Andrew T. Hable
Water Supply Alternatives for the City of Waukesha (Wisconsin, USA)
The City of Waukesha (Wisconsin, USA) is facing various challenges to its water supply system. A rapidly deepening drawdown in its primary aquifer is causing concentrations of radium and total dissolved solids to exceed federal standards. The city has been ordered by the State of Wisconsin to comply with radium standards by 2018, requiring major adjustments to the city’s water supply system. These adjustments come at a time when population growth, climate change, and other changes make the future highly uncertain. The vast variability of future uncertainties poses a challenge to water management that calls for a transition toward adaptive management styles. Adaptive water supply alternatives are proposed in this study that aim to enhance the ability of Waukesha’s water supply system to operate under a wider range of future variability. The alternatives incorporate water usage reduction as a means to minimize the city’s vulnerability to potential water stresses; groundwater recharge is incorporated as a means to mitigate Waukesha’s exacerbation of water stresses. The alternatives are assessed through a multi‐criteria decision analysis using a holistic selection of metrics. Various weighting scenarios are used to represent the range of value systems held by stakeholders. The results demonstrate that the adaptive techniques improve Waukesha’s groundwater-based alternatives in terms of monetary cost, environmental impact, and social benefits. However, the results also indicate that this study’s proposed alternatives remain less preferable than Waukesha’s proposal to transfer and return Great Lakes water. The results lead to a series of context‐specific recommendations that are intended to remove barriers currently obstructing transitions toward adaptive water management.