The instrument will function without failure, in spite of, for example,
the presence of sand and gravel on top of the logger. A stilling well is
not necessary, as a matter of fact a stilling well is not advisable because
of the accumulation of fine sediment in the closed environment of the stilling
well.
It is not necessary to install the logger in the deepest point in the
river, the logger must be installed below the minimum water level expected
in the river. In this case it is necessary to know the difference in height
between the point of installation and the deepest point in the river to
get proper water level of the river.
Because the Absolute Pressure Logger type for this application is measuring the absolute pressure (the total of water pressure and the air pressure) , a reference logger is necessary to measure the air pressure. With the Tirtaharapan Data Viewer the air pressure can be subtracted from the water+air pressure recordings so that the result will be the water pressure milli bar which is equal to the water level in centimeters (1 mbar = 1 cm of water pressure).
The Absolute Pressure Logger is available in two ranges, 2 Bar and 5 Bar. The 2 Bar range can measure 10 meters of water pressure and the 5 Bar 40 meters of water pressure. The 2 Bar range is ideal for measuring in open channels and for the measurement of air pressure. The 5 Bar range can be used to measure in wells or bore holes in which the water level fluctuates more than 10 meters.