The accident happened Sunday around 7:30 p.m. in the 18900 block of Sandridge Court, where Sheriff Ed Gonzalez said a boat struck a bulkhead, which is essentially a wooden retaining wall behind houses along the water.
Neighbor Letty Battistoni said patrol cars, an ambulance and even a helicopter filled her street after the crash.
"I took a picture of the boat because I wasn't sure if it was a boat or not. It was so mangled," Battistoni said.
Gonzalez said Ruiz suffered severe leg injuries and was transported to a hospital via Life Flight. A woman was also rushed to the hospital by ambulance. But a third person, a man, is still missing.
Ruiz and the woman who was injured were not wearing flotation devices, authorities said.
"With a car crash, your evidence is on the ground or with the vehicles and with a vessel, our first problem is keeping evidence afloat and finding victims. So there's some obstacles we've got to work through," said Eric Minter, Texas Parks and Wildlife Department Game Warden.
Investigators credit fast-acting residents with saving the lives of the two people who went to the hospital.
Officials told ABC13 the boat was seen going very fast right before it crashed and alcohol was found on board.
"From what I've seen there was a severe impact, so it was a serious collision," Minter said.
Investigators are working to reconstruct the accident and find the man who went overboard. Minter says boats and barges traveling on the river could make that more difficult.
Meanwhile, Sean Teare with the Harris County District Attorney's vehicular crimes division, said the driver is being charged with boating while intoxicated, causing serious bodily injury. Teare, who didn't initially release Ruiz's name, revealed that he does have other alcohol-related charges in Texas.
Teare said the driver could face more charges if the missing person is found dead.
Follow Katherine Marchand on Facebook and Twitter.