The Bay Model to the Rescue


October 22, 2014

Imagine a 600 foot wide earth and rock dam where the Richmond Bridge stands today. Imagine that where the Larkspur Ferry currently plies the sparkling waters, there was a huge concrete submarine base, and that Richardson's bay from mid-Sausalito to the north end of Belvedere had been filled in to accommodate a torpedo boat base.

These and other indignities might well have come to fruition had it not been for the United States Army Corps of Engineers and the hydrologic model it built in the former outfitting warehouse of Sausalito's abandoned Marinship Ship Yard in the 1950s.

John Reber, a promoter and former theatrical producer, had stirred up great controversy following World War II with a plan to dam San Francisco Bay. His plan was to create two huge fresh water lakes by impounding the waters flowing through the delta from the Sacramento and San Juaquin Rivers. 

Not content with just turning San Pablo Bay into a 160,000 acre lake and the South Bay into a 120,000 acre one, Reber also wanted to extend the shore-side of Berkeley and Richmond into the bay.

It would have been tremendously expensive. But would it have worked? Answering that question became the job of the United States Army Corps of Engineers who have authority over the navigable waterways of the nation, including the San Francisco Bay Estuary.

In the days before high speed computer modeling, the only way to predict how complicated waterways would behave under changing conditions was to construct a simulation of the system and watch how it behaved. 

The Corps took on the challenge of modeling the complex estuary with its fresh water inflows from the Delta and its salt water flows in and out of the Golden Gate with the tides. This is one of the largest and most complex hydrological systems in the world and and it is constantly changing.

Before the Gold Rush of 1849 it covered nearly 700 square miles including San Pablo, Suisun and Richardson's bays. By the 1960s and 70s the incredible shrinkage of the water area had become obvious with not much more than 450 square miles left. What’s more, the depth of the water had been drastically reduced, mostly by the sediment washed down the rivers from hydrologic mining.

Congress authorized the Corps to construct a physical simulation of the bay - a gigantic bay model - with which it could predict just what would actually happen if Reber's plan was put into effect. 

The Corps built a model that covers 1.5 acres with most of the geography of the Bay Area recognizable at a glance. There's the Golden Gate Bridge – they put a model bridge over it even though the span above the water doesn't affect the flows – the shoreline of Sausalito, Belvedere, Strawberry Point and other features all the way down the peninsula around the South Bay and up past the Port of Oakland, Berkeley, Richmond and around San Pablo and Suisun Bays. On one side is the expanse of open ocean from which tides surge in and out, and on the other is a winding network of channels representing the delta.

With the model in place, the Corps was able to place dams in the locations envisioned by Reber and then watch what happened. 

The result? The South Bay, which has no major river flowing into it, would rapidly evaporate becoming one big salt flat. Evaporation would also affect the North Bay "lake" which would worsen rather than improve the delta's ability to help meet the water needs of agriculture, industry, residential communities. 

Those results were published in 1963, sounding the final fatal knell for the Reber Plan which had already begun falling out of favor as the environmental movement and efforts to "Save the Bay" began to take on increased importance.  Cleaning up the bay became more important than closing it off. 

Reber, meanwhile, did not have to read the final report. Corps Ranger Linda Holm, who leads visitors through the Bay Model today, says he died a year or so earlier. 

Today, the Bay Model is no longer used as a hydrologic model. Instead, it is a gigantic educational tool open to students, residents and tourists who want to learn about the history and the promise of the San Francisco Bay Estuary.