California Dreaming

Thanks for the suggestions on the possible content of the WU climate page. Always collecting ideas here - keep them coming.

When I was on sabbatical at Lawrence Livermore National Lab a couple of years ago, I started exploring the delta of the San Joaquin and Sacramento Rivers. This is a fascinating region, especially as it stands in contrast to the San Francisco - Oakland metro areas and Napa and the Central Valley - all of which border the Delta. If you come to the Delta from Vasco Road, north out of Livermore, you curl through part of the huge field of wind turbines that are part of the Altamont Pass. To the west, Mount Diablo bulges from the ground. After you cross the San Joaquin River Bridge, you are driving on top of levees. Many of these levees were built by Chinese laborers after they had built the railways. The towns, which sit below the levees, with the rivers held above, have old Chinatowns and Japantowns.

These levees stand between the salt water of the San Francisco Bay and the interior of California. They hold back the snow melt of the Sierra Nevada, and this is the drinking water for millions; it allows the agriculture of the Central Valley. In the islands of land below the levees there are fields of fruits and nuts, and small towns in varying states of robustness. What struck me first was seeing the elevation of these towns, many miles from the Ocean and the Bay - 11 feet above sea level.


Worrying types like me marvel at the importance and vulnerability of this area. There is so much hydraulic pressure on these levees that fresh water rivers, many miles from the coast, feel two foot tides. This is an area of great earthquake risk. The levees age. The land sinks. Sea level rise of only a few feet increases the pressure on the system. The potential risk of climate change on this area appears, to me, as great as any hurricane risk to Gulf Coast and Atlantic cities.

On a clear day you can see, to the east, the Sierra Nevada across the Central Valley --- The Big Valley, anyone remember The Big Valley? This part of the U.S. has a distinct wet-dry season climate. It is strongly impacted by El Nino. It has rain on the upslope of the mountains and desert in the rain shadows. Historically, the Sierra Nevada Mountains have held a lot of water in snow. That melt is earlier; the Delta has to accommodate greater surges of water. There is water management engineering of every type.

This area is under stress from population and demand. This is irrespective of climate change, but climate change amplifies the stresses. This is the case in many of the impacts of climate change - amplification of existing stresses. This vulnerability to climate change is one of the reasons, very concrete and pragmatic reasons, that California has taken such assertive steps on climate change policy.


Here's a picture from California's Climate Change and Water Resources page.

Here you can see how one state is thinking about the problem.