Landslide hazard map planned for Da Lat

Nguyen Ngoc Phuc, Lam Dong’s vice chairman, announced the plan at a meeting Wednesday with three Japanese experts from the Kawasaki Geological Company, who were invited to survey a landslide area that resulted in two deaths in Da Lat late last month, in order to help prevent future incidents.

One of the experts, Takami Kanno, said houses in Da Lat were usually built on uphill areas that needed retaining walls to reinforce soil, and increase soil resistance to help structures withstand the lateral pressure of soil.

As a result, residential areas in the city always face the threats of landslides.

Kanno said a landslide hazard map was necessary to detect possible landslides and based on such a map, the authorities could decide if constructors should build retaining walls for a new project.

Areas where retaining walls are built must be checked periodically to make early detection, he said.

According to the U.S. Geological Survey, “an ideal landslide hazard map shows not only the chances that a landslide might form at a particular place, but also the chance that it might travel downslope a given distance.”

Da Lat has experienced frequent landslides in recent years, with the latest incident being the collapse of an embankment on June 29 that buried seven people, two of them dead, and damaged dozens of homes. The embankment belonged to the construction site of a retaining wall.

After the deadly accident, the Lam Dong’s Department of Construction said the amount of soil used for building the retaining wall of the project “was too large and lost the bearing capacity under the impacts of heavy rains lasting for several days in a row.”