Oakland has performed many large feats of civic strength on its way to greatness. I think the largest one was turning a shallow slough into a world-class harbor. It began with a pair of big stone walls.

Oakland was founded in 1852 beside a gentle inlet, named San Antonio Creek for the hamlet around the boat landing at its eastern tip, which served the Rancho San Antonio starting in the 1830s. The creek had a meandering channel deep enough for small vessels to use, provided they could sail over an offshore bar that was barely knee-deep at low tide. Here’s how San Antonio Creek was mapped in 1857.

Soon efforts began by town citizens, and later by the county, to dredge a ship passage through the bar so the ferries would no longer get stuck there. Shipping traffic grew, but not fast enough for the ambitious town — nor for the railroads. The Union Pacific Railroad, which co-owned Oakland’s waterfront through its unholy alliance with founding scoundrel Horace Carpentier, used that land to run long extensions past Oakland to terminals out in the Bay, where ferries brought freight and passengers directly to and from San Francisco. Other railroads built long jetties from Alameda with the same scheme. Oakland contended against San Francisco at state and federal levels to get a fair share of port traffic for the good of California and the nation.

In March 1873, Congress ordered the Army Corps of Engineers to create a plan of long-term improvements that would make Oakland’s harbor second to none. The Oakland Daily Transcript predicted that the federal project “will pay for itself one hundred fold within the next twenty years” and gushed that “among all the growing cities of the Pacific none has a brighter prospect before it than Oakland. As the terminus of railroads and a harbor for ships, it is a center of traffic. . . . The basis of its future greatness is as secure as the foundation of its lasting hills.”

The engineers’ dream plan came out a year later and had four working parts. First, a pair of long stone walls 800 feet apart would direct the flow of the tides to flush the channel clean and remove the need to dredge it. Second, a large excavated basin just past the harbor would collect more tidal water to increase the flushing. Third, a canal would connect the harbor to San Leandro Bay and bring in even more flushing water. And fourth, a dam at the mouth of San Leandro Bay would trap water at high tide to provide still more flushing power. (The same scheme had worked for Lake Merritt a few years earlier.) It would be up to the city and private investers to add wharves and piers to the picture.

The calculations made sense, Congress passed some money, and contracts for the stone “training walls” went out later that year. At first the rock was delivered from quarries on Yerba Buena Island, then known as Goat Island. The work had good results by 1876, when Mayor Mack Webber reported that the improved current had scoured the bar to a depth of eight feet, allowing larger ships to visit Oakland.

Training walls of this type were a standard technique at the time, but ours is the best-preserved example still at work today. The two walls were built cheaply but efficiently of riprap, stones a foot or two in size, carefully faced on top and sides with dry-stone masonry, using larger slabs, to protect the pile from storm waves and ships’ wakes. You can still see it on the Alameda side of the channel, where the south training wall is intact.

Work took much longer than anticipated, and Major George H. Mendell, who oversaw the work to uniform high praise, had himself a whole career here. As the Tribune lamented, “There is only one thing Congress can be counted on to do, and that is to cut down about 75 per cent. of the amount needed and asked for.” From 1878 to 1880, funding ceased while the railroad absurdly claimed to own the whole territory. Work resumed with rock from Point San Pedro, then from Telegraph Hill.

The training walls were basically done in 1884, but more work went on another ten years. In the end, the Tribune reported, “the stone employed came from the Poligate quarry on the San Bruno road; the Jordan quarry, at Point San Pedro, on San Pedro [now San Rafael] bay; [and] the Second street quarry, and the Chase and Kelso quarries on Telegraph hill.”

The railroads took advantage of the training walls immediately: the Southern Pacific pushed a new jetty into the Bay along the southern wall, and the Central Pacific put up wharves on the northern side. As further dredging deepened the channel, the spoils were pumped onto the shore to reclaim the marshlands. The USGS topo map from 1899 shows how things stood when the work was done.

Oakland’s own harbor came last, after the railroads, and after Alameda had turned its side into a great shipbuilding center. Once Oakland regained ownership of the waterfront in 1909 and established the autonomous Port Commission in 1925, the harbor area was entirely remade to its prosperous state today. We keep dredging the harbor channels deeper, past fifty feet, to fit the world’s largest ships.

Here’s the channel entrance today, defined by the training walls.

The northern training wall was dismantled in 2001 as the harbor was improved, but stones from it were made into the short replica pier in Middle Harbor Park. The variety of the stone sources accounts for what I consider its singular attractiveness.

The southern training wall is still on the job; its presence governed how the entire west end of Alameda was built out. Today the wall has sunk a bit, and the sea has risen a bit. It used to stand higher above water. It’s not being maintained.

But this sturdy piece of old history still plays a crucial, visible role in our prosperity.

This entry was posted on 28 September 2026 at 8:03 am and is filed under Deep Oakland, Geoheritage, Oakland stone. 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.