SANTA CLARA, Calif.—Great America amusement park reopened its wave pool with new restrictions Saturday, six weeks after a 4-year-old boy drowned in the attraction.

Carlos Alejandro Flores of San Jose was found unconscious July 12 in two feet of water in the 355,000-gallon Great Barrier Reef wave pool. He was the first person to die in a wave pool in California, according to the state's Department of Industrial Relations, which created new rules for the attraction.

Under those rules, children less than 4-feet tall must wear life vests, kids shorter than 42 inches have to be accompanied by an adult and all children must wear color-coded wrist bands to let lifeguards know their height range.

The rules could be extended to wave pools at other amusement parks when the final investigation into last month's drowning is complete, officials said.

The industrial relations department also said the park must develop new rules to reduce the number of children and adults in the pool, which some parents complain is too crowded for six lifeguards to monitor.

Park officials will add additional lifeguards to supplement the six on duty at all times if they see the need, said park spokesman Gene Fruge.