Vietnam: real-time river discharge measurements and new monitoring stations to prevent and manage floods

"Vietnam Managing Natural Hazards Project" (VN-Haz) is a project funded by the World Bank that aims at increasing the resilience of the population and of the local economy to natural hazards in some specific watersheds and the related administrative areas.

One of the main elements of this project is the establishment of specific Centres dedicated to the management of disasters in each target province; this will bring to a strengthening of the ability to issue weather bulletins and to an improvement of the Early Warning systems. The enhancement of the forecast and early warning systems will be performed by expanding and strengthening the hydro-meteorological monitoring network managed by the provinces of central-southern Vietnam.

The public call for tenders was directed to Vietnamese firms only and the works were let out on contract to a historical partner in Vietnam of our Bolognese firm. The works include the supplying and installation of 14 new stations equipped with automatic hydrometers and rain gauges, GPRS connected to the Nha Trang Regional Centre.

For 8 of these new 14 installations, a surface speed sensor, a camera and a water temperature sensor will also be implemented. Apart from increasing the number of measurement points, for the first time this implementation will allow us to export to Vietnam some of the latest technologies developed by CAE, after the testing phases. Specifically, a system for calculating real-time river discharges and image monitoring will be implemented in various areas in Vietnam.

After an initial calibration of site-specific parameters, this will allow us to estimate the average speed of the water flow inside the measurement section, starting from the surface speed data, obtained by using radar sensors, as well as to combine them with the wet area for each hydrometric level measured; the result will be a reliable real-time river discharge measurement at the site of installation.

This system allows us to:

- measure river discharges in real time with an improvement in the precision in determining them;

- recognize the loop rating curve;

- measure speed as a forerunner of the flood peak;

- highlight any substantial changes in the geometry of the riverbed in the measurement section;

- perform a correct measurement even in case of solid debris on the bottom of the riverbed;

- monitor the watercourse through the use of images in order to identify any obstructions,

by using a technology which is not immersed in water, in order to greatly reduce the risk of failure and maintenance needs.

The main objective of this system is to allow us to perform complex activities and procedures to support the risk mitigation and to allow maximum sharing of information among all those who are involved in carrying out monitoring and prevention activities.