Doñana records 300 mm of rainfall since September, but several wet years would be needed to make up for the current water deficit
Rainfall levels in Doñana are within the winter average. The marsh currently has a broad and adequate flooded area, of approximately 16,000 hectares, though the water remains shallow for this time of year

Areal view of Doñana by the Sentinel-2 satellite on January 15 (left) and February 4 (right), 2025. // EBD-CSIC
Since September, 300 mm of rainfall have been recorded at the Palacio de Doñana manual station in the heart of the National Park. This figure is above the average of the past ten years but falls within the typical winter range for Doñana. The marsh has an extensive sheet of water, with around 16,000 hectares flooded, though the water is shallower than usual for this time of year.
The hydrological year, running from September to August, started with good rainfall in October, followed by a dry November and December, leaving Doñana with scarce water at the start of winter. However, the rainfall in January has brought levels close to the historical average.
In a typical hydrological cycle, the lack of rainfall and high temperatures during the summer dry out the marshes, which remain dry until the arrival of autumn and winter rains. The marshes rest on a clayey substrate that needs to rehydrate after the summer period. It is estimated that around 200 mm of accumulated rainfall is required for the marshes to begin flooding.

Before the rains of January, the flooding of the marsh was limited to areas like Madre del Rocío, Caño de las Madres, Lucios del Caballero, Vetalengua, and Membrillo, which are usually the first to flood with the onset of the first rains. The significant difference this year, compared to previous years, is that more than 100 mm were recorded in January. This, together with the prior rainfall, has activated the entire hydrological system. Streams such as Los Sotos, La Rocina, La Cigüeña, and the Guadiamar River contribute to filling the marsh with river water, not just rainwater. According to data from the GIS and Remote Sensing Laboratory of the Doñana Biological Station (CSIC), the water surface area of the marsh is currently quite large, covering around 16,000 hectares.
The flooded areas are mainly the northern and central marshes of Hinojos (Gallega marshes) and Aznalcázar (Travieso marshes). However, despite its extension, the water coverage remains shallow. The Honduras del Burro hydro-meteorological station records a depth of approximately 37.5 centimeters, while Guadiamar Millán and Vetalengua measure around 20 centimeters—both below the typical levels for this time of year.
Data from ICTS Doñana, part of the Doñana Biological Station - CSIC, indicate that while recorded rainfall so far is close to the average of the past decade, it remains insufficient. This is due to a significant water deficit, preventing the marshes from reaching their typical winter levels.
Abel Valero, technical manager of the Doñana Biological Reserve's Information Technology Infrastructure and Services, explains: "It hasn't rained as much as it seems. Moreover, we are starting from a deficit situation. To restore the normal functioning of the ecosystems, there needs to be a substantial surplus—meaning above-average wet years—as well as a reduction in water extractions from the overexploited aquifer."
It is also important to note that in Doñana, Atlantic weather fronts tend to bring less rainfall to the marshes. Precipitation is usually higher in the northern periphery and along the coast than in the core of the Natural Area's marshes. This variability is evident in the data: while the Palacio de Doñana station has recorded 300 liters per square meter since September, other stations in nearby municipalities, such as Moguer, have recorded more than 450 liters per square meter.
A large water deficit
"The importance of Doñana lies in its water. Without water, Doñana has no life," explains Javier Bustamante, deputy director of the Doñana Biological Station and head of ICTS Doñana.
Due to the prolonged dry period in recent years and the high water demand, which exceeds the annual recharge rate, the aquifer level is steadily declining and Doñana’s lagoons and natural springs, which supply water from the dunes, are disappearing. In times of water deficit, Doñana’s biodiversity becomes increasingly dependent on the aquifer, which spans nearly 200,000 hectares—far beyond the boundaries of the protected area. However, the water table remains at historic lows, significantly affecting both the quantity and quality of the aquifer’s water
The latest report from the Guadalquivir Hydrographic Confederation states that three of the five water bodies in the aquifer surrounding Doñana are at risk of failing to achieve a good ecological status. For instance, the piezometer at Carril del Corte shows a drop up to 1.61 meters over the past four years.
This decline has severe consequences for Doñana’s lagoon system, which is highly dependent on groundwater. It has even led to the drying up of Santa Olalla, the Park’s largest lagoon, for the past three consecutive years. The impact is particularly significant from a biological perspective: historically, Santa Olalla was a permanent lagoon, and over the last 45 years, it had only dried up on a few isolated occasions. Traditionally, bird censuses were conducted at the lagoon during the summer months of July and August, when it served as a crucial refuge for a diverse range of bird species, amphibians, fish, and other wildlife.
Another consequence is the water stress affecting the vegetation, particularly the cork oak, whose groves have been one of the park’s most iconic landscapes. "This community of trees is drying up," says Bustamante.
Doñana faces the risk of becoming an endorheic system—an area cut off from the influence of rivers or the sea. The biodiversity of its marshes depends largely on the water they receive from tributary streams, particularly the Guadiamar. However, its main branch, the Caño Guadiamar, has been disconnected from the marshes since the mid-20th century.
For this reason, the reconnection and restoration of the Caño Guadiamar are crucial to securing Doñana’s future. These actions are part of the Framework of Actions led by the Ministry for Ecological Transition and Demographic Challenge and the Regional Government of Andalusia.
Doñana's environmental monitoring

Ricardo Díaz-Delgado, coordinator of ICTS Doñana Environmental Monitoring, explains: "In Doñana, the ICTS monitors meteorology and hydrology using fixed instruments in the field, allowing us to access real-time information. The importance of this automatic monitoring lies in detecting when and where changes occur, enabling the management team to respond quickly and make informed decisions."
ICTS Doñana’s field sensors measure the water level of the marsh every five minutes. Additionally, manual measurements are conducted every two weeks, coinciding with sensor maintenance and calibration. "This approach allows us to track meteorological, environmental, and biological fluctuations and changes," Díaz-Delgado adds.
The Doñana Singular Scientific-Technical Infrastructure (ICTS Doñana) was established in 2006 to facilitate research access and support in Doñana, while also developing and implementing infrastructures for the automated monitoring of its wildlife and ecosystems.
Since then, a radio and Wi-Fi network has been deployed across the Biological Reserve, the National Park, and part of the Natural Park to enable automatic monitoring of environmental variables, including hydrology and water quality, meteorology, greenhouse gases, piezometry, and multimedia data from cameras. This network provides real-time connectivity for field instrumentation and sensors, allowing the continuous upload of collected data to the Internet.
Always at the forefront of innovation, ICTS Doñana is now working on the development of a Smart Environment—an advanced Internet of Things (IoT) network designed to complement the existing radio and Wi-Fi infrastructure.