Tidal Measurement and Analysis
The measurement of tidal flow and other parameters in a tidal river is usually carried out based on field observations. The measurements include some form of current velocity, water temperature, salinity and sediment. The representativeness of any set of measurements is dependent on the choice of sampling locations, sampling rate and duration of study. A rational procedure of analysis and synthesis of data is also an essential requirement. Nowadays thermistors have replaced ordinary thermometers as preferred sensors for temperature measurements. The current velocity varies greatly both in magnitude and direction relative to its resultant value over the predominant tidal period. The current velocity is obtained by a currentmeter which can either be suspended from the surface or installed at a fixed distance above the bottom. The direction is usually sensed through a vane which is allowed to rotate in the horizontal plane or the meter itself swings with the current.