Low water levels in Río Santa have made rafting and kayaking less accessible in recent years. Water levels continue to be the highest between November and May, but year-round the water is murky. Consequently, Huaraz [1] is a good option for the beginning kayaker or rafter.
During high season, Ario Ferri (arioferri [at] naturevive [dot] com, also available through Casa de Pocha 1.5 km east of town, tel. 043/961-3058, lacasadepocha [at] yahoo [dot] com, www.socialwellbeing.org [2]), prices vary depending on group size and trip length) offers beginning kayaking classes, which start in the pool at Casa de Pocha, a guesthouse in Carhuaz [3], and finish with a day on Río Santa. Ario is also a proficient raft guide and can organize river trips.
Links:
[1] http://www.moon.com/destinations/peru/huaraz-and-the-cordillera-blanca/huaraz
[2] http://www.socialwellbeing.org
[3] http://www.moon.com/destinations/peru/huaraz-and-the-cordillera-blanca/callejon-de-huaylas/carhuaz