Bon Tempe Lake is a reservoir existing in the Mount Tamalpais Watershed nestled on Mount Tamalpais in Marin County California. Access to Bon Tempe Lake reservoir is possible by paying a toll to the Marin Municipal Water District at the Ranger Station on Mount Tamalpais. Bon Tempe Lake’s reservoir was originally constructed in 1948, well after the only concrete dam in the watershed, Alpine Dam, was established. The Bon Tempe name is, according to the Marin Municipal Water District, to be an “Americanization” of a local ranching and dairy farming family’s last name, Bautunpi. The Bautunpi brothers ranch and dairy operation was ultimately moved in order for the Bon Tempe and Alpine Lake reservoirs to be created.1 The watershed area had long been in development though by the municipal department, with the Marin Municipal Water District having purchased nearly 25,000 trees from the Fort Bragg area in order to properly reforest throughout the Mount Tamalpais Watershed.
(Bon Tempe Lake, https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Bon_Tempe_lake_%28294925189%29.jpg/264px-Bon_Tempe_lake_%28294925189%29.jpg)
Today, there are five reservoirs in the Mount Tamalpais Watershed, collectively capturing millions of gallons of rainwater annually for the community. This water is cleaned and supplies nearly 200,000 of approximately 250,000 Marin County residents.2 Without Bon Tempe Lake and the other Mount Tamalpais Watershed reservoirs there would not be enough water for the community to thrive. With the remainder of the Marin County population getting their water from the Russian River due to their proximity, failing to preserve Bon Tempe Lake reservoir means failing to protect Marin County resident’s access to clean drinking water. Beyond the practical use for Bon Tempe Lake, there are also the recreational and societal contributions the landmark brings to the community. Like the surrounding Mount Tamalpais area, Bon Tempe Lake’s scenery is remarkable.
The calm but sunny lake rests about 720 ft above sea level but based on the serenity felt there that doesn’t feel right. The quiet but not lonely atmosphere creates the illusion of being high in the mountains at a place only locals know, when in reality Bon Tempe is about thirty to forty minutes North of the Golden Gate Bridge. Being such a unique blend of close to San Francisco but feeling hundreds of miles from any big city is only a fraction of the significance of Bon Tempe Lake. The lake is 140 acres across its surface, and features trails wrapping around the shores creating a four-mile loop that is frequently walked by visitors. Because of the other components of the Mount Tamalpais Watershed nearby, there is a vast network of trails linking lake reservoirs together too, making this area extremely popular for walking, hiking and cycling.3 Bon Tempe Lake is home to not only incredible scenery and recreation though, but also many different species of plants and animals.
(Mount Tamalpais State Park, https://www.alltrails.com/_next/image?url=https%3A%2F%2Fimages.alltrails.com%2FeyJidWNrZXQiOiJhc3NldHMuYWxsdHJhaWxzLmNvbSIsImtleSI6InVwbG9hZHMvcGhvdG8vaW1hZ2UvNjM0MDIxMTQvNzM5MzU0MTQ3YjgwYmMzOTExMTg4ZjFiYTdlOWZlMzAuanBnIiwiZWRpdHMiOnsidG9Gb3JtYXQiOiJ3ZWJwIiwicmVzaXplIjp7IndpZHRoIjoxMDgwLCJoZWlnaHQiOjcwMCwiZml0IjoiY292ZXIifSwicm90YXRlIjpudWxsLCJqcGVnIjp7InRyZWxsaXNRdWFudGlzYXRpb24iOnRydWUsIm92ZXJzaG9vdERlcmluZ2luZyI6dHJ1ZSwib3B0aW1pc2VTY2FucyI6dHJ1ZSwicXVhbnRpc2F0aW9uVGFibGUiOjN9fX0%3D&w=3840&q=90)
Marin County’s Bon Tempe Lake is a refuge for nature and wildlife. Mount Tamalpais itself is home to many mammals. According to the California State Parks website, you can expect to see “raccoons, gray foxes, squirrels, bobcats, coyotes, black-tailed deer, and mountain lions…”4 many of which are often found drinking at Bon Tempe Lake. There are also over 150 different species of birds in the area, with red-tailed hawks, harriers and turkey vultures often soaring above the reservoir waters, making bird watching a common recreational activity in the area. The shores of the lake have hiking and cycling trails, along with fishing and non-fishing spots. Those fishing the Bon Tempe Lake reservoir can expect to catch primarily the beloved rainbow trout along with occasional bass or sunfish. Weather is almost never a concern for visitors of Bon Tempe Lake reservoir.
(Rainbow Trout I'd caught on my visit to Bon Tempe Lake)
Thanks to the relatively stable climate of coastal Northern California, most days of the year the lake and its surrounding trails are easily navigable. That mild climate also means that an abundance of plant life is able to thrive on Bon Tempe Lake reservoir’s shores. Mount Tamalpais, which Bon Tempe Lake is on, is home to over 750 different native plant species, including massive swaths of forests. In the nature nearby, there are more than 2,000 acres of oak woodlands, more than 6,000 acres of coast redwood forests, almost 7,000 acres of Douglas Firs, and another nearly 4,000 acres of coastal shrublands.5 This nature surrounding Bon Tempe Lake is essential to protecting and preserving the Mount Tamalpais Watershed. With the aggressive fire seasons, especially recently in California, there is usually some form of fire safety evidence to be seen nearby the Bon Tempe Lake shores, such as manicured woodland fields or piles of dead material in the trees to be removed.
Recently, Marin Water has proposed connecting Bon Tempe Lake Reservoir with another of the Mount Tamalpais Watershed lakes, Phoenix Lake, via an eighteen-inch diameter pipeline in order to improve operational accessibility and efficiency. During the environmental review for the proposed project, it was determined that there shouldn’t be adverse effects on the environment as result of the project.6 One owl population, the Northern spotted owls nesting season conflicted with construction work. This conflict was taken into consideration when planning construction phases so the animals would not be disturbed. This dedication to preserving the natural beauty and ecosystem surrounding Bon Tempe Lake is part of why the landmark is significant in the community.
The importance of the Bon Tempe Lake reservoir, along with the other Mount Tamalpais Watershed waterbodies to Marin County cannot be overstated. Providing the county with clean drinking water, along with serving as the home to a plethora of animals and plant life. Marin County’s primary source of water is much more than a holding chamber for rainwater, and more so a representation of the community’s dedication to nature and preservation.
Work Cited
1 “Historical Highlights - Marin Municipal Water District.” Marin Water - Historical Highlights, 2020, www.marinwater.org/sites/default/files/2020-11/Historical%20Highlights%202020.pdf.
2 “About the Mt. Tam Watershed: Marin Water.” About the Mt. Tam Watershed | Marin Water, www.marinwater.org/AboutMtTam. Accessed Feb. 2025.
3Bon Tempe Lake Loop | Map, Guide - California | Alltrails, www.alltrails.com/trail/us/california/bon-tempe-lake-loop. Accessed Feb. 2025.
4 California State Parks. “Natural and Cultural History.” California State Parks, www.parks.ca.gov/?page_id=28500#:~:text=Wildlife,-Mammals&text=Raccoons%2C%20gray%20foxes%2C%20squirrels%2C,before%20the%20park%20was%20established. Accessed Feb. 2025.
5 “Plants & Fungi.” Plants & Fungi | One Tam, www.onetam.org/peak-health/plants. Accessed Feb. 2025.
6Phoenix - Bon Tempe Connection Project, www.marincounty.org/-/media/files/departments/ar/county-clerk/noa-filings/noa-phoenix--bon-tempe-connection-project.pdf?la=en. Accessed Feb. 2025.
