ALBI 
   Environment

   A battle plan to
save Tarn river banks

 

 

 

     The town has just launched a protection program in order to secure certain parts of the Tarn river banks, victims of a strong erosion.
First protection work, rue de Gardès. Spectacular    

 

Warning, danger. The area, under work   since  eight days, along the Tarn banks, rue de Gardès, is secured at night so as to prevent any slip and fall, 34 m lower. At day time, this bank panel, heavily eroded, is being reinforced. The geothermic studies, dedicated to determine the instability zones of the river banks, have been clear. Three zones are being aimed at and will undergo consolidation works. Including rue de Gardès, behind the Castelviel. « Subterranean sources have contributed to weaken this natural cliff on a 20 m length, explains Geneviève Parmentier, elected environment representative. These works will reduce the risks of cliff rupture and will protect this area from erosion phenomenons.

Serious caution must be taken on these cliffs at a 37° slope.
.Photo DDM, Emilie Cayre

"We had to operate rapidly for safety reasons…" 

 
                                                                                         

 

    MTPS, the local specialized company and the « speleos » from Versant Specialized Works are now achieving 8 m horizontal drillings on a 37° slope. The sight is worth an eye. On these concrete piles a steel wire net will be affixed while metallic plates will be placed on the lower part of the banks. The said wire net will then be vegetalized, this area being environmentally protected.
Total cost of operations : 210 000 €. Works duration : 9 weeks.

The geothermical studies have also put forward two endangered zones. Including the area between Bondidou bridge and the cathedral. 270 m of river banks are concerned. The Échappée verte path, condamned for 2 years following landslides, will be reopened after the consolidation works. Cost : 300 000 €. Last zone concerned, that of the Moulin du Chapitre, its natural banks and its retaining wall in poor condition. Tests are being carried out, under the eye of the Bâtiments de France and the archeologues because the Moulin is situated at the heart of the Unesco protected sector. Delicate works, at a cost of 350 000 €, will start next year, outside flood periods, on a nearly 100 m long zone. There too, not just anything may be done to protect the banks and save them from water, frost and vegetation. The experts are watching.
                                                                                                                           P.S.

 

Figures : 330 m2 > wire net. the area covered by the wire net affixed on the cliff will be of 330 m2.

The acacias did not resist A thick vegetation covers the whole length of the cliff but the water ingresses, coming from underground sources, have wreaked havoc. The acacias, though known to have a strong roots network, did not resist the erosion before draining could be undertaken, in order to better manage the underground water flows and limit llow pressures.