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Average humidity in year is the average of average relative
humidity of all days in the year.
The water level is elevation of the water surface at the observation
place in relation to the sea surface, measured in centimeters (cm). A system
of piles, rulers and self-recording machines are used to monitor the
water level.
Water flow is the amount of water flowing through a cross section
of the river in a unit of time, measured in m³/s. Monthly average flow is
the average value of flow of the days in the month. Water flow is
measured by flowmeters, drifting buoys or ADCP machines.
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