Light Blue Snake; Found In Mountains Of Southern California Who Was Able To Stand Vertically. Can You Help Me Find The Origin And Name Of This Snake?

I saw a snake similar to this swimming in my friends lake in southern illinois. It did not seem aggresive but it did not like being bothered either.  It was red on the top and the blue on this page on its belly. Is this similar to the snakes you saw?

The same thing happened to me but my encounter was next to Lake Alminore, California and it was in the 1950's. My snake was turquoise blue actually close to the color of the blue lettering on this page. It stood about 3 to 4 feet high in grass. It definetly stood above the wild oats. I saw it twice and have always wondered what I saw. I didn't think there was any snake other than a cobra that could stand vertically.

Well I do not know but I came across one hunting in Illinois. The snake I came across was the same color blue found on this page. (check spelling)