ABSTRACT

Fig. 7.2 shows a typical cross-section of a natural river channel with contours of velocity superimposed. These would normally be inter­ polated from point velocity data obtained by traversing with a current meter. This instrument (Plate 1) is extensively used for purposes of discharge measurement in rivers and artificial channels. Its construction is such that the angular speed of the rotating element, either propeller or mounted cups, is proportional to the water velocity. An electrical

make-and-break circuit transmits signals to a revolution counter or headphones.