Some Statistical Issues in Water Quality Assessment
Sylvia Esterby (University of British Columbia)
Friday 23rd November, 2012 15:00-16:00 Maths 203
Public awareness of environmental problems brings the need to keep the public informed about the health of the environment and to provide decision makers with the information which permits the development of evidence-based policies. Environmental indices have become a tool for this reporting and various agencies have constructed aggregated indices. For water quality in Canada, the Water Quality Index (WQI) formulated in British Columbia was adopted by the Canadian Council of Ministers of the Environment (CCME) in 2001. The CCME WQI makes a comparison of water quality measurements against quality guidelines for a set of water quality variables and reduces many observations to one number. Questions have arisen as to what such a number represents, which variables should be included, whether an alternate formulation of an aggregated index is better, and whether a single index is appropriate. The historic reporting of status and trend using multiple water quality variables will be considered, reviewing various methods for trend. This will be compared with the use of the CCME indicator in the Canadian context.