1979 | San Joaquin Delta
Don’t let the dry land here fool you — much of it is below the high tide line, or high levels when rainfall or Sierra snowmelt churn through the combined Sacramento and San Joaquin River deltas. These two streams drain almost sixty thousand square miles, and the outflow must eventually pass through the narrow Golden Gate, only a single-span bridge wide.
The Delta region itself is over a thousand square miles, much of it farmland. To claim this as such, a thousand linear miles of levees have been constructed to convert this area from marsh and lowland. The problem with levees is that they sink into the soft geology below, and when more fill and rock is added to their tops, this subsidence is aggravated.
During this photographic survey project in 1980-81, I spoke to many engineers along the route of the California Aqueduct (whose first of eight pumping plants is near here), and several of the Delta specialists spoke of the area with deep sobriety, describing the whole region as a “time bomb” — if one levee should fail in a substantial way, the breaches would cascade, and many other levees would fall like long dominoes, and brackish water would roll in with the tides, salinating the topsoils and building marshlands again.