Rio Mantaro (Source of the Amazon): Class III rafting trip: La Oroya Canyon (5 days)

RÍO MANTARO (2): Cañon La Oroya/Mantaro Valley

164 km (100 miles), class III, 6 days

Anytime of year (best May): rendezvous in La Oroya. RESERVE

The Mantaro River (Río Mantaro) is the most distant source. Join the discoverer of this fact on a guided expedition to paddle the mellow upper section of river starting at Presa Malpaso down to the end of the Mantaro Valley near Huancayo. We'll see the upper mines, tour and soak in mineral springs, visit some Incan ruins, tour Huancayo and enjoy some good camp time.

AREA ARTICLE (new source)
PETITION (protest the dams!)
ARTICLE (Int. Rivers)
FILM (20 min Vimeo)


The Amazon River is a complex huge river system. Although its true headwaters are on Río Marañon, its most distant source is on Río Mantaro. As such, Río Mantaro has a special unique status. Join the discoverer of this fact (Rocky Contos) as he leads a rafting expedition down much of the upper Mantaro River. On Rocky's expedition in 2012 he did the first reconnaisance to the source area and the first descent of much of the Mantaro.

The sections we will paddle are the class III La Oroya Canyon and the class II Mantaro Valley. The entire run is scenic in high Andes. We will camp several nights as we make our way down the ~200 km of river from Presa Malpaso to the end of the Mantaro Valley. Rapids are generally mild class II-III, so you might get splashed a bit but there is no danger of flipping a raft.

Come share in an unforgettable experience as you learn more of this unique place and all the sources of the Amazon. Take a moment to help preserve the Upper Amazon from dams by signing a petition. The trip is open to everyone: rafters, kayakers, IKers, and passengers. No prior whitewater experience is necessary.

Consider joining the full descent of the Mantaro:
Mantaro(1): Source and Bosque de Piedras Canyon
Mantaro(2): La Oroyo Canyon and Mantaro Valley
Mantaro(3): Izcuchaca and Tablachaca Canyons
Mantaro(4): Abyss and Lower Canyons

Peru is a travel-friendly country that readily offers tourist permits for up to 90 days. Flights would be into Lima. You will be traveling to high altitude so you might consider getting a prescription of acetazolamide.

The policy we will take on the trip is that the trip leader will have main authority when it comes to decisions for the group regarding river progress, camp, etc. If a participant has overestimated their ability to row or kayak, he/she may be mandated to ride on a raft and or be assessed other penalties. Trip leader decisions can be vetoed by a majority vote of the group. Any participant always has the right to leave the trip if they so desire.

Day 0: rendezvous in La Oroya; meet Rocky; orientation
Day 1: Launch on Río Mantaro near Presa Malpaso; paddle down to near La Oroya; hotel
Day 2: Rio Mantaro paddling: La Oroya Canyon (class III): camp/bungalows at mineral springs
Day 3: Rio Mantaro paddling La Oroya Canyon/Mantaro Valley (class III): camp or hotel in Jauja
Day 4: Rio Mantaro paddling Mantaro Valley (class II): camp (or hotel)
Day 5: take-out by Puente Choruro and return to Huancayo; artisans in market; hotel

The trip occurs at relatively high altitude (3700 to 3000 m) so it is cold. Expect high/low temperatures of 23oC/5oC (74oF/45oF) about midway through the trip. There are no bugs of note. We will have campfires when we camp. Tents, sleeping bags, and ground pads can be provided.

LA OROYA: The main rendezvous point will be La Oroya. Logistics will be coordinated before the trip. You should arrive to 2000-3000 m altitude 2 or 3 days before the launch date. We will have vans/taxis transport us to the river at the start and to Huancayo at the end.

This trip is being run to raise more awareness of the dams planned for the Upper Amazon and generate revenue for conservation campaigns. If you are interested in joining the trip and/or helping in the effort,
send Rocky a note briefly describing your interest as well as:

-how you were directed to the webpage
-yourself (age, health, occupation, what country/city you live in, if you speak Spanish)
-if you'd like to paddle a raft, be a passenger, row, and/or kayak (hardshell or IK)
-who else you might get to come along on the trip
-what you think an appropriate contribution amount

If interested in joining a trip, start a discussion by sending Rocky a note ( stating how you found out about the trip and a little background info about you and your paddling experience, what dates might work for you, and what sections of the expedition you are most interested in joining. Once you get the go-ahead from Rocky, you will need to provide a deposit to reserve your place on the trip. The balance must be received prior to trip commencement. See PAYMENTS for payment options, deposit amounts, and cancellation policy.

