Ventura Park Cancun is, or was, a water park located in the southern part of Cancun’s Hotel Zone.  From what I could discover, no definite reason has been given for its closure, but the park has been in existence for many years so it might have closed for renovations.

If you are looking for an alternative water park, there is Jungala Aqua Experience which is located within the resort of Vidanta Riviera Maya–this is not an all-inclusive resort so you can readily access this water park.  Vidanta is located next to Valentin Imperial Riviera Maya.