The Pacific DC Intertie - runs about 500kV, 3,000MW+, terminates in Sylmar, CA, right about the same place that the California Aqueduct comes over the mountains down into Sylmar as well. If you're ever in California, this area is just south of where California Route 14 merges with I-5, just north of where I-210 merges with I-5.

http://www.abb.com/cawp/gad02181/c3e8e6cc588aa8c3c1256d8800402284.aspx

When I was working in SoCal, I went to a couple of IEEE meetings where the evening's discussion was on the challenges of the DC Intertie. One of them was the study required to show pipeline operators that the saltwater return circuit was sufficient to avoid galvanic corrosion of the pipelines running up/down the coast near the Intertie.