San José, Costa Rica, since 1956
Costa Rica

Is there a landslide risk for Tres Ríos?

The potential risk of a major landslide near the town of Tres Ríos in the Cartago canton of La Unión has sparked a controversy over whether or not owners of a local farm should receive permission to mine rocks and other material along a local river.

Open-air mining permits are hard to come by in Costa Rica, and some locals think the specter of a landslide is being used as an excuse for a lucrative mining business.

La Unión is located in a mountainous area east of San José traditionally known for its extensive coffee plantations that produce top quality beans for the international market and companies such as Starbucks. The canton in recent years also boomed as an important destination for the development of commercial and housing projects.

Talk of landslide risks in the area along the Chiquito River has swirled for several years. In 2011, experts from the National Emergency Commission (CNE) and geologists from a consulting firm hired by the owners of local farm Hacienda San Rafael confirmed the falling of debris on the property in a location where the river forms a canyon.

Debris fall in recent years had mostly concentrated in an area known as Las Cazuelas, where according to both reports the culprit is the river’s current. The river flow has eroded the base of the canyon’s slope over some 40 years, causing falling debris, the CNE reported.

At the time, the CNE issued a list of recommendations for municipal officials, including periodic inspections to evaluate the accumulation of debris along the river. La Unión Deputy Mayor Alex Montoya Richmond said Friday that they have complied with the monitoring as required.

The CNE last week issued a news release dismissing “the possibility of an imminent landslide that would affect Tres Ríos residents,” and that “an eventual landslide along Chiquito River would affect only the mountainous areas along the riverbank.”

Lidier Esquivel, a geologist and director of CNE’s Risk Prevention Department, said the current amount of debris in the area does not represent an imminent risk of a major landslide, and materials mostly include small and medium-sized blocks of soil that fall directly into the river current.

“We recommended that the Municipal Emergency Committee keep monitoring the falling of materials, but we believe that a major landslide would only occur under extreme weather circumstances or by an earthquake,” he said.

The official noted that the last time major falling debris occurred in the area was during Hurricane Mitch in 1998. The phenomenon caused thousands of deaths in Central America, and the U.S. National Oceanic and Atmospheric Administration considers Mitch the deadliest Atlantic hurricane since 1780.

It appears that local and national officials are poised to grant a mining permit to the owners of Hacienda San Rafael, under the guise that removing material from the area would help prevent a potential landslide. Tres Ríos residents have been voicing concerns in recent weeks about the potential permit, with some saying that open-pit mining would actually provoke a major landslide and potentially put at risk some 25,000 residents of northern Tres Ríos.

In the same news release in which the CNE dismissed the imminent risk of a landslide, the commission advised the Environment Ministry and La Unión municipality to ensure that all mining activity in the area is properly conducted “so that it helps to stabilize the mass of debris and avoids affecting the area’s current situation.”

Public funds to address problem lacking

Vice Mayor Montoya said the municipality has taken all necessary preventive measures and conducted periodic inspections of the eroded area. Those inspections have shown, he said, that even though there is currently an accumulation of debris, it does not represent an immediate risk for Tres Ríos residents. Still, Montoya, who is also director of the Municipal Emergency Commission, said authorities are aware that the erosion should be addressed. But he said fully eliminating the problem would require funds that the city currently does not have.

“We estimate the funds needed to fully eliminate all risk scenarios in the canyon would represent the full budget of the CNE for three years, and obviously we don’t have that kind of money,” he said.

Erosion of the canyon’s base causes periodic falling of debris from its slopes.

Courtesy of Geotec

Mining would fund the project, farm owners say

The owners of Hacienda San Rafael contend that there is a major landslide risk, and they have a plan to address it — if they get government approval.

The site of the most recent debris fall is located about 800 meters from downtown Tres Ríos, “therefore the CNE’s statement [that there’s no imminent risk of a landslide] seems strange to us,” Leonel Rojas Castro, a geologist hired by the owners of Hacienda San Rafael, told The Tico Times.

Rojas explained that the erosion process is active and currently wearing the riverbed and the canyon slopes. He also believes the amount of debris that could erode from the canyon slopes is enough to form a landslide capable of reaching populated areas.

“I believe that a heavy shower or an earthquake with an epicenter located near this area could provoke the falling of debris enough to block the river, and considering the ground conditions, to form a landslide of important proportions,” he said.

The river in that area is just 1.5 meters wide, therefore it wouldn’t take much to block its flow and accumulate enough debris to cause a big landslide, Rojas said.

The geologist said that he and his clients are aware of the high cost of the work needed to fully clean the area, remove all the materials and stabilize the canyon slopes. Therefore, the property owners presented the municipality with a proposal to carry out the project.

The plan includes a petition for obtaining a mining license that would allow them to sell the materials removed from the canyon in order to finance the cleaning and stabilizing works. “That’s the reason why the farm owners applied for the [mining] license, to reduce costs for the project,” he said.

On Tuesday La Unión Mayor Lydia Garita Rodríguez said in a written response that the mining license request is currently under study. She said the municipality’s legal department last Jan. 19 initially green-lighted Hacienda San Rafael’s plan, including the extraction and selling of materials from the riverbed, as long as works also involve the expansion of the riverbed and the stabilization of slopes in the landslide area. Final approval is still pending.

Local officials, following CNE orders, are required to clean up the riverbed and implement an early warning system for potential emergencies.

The Environment Ministry has already approved the mining plan.

Area of the landslides found in 2011 less than 1 km from downtown Tres Ríos:

Contact L. Arias at larias@ticotimes.net

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