Suicide by bridge is gruesome, and death is almost certain. People have survived the fall, but not many. You might survive if you hit the water feet first and come in at a slight angle.
The impact is tremendous. The body goes from roughly 75 to 80 mph to nearly zero in a nanosecond. The physics of inertia being what they are, internal organs tend to keep going. The force of impact causes them to tear loose. Autopsy reports typically indicate that the jumpers have lacerated aortas, livers, spleens and hearts. Ribs are often broken, and the impact shoves them into the heart or lungs. Jumpers have broken sternums, clavicles, pelvises and necks. Skull fractures are common.
Which means you die one of two ways, or a combination of both. One, you hit the water and the impact kills you. Sometimes the jumper is knocked unconscious. Other times, the jumper survives for a time. The person can be seen flailing about in the water, trying to stay afloat, only to succumb to the extensive internal bleeding. Death can take seconds or minutes. Two, you drown. You hit the water going fast, and your body plunges in deep. Conscious or otherwise, you breathe in saltwater and asphyxiate.
You can usually tell which bridge jumpers drowned: Frothy mucus bubbles from the nose.