A minimum of 8 particpants will assure a general SierraRios trip occurs, while our maximal limit is 20 on any trip. We may allow trips with fewer folks depending on circumstances. The current boats available allow for two trips at a time. If interested in doing a trip on a date not listed, send Rocky a message about optimal scheduling for you, as well as a little info about you. We may list the launch date, and if enough folks sign up by the 3-month cut-off, we'll organize it.


(1) Rocky Contos (scheduled trip leader on the Sep and Jan launches), descended the entire Mantaro from its headwaters in May 2012, as well as Ríos Apurímac, Marañon, and Urubamba as part of his Headwaters of the Amazon expedition. He also has explored nearly every river in Mexico including >100 first descents covering ~8,000 km of river and ~55,000 m of drop. Rocky believes the Marañon is the finest Grand Canyon-style raftable river in the Americas. He is fluent in Spanish and has organized many Grand Canyon length trips. Several articles have featured Rocky (American Whitewater; Kayak Session; Canoe & Kayak). While attaining his Ph.D. in neuroscience (see CV), Rocky worked as a kayak instructor and guide for UCSD's Outback adventures from 1993-1996 and gained valuable trip planning skills for large groups. Although primarily a kayaker, Rocky started rafting in the mid-1990s in order to introduce more people to the wonders of river travel. Since then and throughout his years as a postdoctoral research associate, he organized numerous large group raft and kayak expeditions, including five through Grand Canyon (18-22 days), three on the Salmon River (4-10 days each), two on Río Mulatos-Aros (8-11 days), four on Río Usumacinta (7-8 days each), and dozens to destinations such as the Salt, Kern, Rogue, Deschutes, John Day, Thompson, Similkameen, and Baja California (2-6 days each). Rocky had dreamed of rafting the Marañon for over 10 years and has all the maps and information. Rocky founded SierraRios with the goal of conserving the rivers of Latin America, and hopes that increased awareness and enjoyment of the resource will lead to protection. He is organizing all aspects of the trip. He likely will be rowing a large cataraft with gear and passengers, but may safety kayak if a competent rower is availlable.

(2) Other guides/trip leaders are to be decided, but likely will be selected from Rocky's Peruvian guide friends - Juan de Ugarte, Pedro Peña, Julio Baca, or others from Apurimac Explorer (Alonso, Romel or Victor).

Food for the river trip will be planned and purchased by our guides. To have an idea of what types of food we generally bring, see below:

Breakfast: usually there is a range of foods to choose from: coffee, tea, fruit, cereals, milk, and perhaps something special such as eggs/omelettes, pancakes, or french toast.

Lunch: Items typically available are trail mix, dried fruits, energy bars, chips, cookies, and sandwiches. Sandwiches can vary: ham/turkey, cheese, avocados, tomatoes, lettuce, mustard, mayo; later maybe tunafish; always PB&J.

Dinner: We will eat what is available in Peru. Pastas, vegetables, stews, curries and sometimes some meat are typical dinners. Meat will always be prepared separate.

We will bring filters and treatment products and provide safe drinking water on the entire expedition. The river often runs with a lot of silt and takes more effort to convert to clear drinking water than many of the clear side arroyos. The arroyos with little or no habitation contain pristine water that is usually much safer to drink and doesn't clog filters. A common method we use is to treat with hypochlorite, but we may also use iodine, a pump or gravity filter, or boiling before drinking. Water will be transported in 5-gallon containers. You should have your own water bottle (or two).

The guides will take care of group camp set-up, food, washing dishes and everything else.

It will be cold, but we will come to some tepid mineral spring baths on the expedition where you can bath. Urinating should be done directly into the river or away from camp and out of sight of others. We will be bringing a toilet on this trip, but it will be set over an excavated latrine hole away from the camp and protected from view. No paddle visible by toilet path indicates it is occupied; an upright paddle indicates it is not [carry to the toilet and use to toss a little sand in the pit when done]. TP and a TP bag will be by the latrine. TP should be placed in the bag for later burning. A handwash station will be nearby; always wash your hands afterward. The latrine will be covered with sand/dirt in the morning before we take off on the river. Alternatively, you may also find your own place to away from camp to somewhere above the high-water line, dig a hole 4-6” deep, and cover your feces. A kayak paddle can come in handy in this regard. Carry your TP back and put in the TP trash bag or burn it at the spot and bury the ashes with the feces.

