Refer to the directions of the upper Maipo to get in the area. Continue upstream 3 km from the Puente El Yeso through the town of Romeral. Turn north, and put in at village of El Volcán 1380 meters. Take out 4.5 km downstream at Puente El Volcán 1255 meters..

This 4.5 KM stretch  of river has average drop of 28 m/km or 147 feet per mile and can be run year round with optimal flows 500-900 CFS making it class 4.

From the put-in to the dam, the non-stop class IV+ rapids are a good warm-up for the intensity that lies ahead. Take out if you are intimidated by these pushy drops. The Volcán gets much tougher downstream. After a river right portage around the dam, the river swiftly progresses from gravelly class III to IV. Below two bridges, the river channelizes and intensifies until a third hanging bridge. A couple of class V rapids follow that must be scouted. The whitewater eases until a 4 m-high gravel bar on the left marks the start of the grand finale: three thumping class V rapids interspersed between continuous class IV+ boulder gardens.

Cerro Morado (4490 m) and Cerro Mesón Alto (5257 m) crowd the horizon while you drive up this classic, glaciated valley located within the confines of Parque Nacional El Morado.

Refer to the upper Maipo or Yeso directions to get in the area. Continue upstream 3 km from Puente El Yeso through the town of Romeral. Turn north, and follow the signs to the take-out in the village of El Volcán elevation 1380 meters. Put in 12 km upstream at Puente Baños Morales elevation 1775 meters. River has overall average drop of 33 m/km or 174 FPM with heaviest section at 264 FPM.

The river is class V at flows under 700 CFS and ClassV+ at flows over 1000 CFS.

A typical drop on the Clarillo

The river is short but sweet and can be done several times in one day and enjoyed by class 3,4 and 5 boaters alike. With no portages and boat-scoutable drops it is a natural choice for first time creek boaters with a solid roll.

The river lies entirely within the boundaries of Parque Nacional Río Clarillo, which has successfully protected a spectacular desert environment from the ever-encroaching megalopolis.

The river is rated Class III+ and flows in winter and spring with optimal flows 200-400 CFS (although higher would be no problem only pushier and solid class IV).

To reach the river from Santiago take Avenida Vickuña Mckena south out of the city to community of Puente Alto. In Puente Alto turn left (east) on any road and go a few blocks until reaching Av. Concha y Toro. Turn right (south) and cross over the Maipo River on Puente San Pedro and go to “T” intersection in community of Pirque. Turn right following sign to Los morros and go 1.5 KM to the statue of Virgen and go left following signs to “El Principal”. Continue staright (5.6 km) passing over a small creek on Puente Blanco until a small sign is reached for Parque Clarillo. Turn left and continue 1.4 km to another “T” intersection and turn left. Go 3.7 km to the National park office. Here you will be charged (2500 pesos at time of this writing) for each person entering the park. Proceed 3.6 km on a the now dirt road thru a white gate and use the parking area here for sector Maitenes as the takeout. A good trail leads to the river.

The put-in is 3 km upstream at the end of the road in Sector Rodeo. Another good trail leads to river

The visitors center at the takeout has an interesting display of the local flora and fauna. There are also a few short hikes within the park and plenty of areas to have an afternoon asado.

If you plan to run the river my biggest suggestion is to carefully SCOUT from your car before you put on. Have a plan and know exactly where you will take out and where you will portage.

Lower death sieve

To get to the river from Santiago simply reach “Las Vizcachas” at the mouth of the Cajon de Maipo and proceed upstream. A few KM after the town of El Manzano you will reach Puente Colorado. Just prior to the bridge is a dirt road that goes upstream 1-1/2 km to the Instituto Río Colorado. Here an ancient bridge over the river collapsed and a massive boulder rolled into the river creating the lower death trap sieve we call # 1. If you plan to boat this far carefully plan exactly which eddy you will use to get out and portage horrible sieve. At strong water flows you will need to exit at least 300 km upstream as no eddy exists on the approach.

