Antonio Morales states that the storms that have arrived since November, especially 'Therese', have caused the storage to rise from 2,3 to 39 million cubic meters, which is 17 times the level at the end of 2025.
Six of the seven dams owned by the Gran Canaria Island Council are currently in a state of filling and relief, and only the Chira dam is at 51% of its capacity
“The network of dams in Gran Canaria currently contains a total of 39 million cubic meters of water, which will allow the primary sector of the Island to have water for a period of five years, between the water contributions and the recorded storage, and this will increase with the new contributions made through industrial water.”
This was made clear on Monday by the President of the Gran Canaria Island Council, Antonio Morales, at a press conference held to inform the people of Gran Canaria about the island's water situation following the effects of successive adverse weather events that have struck the island since November 2025, with the arrival of Storm Claudia, up to the devastating Storm Therese, which ravaged the island last week. He was accompanied at the press conference by the Councilor for Primary Sector, Food Sovereignty, and Water Security, Miguel Hidalgo, and the manager of the Gran Canaria Island Water Council, Carmelo Santana.
In fact, President Morales made it clear that, while the rainfall brought by 'Therese' to Gran Canaria can be described as "historic," so too have been the contributions of surface water that have reached the network of Gran Canaria dams, not so much due to the filling and relief of the reservoirs, but due to the distribution of rainfall that has spread throughout the island territory, generating the unprecedented fact of the simultaneous filling of dams throughout the Island.
“Normally, the filling of reservoirs is usually related to storm phenomena that come from the north or southwest, allowing contributions to the reservoirs through localized areas of the territory, but a situation like the current one, in which it has been distributed throughout Gran Canaria, has hardly occurred,” he explained.
In his speech, the president of Gran Canaria highlighted that the most significant values that have been given in this area can be summarized in the fact that, today, on the Island there are 35 dams full and releasing water, and another five reservoirs could be filled in the coming days.
In detail, Morales explained that before Storm Claudia, the volume of water stored in Gran Canaria's reservoirs reached 2.3 million cubic meters. Subsequently, between Storm Claudia and Storm Therese, that is, between November 2025 and February 2026, an additional 5,4 million cubic meters were available. However, last week, Therese added another 23,6 million cubic meters to the island's storage. Therefore, the total stored volume reaches the aforementioned 39 million cubic meters. While water continues to be added to the reservoir network, this additional water is unlikely to significantly alter these figures.
“The storage capacity in the dams of Gran Canaria has increased from 2,3 to 39 million cubic meters, which represents a 17-fold increase over the reduced storage situation at the end of the 2025 agricultural period,” the island president emphasized.
Furthermore, he reported that six of the seven reservoirs owned by the Gran Canaria Island Council are currently being filled, with six of them undergoing relief operations, and only the Chira reservoir is at 51% of its capacity. “The increase in water stored during the storm in the island's reservoirs has been 6 million cubic meters, leaving a total water capacity of 7,8 million cubic meters, with a filling percentage of 73%,” he specified.
Morales also referred to the essential role that dams have played during the management of Storm Therese, as elements for regulating the flow of water in the ravines. “It can be said that dams were not designed to maintain large buffer zones, but rather to make the most of the available water, given the structural scarcity of this resource in the Islands,” he stated. “Thus, their performance during intense rainfall is clearly positive, because they absorb the surge of water, regulate it, reduce the peak flow, and distribute it over time, preventing it from arriving abruptly in the lower-lying areas of the territory.”
“When a dam overflows, it doesn't mean it's creating more risk; rather, it means the water is being released through the spillway in a controlled manner. The reservoir has already received and mitigated the incoming water, distributing it primarily across its surface. It's important to emphasize that a dam never increases the flow of rainfall; it reduces and softens it,” he explained. “Therefore, in terms of safety, the dams have performed flawlessly during this period of rain, demonstrating their essential role as a water-regulating element.”
Nevertheless, he asserted that the dams must continue to be improved and adapted to the new regulations approved by the State. This is a process in which publicly owned reservoirs are already making progress, and in which privately owned ones will also have to do so. “But we cannot lose sight of the fact that, for the most part, they are well maintained and have responded very well to this rainy season,” he affirmed.
On the other hand, he emphasized the behavior of rainfall on the island's aquifer, asserting that "it can be confirmed that it has been tremendously positive."
In this regard, he emphasized that the Cuevas Blancas borehole level, used as a reference to determine the island-wide isometric level, rose to 18 meters during the storms experienced since Storm Claudia. However, during Storm Therese, it reached 122 meters. Therefore, he asserted that “it is very important to point out that these rains have also been very beneficial, not only filling the reservoirs but also replenishing the Gran Canaria aquifer.”
“Doubly historic” rainfall
Antonio Morales highlighted that the high-impact storm 'Therese' brought intense rainfall, strong winds, and a tense situation that resulted in torrential downpours in some parts of the island, especially in the southeastern corridor, during the early hours of March 24th. "These are convective phenomena, which don't occur frequently, but which generate a brutal impact on the environment," he added.
According to his account, the days with the greatest impact were March 21 and 24, when high rainfall was recorded in the central and northern parts of the island. From a rainfall perspective, the values recorded at the summit classify the event as "doubly historic," and although data is still being collected, it can be stated that some of the rain gauges in this area have recorded daily rainfall totals that rank among the five highest in the entire historical record, which spans more than 70 years. "In those two areas, the totals exceed 500 liters per square meter and 379 liters per square meter, respectively," he noted.
At this point, he emphasized that many areas of the island have received more rain in a single week than they typically receive in an entire year. Furthermore, regarding duration and persistence, he noted that rainfall in the Canary Islands is usually short-lived and intense, but in this case, it has been continuous.
To illustrate the particular significance of the phenomenon, he referred to the case of the northern coast, specifically Arucas, where rainfall jumped from almost zero to 160 liters per square meter on March 24th in the Bañaderos area. This is the highest value in the entire historical record. "This figure is clearly representative of the events that occurred there, and it's worth noting that the riverbeds functioned properly," he commented.
Finally, to illustrate the magnitude of this event, he emphasized the rainfall in the mid-altitude areas of the north, specifically in the municipality of San Mateo, in the Las Lagunetas area, where nearly 400 liters per square meter of rain fell in just one day. "All of this caused numerous landslides, which are still occurring, in all these areas," he concluded.
