This thesis describes the historical development of the urban structure of three Swedish cities, which have each suffered from a large fire at some point during the 19th century. Using a collection of historical maps, as well as contemporary geographical data, this work aims to assess the impact these fires had on the built-up urban structure at the time immediately after they occurred, as well as their impact upon the urban structure of the contemporary city. The urban structure is composed of three primary elements, which are the streets, buildings, and land-use plots, which over time changes at differing rates. In order to determine whether the fire had an impact on the ordinary rate of change to the city, historical maps of the three Swedish cities are used, depicting them as they were before and shortly after the fire occurred. The pre- and post-fire maps are used to produce composite maps detailing the amount of change which occurred in the time period before and after the fire. The maps depicting the cities after the fire are then in turn overlaid with modern geodata of the contemporary cities, in order to determine whether the fire could be considered to have had a significant impact on the development of the present urban structures. The comparison of the maps of the case-cities shows that a significant amount of change occurred between their pre- and post-fire states, and that the post-fire structure closely aligns to the present urban structure. In each of the cities then, the urban fire could be considered an important component to the historical development of their urban structures.

The purpose of this dissertation is to address risk and consequences of and effective mitigation strategies for urban fire events involving two critical infrastructures- water distribution and emergency services. Water systems have been identified as one of the United States' critical infrastructures and are vulnerable to various threats caused by natural disasters or malevolent actions. The primary goals of urban water distribution systems are reliable delivery of water during normal and emergency conditions (such as fires), ensuring this water is of acceptable quality, and accomplishing these tasks in a cost-effective manner. Due to interdependency of water systems with other critical infrastructures-e.g., energy, public health, and emergency services (including fire response)- water systems planning and management offers numerous challenges to water utilities and affiliated decision makers. The dissertation is divided into three major sections, each of which presents and demonstrates a methodological innovation applied to the above problem. First, a risk based dynamic programming modeling approach is developed to identify the critical components of a water distribution system during fire events under three failure scenarios: (1) accidental failure due to soil-pipe interaction, (2) accidental failure due to a seismic activity, and (3) intentional failure or malevolent attack. Second, a novel evolutionary computation based multi-objective optimization technique, Non-dominated Sorting Evolution Strategy (NSES), is developed for systematic generation of optimal mitigation strategies for urban fire events for water distribution systems with three competing objectives: (1) minimizing fire damages, (2) minimizing water quality deficiencies, and (3) minimizing the cost of mitigation. Third, a stochastic modeling approach is developed to assess urban fire risk for the coupled water distribution and fire response systems that includes probabilistic expressions for building ignition, WDS failure, and wind direction. Urban fire consequences are evaluated in terms of number of people displaced and cost of property damage. To reduce the assessed urban fire risk, the NSES multi-objective approach is utilized to generate Pareto-optimal solutions that express the tradeoff relationship between risk reduction, mitigation cost, and water quality objectives. The new methodologies are demonstrated through successful application to a realistic case study in water systems planning and management.