Research On Tidal Discharge Measurement System

The tidal river in plain estuary is influenced by the interaction of tidal current, runoff and waves. The water level and velocity of flow are fast changing with space time, and the flow direction is also changing to and from, all those constitute the complicated hydrological phenomenon. Therefore, it' s more difficult to carry on the tidal hydrology especially the tidal discharge measurement in river net district of spacious river surface and busy shipping than in the tireless river no matter in the aspects of instruments for measurement, methods of measurement, data analysis and compilation, having much difficulties and disadvantages over the high risk in measurements, heavy work of measurements, high investment in manpower and property, low accuracy of measurement and compilation. As a result, the advancing study on the automatic observing system of the tidal river discharge, the depending on the technological power and the using of the advanced hydrological instruments in the world, all those achieve the continuous real time observing over tidal discharge.The thesis is concerned with the tidal river discharge automatic observing system, which is constituted of the horizontal H- ADCP velocity mainframe, the automatic water lever recorder with code, lift bracket lift control winch, console, the connected optical fiber, the industrial control computer, system software, system control(the data collection and processing) and so on. The H- ADCP is fixed on the position of certain flow depth in the cross section, measuring the horizontal velocity of flow in water layer in a certain range in the river. The center control computer observes the tidal discharge by sending orders to the water lever and velocity instruments through the optical fiber cable automatically.This thesis researches on the choices and fixing of the instruments, the H- ADCP' s velocity representation of observing, the control system software etc; taking the successful invent of the tidal discharge automatic observing system in Tianhe hydrometrical station in the Pearl river delta as an example, and expounds the constitutes, function and working process of the tidal discharge observing system in the tidal river. The tidal river discharge observing system of this thesis gives a new method and experience of the hydrology observing to the river reach and cross section with complicated landform and flow, or busy shipping. This system has achieved 3 innovations: instruments for measurements which use the unmechanized rotor and continue measuring ADCP as the velocity mainframe; methods of velocity measurement which change the vertical velocity measurement to horizontal velocity measurement; the tidal discharge measurement which solve the problem that current method of discharge measurement can not achieve the accuracy of the criterion according to the continuous real time observing over the velocity of flow.