6. Performance monitoring and maintenance

Performance monitoring must cover both the hydraulic and chemical aspects of the system, in order to verify :

• that the system correctly drains groundwater to the reactive zones;

• that head losses remain within an acceptable range, with no risk of groundwater bypass outside the reactive zones;

• that the regulatory targets for groundwater treatment have been met;

• the filter's efficiency in terms of chemical removal and its saturation rate, with a view to planning a possible change of material.

Hydraulic monitoring is carried out by monitoring the piezometric level on site, via a network of piezometers placed upstream and downstream of the barrier, as well as at each of its ends. On some systems, percolation...