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Human History

Lake Merced has been home to many different people and important events throughout history.


The Ramaytush Ohlone were the first noted inhabitants of San Francisco. Archaeologists have found evidence of their habitation at the lake; a pestle for crushing acorns was found on the San Francisco State University Campus, and an obsidian tool was found near the SFPUC’s Southwest Treatment Plant. The Ohlone used Lake Merced for its abundant tule reeds, used to build homes and boats, and would have fished and hunted the abundant wildlife at the lake.

Mexican Land Grant

The first Spanish explorers to arrive at Lake Merced were Don Fernando Rivera and Father Francisco Palou, though the De Anza expedition is often credited as the first group to discover San Francisco. The land was in Mexican possession throughout the early to mid-1800’s until squatters gained the land after the passage of the Homestead Act in 1862.

map highlighting pipelines and the lake in 1922

If you were a kid at Lake Merced in 1869, the lake would look very different. There was no boathouse and no paved roads. There were far fewer trees around the lake, mostly just live oaks and willows. A few years ago, you might have swum in the lake, but not since the purchase of Lake Merced by the Spring Valley Water Company for drinking water in 1868.

The shores of Lake Merced were home to one of the most famous duels in U.S. History between Senator David Broderick and Associate Justice of the Supreme Court of California, David Terry. The stated reason for the duel was the Senator and Justice’s opposing views on slavery, but in reality, a political feud between the two was the real reason for their duel. Broderick, the abolitionist, perished in the duel, but his death fueled abolitionist support and helped usher in the end of dueling as an acceptable way to settle disputes

SVWC and San Francisco

Spring Valley Water Company (SVWC) purchased the water rights to Lake Merced in 1868, and began delivering Lake Merced water to the City of San Francisco in 1895. After the 1906 earthquake and the resulting inability to deliver water to the City of San Francisco, public support swelled in favor of the City of San Francisco purchasing the SVWC and making water a public utility. The City of San Francisco eventually purchased the SVWC in 1930 for $40 million, and used it as an emergency water supply from 1932 onward.

The post-World War II period saw rapid development of the area around Lake Merced into mostly single-family homes with a few notable exceptions such as Parkmerced. This changed the nature of Lake Merced from a rural landscape on the outskirts of town to a suburban area, and it meant that Lake Merced became utilized as a recreation destination. The SFPUC gave recreation duties to the Recreation and Parks Department in 1950, solidifying recreation as a major use of Lake Merced.

Dedicated Stakeholders

The increased use of land around Lake Merced corresponds with an increased use of the groundwater which made up Lake Merced. This caused a gradual decline in Lake Merced’s water levels until the lake hit its lowest level in 1993. A group of dedicated stakeholders rallied around the lake and worked to restore the lake level. Learn more about their efforts in the Lake Merced Watershed Report.

Birding Destination

Today, Lake Merced is a vibrant ecosystem, and a great birding destination cherished by generations of Bay Area residents. It is utilized by humans for various purposes, some of which are the same as the original Ohlone inhabitants – fishing, boating – and some are entirely new, such as golfing, picnicking, jogging, and as an emergency non-potable water supply.


Natural History

Prior to the 1870s Lake Merced was a coastal estuary; during large rain events, the lake would fill up with water and overflow, creating a stream which connected the lake to the ocean. The lake drained an area of 6,320 acres in size, approximately 10 square miles which included Daly City, Westlake, and the Stonestown area of San Francisco.


a glimpse of Lake Merced in 1869

In 1895 , the Spring Valley Water Company built a dam at Lake Merced, disconnecting the lake from the ocean. This allowed the company to use the lake for drinking water.

Disconnecting the lake from the ocean allowed the Spring Valley Water Company to use the lake as a source of drinking water. As the city grew in the late 1800’s, so did its need to protect water sources for drinking. The sewer system was built to divert the creeks that drained into Lake Merced, protecting the lake from debris. After the SVWC was purchased by San Francisco, Hetch Hetchy water replaced Lake Merced water in 1934.

During the 1940s, the character of Lake Merced changed as new homes and roads were built. Lake Merced was officially designated as a park to be operated and maintained by San Francisco Recreation and Parks Department in 1950.

During the 20th century, droughts and groundwater pumping lowered the lake level. The lake is hydraulically connected to the Westside groundwater basin and is a surface expression of the shallow aquifer. Extensive pumping of the Westside Basin by golf courses, municipalities, and cemeteries developed in the post-War years lowered groundwater levels within the basin and surface water levels in the lake. The lake hit its lowest levels during the drought between 1989 and 1993. Since that time, the lake level has rebounded, due to the dedication of the SFPUC, CalTrout, the Committee to Save Lake Merced, and many other devoted stakeholders and groups.

Today, Lake Merced is still the city’s emergency non-drinking water supply. The lake also provides incredible habitat for birds and other wildlife and is also home to a vibrant boating community, both of which rely on a healthy watershed. The SFPUC and San Francisco Recreation and Parks Department are committed to maintaining and enhancing the many beneficial values of Lake Merced.

Last updated: 7/27/2018 12:50:43 PM