Blue Race — Represa del Guavio

The Guavio reservoir fills a dramatic mountain basin created by one of the tallest dams ever built. Here in Colombia, the Blue Race is an open water swimming race held in the deep freshwater lake of the Represa del Guavio, set right beside the rugged mountain municipality of Gachalá. Entering this vast mountain lake, swimmers find themselves surrounded by quiet, immense expanses of open water. Held in November, the event gives endurance swimmers the opportunity to test themselves across three distinct distances: 2,000 meters, 5,000 meters, and a marathon 10,000 meters. Whether choosing the shorter loop or tackling the grueling ten-kilometer circuit across the open reservoir, competitors chart their path. Organized by bluerace_swim, the event turns this massive hydroelectric reservoir into a proving ground where navigation and pacing over open water become paramount.

The Alberto-Lleras dam on the Guavio and Chivor rivers

The immense water body where the race takes place was brought into being by impounding the currents of the Guavio, Batatas, and Chivor rivers. At the dam site, the Guavio River rushes forward with an average flow rate of 62 cubic meters per second. Swimming across this quiet reservoir today, it is hard to fathom the wild mountain torrents that gather together underneath your strokes to sustain the basin. The structure that holds back this colossal basin is the Alberto-Lleras dam, an enormous rockfill embankment that rises 243 meters from the canyon floor. When it was constructed, this monumental feat of engineering stood as the third highest dam anywhere on earth.

Behind this colossal rock wall lies a useful reservoir capacity of 950 million cubic meters of deep water, creating a body of water so extensive that long-distance swimmers can stroke uninterrupted toward distant mountain ridges without ever running out of room. Extraordinary hydraulic infrastructure operates unseen within the mountain rock. Located about 18 kilometers away, the Guavio hydroelectric complex utilizes a staggering 1,100-meter nominal head to generate electrical power, sending water rushing through a subterranean discharge tunnel that stretches 5,260 meters in length. Deep at the lake bed, the reservoir was engineered with a specialized bottom discharge system intended to drain accumulated sediment, a subterranean structure that sustained damage during its very first overflow event.

Emerald deposits and Muisca lore around Gachalá

The territory embracing the lake stretches from the high plateau of the Mesa del Guavio down toward the course of the Murca River. Between the Guavio and Gacacuyo rivers, through the wild elevations of the Guaicaramo mountain range, local populations once ventured into the forest to harvest precious wild orchids and plant resins. Since 1954, these rugged river canyons have been known for something far more dazzling, as rich veins of world-renowned emerald mines were uncovered along the Guavio River and throughout the Murca sector. The Chío people, who formed part of the historic Muisca Confederation, conducted secret ceremonies and sacred rituals along the shores of nearby mountain waters such as Laguna Verde.

To hide their most sacred treasures from the arriving Spanish conquistadors, the Chío cast extraordinary offerings of gold and raw emeralds deep into the aquatic depths. Ancient legends grew around these hidden treasures, recounting that the lagoon's waves would churn with sudden violence to trap anyone who dared approach looking to plunder the submerged gold. Regional myths even spoke of the mythical mohán transforming into an aquatic dragon that summoned raging storms across the surface of the lagoon, where reeds, lotus flowers, and riparian grasses grow along the banks. For modern swimmers, however, the broad surface of the Guavio reservoir today presents a completely peaceful playground, safely frequented for recreation without the spectral tempests of ancient mountain lore.

Waterfront lookouts and boating around Gachalá

Following the filling of the river valley, the local residents quickly embraced the new watery landscape, turning the shores into a vibrant destination for fishing and nautical sports. Today, visitors and athletes can step down to the shores of the Guavio reservoir at designated access areas. Taking a boat tour across the reservoir offers a striking view of the towering rockfill dam face, allowing visitors to truly grasp the sheer scale of the barrier from the waterline. Above the lake, the surrounding roads and the hilltop town of Gachalá itself boast natural viewpoints that look out over the sprawling, flooded river canyons below. The entire Guavio region is defined by a temperate to cold mountain climate, where year-round rainfall nurtures lush, verdant slopes that plunge directly down to the water. This constant moisture envelops the valley in fresh mountain air. When you step up to the starting line on race morning, that misty Andean landscape frames a singular challenge: plunging into the heart of Colombia's emerald mountains.