CAO Cases

Arne Hoel, The World Bank

Latin America & the Caribbean

Chile / Alto Maipo-01/Cajon del Maipo

Affected communities
Date Filed
January 24, 2017
Water shortage and contamination, noise pollution
Case Status
Open - Compliance


Project Overview

IFC has an active project with Alto Maipo SpA. According to IFC, the project comprises the construction of two run-of-the-river hydroelectric facilities connected in series with a combined capacity of 531 MW for the purposes of providing baseload electricity to the Chilean Central Interconnected Grid or SIC. It will be developed in the Upper Volcan River, Upper Yeso River and Colorado River, all in the Maipo River Basin and 90% of the Project’s infrastructure will be underground, which will include powerhouses, siphons, access tunnels and water conveyance systems, including a total of 67 kilometers (km) of tunnels.


CAO received a complaint filed by a local organization, La Coordinadora Cuidadana No Alto Maipo, and Ecosistemas, a Chilean environmental NGO focused on ecological and socio-cultural concerns at the national and international level, on behalf of affected communities. The complaint alleges that the project will lead to diversions of the Maipo river resulting in impacts on water access and quality, farming, tourism and the environment. Further, the complaint raises concerns with regards to the Project’s impact assessment and alleges that the Project construction activities have resulted in impacts for two communities, notably noise pollution.


CAO Action

CAO found the complaint eligible for further assessment in March 2017 and an assessment trip was conducted in April 2017. During the assessment, there was a lack of consensus amongst the parties to engage in a CAO facilitated dispute resolution process. Hence, in accordance with CAO’s Operational Guidelines, the case has been referred to CAO’s Compliance function. 


CAO concluded its compliance appraisal in May 2018, and decided that an investigation was warranted in relation to the issues raised in the Alto Maipo-01 complaint. In reaching this conclusion, CAO has considered a number of issues. Firstly, CAO notes that this is a category A project, which by definition has potential significant environmental and social risks and impacts. Secondly, CAO notes that the complaint raises a range of issues regarding project impacts that are serious in nature, and require further expert review. Thirdly, CAO notes that, as part of the regulatory supervision process in Chile, the national environmental authority has raised a number of concerns about project impacts that are aligned with those raised by the complainants. CAO noted, however, that the signatories of the complaint do not include workers employed by the client or contractors of the project. Therefore, CAO has decided to exclude issues raised regarding labor and working conditions.


The case was merged with the Alto Maipo-02 complaint for the purpose of the compliance investigation. CAO published the Terms of Reference for this investigation in August 2018.



A compliance investigation is underway.


Status as of August 08, 2018.


Project information

Project Name & Number
Alto Maipo 31632
Alto Maipo SpA
Large Hydro - Renewable Energy Generation
Latin America & the Caribbean
Environmental Category
Debt US $150 million

Case Tracker


  • Eligible: Completed
  • Assessment Period: Completed


  • Under Appraisal: Completed
  • Under Audit: In Process

Useful Links