Municipal water supply well maintenance at well field North of Toronto, Canada

Abstract

This paper discusses short and long term asset management practices applied at a well field consisted of 41 municipal water supply wells (production wells) North of Toronto, Ontario, Canada to assure sustainable well operation. Short term practices conducted annually and approximately every five years. Annual assessment reviews groundwater level from production and monitoring wells along with the flow data to examine well performance consistency. Step tests conducted either upon recommendation of annual assessment or approximately every 5 years to identify need for rehabilitation. Long term asset management procedure developed to identify wells in need of replacement or major modification over a 20-year horizon. In this procedure a prioritization matrix was developed which considers well age, average number of rehabilitations per 10 years, history of well condition and chloride concentration status. As a result, 33 wells were identified to be in good condition and replacement was not considered likely. Seven wells were identified as likely and 1 needed replacement.