The DVP (Depth Velocity Position) bar—a multiplex instrument for physical habitat measurements in small riverine domains

Abstract

The measurement of physical habitat components in small rivers can be a complicated and resource‐intensive task. The characterisation of the complexity and dynamics of such domains requires manual collection of large amounts of data in the shortest possible time. The physical microhabitat variables that are usually measured for assessment/modelling purposes are channel geometry, water depth and velocity. Simultaneous collection of these variables, combined with automatic data logging can significantly reduce sampling time. In this paper, a depth velocity position (DVP) bar developed to achieve this task is described. The prototype of the instrument was built in 1996 and tested intensively in the summer and winter of that year, yielding encouraging results. This multiplex instrument consists of three probes simultaneously measuring depth plus mean column and near‐bottom velocities. In addition, a geodesic prism or global positioning by satellite (GPS) rover can be mounted on the top of the instrument for accurate position recording. Water depth is registered by pressure transducer and near‐bottom velocity by a one‐dimensional electromagnetic probe. The integrative mean column velocity is measured using a modified ‘dipstick’ (Jens, 1968, Dtsch. Gewässerkdl. Mitt., 12. Jahrgang, 4, 90–95). The torque that results from velocities influencing the dipstick is registered with an electronic tension stripe and translated to the mean column velocity. All of above variables are data logged every second for the period set by the operator. Copyright © 1999 John Wiley & Sons, Ltd.