Landslides in Public: BRGM submits its report

The section of road leading from the entrance to the commercial port to Gustavia is expected to remain one-way for several more weeks. Following a rockfall on November 20, the Guadeloupe office of the Bureau de Recherches Géologiques et Minières (BRGM) was called in by the local authorities and sent a scientist to Saint Barthélemy at the end of December (JSB 1644). The scientist examined several sites designated as "sensitive," including the massif overlooking the road connecting the entrance to the commercial port to that of Gustavia. The specialist wrote a report based on his findings, which he submitted to the local authorities during the holiday season. The document provides an overview of the situation and makes a number of recommendations. The main recommendation, to be implemented "without delay," is to maintain the partial closure of the road while installing a permanent monitoring system for the rock massif.

A "highly fractured" rock
Although the JSB was not authorized to consult the report, territorial councilor Fabrice Querrard, who is also chairman of the commission for territorial development and modernization, agreed to disclose its contents during an interview. The elected official explained that the document submitted by the BRGM to the local authority noted that approximately 50 cubic meters of rock fell during the incident on November 20. This included blocks measuring four to five cubic meters.
The report highlights "the highly fractured nature of the rock," whose condition was "aggravated by the root system of the vegetation, which further widens the fractures." These effects were compounded by episodes of heavy rainfall, which further weakened the site.

"Unstable and threatening" blocks
For the time being, according to the excerpt from the report revealed by Fabrice Querrard, "the danger has not been averted" and "other areas of potential rockfalls are visible to the naked eye." Several cubic meters of rock are likely to break away from the massif, as are "unstable blocks hidden by vegetation and located halfway up the slope ." The report warns that a "sudden rupture could occur in the short term." In addition, other "threatening blocks" have been identified on the southern slope of the massif, above the section of road leading to Gustavia.
The BRGM report contains several recommendations to secure the area. First, as indicated above, the road should remain open to one-way traffic. This measure must be accompanied by increased monitoring of the massif. To this end, "cameras are being deployed and directed towards the massif," explains Fabrice Querrard.
In the coming weeks, the BRGM report suggests that direct action may be taken on site. In this case, this would involve causing a controlled fall of rocks designated as potentially dangerous. "We will also need to test the questionable rock compartments," says Fabrice Querrard.

An in-depth biotechnical study
In the longer term, the report by the geological and mining research bureau recommends conducting an in-depth biotechnical study before undertaking any reinforcement work. "This includes wrapping or nailing the rocks in order to secure large elements and install safety nets or wire mesh," emphasizes the president of the commission for land development and modernization. Nevertheless, for the time being, the issue is under consideration by the local authorities.
"Decisions will be made in the coming weeks on the solutions to be adopted," says Fabrice Querrard. However, the elected official assures that if heavy rains occur, quick solutions will have to be put in place. In the meantime, the section of road between the commercial port and the entrance to Gustavia seems destined to remain one-way for an indefinite period of time. Safety barriers remain in place on the left lane, along the mountainside. It is easy to see that small rocks fall daily in this area.