The ADCP (Acoustic Doppler Current Profiler) is a powerful instrument for measuring river flows. The cylindrical device is mounted on a floating device and travels along the river section to be measured. Several acoustic emissions are used to measure the river bottom and the current velocities over the entire water column in real time. At the end of the journey from one bank to the other, the velocity field and the wetted section are measured and allow the flow rate to be calculated.
Artificial tracing is a technique that allows the determination of the groundwater pathways from upstream infiltration zones to downstream release zones (typically springs). An artificial tracer (neutral for the environment) is injected upstream, after which a network of outlets is monitored. Fluorescent tracers are commonly used. Monitoring at sources is then done by following the variations in the fluorescence of the water.
The radioactive isotope of radon 222 is a decay product of uranium 238 in gaseous form. It is naturally produced by all types of rocks and is found dissolved in groundwater. Radon 222 is therefore an excellent groundwater marker. The platform is equipped with 4 RAD7 devices capable of measuring the radioactivity emitted by radon. Beforehand, water must be taken from the ground, the gas contained in the water must be decanted and the water vapour must be removed by absorption on a desiccant material.