Evaluation of the vulnerability to contamination of drinking water systems for rural regions in Québec, Canada

Abstract

The aim of this paper is to describe a method for evaluating the vulnerability of drinking water systems to contamination, in particular in rural regions used intensively for agriculture. To do so, various indicators were developed to represent the source to tap multi-barrier approach for drinking water safety. These indicators correspond to four barriers: source susceptibility to contamination; water treatment efficiency; distribution system management; and, overall management of water quality. The indicators were classified, regrouped and weighted within a model based on a multi-criteria analysis. The method was developed and applied to 39 municipal water systems of rural Quebec, Canada. The model obtained can be used for planning purposes to prioritise water systems requiring improvements.

Key words:

• drinking water
• rural water
• contamination
• multi-criteria analysis
• vulnerability

Acknowledgements

The authors wish to thank the managers of the 39 water systems under study. They also thank the panel of experts who contribute to indicator selection, weighting and evaluation. This study was supported by the Fonds Québécois de Recherche sur la Nature et sur les Technologies (FQRNT).

Notes

1. Vulnerability is represented here as the relative susceptibility of a drinking water system to be contaminated by pathogens.

2. Animal unit: A measure of livestock numbers by which types, classes, sizes and ages are converted to an approximate common standard in relation to feed and forage consumed, based on a mature cow of approximately 1000 lb live weight ( www.granddictionnaire.com).

3. Land in crops: all crops including greenhouses, Christmas trees, etc.

4. Phosphorus balance: total phosphorus input to a territory minus the total phosphorus intake from the ground in that same territory.

5. Conventional treatment includes coagulation, flocculation, decantation, filtration and disinfection.

6. Partial disinfection includes DWS with its water disinfected temporarily or DWS with part of its water not disinfected.

7. Student's t-test: signification value = 0.297.

8. Student's t-test: signification value = 0.007.