Bègles: between arsenic pollution and underground parking, a real estate program examined on the Toulouse road

Delivered at the end of July, the opinion of the Regional Environmental Authority Mission (MRAE) offers an overview of the problems facing one of the Béglais real estate programs located in the concerted development zone, straddling Villenave-d'Ornon.

The relevance of an underground car park, management of arsenic soil pollution, rising water table in the event of heavy rains... Delivered on July 25, an opinion from the Regional Environmental Authority Mission (MRAE) puts on the table an instructive list of issues related to the densification of the Toulouse road, one of the main axes of the Bordeaux metropolitan area. In the sights, on the Bègles side, the "CA1" block, currently occupied by a disused Midas workshop and a suspended car park at the corner of the avenue leading to the Vaclav-Havel high school. In 2021, six buildings and 188 housing units were planned there, as part of the Concerted Development Zone (ZAC) Toulouse road, a variation of the metropolitan operation "50,000 housing units around public transport routes", here straddling Bègles and Villenave-d'Ornon.

And it's an updated opinion that the environmental administration has issued, at the request of Clément Rossignol Puech, the Green mayor of Bègles. Because the project has evolved, with social housing provider Domofrance and Araucaria, a subsidiary of the Pichet real estate group, now announcing 321 housing units, including 185 reserved for students. Two Araucaria buildings are increasing from five to six stories for one, and from three to six stories for the other. This densification which, paradoxically, goes hand in hand with a reduction in the number of parking spaces: from 191 to 159 (including 76 underground), with one of the two underground parking lots being reduced.

The MRAE notes that "the reasons for this reduction in the overall parking supply are not explained" in the impact study file, except "in a general and indirect manner" through a "desire to increase open space" and the "search for economic profitability". But it actually questions the relevance of the second underground car park, due to the immediate proximity of tram line C and cycle paths and the "proven risk of rising water tables".

This is another aspect of the opinion: the MRAE notes that the sizing of rainwater management structures is calibrated on a ten-year frequency of heavy rain. A "choice" that it invites to justify "in light of climate change." "If necessary," it suggests adapting "the sizing of rainwater management devices." "The contribution of an underground car park as an aggravating factor is not studied," it also notes.

Added to this is the problem of soil pollution , namely "the presence of an area of embankment with a high arsenic content […] in the northern part of the project" allocated to Araucaria. It was to be moved about thirty meters and confined under one of the Domofrance buildings. In the first version of the real estate program, the developer stated that this pollution had no impact on groundwater, referring to studies which "were not, however, attached to the file." "The 2025 version of the impact study also does not include these studies and does not provide any additional information […]," regrets the MRAE.