath the Sierra foothills. City workers competed with contractors in tunnel-building speed—the city employees won, setting a new national record of 803 feet in a month, in September 1926. Next, they built 47.5 miles of pipelines across the San Joaquin Valley, and finally, the toughest job of all: a 25-mile-long tunnel under the Coast Range to San Francisco Bay.

The tunnels were key to making the system transport water entirely by gravity—no fuel-gulping pumping stations to force the water uphill. The gravity-based system delivered water at a lower cost, but took longer to build.

Construction of the Coast Range Tunnel began in 1927, after critics warned of the hazards: gases, groundwater, quicksand, and swelling ground. In one spot, the 18-foot-diameter tunnel was squeezed by ground swelling in 24 hours to just three feet in diameter. To solve this problem, portions of the tunnel were lined with a 3-foot thick shell of cement-like gunite.

On July 17, 1931, a methane explosion killed 12 workers. Construction halted for two years, but the two ends of the Coast Range Tunnel finally met on January 5, 1934, with O'Shaughnessy, joined by Mayor Angelo Rossi, extending his hand through a hole in the rock to Tunnel Foreman Pete Peterson. It was the world's longest water tunnel.

To celebrate the arrival of Hetch Hetchy water after 20 years of construction (and the deaths of 89 workers), city engineers built the Greek-columned Pulgas Water Temple, where visitors could see the clear Sierra water, 20 feet below them, pouring into a conduit to Crystal Springs Lake. The temple still stands along Canada Road in San Mateo County. Interior Secretary Harold Ickes came from Washington, D. C. to attend the opening ceremony on October 24, 1934. Twenty thousand people gathered around the Water Temple, but O'Shaughnessy didn't make it. He died of a heart attack on October 12, at age 72 – after 22 years building the Hetch Hetchy system.

Hetch Hetchy System Became Like "Winchester Mystery House"

In the heart of Silicon Valley is a bizarre, 105-room Victorian mansion, the Winchester Mystery House, built in the late 1800s by Sarah Winchester, widow of the man who invented the Winchester repeating rifle. She believed that as long as she kept building the house, she would stay alive. So she kept carpenters working on it for 38 years, until she died. But the city of San Francisco outdid Sarah Winchester, building and expanding the Hetch Hetchy Water and Power system for 58 years, starting in 1914.

In October 1933, even before Hetch Hetchy water reached San Francisco, O'Shaughnessy led the campaign for his last bond proposition—this one to finance raising the dam 85.5 feet, to a total of 311.5 feet. Voters approved, and when work was completed in 1938, after O’Shaughnessy’s death, city officials renamed the dam in his memory.

The O'Shaughnessy Dam, completed in 1923 and raised to its current height in 1938, drowned the Hetch Hetchy Valley.

Photo: David D. Schmidt, 1998

In 1941, city engineers began planning their next dam at Cherry Creek Canyon, 17 miles northwest of Hetch Hetchy. In 1947, San Francisco voters approved funding for a second pipeline across the San Joaquin Valley, and a pipeline around the southern end of San Francisco Bay, to more than double the system's capacity to 150 MGD, completed in 1952. In 1955, voters approved bonds to build two more hydroelectric power plants, finished in 1960 and 1967.

After voters approved another bond proposition in 1961, the city built a third San Joaquin Valley pipeline, doubling the system's capacity again, to 300 MGD, when the pipeline opened in 1968. Construction of the New Don Pedro Dam, downstream from the Moccasin Powerhouse, got underway in 1967. The dam was dedicated in May 1971, and a fourth South Bay pipeline was completed in June 1972. By this time, Hetch Hetchy was supplying water not just for San Francisco but for San Mateo County, Hayward, Fremont, and parts of Santa Clara County.

