Surprisingly, most tourist literature does a lousy job expressing just how captivating the Aratiatia Rapids really are. Here's my spiel: The Waikato River, pouring out of Lake Taupo in aquamarine glory then spilling over Huka Falls, soon becomes a damned 'lake' behind the Aratiatia dam. But, instead of totally killing the river, the clever Kiwi engineers have created a magnificent menage-a-trois of economics, ecology, and tourism! Most of the Waikato River is funneled underground at Aratiatia into turbines...but HOORAY!, every two hours (10am, 12, 2, and 4pm) bells and whistles sound as the flood gates are raised and a half-hour torrent is allowed to rage through the natural river channel. And RAGE it does, arguably outdoing Huka itself! The instant river surges to life like a motorbike race - it blasts into the first turn then zigzags into a steep boulder garden, all the while gaining both fury and resplendent blue-ness. You gotta see it!
You can watch it from the bridge or take the nearby trail to the downstream view platforms - actually do them both...you've got time.