The Arava Stream is a channel that is continuously supplied year-round with brine water originating from the Dead Sea. These waters are pumped to the Dead Sea Works, undergo evaporation and mineral extraction processes, and are subsequently discharged back into the channel as surplus water. Despite its uniqueness, the flow characteristics, velocity fields, and bathymetry of the stream have scarcely been quantified to date. This study presents a detailed characterization of the flow-field structure in the Arava Stream, based on acoustic measurements acquired using an autonomous boat (SurfBee) equipped with a SonTek M9 ADCP.
Measurements were collected through repeated cross-stream transects along a selected reach of the stream, such that each transect provides a velocity field as a function of channel width and depth. Data processing included rotation of the coordinate system from a global reference frame to a stream-aligned local system, filtering based on measurement quality and platform motion, and spatial binning of velocities across cross sections to generate continuous flow fields. From these data, time-averaged flow components, bathymetric structure, and dynamic metrics describing secondary circulation were derived.
The results reveal pronounced lateral variability of the downstream velocity component across the channel cross section, with local velocity maxima directly associated with depth variations and bathymetric features. Mean velocity profiles exhibit consistent lateral asymmetry, indicating the influence of channel geometry and banks on flow distribution. In addition, secondary flow fields display organized patterns of lateral and vertical velocities, expressed through spatially varying vorticity and divergence. The total discharge of the stream was calculated based on spatial integration of the measured velocity fields and water depth, demonstrating the capability of autonomous-boat-mounted ADCP measurements to derive integral flow quantities. These findings provide a first quantitative description of the coupling between channel geometry, velocity structure, secondary flow, and discharge in the Arava Stream.