Exactly what caleb said... but since your here, that means no matter what we say... your probably going to jump anyway. So i might as well advise the safe way. Its about 20ft deep but there are rock shelves on the right that you can't see so jump out and in the middle, make sure you wear shoes and cross your arms like your going down a bullet slide and grab some goggles take a swim and kinda scout the area before hand. If the police are present then you'll be sentenced to suicide classes due to the height. Your not supposed to do it and i shouldn't be typing this... but i'd rather tell you the right way before you mess up and get hurt.
12-16feet maybe, no more
If youre thinking about jumping into the water from the bridge, I'd advise against it. People have gotten seriously injured, become paralyzed, or died jumping from the south bridge. The water flowing under the north bridge is maybe knee deep.
Thanks! Your answer is awaiting moderation.