As per ISS 9116/float type graphical recording with 7 days by electronic clock. The horizontal chart drum of the type F, Automatic water stage recorder is actuated by float action trough the float pulley and is rotated proportional to the changes in water levels. The pen moves across the chart form left to right at a multi-speed by mean of a quartz clock operated by 6 VD.C. cell The simultaneous movement of the chart drum and the pen automatically a graphic record of water stage against time.
| Mechanical Clock |
| Digital Clock |