Figure 15.15 shows the general arrangement of the automatic water level recorder.Īn enamelled gauge plates are also fixed on the stilling well from outside to record the water level by visual observations during inspection visit. A ladder is provided in the stilling well for inspection and cleaning purposes. The stilling well is connected to the river by means of intakes. On the top a roofed shelter with locking arrangement is constructed to house and secure the recorder. The stilling well may be constructed with corrugated iron sheet, concrete or masonry. The water level recorder is a compact unit which is installed on a platform constructed over a stilling well. Figures 15.15 and 15.16 show the automatic water level recorder and the strip chart with recorded water levels respectively. Depending upon the type of clockwork mechanism, available fall for clock counter weight and length of the strip chart the continuous record may be obtained from 1 to 6 months. The recorder chart thus gets wound slowly at a uniform rate and the recording stylus traces the water level fluctuations laterally on it to provide a continuous record of water levels. The recorder chart is connected to a clockwork mechanism which moves it at pre-determined speed continuously. The recorder chart is a tracing quality strip paper wound over rollers or a drum. It moves laterally and traces the water level fluctuations on a recorder chart. The float line passes over a pulley and transfers the changes of water level to it.Ī recording stylus is attached to the pulley. The most common type of automatic water level recorder uses a float line with a metal float at one end and small counter weight at the other end. Like the recording rain gauge the automatic water level recorder also works on the principle of a float. Sometimes the enamelled gauge plates are fixed or painted on the bridge piers to record water levels.
It is normally read twice a day and on hourly basis during the flood season. The staff gauges are read by an observer or a gauge reader.
To secure the staff gauges they are fixed in the concrete blocks constructed along the banks. The gauges are generally constructed on both the banks on one section line with same levels. They are so constructed that the top of the lower gauge continues the reading from the bottom of the next gauge. They are constructed along the slope of the bank as shown in Fig. Each staff gauge is generally 2 m in length. The staff gauges are the wooden posts on which enamelled metal plates graduated to 0.01 m are fixed. It is a simple device used to record the water level.
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