Agde: “Drying the Bagnas is essential”, says scientist Clara Rondeau

The drought in the marshes surprised more than one visitor to the natural park this summer. But this episode would be above all a lifesaver.

This summer, the drought raised doubts among visitors who came to observe the birds of the Bagnas nature reserve. It must be recognized that seeing these generally marshy extensions crack under the sun is not necessarily common, although the phenomenon is beneficial in more ways than one, as Clara Rondeau, responsible for scientific studies, explains. “This drying of the pond is called drying, it is a fundamental step for its proper functioning,” she believes. “In the Mediterranean, the natural evolution of water levels in a marsh sometimes predicts a drying up in summer. Adena, as manager of the Bagnas, has the task of managing, conserving and enhancing this natural area. The water levels in the pond are thus defined by the management plan to guarantee the maintenance and development of biodiversity, so we respect these heights, opening valves, called hammer boxes, which allow managing the circulation of water from the Canal du Midi, but also rainfall”.

The Grand Bagnas Pond has dried up by simple evaporation

Since the beginning of winter, the hydraulic structures have remained open to the maximum on the Canal du Midi side. Due to lack of rainfall, the Grand Bagnas Pond did not recover high enough water levels before the summer season. Thus it ended up drying without draining, by simple evaporation. . “Since the last drought in 2016, the pond was already showing significant signs of sedimentation. Possible eutrophication (a natural form of pollution) of the pond. This year’s drainage will help mineralize organic matter, revitalize this meadow and maintain biodiversity.” ” However, with a drawback: the drought limits the possibility this year of offering good conditions for the migratory stopovers of the birds.

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