The Establishment of Water Quality Assessment at Inanam Likas River Basin Based on Phytoplankton as Bio indicator Using the Integrated Environment Water Quality Index (DoE WQI) and Fuzzy Inference System / Herman Umbau Lindang

Best assessment practise in river basin should emphasize on conservation and
sustainable aspect of freshwater organism especially the phytoplankton. Since
phytoplankton are the primary producer in the aquatic life cycle, sustaining its diversity
are the main priority. Consequently, human knowledge and experiences by the local
authorities and researchers in sustaining the phytoplankton ought to be adapted in a
water assessment. Fuzzy theory can incorporate both hydrological data and human
knowledge in developing the best water assessment practise. Therefore, this research
proposes a water quality assessment emphasizing on the needs of the phytoplankton
community by integrating it with the current Department of Environment Water
Quality Index (DoE WQI) adapted in Malaysia. This research was driven by three main
objectives. First, the diversity of phytoplankton community had to be determined and
followed by determining the relationship of the diversity of the phytoplankton with the
selected physicochemical parameters. Followed by the evaluation of water quality
assessment based on the Fuzzy Inference System (FIS). FIS comprises of 5 major steps;
Fuzzy Input, Fuzzy Output, Inference Rule, Aggregation and Defuzzification. Thirdly,
validation of model using one-at-a-time local sensitivity analysis (OAT-LSA)
approach. Inanam Likas River Basin (ILRB), Kota Kinabalu was selected as the case
study to demonstrate the feasibility of the proposed model. Finding of the research
shows the hydrology parameter of Ammonium, Dissolved Oxygen and pH value has
positive relationship with the diversity index of phytoplankton (H'). Meanwhile,
Turbidity has negative relationship with H'. Apart from the identified correlations,
phytoplankton under the phylum of Euglenophyta and Dinoflegellata was identified to
be having increasing trend from the upper stream to the lower region. Moreover, the
establish water assessment model constructed was able to evaluate and execute the
input into a single index. The condition of ILRB was able to determine from poor to
excellent condition of the water quality. Finally, OAT-LSA was demonstrated for
validation purpose. It was done through perturbation of input parameter by ± 10% and
it shows the constructed model was consistent. Therefore, the proposed water
assessment model able to consistently execute the assessment based on the local needs
of the phytoplankton. It definitely can be practise by the Department of Environment
Malaysia, benefits the local community and most importantly able to sustain the
phytoplankton community in Inanam Likas River Basin.