and considering the enormous amount of energy needed to pump that water from either the Colorado river, or from the Delta and over the grapevine

Actually it goes through the grapevine. There is a long tunnel going through the mountains there.

http://www.hellolosangeles.com/Landmarks/Tunnel/269567/Aqueduct_Tunnel.cfm

I tried to find pictures of it before it was put into use. I found them once before. In addition, energy reclamation techniques such as siphoning (the water going downhill in the pipe is used to push/pull the water up the hill) and using the downfall to generate electricity are used. Even so, moving water around CA requires an incredible amount of energy.

http://www.spannertech.com/water/
http://wsoweb.ladwp.com/Aqueduct/historyoflaa/worldrecords.htm
http://www.ladwp.com/ladwp/cms/ladwp004409.jsp