In the 1960s, concerns over the purity of water in the Calaveras and San Antonio Reservoirs in the East Bay, where cattle graze upstream, prompted the city to build the Sunol Filtration Plant, completed in 1966. At the Crystal Springs Watershed in San Mateo County, cattle were excluded after 1940, but the possibility of contamination from other sources, such as runoff from the I-280 freeway (completed in 1973), led the city to build the San Andreas Filtration Plant, completed in 1972 and greatly expanded in 1992.

These facilities filter and disinfect all water in the system. The disinfection was originally done with highly toxic chlorine, but chlorination of water with organic materials in it (such as dead leaves) was shown in the 1990s to create toxic by-products. So in 2003 San Francisco joined many other cities disinfecting with chloramine, a compound of chlorine and ammonia.

In the 1970s, San Francisco's once-mighty construction program turned from expansion to maintenance. By 2000, the city struggled to maintain its aging water system. Pipelines and other facilities built in the 1920s and 1930s, and even earlier, needed replacement. But funding from Hetch Hetchy electric power sales, which had helped build the system, was largely unavailable in the 1980s and 1990s because Mayors Diane Feinstein, Art Agnos, Frank Jordan, and Willie Brown diverted a staggering $670 million to fill gaps in the city budget.

In 2002, Brown and the Board of Supervisors placed on the November ballot a $1.6 billion bond proposition to repair and rebuild the system. Feinstein, then a U.S. Senator, starred in ads paid for by the city’s Chamber of Commerce urging voters to approve it. The Sierra Club was opposed, contending that the bonds would not just replace aging infrastructure, but allow the city to build a fourth pipeline to take more water from the Tuolumne River, threatening fish and encouraging urban sprawl.

Voters approved the measure by a 53.3% margin—nothing like the 20-1 margin in 1910, but sufficient to pass. Five days later, as if on cue, one of the aqueduct's three pipelines ruptured in a farm field near Modesto, sending up a 100-foot geyser of water for nine hours before workers shut down the pipeline and patched it. At the Moccasin Powerhouse, when workers began reopening the gate regulating water flow into the pipelines, a six-inch metal pin broke, immobilizing the gate. Water delivery was cut in half as city engineers scrambled to find a replacement part, have it flown in from Colorado, and installed it. The $1.6 billion turned out to be just the down payment on a series of 83 water infrastructure seismic safety rebuild projects in the Bay Area (35 of them in San Francisco alone), completed by 2018 at a cost of $4.8 billion. New technology has given the joints in the system’s pipelines the ability to flex up to six feet, or compress without breaking, in an earthquake.(5)

The fourth Hetch Hetchy pipeline was never built, but another major renovation got underway in early 2022 when workers began repairing the 19-mile-long Mountain Tunnel, which transports water from the Kirkwood Powerhouse to Priest Reservoir in the Sierra foothills. The work can only be done during winter, when water demand is lower and the tunnel can be de-watered. The target date for completion was 2027.(6)

Questions? Email the author: davidnaturesf@gmail.com

Notes

1. There are no mountains around “Mountain Lake.” It was a bad translation of “Laguna de Loma Alta”: Lake of the High Hill, according to Gudde, Erwin G., and William Bright, California Place Names, Fourth Edition (Berkeley: UC Press, 1998), p. 250.

2. Nolte, Carl, “Tunnel tells tale of 1850s dream: Relic of ambitious project found in Presidio,” San Francisco Chronicle, Oct. 11, 2010.

3. Kamiya, Gary, “Barrel system washed out by city’s 1st water company, San Francisco Chronicle, Feb. 20, 2016.

4. Rogers, Paul, “Calaveras Dam project reaches major milestone,” San Jose Mercury-News, April 18, 2016.

5. Johnson, Lizzie, “Water system now set for the Big One,” San Francisco Chronicle, July 31, 2015.

6. Hao, Claire, “Huge tunnel for water getting urgent repairs,” San Francisco Chronicle, April 17, 2023.

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Excerpted from David D. Schmidt's San Francisco Bay Area: An Environmental History. Available from Backcountry Press.