I always thought that the delta was a triangle that was approximately
Sacramento-Stockton-Benecia. Most of this area is actually islands
that are just above or below sea-level, protected by dikes (like
holland). They are very impressively fertile.

And thus I never thought of Lodi as the Delta - it would be just to the
east of it, actually on real dry land. And most of the Contra Costa
vineyards are just to the south of it, again on dry land, near Byron
and Antioch.

The winds blow there a lot, especially in the evenings through the
summer. These areas are cooler than the rest of the Sacramento/San
Joaquin valley because of this, but they're still going to be a lot
warmer than the Carneros district (the part of Napa/Sonoma that is
right against the north edge of the SF bay). And with the high
fertility and water table, these vines are probably never stressed.

Don't know what that means for quality winegrape growing, but I can
tell you that I used to drive through the area a lot and never saw a
grapevine.

Rob