Sunday, December 17, 2017

Screw Pump symbolizes salty East Bay history

A stark angular wooden construction with fan blades rises out of the murk. At first glance it looks like a medieval instrument of torture, or a failed attempt at early flight.

It is neither, of course, though it is an important iteration of an ancient technology; it a wind-driven Archimedes screw pump, a remnant of the once thriving trade in salt endemic to the East bay.

Long before white settlers discovered the beds of evaporites along the sea shore near modern day Coyote Hills and Edwards reserve, Ohlone people traversed the estuaries in reed canoes, harvesting the naturally deposited sea salt by scraping it from plants or simply scooping it into woven baskets. When the Gold Rush drew thousands to the Bay Area in the early 1850s, Swedish immigrants were among the first to realize the area’s commercial potential. Salt was in demand at the time, not only for seasoning, but food preservation, tanning, and a host of industrial uses.

In 1852, Scandinavian sailor Josh Johnson expanded the naturally occurring ponds of the estuary by having Chinese laborers drain the marshes and create levees from wood, stone, and mud. At high tide the waters would flow through gates in the levees, then remain there to evaporate, leaving “bay salt” behind for collection.

Johnson sold his outfit to Swedish sailor August Ohleson in 1872, who changed his name to Andrew Oliver. Oliver’s family provided salt to tanneries, food processing, and packaging companies until 1982. It was Oliver who introduced the wind-driven screw pump to his salt production process. The pump was used to transfer water from one pond to another. Oliver also introduced a process of spraying sea water onto logs, where it would evaporate and leave salt to be scraped off, in imitation of the Ohlone method, but on a larger scale.

At the turn of the twentieth century there were about 17 salt businesses within the fifteen miles between San Leandro Creek and Centreville. The average wholesale price was about $35 per ton, with 17,000 tons produced annually. H. H. Wood’s 1888 history of Alameda County values the industry at more than one-and-a-quarter million dollars, with over a hundred workers employed in the trade.

The early years of the salt trade encountered foreign competition. Wood notes that speculators abroad would ship commodities to be auctioned at the port of entry. In this way, salt from Liverpool and the East came to California. Because of the abundance of native product, the allure of imports rested solely in the low price they had fetched at auction. Soon, however, the imports gained ground because of their higher quality. Only with improvements in processing introduced by Oliver and others did the quality of native salt equal the imports, and at a better price.

Improvements in salt-making included better management of the salt pond levels and salinity, which the screw pump facilitated. Archimedes (287–212 BCE) is credited as the inventor of the screw pump. It is most often used in irrigation, and consist of spirals encased in cylinders that raise water when turned. They have been in constant use for over two thousand years; the earliest versions found in Rome, Eqypt and Japan were turned manually. In the seventeenth century, the Dutch applied wind vanes to the pumps, a design forerunner to those built by Oliver, of which two survive. In 1984 the American Society of Mechanical Engineers designated an Oliver pump, restored in 1978, a Historic Mechanical Engineering Landmark. The original location was on a site now owned by Cargill in Newark, but In November of 2016, ASME and Cargill commemorated the moving of the pump to its new location at the Hayward Shoreline along the Oliver Brothers Salt Loop Trail (the commemorative 1984 plaque got a polish, too.)


Today, airline passengers arriving over the East Bay can spot from the air the salt marshes that still exist, due to their intense color. Microorganisms of different colors and saline tolerances, as well as brine shrimp, provide the rich hues, which can change with the weather. At one time over 80% of the Bay’s wetlands succumbed to salt farming and related industry, but in 2003 Cargill, Inc. who owned more than 16,000 acres of the affected wetlands sold 15,100 acres to State and Federal agencies as well as private foundations, like the South Bay Salt Pond Restoration Project, who are in the process of restoring them to their tidal wetland beginnings by reintroducing bay water to the ponds and attracting wildlife.

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