Scientists propose solutions to prevent landslides

Topographical factors, slope, geology, and the impact of climate change with heavy rains after storms are the causes of flash floods and landslides in Lang Nu village (Lao Cai) as well as in mountainous provinces. This is one of the contents mentioned by scientists at the scientific seminar "Lang Nu disaster - Causes and prevention solutions" organized by the University of Natural Sciences, Vietnam National University, Hanoi on October 2, in Hanoi.

Professor, Dr. Do Minh Duc, Head of the Department of Geotechnical Engineering and Infrastructure Development, Faculty of Geology, University of Science, Vietnam National University, Hanoi, speaking. Photo: Dieu Thuy - VNA

The cause of the "Lang Nu disaster" was a mudslide.

Professor, Dr. Do Minh Duc, Head of the Department of Geotechnical Engineering and Infrastructure Development, Faculty of Geology, University of Science, Vietnam National University, Hanoi, said that more than 3 weeks after Typhoon Yagi and its circulation caused floods and landslides, many localities in the northern provinces suffered heavy damage, of which Lao Cai was the most severely devastated province (118 people died and 50 people were missing). The landslide and flash flood in Lang Nu village, Bao Yen district on the morning of September 10 buried all 37 households with 158 people there. To date, the number of deaths recorded is 58 people, and 9 people are missing.

According to Associate Professor, Dr. Nguyen Chau Lan, Deputy Head of the Department of Geotechnical Engineering, Faculty of Construction, University of Transport, the university's research team had a field trip to Lang Nu village (Phuc Khanh commune, Bao Yen district, Lao Cai province), initially determining that the cause of the Lang Nu disaster was a mudslide.

Associate Professor, Dr. Nguyen Chau Lan analyzed that the flood on the morning of September 10 in Lang Nu village had a landslide location at Con Voi mountain. The main materials that created the flow were biotite gneiss, biotite quartz schist, and marble lenses. The landslide area on the top of Con Voi mountain was 774 m high, the lowest affected area (Lang Nu village, which is the area where mud and rock were deposited) was 160 - 200 m high. The length of the mud and rock flood (from the top of Con Voi mountain to Lang Nu village) was 3.6 km; the affected area of ​​the mud and rock flood was about 38 hectares. Associate Professor Nguyen Chau Lan assessed that in Bao Khanh commune, the accumulated rainfall on September 9 was 500 mm, so it is likely that the landslide at the top of Con Voi mountain initially occurred on September 9.

“The location of Lang Nu village is a geological fault. This is a dangerous location when a geological disaster occurs, so the government should advise people not to build houses in these locations,” Associate Professor Nguyen Chau Lan commented.

Associate Professor, Dr. Nguyen Chau Lan, Deputy Head of the Department of Geotechnical Engineering, Faculty of Construction, University of Transport, analyzed the cause of the Lang Nu disaster. Photo: Dieu Thuy - VNA

Authorities need to respond promptly.

Currently, many geological cracks have appeared in mountainous provinces such as Ha Giang, Lao Cai, Yen Bai... However, there is still enough time for authorities to respond promptly. To prevent similar disasters, scientists recommend that people avoid building houses near streams and areas at risk of landslides. One of the immediate solutions is to cover the cracks with tarpaulin, combined with a horizontal drainage and drainage system, to prevent water from seeping deep into the ground, limiting the risk of landslides. "This is a simple measure that localities can quickly deploy, then use other technical solutions to handle the cracks," Associate Professor Nguyen Chau Lan shared.

To detect early and prevent potential disasters similar to Lang Nu in mountainous areas of Vietnam, Professor, Dr. Do Minh Duc and his research team have proposed a number of specific solutions. Regarding immediate solutions, relevant ministries, branches and units need to build a database, establish a system of maps of various scales, thereby identifying high-risk areas; build risk maps and response scenarios to serve risk management and control, ensuring safety against natural disasters on steep land areas....

Regarding medium-term solutions, ministries, branches and units need to prioritize ensuring safety in densely populated areas; controlling the negative impacts of rainwater and surface water: Collecting and draining rainwater and surface water to reduce human impacts on sloping land, in some cases, underground drainage is also required.

Geological experts propose solutions to prevent landslides in mountainous areas. Photo: Dieu Thuy - VNA

Many geological experts suggest that before each rainy and stormy season, specialized agencies need to conduct surveys and assess the possibility of flash floods in the area where they are living and have plans to prepare for drills and evacuations when necessary. In particular, after resettling people, local authorities need to assess the possibility of further landslides in this area to come up with appropriate land use plans; there should be environmental protection programs, forecasts, and drill plans to help people respond quickly to natural disasters that may occur soon.

Dieu Thuy (Vietnam News Agency)

Source: https://baophutho.vn/tu-truong-hop-thon-lang-nu-cac-nha-khoa-hoc-de-xuat-giai-phap-phong-tranh-sat-lo-dat-220183.htm