Evaluating Interactions of Drought and Climate Change Adaptation Policy for Urban Water Resource Management

Climate variability is already a major concern for urban water resource managers, and municipalities have responded by enacting policies to cope with temporary reductions in water supply such as increasing water storage, new price structures, water-use restrictions, and incentives for conservation. Yet, there is little knowledge regarding how policies enacted in response to short-term shortages will affect municipalities' ability to respond to long-term climate change. Given that maintaining flexibility and options is an important near-term strategy in the face of uncertain future climate change, it is especially important to understand whether policies put in place to reduce short-term vulnerabilities might in fact decrease the adaptive capacity of urban water resources to long-term climate change.

To address this question, the Interactions of Drought and Climate Adaptation (IDCA) for Urban Water project will develop indicators for characterizing the vulnerability of urban water systems to both short-term and long-term climate risks. These indicators will be applied in three municipal case studies to assess how policies designed to manage short-term risk may impact the ability of U.S. urban water systems to adapt to long-term climate change. Using both qualitative and quantitative data, the project will identify robust management policies that enhance the resilience of urban water systems in the face of changing climate risks.

This poster describes the study's three-step approach and presents preliminary results. First we outline the methodology for the selection of the three municipal case studies, which was done in consultation with our Advisory Working Group. An initial data scan of approximately 20 municipal water providers was completed to obtain data on two overall criteria for each provider. The first set of criteria includes the provider's history of drought impacts and policy responses in recent decades, as well as measures to ensure a range of diversity of climate, geography, and system size among cases. The second set of criteria includes specific attributes of water systems such as water source, storage capacity, supply and demand buffers, and existing management and planning policies. Through application of these criteria we will formulate representative system “typologies” for our three case studies, which will enable the simulation and comparison of drought management impacts on long-term vulnerability under a variety of climate change scenarios.

Next, we present the findings of a review of the literature on drought and climate change vulnerability. This review will be used to generate a roster of drought and climate change vulnerability indicators that are specific to the urban water management sector. While extensive literature exists for drought indicators, less has been written about evaluating vulnerability to climate change in urban water management. We will highlight challenges to defining operational measures of climate change vulnerability and the ways in which existing measures of drought vulnerability may overlap with or diverge from vulnerability measures for longer timescales.

Lastly, we will highlight our strategy for the final stage of analysis. This portion of the project will aim to assess the impact of drought response at various timescales for the three case study water providers, using both quantitative and qualitative data. We will discuss how we plan to apply a set of vulnerability indicators to test likely outcomes in system performance, given adjustments made in response to drought and climate change, using simulation tools available through the University of Colorado's Center for Decision Support in Water and Environmental Systems.