Citizen protests against Alto Maipo, Santiago, RM.

Alto Maipo Hydroelectric Project (PHAM)

In recent years, NGO Coordinadora Ciudadana “No Alto Maipo” has promoted an intense campaign against the implementation of the Alto Maipo Hydroelectric Project (PHAM), denouncing to various authorities the irregularities that the project owner has committed, and presented various actions around the rights of water use.

The PHAM aims to divert the waters through a tunnel 70 kilometers long and 6-8 meters in diameter. All the settlements of Cajón del Maipo would be left with flows much lower than normal.

Seismic faults and volcanic activity were not considered in the project proposal, so the work is not being built to face a grade 8 earthquake, as occurred in 2010. In addition, it cannot be stated with certainty and guaranteed technically or scientifically that there is not a huge risk to the water supply of the Metropolitan Region, and for tourism, which is the basis of Cajón del Maipo’s economy, as well as for the other environmental and residential services provided by the basin.


Alto Maipo Project Map.

Environmental resilience must also be considered if a certain level of human intervention is allowed in an area and it loses its natural ability to recover. If PHAM and other energy and mining projects continue their development, these modifications would drastically affect the complex water system of the basin.

Despite strong public opposition, today Alto Maipo is in the process of being built. However, together with the Coordinadora Ciudadana, Guete Conservacion Sur presented in February of 2016 an appeal holding the owner liable, due to studies that indicate that the waters of the Maipo river basin would be contaminated by heavy metals, which was partially accepted by the Court of Appeals of San Miguel, an action that today is pending in the Supreme Court. Currently, along with the Coordinadora Ciudadana, we are working on future actions to stop the construction of the project.