Monitor rainfall to prevent and respond to flash floods and landslides

As the rainy and stormy season approaches, experts and scientists recommend that localities, units and people in areas at risk of flash floods and landslides proactively monitor disaster forecasts and warnings, especially information warning of excess rainfall, to proactively prevent and respond to these two dangerous types of natural disasters.

Automatic rain gauge and automatic disaster warning station at Tak Pat resettlement area, Tra Leng commune. Photo: HOANG HIEP

Increased alert

The National Center for Hydro-Meteorological Forecasting regularly issues disaster forecasts and warnings, including real-time warning information for areas at risk of flash floods and landslides on the website http://luquetsatlo.nchmf.gov.vn/ so that localities and units can monitor, grasp warning information and proactively deploy prevention and response solutions.

In addition to the above tools, to better suit the reality of each locality, residential area, river basin, stream..., units and localities deploy the installation of natural disaster monitoring and warning stations.

Currently, in Tra Leng commune, there are 2 rain gauge stations installed to monitor rainfall and a number of automatic warning radio stations connected to the rain gauge station to broadcast through the loudspeaker system when rainfall exceeds the threshold, to warn people about the risk of flash floods, landslides, etc.

With the nature of flash floods and landslides occurring quickly, unexpectedly and causing great damage, early warning of the risk of these two types of natural disasters helps people have time to prepare and implement preventive and response measures...

MSc. Nguyen Ngoc Vinh, Central Highlands and Central Region Institute of Water Resources Research , acknowledged that there are many causes of landslides, but the main and direct cause of landslides is rain. The serious landslide in Tra Leng commune in October 2020 was a mudslide triggered by heavy rain. Therefore, landslide forecasting and warning based on rainfall should be given attention.

According to Water Resources Engineering Development and Consulting Joint Stock Company (WATEC), the company has installed 81 rain gauge stations in Da Nang city and automatically transmits continuous rainfall monitoring data to the specialized rain gauge system Vrain.

There are many causes of landslides and flash floods, but the impact of heavy rain (both in intensity and amount of rain) is still the direct cause, so there needs to be a solution to warn of these two types of natural disasters based on actual and forecasted rainfall. In particular, it is necessary to pay attention to determining the warning threshold for flash floods and landslides in order to drastically implement response measures to minimize damage.

After the flash flood and landslide occurred in Nu village, Phuc Khanh commune, Lao Cai province in September 2024, some scientists studied and proposed the warning threshold for flash floods and landslides is the rainfall intensity is greater than 40mm/hour and the cumulative rainfall in one period is greater than 250mm/period.

Effective warning tool

Regarding solutions and warning tools, WATEC has been deploying a warning system for heavy rain, landslides and flash floods through automatic warning stations connected to rain gauge stations via LoRa wireless network, such as the warning station in Tak Pat resettlement area in Tra Leng commune is a typical example.

Technicians of Water Resources Engineering Development and Consulting Joint Stock Company (WATEC) are checking automatic rain gauges and warning stations for excess rain before the storm season. Photo: HOANG HIEP

Accordingly, in areas identified as at risk of flash floods and landslides, when actual hourly rainfall (rain intensity) or cumulative rainfall exceeds the warning threshold, the system will automatically activate a warning broadcast via high-power loudspeaker with a pre-set voice message or siren.

Flash flood and landslide warning information based on actual rainfall measured from Vrain rain gauge stations in communes at high risk of flash floods and landslides is also integrated into Watec's disaster response decision support software and new application development.

In addition, WATEC deploys heavy rain warnings via the Vrain application on smartphones (Mobile Apps) and heavy rain warning messages exceeding the threshold; warning information via the Zalo ZNS platform, SMS messages to disaster prevention agencies... At the same time, it is coordinating with Weathernews Inc (Japan's leading weather forecasting company) to conduct highly reliable rain forecasts nationwide, especially extremely short-term rain forecasts (Nowcast).

Chairman of the Board of Directors of Water Resources Engineering Development and Consulting Joint Stock Company (WATEC) Van Phu Chinh said that in order to effectively carry out flash flood and landslide warnings, it is necessary to have detailed and quantitative rainfall forecasts with high reliability. Therefore, it is necessary to increase the density of automatic rain gauge stations and install additional weather radar stations, including socializing the installation of small weather radar stations (X-band) at appropriate costs.

In addition to the impact of heavy rain, flash floods and mudslides are also caused by blocked flows, forming temporary reservoirs upstream, so localities need to check for signs and risks of landslides and flash floods in upstream areas of rivers, streams, and residential areas...

Besides, localities need to drastically implement appropriate prevention and response solutions as soon as flash flood and landslide warnings are issued.

Source: https://baodanang.vn/theo-doi-luong-mua-de-phong-tranh-ung-pho-lu-quet-sat-lo-dat-3299740.html