I've actually found it really difficult to find area-specific information on growing particular plants. For example: I needed information on blueberries recently and didn't find much here or online in regard to how they'd handle my zone.
Call a local nursery. Not a chain store like Lowes, but a ma-and-pa shop type. Or call around and ask the same questions until you get someone really helpful, then stick with them.
For example: I did some research on blueberries so I had a general idea of what I needed to do, but couldn't find out what variety was best for here and how well it would do. I called a local nursery, and the guy on the phone was able to tell me what types they had for sale that would grow well here, how to plant them, when was best to plant them, what type of sun they like here, what I needed to do to my local soil, how old the plants were and how I needed to care for them, the price per plant, you name it!
So in regard to your wine grapes (Oh how I envy you for having the water to grow them!!), definitely call local nurseries until you get one that can tell you all of that and more about your grapes. And when you do get them established and fruiting, please post pictures because I'm an avid Wine-o and swoon at the Cab and Zin grapes.
Good luck!
-Habs
