Development of Water Quality Index for Coastal Zone and Application in the Hạ Long Bay
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Abstract
Abstract: In this study, a water quality index (WQIHL) was developed in accordance with the nature of coastal zone and applied to assess the water quality in Ha Long Bay. Nine parameters, including %DOsat (0.08), COD (0.11), TOC (0.08), oil and grease (0.17) total coliforms or feacal coliform (0.07), TSS (0.17), TN or NH4+ (0.11), TP or PO43-(0.11) and chlorophyll a (0.11) are employed for the estimation of water quality. Numbers in the parentheses indicate weight of each parameter. Sub-indices are built based on the QCVN 10:2008/MONRE, the standards on coastal water quality of ASEAN, Australia, Japan … and other requirements for water quality in marine ecosystems. Assessment of the eclipsing and ambiguous effects and the sensitivity of four aggregation functions reveal that weighted geometric mean function is the most appropriate to calculate WQIHL with selected weights. The application of the developed WQIHL in the Hạ Long Bay shows that water quality in the core zone is good, except some tourist areas and fishing villages. The buffer zone of the Bay possesses poor water quality. The WQIHL formula can be a good tool for water quality management and planning, which supports for the integrated coastal zone management.
Keywords:Water quality index, weighted geometric mean function, coastal zone, Hạ Long Bay.
References
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