« Thanks to the purchase of Imageau’s devices Saur can now offer
the service of an innovative process to communities seeking to anticipate droughts, ensure optimal quality water and eschew
excessive operating costs. »
Louis-Roch Burgard - 2017 - Saur executive president
With the aim of increasing their knowledge on the functioning of their subsurface resources, the Rocailles and Bellecombe syndicates propose the realization of a vast hydrogeological assessment of the Rocailles aquifer in the lower valley of Arve (Haute-Savoie). This aquifer composed of ancient Arve alluvions is located under more than 30m of morainic overlay. During the lasts glaciation and deglaciation periods, these moraines have sculpted the morphology of this ancient alluvial aquifer by partionating it. Up until now, the knowledge of its geometry and the possible links with the course of the Arve and the adjacent aquifers ask to be investigated. This heritage data for the Rocailles aquifer will allow a better management of this water reservoir.
Thus, in the scope of this study, our team of geophysicists and hydrogeologists realized the entirety of the auscultation and investigation work in the Scientrier aquifer. To do so more than 16500m of electrical panels have been done. The interpretation of this campaign profited from the most recent inversion methods developed by the academic world. Afterward, 10 piezometers with an average depth of 60m had been realized to accomplish a quantitative and qualitative monitoring of the aquifer. These new data will allow to bring clearer elements of response to characterize the Rocaille aquifer geometry and dynamic.
Within the scope of the European project AquaNES (H2020) conducted in partnership with BRGM (French Geological and Mining Research Bureau), Geo-hyd and microLan, imaGeau installed a salt water intrusion monitoring network in the commune of Agon Coutainville. The goal was to characterize the impact of artificial recharging in the aquifer to push back the salt water wedge. Indeed, the Agon Coutainville water treatment plant re-inject its treated sewage water in the sandy aquifer via a reed bed located 500m away from the littoral. This research project aims to demonstrate the interactions of an artificial recharging system (MAR) to counter the salt water wedge.
With the intent to increase the knowledge on the functioning of its resources and thus ensure an equilibrium between demands and needs, the Water Syndicate of Rocailles Bellecombe proposed the realization of a vast hydrogeological assessment of the Arve alluvial aquifer in the commune of Etrembières. Taken over by imaGeau, this assessment integrated every steps of an hydrogeological characterization : geological reconnaissance, geophysical prospection with electrical panels (3800m), production of 11 piezometers, site instrumentation (piezometry, pluviometry, stream gauge), water draw-off and analysis, pumping trial, plotting. The investigations done have shown relevant informations for the construction of a representative hydrogeological model able to simulate the aquifer system functioning and to foresee its behavior in response to accidental or chronic contamination.
In February 2016, a monitoring pilot network for salt intrusion thanks to SMD was installed for the first time in island of Reunion at the Baril well (commune of Saint Philippe). The SMD is a ground water monitoring tool installed as piezometer allowing to register water conductivity at hourly frequency along all of the aquifer verticality. Thus at the Baril well, these two piezometers equipped with SMD allows to know in real time the salt water wedge's position and the available water volume (water volume with a conductivity inferior to 1000 µS/cm). These data are retrievable at any moment on a secured data management web application for environmental data (EMI).
Since the beginning of the recordings, more than 15.000 conductivity profiles were recorded that emphasize a visible ascend of the salt water wedge by 5.15m at the JOS 2 piezometrer between June 2016 and June 2017.