Despite their name, this subgroup details equipment for leak detection, tightness control, prevention of the "piping" effect, and continuous flow gauging. They are widely implemented in tailings dams, hydroelectric reservoirs, landfills, artesian wells, canals, and trenches.
The instrumentation includes vented hydrostatic transducers and high-sensitivity float sensors for automatic mapping, portable Dipmeter-style probes with graduated tape, and manual reel probes combined with enameled visual gauges. Additionally, they use standardized deflector plates (V-Notch Weirs at 45°, 60°, and 90° angles) and empirical equipment to measure the passive evaporation rate, consolidating the information through complex analytical platforms.

