I’ve written before about the rocks around Lake Temescal, but not about the lake — the reservoir — itself. It was the East Bay’s first meaningful impoundment of drinking water, and in a way an early example of a typical Bay area human undertaking: the startup.

For a hundred years, starting with the Spanish missions, the residents of the Bay area got their water supplies from wells. Certainly it was true of the Oakland area, starting with the Mexican ranchers and the Americans who moved in after 1850. But pretty soon a few ambitious entrepreneurs set their eyes on the streams flowing from the Oakland Hills. Their businesses would grow with the ambitious city.

Temescal Creek was the handiest candidate, a clean permanent stream with headwaters in the remote farmland behind the hills of Piedmont. Enoch G. Bidleman was first to incorporate and build dams up there on his ranch, where the stream cut a narrow gorge. But his half-built dams were washed out in the winter of 1865, and while he was planning to rebuild them he filed an application with the city of Oakland to run pipes and supply customers. The City Council was sitting on his application.

Anthony Chabot (1813-1888) came to town at that time with big-time water works on his mind. He was already the foremost “water man” around, having innovated hydraulic mining in the Sierra gold fields and started San Francisco’s first water system.

^{From Myron M. Wood and J. P. Munro-Fraser’s History of Alameda County (1883)}

Looking at the hills, he envisioned reservoirs on Temescal Creek and especially on San Leandro Creek. His scheme depended on starting small, building as fast as possible, and bootstrapping his way up. He incorporated the Contra Costa Water Company, with a quarter-million dollars of funding, and applied to the city for a franchise. A few weeks later in July 1866, the Council awarded Chabot a franchise that gave him 18 months to lay down 3000 feet of pipes and connect every customer he could supply — and did the same for Bidleman.

Chabot couldn’t waste a minute. He scrambled to buy water rights in the hills around the valley upstream from Bidleman, a tedious but essential preliminary. As a backup plan he did the same down at Sausal Creek, in the hills above Fruitvale. (Fortunately Bidleman gave up his plans and made no trouble.) Meanwhile he started running six-inch pipes from the waterfront up Broadway, then Telegraph, toward the hills. When the pipes reached the creek at Solomon Alden‘s ranch, near the village of Temescal, he secured an intake there and by June 1867 Chabot had what you might call version 1.0 of his plan in place, serving a few Broadway buildings with the “pure, fresh water” specified in the deal.

In short order he ran pipes to a new intake higher up, above College Avenue, to provide better water pressure and then built a large holding tank on top of Pill Hill that allowed his company to supply the upper floors of the downtown offices — versions 1.1 and 1.2. That fulfilled the terms of his franchise, but Chabot had just gotten started.

All this time he was working on the dam upstream, where a reservoir — at first called Lake Chabot, then Lake Temescal — would deliver version 2.0. The geology there gave him trouble.

I have to take a minute to talk about my sources. Anthony Chabot left no personal papers, or if he did they’re lost. The Contra Costa Water Company ended up part of another water company, and in 1899 all of its records were burned. The newspapers available on newspapers.com from the late 1860s are fragmentary. My main source for this post is the late Sherwood Burgess’s 1992 book The Water King – Anthony Chabot: His Life and Times, which relies on his 1948 master’s thesis about the construction of the reservoir. If and when I read that thesis, I may adjust some details.

Burgess repeatedly says about the canyon where Chabot put the lake that it was a U-shaped valley. I have no map to verify that, but it fits what a stream would do in that setting. The Hayward fault is mapped here in two active strands on either side of the lake, which would create high rocky walls flanking a gully dug where two branches of Temescal Creek converge, the former Kohler Creek from Thornhill Canyon and the former creek in Temescal Canyon, sometimes called Caldecott Creek. This photo of the reservoir from the mid 1880s shows what the hills looked like for thousands of years until the turn of the 20th century.

^{Bancroft Library}

Chabot’s plan was to dig a wide trench down to bedrock where the dam would go, build a high, thick core of clay in the trench, then lay a mantle of dirt and gravel upon the core to create the dam. The first place he tried was a narrow spot buttressed with rock outcrops, but his Chinese crew couldn’t reach bedrock and he had to start again at a wider spot about 300 feet downstream. His crew hauled in the clay with horse-drawn wagons, spread it in layers, and tamped down each layer with the horses. After that, to save time and effort, Chabot used his tested hydraulic methods to wash down dirt and rock from the sides of the canyon and pile the material upon the clay core. The resulting earthen-core dam was 105 feet high when finished, the largest work of construction ever undertaken in the Bay area at the time. Water from the new reservoir reached customers in July 1869.

That was version 2.0, ready just in time for the economic boom everyone knew would happen once the transcontinental railroad arrived at Oakland later that year (and when much of Old Oakland was built). With the success of his water project, Chabot could start his ultimate upgrade to version 3.0, the really big dam on San Leandro Creek and the reservoir now known as Lake Chabot. He accomplished that five years later.

One serious mishap along the way happened some time in late 1868. Chabot had constructed a 50-foot brick tower to house the intake for the main water line, standing inside the reservoir like the one at Lafayette Reservoir. But as the reservoir was gathering water behind the dam, something caused the tower to collapse, and Chabot had to substitute something quick and dirty instead.

Now Burgess says the collapse was blamed on a landslide. I don’t think so. There could have been small landslides in the freshly exposed bedrock or the steepened canyon slopes, true, but I know for sure there was a major earthquake that October, and the Hayward fault definitely ruptured the surface just up the valley where Montclair Village is today. There were also months of aftershocks, which are well known for knocking down previously damaged structures. We may never know for sure, but that’s what I think.

The 1897 topographic map shows the two branches of Temescal Creek meeting at the reservoir, and the lake itself has a forked shape.

It doesn’t look that way today because the eastern part was filled in starting in the 1920s. A more accurate topo map from 1915 shows it better.

Already the electric Oakland, Antioch and Eastern rail line had been pushed through, soon to be followed by roads that became today’s Route 13. (The East Bay Hills Project has all sorts of photos of these changes, a great resource.) Here’s what that railroad bridge looked like in its heyday.

^{Lifted from eBay}

Lake Temescal was a working reservoir through the 1920s, but when EBMUD took over all the private water companies and began delivering water from the Sierra Nevada, that stopped. A few years later it began selling this suddenly-surplus asset to the newly-formed East Bay Regional Park District, and it became the popular swimming and fishing spot it remains today. At that time the park district lowered the water level and took 40 feet off the dam.

I said it here a long time ago and I’ll say it again now: the dam will not fail in an earthquake, even the worst one seismologists can foresee on the Hayward fault. Whether Anthony Chabot knew it or not when he started, he surely knew his first big dam was earthquake proof when he finished.

This entry was posted on 8 December 2025 at 7:55 am and is filed under Hayward fault, Oakland streams and water. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.