9ª edición de Aguas Abiertas Chile

Surrounded by vineyards and rolling hills just south of Santiago, Lago Valle Maipo offers a calm freshwater circuit in the historic basin of San Bernardo. This enclosed venue hosts the 9ª edición de Aguas Abiertas Chile, an open-water swimming race held in the lake waters of the Región Metropolitana. Held in October under early spring skies, the event gathers swimmers from across the country to start their open-water season in protected, flat water. The competition takes place at Lago Valle Maipo along Camino del Inca, an idyllic water body characterized by a small central island. Swimmers navigate the marked course around this landmass, keeping the buoys on their shoulders while turning against a backdrop of cultivated fields. With athlete reception opening early in the morning, the surface is usually glassy and sheltered, allowing competitors to lock into an uninterrupted rhythm without ocean swell. The programme features individual distances of 1,000, 2,000, and 3,000 metres, alongside a fast-paced 3x1K team relay.

The Maipo and Río Clarillo: Andean torrents and snowmelt

The lifeblood of this valley is the Maipo River, which originates high above in the Andes as a steep, narrow mountain torrent before carving its course across 250 kilometres down to the Pacific Ocean, reaching an unstable mouth that frequently closes with coastal sandbars. Among its tributaries, the Río Clarillo winds for 20 kilometres from high mountain sources until it merges with the Maipo. A significant part of this pristine river basin is sheltered within the Río Clarillo National Reserve, preserving native flora and crystal-clear mountain streams. Fed by winter rains and melting snowcaps, its volume rises up to four cubic metres per second in late spring, creating a dynamic seasonal pulse that sustains the entire valley floor before dropping during the drier months when only groundwater feeds the flow.

Huaca de Chena: the southernmost Inca water sanctuary

Long before modern reservoirs were built, the indigenous inhabitants of the valley dug the first irrigation canals from the Maipo, an engineering system later refined and expanded by the Incas. About six kilometres from Lago Valle Maipo stands the Huaca de Chena, officially recognized as the southernmost Inca sanctuary discovered in South America. Perched on a strategic hill far from local springs, the complex was primarily dedicated to the ceremonial worship of water. The fortress-temple features outer defensive perimeter walls designed in the distinct shape of a feline, an animal representing the three distinct realms of Inca cosmovision.

Canal de Maipo: river crossings and transformed plains

Before European irrigation works reached the surrounding basin during the first half of the eighteenth century, these flatlands were arid expanses populated only by thorns and desert scrub. Further west, about eight kilometres from the lake, the historic Jesuit property at Hacienda Calera de Tango had to support its operations through lime quarrying in the Lonquén hills while awaiting water, with buildings later shaken by the massive 1730 earthquake. Bringing flowing water to the region completely altered its soil and allowed permanent cultivation to flourish. The Maipo riverbanks also witnessed dramatic military maneuvers during the fight for independence. On August 26, 1814, patriot leader Bernardo O'Higgins crossed the river from his camp on the southern Mardones estate to confront rival forces in the Battle of Las Tres Acequias, fighting directly amidst the complex web of farm irrigation channels.

After suffering tactical defeat, retreating soldiers fled south back across the river toward the fortified slopes of Chena, allowing O'Higgins to regroup his surviving units on the southern bank the following morning. That strategic river system soon gave birth to modern San Bernardo. In 1820, civic authorities initiated the monumental Maipo Canal project, designed to bridge the Maipo and Mapocho rivers, and the founding of Villa San Bernardo was intimately linked to the construction of these new artificial waterways.

San Bernardo: aristocratic summer air and vineyard lagoons

By the late nineteenth and early twentieth centuries, San Bernardo had gained a reputation as a fashionable summer sanctuary for Santiago's upper classes. Wealthy families fled the city heat in favor of the town's fresh Andean breezes, often preferring its tranquil country avenues over the crowded Pacific shore. Its residential quarters grew into an oasis of shaded streets lined with leafy trees and bordered by clear irrigation ditches, where urbanites strolled between estates.