What are the cautions with using the index?
Applying this index to water quality data sets must be done with due regard to how the index is formulated. Use of the index for purposes for which it was not designed can lead to erroneous conclusions. Therefore, the following points need to be considered: a. Index comparisons should only be made when the same sets of objectives are being applied. The CCME WQI allows the index user to select the objectives on which to compare measured water quality. This increases the versatility of the index but allows for misuse. Different jurisdictions use different objectives for water quality, and different objectives for different water uses. If an index value is calculated on one set of objectives and compared to an index value based on a completely different set of objectives, any conclusions drawn may be erroneous and comparisons must be made carefully. b. Index comparisons should only be made using the same sets of variables. This is common sense apples to apples reasoning. Comparing a site
