On Modernization Of Hydrological Information System

Based on the requirements for monitoring the hydrologic elements of rivers, lakes and reservoirs, The techniques of monitoring, collecting, transmitting and processing hydrologic information are explored in this paper. The major works are as follows:To overcome the problems in relation to the existing water stage sensors, this paper developed a new floating-type stage sensor with an accuracy to millimeter by employing photoelectricity, magnetic reed, power-saving, coding and error correcting technologies. The theory on which the new sensor was developed was stated. The new sensor takes advantages of other sensors in its higher intelligence, larger observation range, higher accuracy, lower power consumption and no abrasion.The intelligence of telemetering control terminal reflects the advance and robust reliability of hydrologic telemeter systems. Under full consideration of high demands by national users and current communication conditions, a common telemetering control terminal named YDZ-YL300 was developed by means of bus technology, communication technology, observing and controlling technology.storage technology and lightning-protection technology. It has been widely used in monitoring hydrologic information, water environment, meteorologic elements and dam safety.By analyzing the characteristics of various communication methods, the paper revealed that ultrashort wave communication is still playing an active role in the telemeter systems and GPRS (General Packet Radio Service) is the direction of development. To reduce the errors of digital communication, the WDTP (Wireless Data Transmission Proof) agreement was proposed for ultrashort wave communication.Through utilizing hardware interfacing,debugging,database and network technologies, this paper developed a set of real-time hydrologic information processing software which have such functions as real-time reception, visual display, accurately storing information, warning when observed hydrologic values being over their limits, and sending hydrologic information to the offices of higher level via the network without the human intervention.A software to process the hydrologic data by computers was developed. It can set up a database by using fragmental hydrologic data according to the national hydrologic data reorganizing standards, and overcome the technical difficulties in determining the stage-discharge cure. Through analyzing the hydraulic characteristics of rivers, this paper presented a new method to determine the stage-discharge relationship affected by both floods and backwater.This paper analyzed the error sources of flood forecasting and suggested that the initial Values of forecasting models should be initially Calibrated followed by real-time calibration on forecasting results. By doing so, the forecasting accuracy can be improved. On the basis of the tank model's structure, a four-layer neural network model was proposed. The order of the model depends on the number and the distribution of rain gauges. The forecasting accuracy can be improved significantly through flow discharges being added to the input layer.