Development of a risk-based tool for groundwater well rehabilitation and replacement decisions

Abstract

Abstract Groundwater wells are critical drinking water infrastructure elements that widely support basic system supply needs while also providing supply reliability, better water quality (in some cases), and comparatively lower operational costs. Well rehabilitation and replacement are thus an area where water utilities could benefit from rational decision support frameworks and quantitative tools that enable them to better navigate the complex trade-off relationship(s) that exist among a variety of environmental quality, public health, financial, regulatory, organizational, and technological dimensions. Consistent with these considerations, a business risk-based prioritization tool was developed for this study that augments/extends California Water Service (Cal Water)'s well rehabilitation and the replacement decision-making process. For this derivation, a business risk exposure methodology is combined with an analytical hierarchy process (AHP), with the AHP being utilized to determine the weights of the factors involved in the likelihood of failure and the consequence of failure calculation. It is expected that the new tool will assist in optimizing inspection and action plans and identify the wells requiring attention and/or additional work for water utilities.