This is a fairly mild river and outing so it is expected to be safe. However, if you are paddling your own kayak you must accept the responsibility for what happens on the river. If you are concerned about the whitewater or other aspects, it is your responsibility to make appropriate decisions whether to run the rapid or not and to stay close to someone who can watch and oversee you (if you desire that level of protection). If an accident occurs, we will do all in our power to help you, see that proper care is rendered, or evacuate you if need be. Rocky is a trained Wilderness First Responder.

Río Mantaro generally has releases from Presa Malpaso all year that are enough for rafts. We expect 90-120 cms.


You will need to pack appropriately for spending several nights out in high altitude Peru. Bring warm layers and fleece. We can provide tent, sleeping bags, and ground pads (mattesses), but consider bringing your own. For the river, we will provide paddle jackets and pants and/or drysuits, but you should have warm underlayers that can get wet (wool, polypropylene or capilene). We will supply a drybag for you to store your warm dry camp clothes in.

River items to bring:
-Shorts, shirt, warm layers (sweater, warm pants, hot hat)
-Water shoes
-Water bottle (preferably with a carabiner to clip onto a raft)

Camp items to bring:
-Basic dry warm clothing (t-shirt, shorts, warm pants, fleece, underwear)
-Camp shoes (these can be the same as your river shoes or a different dry shoe)
-Headlamp (plus extra set of batteries)
-Toiletries (toothbrush, toothpaste, floss, lotions, etc)
-Lighter/matches (remember to check it if flying)
-Tent/sleeping bag (0-20oF)/ground pad [these can be provided for a bit extra]


"I need to do another expedition!!!!! I'm already jonsing for one .... The Marañon trip was one of kind that I will never forget ... the perfect combination of big water, gorgeous scenery and a taste of rurual Peruvian lifestyle! ...  I would do this trip again in a heart beat ... It really is amazing how helpful some people have been along the way. Going way out of their way in order to help..."
Amie Begg; class IV kayaker on 2012 Marañon trip

"The Marañon trip was a magical journey. Big, clean water; big canyons and expansive natural beauty; and big-hearted, friendly people who made us feel welcome along the way, while sharing with us their fears of imminent dams, mines, and petroleum drilling. I hope we can find a way to help them protect this incredible treasure and their ways of life."
Barbara Conboy; SierraRios board member and rafter/kayaker on 2012 Marañon trip

THE TRIP KICKED MAJOR ASS! mike" [2011 Mulatos-Aros trip; 2012 Marañon trip]
ike Doktor (Portland, OR), former raft guide for Ken Warren Expeditions

Hi Rocky, Thanks again for a sensational and unforgettable trip. You did such an amazing job organizing. I especially am psyched to have met you and to have another kayak friend/guide to work with. You guiding me off the waterfall was a big highlight... Erik." [2011b Usumacinta trip]
Erik Weihenmayer, blind mountaineer/author and budding kayaker (see )

"You led one of the best trips I've ever been on... and I've been on a lot. " [2011b Usumacinta trip]
Chris Wiegand, former olympic runner and C1 paddler, founder of Sportainability and guide for Erik Weihenmayer

"Thanks for everything man, it was a trip of a lifetime ... We´ll be in touch and I look forward to conquering new rivers in the future. Salud, Eric" [2011b Usumacinta trip]
Eric Bach, Modern Gypsy (see

"Hey Rocky, Thanks for the great trip... Looking forward to another trip down the road. John"
[2011b Usumacinta trip]
John Post, Modern Gypsy (see

"Great synopsis of a fabulous trip. Expect to hear more from Team Weihenmayer in the future... Cheers, Rob. " [2011b Usumacinta trip]
Rob Raker, climber extraordinaire and guide for Erik Weihenmayer (also see here)

"Thanks again for the great tour and the late-night excitement, Greg" [2011a Usumacinta trip]
Greg Scwhendinger, kayak explorer of Chiapas and Central America (see

"Thanks for everything, Rocky! What a blast that all was.  When's our next trip?!! -Suzy" [2011b Usumacinta trip]
Suzy Garren (Oakland, CA), former Grand Canyon trip participant.

All photos are property of James Contos; reproduction only allowed with authorization