Researchers from Ourense create a flood warning system

12 Dec Researchers from Ourense create a flood warning system

EPhysLab is a multidisciplinary team of the Ourense Campus formed in 2002, formed by researchers in Atmospheric and Ocean Physics and Computer Engineering. They are integrated in the Faculty of Sciences and the School of Aerospace Engineering. In 2017, EPhysLab joined the European project RISC Miño-Limia, led by the Hydrographic Confederation. The objective was to improve the management and responsiveness to the problems associated with extreme events, such as floods and droughts, and mitigate their effects in the international hydrographic demarcation of the basins of the two rivers (Miño and Limia). With a budget of 2.3 million euros, the project will end on December 31, after having been extended due to the situation generated by the pandemic.

One of the main results of the RISC Miño-Limia project was the creation, by EPhysLab, of a warning system that allows the risk of flooding in the most populated areas of the Miño-Sil river basin to be known days in advance. It is called Midas (Miño River Flood Alert System). Moncho Gómez Gesteira, member of the group and Professor of Earth Physics at the University of Vigo, has been one of the architects of this method. “Every day, at dawn, the system automatically enters MeteoGalicia to download its weather forecasts. These data are passed to a simple hydrological model, called Hec-hms,” he explains. It is a public domain model, developed by the Hydrologic Engineering Center of the US Army Corps of Engineers. It calculates the hydrograph (volume of water that has passed through a point in a given time interval) produced by a watershed, if provided with data on the area and precipitation.

“It is a relatively simple model that allows us to know how much water the river can carry in the vicinity of cities. For example, we can know how much will arrive in the next few days to Velle, where we have a control point, since we foresee how much it will rain from the upper part of the river, in Lugo, and in what quantity it will reach Ourense,” explains Gómez Gesteira.

In this sense, he points out that there are currently four control points in the basin, in the most populated areas, but they hope to reach forty.

The warning system does not end here. The next step is for the data to be transferred to the Iber model. It is a two-dimensional mathematical system for the simulation of river flows, canals and natural channels that allows the calculation of avenues and floods and the delimitation of flood zones. The areas where the water will arrive. This tool is developed directly from the Spanish public administration together with several universities. With these two systems (Hec-hms and Iber) it is possible to know how much water will reach the basin in the next few days and what will be its displacement. The system generated by EPhysLab provides the conclusions of all this data in no more than an hour. “At two o’clock in the morning we receive the data from MeteoGalicia and at three o’clock we already have the forecast for the area we are interested in,” he explains. However, as weather forecasts change, the system works on a daily basis to adjust the forecast.

In order to focus the model on the Miño-Sil basin, the researchers also had to analyze and include in the program all the historical data of the basin, which were provided by the Hydrographic Confederation.

“The CHMS supplied us with the historical series on the water that fell into the rivers. We went back 15 years to see how many of the times we predicted there would be floods, there were. And we were right 95% of the time,” he explains.

The system designed by EPhysLab will allow Hidrográfica to anticipate the risks of rainfall. For example, fencing off areas in advance and organizing the work of the emergency services, if necessary. Moncho Gómez Gesteira points out that all the data point to the fact that climate change brings – it is being seen – a greater number of punctual adverse phenomena, in the form of large storms or episodes of drought. The research team’s work led to the conclusion that rainfall will be lower in the future and more irregular. There will be more intense rainfall events and droughts. “We took 40 international models that predict what the climate, rainfall and temperatures will be like in the 21st century. We looked at the ones that best fit our area and settled on ten historical models. The Cedex (Center for Experimental Studies) has made us a map of water resources in the future. One hundred years from now, 10% less water will flow through the rivers of the province. And in particular localities we saw the demand of the users and the forecast of resources. This allows us to take measures,” explains Gómez Gesteira. EPhysLab’s future goal is to be able to expand the meteorological databases to be even more efficient.