Technical NoteSurface flow measurements from drones

•The integration of optical techniques and drones can help in flow monitoring.•Sub-meter channel flow is noninvasively monitored from a low-cost drone.•Surface flow measurements from the drone are in agreement with traditional methods.•Quality of images captured from the drone yields accurate flow measurements.

Drones are transforming the way we sense and interact with the environment. However, despite their increased capabilities, the use of drones in geophysical sciences usually focuses on image acquisition for generating high-resolution maps. Motivated by the increasing demand for innovative and high performance geophysical observational methodologies, we posit the integration of drone technology and optical sensing toward a quantitative characterization of surface flow phenomena. We demonstrate that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies. Specifically, drone's vibrations do not hinder surface flow observations, and velocity measurements are in agreement with traditional techniques. This first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.