Water Underground

NARRATOR
The cars and bikes traveling through this intersection probably miss it. But a square of bricks in the asphalt is a telltale sign that beneath these streets lies a massive cistern holding 16,000 gallons of water. It was installed more than 150 years ago to provide water for fighting fires in a new and growing city. San Francisco is a mostly dry peninsula with no significant rivers and almost no rainfall between May and October. So as soon as the city started growing here in the 1840s and '50s, water became a precious resource for drinking and for fighting fires. Since most of the city's early structures were wood buildings or canvas tents, fires were a regular occurrence, says San Francisco Fire Department Lieutenant Hashim Anderson.

HASHIM ANDERSON 
Most people are aware of the fires that we had following the '89 earthquake and the 1906 earthquake. But prior to 1906, we had about five other major fires that caused a lot of devastation within the city of San Francisco, to the point where it formed the fire department that we have today.

NARRATOR
In addition to a volunteer fire department, the city in the 1850s began to build cisterns—large underground water tanks, like the one beneath this intersection. But as years passed, the city installed a network of drinking water mains, which quickly took over as the primary water supply. Then in 1906, the earthquake ruptured nearly all of these water mains and they were useless during the devastating fires that spread after the earthquake. After 1906, the city knew it needed a better solution, so it planned a completely separate water supply system for fighting fires. This included reinforced high pressure water mains, and a gravity-driven system to pull water from the reservoirs. As a backup system, the city also built 85 new cisterns averaging 75,000 gallons each.

HASHIM ANDERSON 
The cisterns were built in response to the fires that we had in 1906. So the high-pressure hydrant system, the cisterns, the portable hydrants, all came because of lessons that we learned from 1906. 

NARRATOR  
So if you see a circle or square of bricks anywhere in the city, you'll know there's a cistern beneath your feet. Some of the city's 177 cisterns are marked in other ways.

HASHIM ANDERSON
An intersection may have a couple of circles of bricks that surround the manhole covers that access the cisterns, or you could have a large square of bricks that are in the intersections as well. Now not every single cistern is identified by a circle or square of bricks. Some cisterns are identified by a green bonnet white hydrant that is located nearby.

NARRATOR 
Together with the auxiliary water system and state-of-the-art firefighting equipment, cisterns help protect San Franciscans from fires today. To find other cisterns in the tour area, navigate to the digital tour map and select the layer marked "cisterns." 

But what was the state of natural water sources in San Francisco when the cisterns were constructed? Continue on to learn more.

NARRATOR
Even in a city there are watersheds, areas where the topography guides the flow of water both above ground and underneath it. Many decades of urban development has buried the majority of San Francisco's historic creeks and lakes. But one of the few people whose documented the city's historic watersheds is researcher Joel Pomerantz. 

JOEL POMERANTZ 
There were probably somewhere between 15 and 40 creeks flowing in San Francisco during the time when the earliest maps were made. And when I say flowing, I mean flowing enough so that somebody went to the trouble of trapping that water.

NARRATOR
Most of these creeks are now hidden under buildings, sidewalks, and streets, but their water continues to flow underground. The largest creek nearby ran for about five blocks and emptied into a small lagoon, just one block north of here near Jackson and Montgomery.

JOEL POMERANTZ  
The water that came through that spot was flowing out of a spring in a remarkable location right near the intersection where today's Cable Car Barn is. It was remarkable because it was the only place in all of San Francisco's early territory where there was a chasm. It was 60 to 80 feet deep. And it was because of the spring source of this creek.

NARRATOR
One other very short creek formed in inviting pool just three blocks south of here off of Sacramento Street near the Bank of America building.

JOEL POMERANTZ
The alley that used to be called Spring Street—I think that was the location of a spring that was famous because the Hawaiian laborers would go swimming in the pool of water that that spring created on the beach. They would take breaks after working really hard, splash around, dive into the water.

NARRATOR
Both of these creeks flowed into Yerba Buena Cove, a shallow inlet that was later filled and built upon to become downtown San Francisco. To the south of Market Street, the land was mostly sand dunes. Instead of creeks there were variable dune ponds that only formed during wet weather. Around the Fifth Street exit of Interstate 80 was a large tidal marsh. Pomerantz says the late 1800s, this marsh was an obstacle between downtown and the city's other populated district in the Mission.

JOEL POMERANTZ 
When the water route was replaced by roads, those roads were hindered by the marshes that cut off a lot of the direct route from Yerba Buena Cove to the Mission District. So they had to make the roads go in a straight line toward what's now called Civic Center and then curve to the south, which is why we still have a grid of roads that suddenly bend from one angle on Market Street to another angle in the Mission District to get around those waterways that we're blocking the most direct route.

NARRATOR
Still, there were relatively few water sources and not much rainfall in San Francisco. So as soon as the city began growing, there were shortages.

JOEL POMERANTZ
Putting out fires was a big issue when you didn't have good water supplies, and washing clothes and drinking water of course, and of course, animals the beasts of burden, which were the main working power, needed water as well. When San Francisco didn't have enough water to wash your clothes, people just threw their clothes away in the street and bought new clothes because ships coming in with goods would bring new clothes and it would be cheaper than getting your laundry done because water was so expensive.

NARRATOR
Enterprising San Franciscans began damming up creeks to hoard water and sell it at exorbitant prices. They shipped water from springs in Sausalito across the Bay on steamships. By the 1860s water companies began building dams in the canyons farther south on the Peninsula to pipe and sell water to thirsty San Francisco. Dams and reservoirs were added at greater and greater distances from the city, including Crystal Springs reservoir along Interstate 280. Finally, in 1923, the biggest water grab of all brought a dam to Yosemite National Park's Hetch Hetchy Valley, providing a permanent if controversial solution to the city's water needs. Today, San Francisco still boasts some of the best drinking water in the nation.