Embalse El Yeso

El Yeso was built in the 1960s by damming the Yeso river at about 2,500 metres in the Andes above the Cajon del Maipo, and it supplies a substantial share of Santiago's drinking water. The colour is the reason people drive up: glacial flour suspended in the meltwater turns it an intense turquoise against bare brown mountains and, in the right season, snow on the peaks behind. Because it is a drinking water reservoir, swimming and boating are prohibited and the shoreline access is restricted in places. The level drops visibly in drought years, and central Chile has had a long run of them.

Background

El Yeso lies in the commune of San José de Maipo in the Cordillera Province, at about 2570 metres, and holds back the Yeso, a river that feeds the Maipo. Building started in 1953 and the official opening came in 1964, though some sources describe building continuing until 1967. It holds about 250 million cubic metres, is around 6 kilometres long and 1.5 wide, and is more than 50 metres deep. Operated by Aguas Andinas, it is one of the main sources of raw water for Santiago, together with the nearby Laguna Negra and Laguna Lo Encañado.

Source: Wikipedia, "El Yeso Dam"

The landscape

• Turquoise from glacial flour - suspended rock powder in meltwater.
• A drinking water reservoir - much of Santiago's supply.
• Built in the 1960s - by damming the Yeso at 2,500 metres.
• Levels falling in drought - visible in a long dry run.

When to go

November to April; the road is snowbound in winter. A full day.

Practical notes

Swimming and boating are prohibited - it is a water supply. The gravel road is rough, dusty and busy at weekends. Altitude and sun are strong. There are no facilities at the reservoir.

Nearby

Termas Valle de Colina are further up; El Morado is across the valley.

Key facts