The whitewater rafting in Jarabacoa is run by Rancho Baiguate, and you can click on their ad on the main forum page for info. I have been on this trip on the North Yaqui. While a bit tame for veteran whitewater rafters, it is still fun and the scenery beautiful, so I would recommend it if you can take a day to go down to Jarabacoa to do it. Actually, I personally would spend more than a day in Jarabacoa and its surroundings -- I love the place and its people. If you like the outdoors and outdoor sports and a less touristy atmosphere, Jarabacoa is the place.
Best Regards,
Keith