Two minor injuries were reported when a vessel synchronization technical glitch on the Intamin river rapids ride resulted in traffic congestion. One of the boats started to take on water, which caused panic among riders. Source
Accidents
Theme parks and roller coasters are statistically very, very, very safe. Out of the millions of people who ride the thousands of rides every year, there are only a small handful of incidents. You are statistically more likely to be involved in an accident driving to an amusement park than having one at a park. The rarity of accidents is one reason why the media report them, similar to plane crashes.
Every important element of a ride is inspected on a regular basis and every ride is tested every day without passengers before it opens. A ride might not open, or a safety system might activate, if there is an imperfection. For theme parks to operate, they must obtain insurance and one stipulation is their rides are frequently inspected and signed off by a strict Health & Safety governing body. Every theme park does what they can to prevent accidents because the negative press would be bad for business.
Having said all that, theme park accidents still happen…
Tea Cups, Dreamland, Margate, England, UK
A mother and her three-year-old daughter were injured when the spinning teacup they were sitting in detached from its base and sent them crashing into railings. Source
Bounce, Oakwood Theme Park, Pembrokeshire, Wales
Several people were injured when the passenger gondola suddenly dropped to the ground from approximately halfway up the 148 feet (45 m) tall Huss shot ‘n’ drop tower during an emergency stop. Source
Triops, Parc Bagatelle, Merlimont, Hauts-de-France
Three 13-year-old girls were treated for shock after the Vekoma Invertigo coaster stalled nearly 100 feet (30 m) above the ground and about 20 people, mostly middle-school students, were safely evacuated from the ride. Source (in French)
Republica de los Ninos, La Plata, Buenos Aires, Argentina
Several people sustained injuries Sunday when the park’s train derailed. Paramedics treated five adults and a child for minor injuries on-site and transported one girl to a local hospital for observation. Source (in Spanish)
Pool, Wild Rivers Water Park, Irvine, California, USA
A 12-year-old boy experienced a medical-related incident outside a pool at the Los Angeles area water park. The boy was rushed to a hospital, where he later died. Authorities did not disclose the nature of the medical aid call. Source
Banshee, Kings Island, Mason, Ohio, USA
A 38-year-old man was struck in the head by the B&M (Bolliger & Mabillard) inverted coaster and died after entering a restricted area to retrieve his car keys. Source
Pool, Six Flags Hurricane Harbor, Arlington, Texas, USA
A 17-year-old male employee was taken to a hospital after being pulled from a pool at the water park. The incident took place when the park was closed to the public. Source
Froggit Jump n Smile, Lambeth Country Show, London, UK
Four people, including an 11-year-old girl, were taken to hospital after the SafeCo (Spain) manufactured ride malfunctioned at the funfair in Brockwell Park. A man and woman in their 40s were treated for life-threatening injuries, while the child and a man in his 50s sustained minor injuries. Source
Golf Cart, Disneyland, Anaheim, California, USA
A 60-year-old female worker died two days after falling from a golf cart in the backstage area at Disneyland. The employee, who worked as an administrator for Club 33 (the exclusive members-only dining club located above the Pirates of the Caribbean attraction), received a head injury in the fall. Source