Can my employer pay me a lower wage when I request a transfer to another dept?

I was working at a hospital in management as an RN when my position was eliminated due to budget cuts. I was told I could transfer to work as a staff RN in any dept. that had an opening. I transferred to ICU because I had been an ICU nurse ten years earlier, but no recent experience. They transferred me in at the top of the staff nurse pay scale.

Six months later an opening came up in the unit I wanted to work in, which was one in which I had no experience. I was offered the job at approx. $5.00/hr less; and was told it was due to my lack of experience, and that if I transferred in at my current wage rate, I would be making more than nurses who had worked in the dept. for many years.

Is this legal? To the best of my knowledge, other nurses in the hospital do not take a pay cut to move to a dept. they are inexperienced in.

This is a non-union hospital in California.