Risk, it's what moving
Measuring the concentration of a pollutant in the aquifer is necessary to quantify the extent of pollution, but measuring the flux is essential to characterize its dispersion.
A pollutant in low concentration but mobile presents a much greater risk than a highly concentrated but immobile pollution.
Our Flux technology
Direct flux measurement is carried out using a single-well tracer dilution technique.
A tracer is continuously injected into a piezometer and the concentration of this tracer is measured over time troughout the water column.
As the tracer is injected, its concentration will increase, then stabilise once equilibrium has been established between the tracer injected and the tracer carried out of the piezometer by the flux of groundwater passing through it
The groundwater flux is thus known and can be monitored continuously.
Thanks to a double packer system developed by Nagaré, it is also possible to sample groundwater and measure groundwater flux over specific part of the water column, in order to target a specific horizon.
By moving this system over the entire height of the water column, it is then very easy to obtain a vertical discretization of groundwater fluxes and calculate mass discharge.
Acquisition time : 2h – 48 per well
Tracer : Salts, Fluorescent dyes
Diameter min. well : 2 inches
GW flux representative of all screen level OR
Vertical logging to target specific layer
Maximal depth : 100m
Monitoring of groundwater flux changes in existing wells
Which benefits ?
The flux measurements obtained with our technology are coupled with pollutant concentration measurements, enabling us to target the areas where pollutant discharge is greatest, i.e. where it presents a real risk.
Flux measurements could be then used to optimize a future management plan (monitoring or remediation) for the site, in that they could reduce the number of piezometers monitored or treated by targeting preferential discharge areas.
And many more …