Rains in Santiago: Could we still run out of drinking water?

At least four days of rain were forecast for Santiago. It is a frontal system that many meteorologists have already predicted will be “high intensity”.

This generates a certain fear in the population of the capital, mainly due to the event of last June where in addition to the floods and the proliferation of the Mapocho River, a cut in drinking water has been announced.

Considering this, experts say that this new event — which will start at the weekend — corresponds to a atmospheric river a phenomenon where moisture and water vapor pass through the atmosphere from the equatorial Pacific, and that It is the same one that caused, among other things, the turbidity of the Mapocho River in June.

But this time, could the capital once again run out of drinking water? What other risks will this rain front bring? This is what the specialists predict.

—Yes, a situation could reoccur where the drinking water supply is stressed, since the forecasts mention high temperature rains and therefore a strong isotherm. It can’t be ruled out, we have to recognize that it’s a possibility,” he told The third CIGIDEN researcher and associate professor at the School of Engineering of the Catholic University of Chile, Jorge Gironás.

But, What made the capital risk running out of drinking water at the end of June? According to the expert, the problem was caused by heavy precipitation in the mountains and foothills, which fell as liquid water instead of snow, due to high temperatures which are not typical of winter.

— This causes this precipitation, which falls in liquid form, to carry along a significant quantity of matter, to stir up the matter and carry it along. SO, the water becomes cloudy to levels untreatable by the drinking water plant. The plant will simply not be able to eliminate this turbidity. explains Girona.

To this, the physical engineer of the University of Santiago de Chile (USACH), Edgardo Sepúlveda, adds that This rain that descends from the mountain range, through the water basins and natural channels, increases the flow of the rivers and, therefore, also the likelihood of flooding and overflowing of the rivers.

—Apparently, this Saturday we will have an isotherm 0 lower than that of the event of last June, but with a probability that it increases for the following days. Still, it’s not the best of times —reveal to LT the expert.

Gironás also explains that Santiago’s drinking water system has an autonomy of about 35 hours, but if this time is exceeded, it will be necessary to resort to cuts because “there will simply not be the quantity of water necessary to supply the city”.

But this is not the only risk: there are also stream and flood activations in areas occupied by human activity, dwellings or in urban areas.

“Generally, high temperature precipitation is observed during very particular events in summer in the central zone, but certainly not in winter,” says Sepúlveda.

In this line, the expert indicates that The intensity of the phenomena causing rains and disasters is closely linked to the scenario of high temperatures experienced by the world.

“We must remember that the current global warming contributes to conditioning a scenario of high temperatures. For that, we need to add other variables that make 2023 a much warmer year than expected, such as the start of the El Niño phenomenon although this is debatable, he explains.

From the National Disaster Prevention and Response Service (SENAPRED), they assured that under the alert declaration, all sectoral levels must activate their emergency plans.

In parallel, the governor of the metropolitan region of Santiago, Claudio Orrego, assured that they are preparing for any eventuality.

—We cannot deny the possibility or rule out water rationing in Santiago’s future. Look at the situation of mountains and glaciers. It’s really dramatic, especially in the case of a city of 8 million inhabitants that requires or depends on 80% of the water that comes from the upper part of the city,” Orrego said.

To the above, he added that they continue to work on the resilience of the city and that “Prevention is always better than cure.”

In addition, the government has ensured LT which will provide pumps to 14 municipalities — after an investment of 249,900,000 Chilean pesos — to help reduce street flooding, if needed.

After a preliminary study to identify the areas most at risk of flooding in the capital, they chose the following municipalities as beneficiaries of the water pumps: Cerrillos, Cerro Navia, Estación Central, La Florida, Lampa, Lo Espejo, Macul, Maipú, Pudahuel, Quinta Normal, Recoleta, San Bernardo, San Miguel and Santiago.