Water Quality Research Journal of Canada

Vol. 42 (1): 20 - 25 (2007). General issue

Composite Water Quality: Evaluation and Management Feedbacks

   Arkadi Parparov, K David. Hambright

In this article we both outline and offer an approach to quantitative estimation of aggregated water quality, in the form of the Composite Water Quality Index (CWQI), calculated as a weighted sum of rating values for a set of preselected water quality indices. The weighting procedure uses variable weights that are inversely proportional to the separate rating values. We also suggest a simplified procedure for estimating the sensitivity of several common algorithms that may be used for CWQI calculations. Among the different methods of CWQI calculation, Smith’s minimum operator had the highest sensitivity, while an equal weighting procedure based on the arithmetic mean had the lowest sensitivity. We discuss the relationship between the choice of method for a CWQI calculation and the strategy of water resources management, and show that besides its indicative function, the CWQI should serve as a target of, and tool for, water resources management.

water quality assessment, sustainable management, Lake Kinneret, composite water quality index

[view PDF]