The Inter-American Development Bank (IDB) approved loans of US $130 million and US $150 million for Argentina and Chile – respectively – for the construction of a tunnel that will connect the two countries. The Black Water (Agua Negra) Tunnel will cross the Andes mountain chain between Chile in the province of Coquimbo and Argentina in the province of San Juan.

According to Télam, the project is set to improve access to international markets vis-à-vis the Atlantic and Pacific oceans. The connection will improve operational efficiency, reduce travel times, and increase the volume of both passengers and cargo that travel between the two countries. The IDB’s loan proposal indicates that the tunnel is necessary because the Agua Negra pass is almost impassable from May to October, a fact that severely limits traffic volume.

BBC reported that, once completed, the 13.4 km tunnel will be the longest tunnel in Latin America. according to the IDB, the project will take 8 and a half years to finish. It will be the second to cross the Andes mountainsm as the Cristo Redentor one connects Valparaíso in Chile with Mendoza in Argentina. According to a July 12 IDB report, the project will cost US $1.5 billion in total. The project not only includes a new tunnel, but also improvements to surrounding roads.

Claudio Ibáñez, the superintendent of Coquimbo, said that “it was the president of the IDB who highlighted that this is one of the most important works that they have financed, after the Panama Canal.” “And here there has been a great effort and compromise of the government of our President Michelle Bachelet, the ministries of homeland and public works, and the backing of the Argentine government of President Mauricio Macri, and the hard work of San Juan Governor Sergio Uñac, which permitted us to have complete certainty that today we can announce the financing,” he added.


An study conducted by the National University of San Juan – which recommended the project continue – found that it would increase the value of regional trade by US $281.9 million while new mining activities will increase US $277.4 million. In the next ten years, traffic is expected to increase around 30 percent.

The pass was identified by the South American Council for Infrastructure and planning as a priority border crossing as a result of traffic flows increasing 6 percent annually since 2007, infrastructure inhibiting crossings, and inefficient border control processes. The new tunnel is intended to relieve pressure from the Cristo Redentor pass and reduce the environmental impact of crossing the Andes.

Border crossing locations in Argentina, according to the Argentine Highway Administration. Graphic via IDB.
Border crossing locations in Argentina, according to the Argentine Highway Administration. Graphic via IDB.


The main environmental risk identified by the IDB is to air quality as a result of increased emissions. The tunnel’s construction will also have direct geological impacts. “The geological risk has been identified as medium as the region is susceptible to earthquakes and landslides due to the presence of faults, which may become exacerbated as a result of climate change,” the IDB said in the loan proposal.

The financing occurs via a Conditional Credit Line for Investment Projects (CCLIP), a process intended to facilitate efficiency by dividing the program into several components and promote cooperation between Argentina and Chile on regional development. Since 2000, the IDB has approved 25 transportation projects in Argentina worth US $2 billion.

“This tunnel will shorten the current crossing by 40 km, help eliminate curves, and reduce the maximum grade, enabling freight trucks to pass. In addition, it will enable the crossing to be used throughout the year. The subsequent individual operations will include the components needed to optimize border management,” the IDB said in the loan proposal. As the construction begins, Argentina and Chile will move towards greater regional economic integration.