Golden Gate barrier would create many issues

I am writing in response to Dr. Kenneth Olshansky's letter published March 8. His suggestion that we should plan for catastrophic sea level rise in the Bay Area by limiting water flow into San Francisco Bay from the Pacific Ocean seems, at face value, a sensible approach to this looming problem.

Certainly, an adjustable barrier across the Golden

Gate could function like the Thames Retractable Barrier system in England. It protects most of Greater London from very high tides, a problem we already have here on occasion.

The major problem is the practicality of building a movable barrier to a depth of over 100 meters. Moreover, when the sea level eventually rises to the point that, even at low tides, protection becomes necessary, a permanent barrier would be required, similar to the Dutch Afsluitdijk, a dyke closing off a sea inlet creating a lake.

However, doing this would abolish all shipping in or out of San Francisco Bay and Sacramento. Moreover, as runoff from rivers accumulated in the bay, a pumping system would be required. Yet this runoff could convert the bay gradually into a freshwater reservoir for agriculture and household water supply, eventually obviating some or all of the need for pumping to the ocean.

There are many scenarios that have to be considered.

— Ernest B. Hook, San Rafael