View of Colorado River

To reach the put-in return to main road and cross Puente Colorado. A few hundred meters on the other side is a paved road turning to the left. Follow this road and proceed upstream. We put-in about 1 KM above the town Los Maitenes or 23 km up the paved road. We put in just after crossing the second side stream bridge above the town of Los Maitenes which was also first good place to make the 5 minute walk to the river and it was just after crossing under some hydroelectric pipes coming off the mountain.

Our trip abruptly ended at upper death sieve # 2 which is 12-1/2 km below the town of Los Maitenes or 8.7 KM up the paved road from the Maipo canyon. We never scouted this area from the road but should have. The river was running high with full springtime runoff (November 2, 2008). We had just run 13.5 KM of mostly class IV-IV+ boat-scoutable whitewater when we came to a curve in the river with nearly vertical rock walls. The mistake was boating too far and catching an eddy on river left. From here we could not get back upstream nor could we get out to scout what was downstream. The ferry to the other side of the river involved a tight angle thru pushy current and avoiding a juicy hole. One person missed their ferry and got pushed downstream into what turned out to be death sieve # 2. The whole river is blocked by boulders with a large river wide ledge hole just upstream. Our unfortunate boater got pummeled in the ledge whole then proceeded to swim thru the sieve. He survived but the boat and paddle did not. He wound up alone in the canyon amongst its vertical walls. We could not reach him until returning upstream, crossing river, walking up to road then walking downstream on road until we could rapel into canyon to set up belay for climb out. In all it took 4 hours. This could have been avoided if we had scouted the river from the road. The sieve canyon lies just downstream of a campground owned by Luis Vergara Martinez at KM 8.9

Ben May Rapeling into canyon

We estimate the flow of the run was 1500 CFS. Estimate it could be run from 600 CFS up to 2500 CFS. Water is cold but we did not have pogies.

Rio Colorado

The river is referred to as either the “Upper” or the “Lower”

The fury of Frenchman’s corner

To reach the lower drive up the Maipo canyon. A good takeout spot is at KM39 just above Puente Toyo near town of El Melocotón. Put-in at KM47 above the town of San Alfonso. This 8 KM stretch usually takes one hour and is mostly class 3 with one mini canyon (rated class IV at high water) just below San Alfonso. Flows vary significantly from lows in autumn of 1000 CFS to 7500 CFS during full spring run-off. The lower run can be extended by taking out at Parque Los Heroes in San José de Maipo. The only dangers on the run besides big holes are some diversionary water intakes.

The “Upper” Maipo is a step up the evolutionary ladder. To reach the put-in drive upstream from San Alfonso to Puente El Yeso 2 km upstream from San Gabriel. Run the last stretch of the Yeso into Maipo. From here it is mostly class III-IV whitewater until reaching the “Frenchman’s corner”. It was here that an unsuspecting Frenchman blindly rounded the corner years ago to encounter some serious whitewater. At super high flows this whole stretch could be considered class V+ but even at extreme low flows would always be solid class IV.

To get to the takeout head up the Maule canyon thru San Alfonso then continue thru San Gabriel until you reach Puente Yeso. This is the takeout. To reach the put in cross the bridge and go approximately 1 km and turn left on the road to Embalse El Yeso. Go 2-3 KM upstream until you find a good place to hike to the river.

Brent Heitzenroder scouting a tight spot on the Yeso

The river can often be too high in late spring early summer but due to unknown flow schedules of the dam it is hard to know in advance. The best wasy to find out is go to the takeout and look at the river. If it looks good then it will be.

The average gradient on the river is close to 200 FPM. Mellow flows are 100-400 CFS. Above this level the river gets pushy and turns into continuous class five. Other good runs in the area are the class 5 Volcan and the big water class 4 upper Maipo. Yeso is Spanish for “Plaster” and named for the Gypsum mined in the area.