Water environment early warning index system in Tongzhou District

Water environment warning system is an effective way to reduce water environment degradation. It protects lives and property in a timely and preventive manner from a pollution accident-prone area. Two water environment early warning index systems, gradual changing warning index system under drought conditions and sudden water pollution acute events index system, were established in Tongzhou District, Jiangsu, China. The methods and procedures for the two index systems were investigated. Indicators were chosen and justified based on recent research. Gradual changing warning indices included precipitation anomaly percentage, continuous non-precipitation days, and river levels, while socioeconomic effect indicators and natural environment effect indicators were included in sudden water pollution indices. Analytic hierarchy process was adopted to build the systems. Comprehensive evaluation method was used to evaluate the warning level. Both one- and two-dimensional unsteady-state water quality models were applied to calculate pollutant concentration variation for acute events. Preliminary results indicated that both water environment warning index systems could be established and used practically in Tongzhou District. Different warning levels could be determined according to specific assessment supported by empirical data and theoretical evaluation. Use of the warning systems could provide economic and environmental benefits for this area.