The floods of last December in the Santiago el Mayor neighborhood of Nueva Montaña were due to the exceptional rainfall that were recorded in the area, with a total of 427.2 millimeters of accumulated precipitation, when the normal value is 118.4 millimeters, that is, four times more than usual.
This is how the technical report made by the Institute of Hydraulics (IH), commissioned and financed by the Santander City Council. Mayor Gema Igual explained that the City Council commissioned the report that cost 20.600 euros to the IH Cantabria “with the knowledge and consent” of all the parties involved, the Demarcation of Coasts, General Directorate of Roads, Port Authority and Fundación Naturaleza y Hombre.
The report shows that once the causes and possible solutions are known, the most immediate and agile would be the construction of a protection dam. This was explained by the IH researcher and head of the project, César Álvarez.
When the floods happened, between December 8, 2020 and January 3, 2021, exceptional precipitation events occurred, according to Álvarez. “Only in the first 10 days of December 246.5 mm were registered, double the average rainfall accumulated in that month ”, he highlighted.
It has also specified that, to this exceptional circumstance, the existence of obstructions of a different nature in the drainage works of the lagoon system was added. On the one hand, the presence of an invasive species, which creates crusts of calcareous tubes; and on the other, a structure that supports the Nueva Montaña pipe, a deep beam located transversely to the flow.
However, and as the report assures, “the The fundamental cause of the Santiago el Mayor flood was the intensity and the extraordinary persistence of rain, and even if there were no partial obstruction of the drainage elements of the lagoon system, the result would have been similar ”, Álvarez clarified.
Despite this, the IH has established that, as the climate change forecasts point to a rise in sea level that will reduce the drainage capacity of the estuary by 21.5% in the face of intense rainfall and, to avoid that, in the future, the neighborhood floods again, it is necessary to articulate some performances.
Specifically, they propose four: the construction of a sewer pipeline through the new port fill; cleaning exits and removing obstructions; the recovery of marsh spaces; and the construction of a protection dam in the Santiago el Mayor neighborhood.
This last action, according to the IH, is the most effective and quick administratively to avoid floods, building a perimeter protection structure that protects the neighborhood from the overflow of the Raos estuary.
The City Council has given a deadline of one month to the rest of the administrations involved to decide “what, when and with what funds” to undertake the actions established in the study.
Mayor Gema Igual has transmitted a message of “tranquility” to citizens given that the probability that such an exceptional situation will recur is negligible, although it has emphasized that the City Council “undertakes to work on the solutions” established in the study “with the joint responsibility of the rest of the administrations involved”.
“For our part, we are not going to leave the neighbours: we will continue to support you as we did from the first moment, with all the services at your disposal in the area during the floods, building the ‘ridge’ to reduce the effects of extreme rains and ordering and paying for the report to find out what happened and what to do so that it doesn’t happen again ”, he remarked.
Gema Igual has been very clear: “We have given a step forwardWe have commissioned and paid for the study, we have shared the report with all the administrations and now we ask that each one assume their responsibilities, carry out their duties, and determine, with the collaboration of all, how the solutions are financed ”.
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