The Town Hall of Torrejón de Ardoz has launched its amphibious boat to eliminate aquatic plants from the Henares River, the main breeding ground for the black fly. The mayor and the councillor for the Environment supervised the work along 7 kilometres of river.
An amphibious machine of Swedish origin is currently navigating the Henares River as it passes through Torrejón de Ardoz with a very specific mission: to cut the black fly problem at its roots. The boat, equipped with a submerged blade, removes the aquatic plants where these pesky insects deposit their larvae, which test the patience of residents every summer.
The mayor, Alejandro Navarro Prieto, and the councillor for the Environment, Esperanza Fernández de Mesa, supervised the operation on Thursday over the 7 kilometres of river that stretch from the M203 —upstream of the Torrejón University Hospital— to past the Castillo neighbourhood. This is the thirteenth year that the municipality has resorted to this vessel, one of the few of its kind in Spain.
A boat with cutting-edge technology to tackle the larval focus
The amphibious vehicle, imported from Sweden, carries out two four-week sessions during the summer: two in July and two later on. Its submerged blade mows down the aquatic vegetation, precisely where the black fly —a small black dipteran— lays its eggs and larvae. By removing this support, it prevents the insects from completing their development cycle.
“It is the most effective tool we have,” municipal sources explained. The work focuses on the areas closest to the river, such as Soto Henares, Mancha Amarilla, Torrenieve, Parque de Cataluña, Barrio del Castillo, and Parque Europa, where green and sports areas are prioritised, according to studies from the Superior Council for Scientific Research (CSIC) and municipal inspections.
Biological treatments and bats as allies
The fight against mosquitoes is not limited to the amphibious boat. From March to October, the Town Hall applies biological larvicides in the river, streams, ponds, ornamental fountains, and drains. These products, according to the City Council, are “completely harmless to humans and the environment.” The actions are georeferenced and complemented with specialized traps to identify species and monitor environmental conditions.
Additionally, the municipality has introduced colonies of bats as a natural biological control. “Even before summer, we began the necessary treatments to reduce the populations of larvae and common mosquitoes, trying to prevent them from having a significant impact on residents,” the mayor highlighted during the visit.
Residents of the riverside neighbourhoods are the most benefited by these actions. The black fly, whose cycle accelerates with heat, causes painful bites and can generate allergic reactions. By removing the aquatic vegetation, its reproductive capacity is drastically reduced.
For any inquiries, the Environment Department can be reached at 91 678 95 94 and via email at medioambiente@ayto-torrejon.es. Meanwhile, the amphibious boat will continue to navigate the Henares, cutting plants and, with them, the nuisances of a relentless summer for the residents of Torrejón.
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