Design and Application of Water Environment SCADA for Tuojiang River

To protect the water environment of Tuojiang River, a supervisory control and data acquisition (SCADA) system was designed as three-tier structure: monitoring station, central station, and control & management center. In monitoring station, data from survey instrument were transmitted to computer system through RS-232. Because of geographical and economic conditions, there were several different plans for data transmission between monitoring station and central station. A classic one was based on MOTOROLA SCADA (MOSCAD), mainly including MOSCAD-M RTU, MOSCAD FIU, and MDLC. Usually Internet connects central station and control & management center. To draw concise and accurate conclusions of water pollution, factor analysis method was used to process the original data by statistical program for social sciences (SPSS). According to the results, the accumulative contribution rate of 6 common factors accounts for 94.053%, including most information of 14 original indexes. It proves that at present total inorganic nitrogen, total phosphorus, and organic pollutants mainly pollute the water of Tuojiang River. So the work of protection should focus on industrial pollution, agricultural irrigation, and domestic sewage. The system has been applied for 2 years and it has been proved that the reliability, accuracy and real-time performance can be used as needed.