For most cities, it is very challenging to both collect information from throughout a city, irrespective of agency or city function, and integrate this information into a broad decision-support environment. For example, this is particularly challenging for mature cities of the size and complexity of New York City, Tokyo, and London and for their managing agencies. Resource management for a city spans multiple domains including water and sanitation, buildings, transportation, energy, security, citizen services, and regional development. Implementing processes, policies, or interoperability features across multiple domains in a legacy city, as defined in this paper, requires significant coordination and Bpermission[ among the agency players. Here, we propose a novel smarter-city maturity model that depicts the cross-domain and agency-to-agency interactions in response to an event (such as a water-main break). We also propose an enabling system architecture and multidomain-aware command portal that provide a detailed plan to address and optimize the management of resources for complex events. Finally, we propose a value-modeling method for quantifying the estimated cost of alternative scenarios and of selecting the best response to an event. To illustrate the approach, an example is given for a rainfall event. © 2011 by International Business Machines Corporation.