Fuzzy assessment for water quality in inanam likas river basin, Sabah, East of Malaysia

Water Quality Index is an important water assessment that sustain and conserve the aquatic ecosystem. In Malaysia, the current classification practice on Department of Environmental Water Quality Index (DOE WQI) shoes rigid value in term of assessing the input of parameters that close to a class boundary. Hence, this study proposed a technique to assess the parameters in a holistic manner by using the Fuzzy Inference System (FIS). The approach as an assessment tool represents the classes of various ranges and aggregating the parameters using membership function and Centroid Function respectively. A numerical example based on actual data from one of the sampling station from Inanam-Likas River Basin was adapted in this study. It was adapted to demonstrate the proposed approach. Findings shown using the proposed method indicate that the river has poor water status. Overall, FIS is able to assess the parameters and execute into a single index that represent the condition from poor to excellent scales of the water quality.