Interpreting Flow-Driven Acoustic Signatures in Vadose Passages

Vadose streams don't flow the way phreatic conduits do — and the acoustic signature reflects it. EchoQuilt classifies free-surface flow by turbulence signature so surveyors read geometry from sound.

A phreatic conduit is fully water-filled; flow moves as pressure transmission through a pipe. A vadose passage is a stream with air above it, and the physics are completely different — turbulence interacts with a free surface, flow velocity varies with channel width and slope, and the acoustic field reflects off water-air boundaries that simply don't exist in a phreatic conduit. The USGS karst-aquifer overview defines the regime distinction: conduit-dominated vs. diffuse-flow, with vadose passages hosting most of the conduit-dominated free-surface streams in mature karst systems.