The Cordillera Andina is arguably the most impressive contiguous mountain range in the world, stretching 4,500 miles from the coastal plains of the Venezuelan Caribbean through Patagonia down to Cape Horn at the southern edge of the continent. The Andes is also the world’s highest-altitude mountain range outside of Asia. Mt. Aconcagua, in Argentina, rises to an elevation of almost 23,000 feet and Mt. Chimborazo, in Ecuador, straddles the equator and is farther from the Earth’s center than any other location on the planet.

Torres Del Paine in Patagonia

During my climbing years, my friends and I had the opportunity to scale some of the easier Andean peaks and enjoyed epic adventures on Chimborazo and Cotopaxi in Ecuador, as well as Aconcagua. Other Andean peaks were beyond our mountaineering skills, so we opted to hike around the rugged massifs of Torres de Paine and Fitz Roy in Patagonia. I still remember marveling the iconic spires looking like a giant set of broken incisors glinting orange in the sunset. They are truly a must-see for any nature enthusiast!

The geology of the high Andes is otherworldly, and the fauna is rich. Here, wild herds of vicuña and guanaco roam the altiplano, and the condor, the largest bird of its kind in the Western Hemisphere, soars high in the strong winds above the lofty peaks. The weather in the central Andes can be very tempestuous when the eastbound Pacific weather storms slam into the Chilean mountain ranges. Large amounts of snow and rain fall and feed some of the most voluminous, longest and wildest rivers in the world.

Guanacos in Patagonia

In 2003, one of these pristine Andean-fed rivers, the Bio-Bio, caught the interest of some of us in the California river-rafting community. At that time, we had sharpened our river running skills in California, and some had descended the Colorado River. But we were on the lookout for more exotic excitement. In 1978, adventure legends and river guides Richard Bangs and George Wendt did the first descent of the Bio-Bio. In the early 1980s, the Bio-Bio River became the world’s premier whitewater rafting venue, encompassing an adventurous seven-day journey on a pristine river through some of Chile’s wildest natural places. Tales of monster holes, dangerous undercuts and crazy white water abounded, but that did not deter us. So when some of my guide colleagues from the upstart Bio-Bio Expeditions asked us to bring some gear down to the river in exchange for using it for free on the first run of the season, it was a no-brainer. We assembled a team of hippie river enthusiasts and headed south of the equator to the put-in on Bio-Bio.

The river is the second largest river in Chile. It originates from Lago Galletué in the Andes and flows 380 kilometers to the Gulf of Arauco near Conception on the Pacific Ocean. The name “Bio-Bio” originates from a native Mapuche word and mimics the chirping song of the fio-fio, a small ash-gray-colored bird with long crown feathers and dark gray wings tinted light olive.

Fio fio bird in Chile

Driving along the shores of the upper river and trying to find a calm put-in spot was easier planned than executed. The usual launch beach was three feet under water and when checking with the locals, they shook their heads and muttered something like “loco gringos!” They were probably right. The river flow exceeded 100,000 cubic feet per second—twice the normal rate. We decided, perhaps foolishly, to ignore the warnings and put in little lower down near the town of Longimay. This meant that we had only a little warm up time on the upper, more languid river portion before we were forced to launch straight into the roaring upper part of the river canyon.

The first white water we encountered was Lava South, named after the biggest and longest rapid on the Colorado River, except that this one was fiercer than its northern namesake. The flow was so fast that the usual pools below the rapids were fast-flowing water with no recovery room for picking up any flipped boats or people. I was the guide on the first paddle raft with six paddlers—we had three other rowing frames along, as well. I instructed my crew to paddle like maniacs to get enough momentum not to get stuck in the large reversal below. I told my nervous crew that the key was not to fall out of the boat when hitting the monster hole in the middle of the river. Miraculously, we all stayed in the boat—although the run was totally out of control.

And so it continued day after day—with one class V adrenaline-producing rapid after the other. We survived legendary white water like Lost Yak, Cyclops and even the infamous Royal Flush, which are five crazy class V rapids in quick succession—from the King to the Ten. It was our destiny to flip in the 13th of large rapids, where we all catapulted out of the raft for a long, cold swim. I have never been so scared, careening down the river over 10-15 feet drops, getting submerged in air-filled water foam and hitting big boulders at high speed. It took me a long time to recover after a mile of swimming in freezing water, but somehow, we found all of our gear and reassembled the group with mostly psychological bruises. We were deeply humbled by the display of the river’s raw power.

On one of the last days after no human encounters in pristine wilderness, we suddenly heard loud explosions above. Looking up, we spotted belching trucks digging into the mountains above our heads. We eddied out and walked up the hill to see what was going on. From that vantage point, we could confirm the rumors that a dam was being built across the Bio-Bio. Stunned and sad, we took some quick snapshots before we were shooed away by the construction crew.

We realized that we would be some of the last rafters to experience the wild Bio-Bio. What we had discovered was the construction of a dam built by the Chilean power company Endesa. The project was controversial, since an indigenous graveyard had to be flooded by the reservoir and native people were going to be displaced from the river banks where they had lived for centuries.

Dam building like this has been controversial. The world’s rivers are in crisis, and the drivers of river degradation are numerous. While pollution in its many forms impairs the quality of our rivers’ waters, dams impact both water quality and the very functionality of rivers, including many of the planetary life-cycle processes. Roughly two-thirds of the world’s rivers have suffered harm from the 50,000 large dams built the last 40 years and a third of remaining freshwater fish species are threatened with extinction—all as a result of dam construction and operation.

South America is a vast and ecologically diverse region known for the power and beauty of its river systems, including the Bio-Bio. Unfortunately, local governments are aggressively promoting hydroelectric dams as a way of accelerating economic growth by offering publicly-subsidized energy to cities and energy-intensive industries. For now, those are bigger and more powerful audiences than river enthusiasts and nature lovers like us.

We were lucky—although a little bruised. We had the chance to experience the raw natural forces of the Bio-Bio River before it died. We can only lament that man continues to tame and destroy such rivers. The source of these rivers—including the lakes, glaciers and peaks of Pataongia—are still standing tall in defiance.

Patagonia Torres Del Paine