Development of New Water Quality Model Using Fuzzy Logic System for Malaysia

Proper assessment of water quality status in a river system based on limited observations is an essential task for meeting the goals of environmental management. Various classification methods have been used for estimating the chang- ing status and usability of surface water in River basin. However, a discrepancy frequently arises from the lack of a clear distinction between each water utilization mode, the uncertainty in the quality criteria of water employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methologies like water quality index (WQI) when describing integrated water quality conditions with respect to various chemical constituents, biological aspects, nutrients, and aesthetic qualities. In recent years, the fuzzy logic based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess water quality is proposed. This pa- per presents a comparative study using fuzzy logic technique to assess status of river water quality by comparing the out- put generated by fuzzy with that of conventional methods. The model is based on observations made from Semenyih River in West Malaysia. The findings clearly indicate that the fuzzy inference system (FIS) may successfully harmonize inherent discrepancies and interpret complex conditions. This river water quality model can be extended to determine the non-regulated contaminants in water.