When designing urban water systems (i.e. water distribution and sewer systems) it is imperative that uncertainty is taken into consideration. However, this is a challenging problem due to the inherent uncertainty associated with both system loading requirements and the potential for physical components failure. It is therefore desirable to improve the reliability of each system in order to account for these uncertainties. Although it is possible to directly evaluate the reliability of a water distribution systems (WDS) (using reliability measures), the calculation processes involved are computationally intensive and therefore unsuitable for some state-of-the-art, iterative design approaches (such as optimisation). Consequently, interest has recently grown in the use of reliability indicators, which are simpler and faster to evaluate than conventional direct reliability methods. In this thesis, a novel measure (the RUF) is developed to quantify reliability in urban water systems with a view to enhance their robustness under a range of future scenarios (Policy Reform, Market Forces, Fortress World and New-Sustainability Paradigm). The considered four future scenarios were synthesized in the EPSRC supported multidisciplinary 4 year project: Urban Futures. Each investigated urban future scenario is characterised by a distinct household water demand and local demand distribution (emerging due to different urban forms evolving in future scenarios). In order to assess the impact of urban futures, RUF has been incorporated into Urban Water System (UWS) dynamic simulations for both WDSs and Foul Sewer Systems (FSSs) using open source codes of EPANET and SWMM. Additionally, in order to overcome extensive computational effort, resulting from the use of traditional reliability measures, a new holistic reliability indicator, the hydraulic power entropy (IHPE) has been developed and compared to existing reliability indicators. Additionally, the relationship between the new reliability indicator and the above mentioned RUF reliability measure is investigated. Results suggest that the magnitude of the IHPE in network solutions provides a holistic indication of the hydraulic performance and reliability for a WDS. However, the performance of optimal solutions under some Urban Futures indicates that additional design interventions are required in order to achieve desired future operation. This thesis also proposes a new holistic foul sewer system (FSS) reliability indicator (the IFSR). The IFSR represents sewer performance as a function of excess pipe capacity (in terms of available increase and also decrease in inflow). The indicator has been tested for two case studies (i.e. different sewer network layouts). Results suggest that the magnitude of IFSR has positive correlations with a number of identified key performance indicators (i.e. relating to capacity, velocity, blockages). Finally, an Integrated Design Approach (IDA) has been developed in order to assess the implications of applying design interventions on both a WDS and downstream FSS. The approach holistically considers present and future operation of each interconnected system. The approach was subsequently demonstrated using two proposed design interventions. Results suggest that, for the considered design interventions, there is trade-off between the simultaneous improvement of both WDS and FSS operation and reliability.

Cities are increasingly important for the well-being of humans, other species, and the whole biosphere. Recently, there has been growing awareness of cities being inhabited by multiple species whose needs are entangled. In this thesis, a set of positive scenarios and pathways towards multispecies cities were created with the aim to evoke the reader’s imagination, stepping away from quantitative and linear methods of scenario building on the one hand and negative imaginaries of environmental and social destruction on the other hand. Using Solarpunk stories as input to a backcasting process that combined the theories of the Nature Futures Framework, climate resilient development, and multispecies sustainability, the thesis suggested new imaginaries of how the future of cities might look through a multispecies lens. Examples include multispecies climate adaptation, animal social security, and interspecies relationships. An interactive story communicates the results of the thesis with the potential to engage a wider audience beyond academia and challenge the readers’ current beliefs about the future of cities. The story can be played here: https://reettarossi.itch.io/multispecies-cities. The thesis contributes to the pursuit of developing transformative representations of the future that inspire action and help people make better decisions today. Since everybody has their own ideas of what is a desirable city, there is a need to continue developing a plurality of desirable images of urban futures.

Les transitions écologiques et numériques, ainsi que les préoccupations relatives aux inégalités sociales, signalent l’avènement de nouveaux défis complexes pour les villes contemporaines. Ces changements soulèvent la question de la capacité dynamique des urbanistes, plus précisément leur capacité à revoir leurs outils et leurs routines de planification dans les projets urbains afin d’explorer le potentiel des nouveaux paradigmes d’action collective et de favoriser des voies de transition innovantes pour les villes. Les entreprises européennes, en particulier dans le domaine des transports publics, ont relevé ce défi, avec des résultats convaincants, en développant des outils basés sur des théories de conception innovante. L’un de ces outils méthodologiques, le processus Définition-Connaissance-Concept-Proposition (DKCP), a été utilisé pour générer une nouvelle gamme d’options de planification dans trois recherches-interventions à Montréal, au Canada. La routine traditionnelle du planificateur se concentre généralement sur une seule activité du processus, la formulation de propositions (phase P), en adaptant légèrement les anciens projets au contexte et aux règles locales. Cependant, la routine des futurs urbanistes devrait inclure de nouvelles capacités de gestion des étapes en amont des projets sous la forme d’une succession de phases DKCP. La nécessité de relever les défis complexes de la ville du XXIe siècle ouvre la voie à une nouvelle identité professionnelle : celle de « l’urbaniste innovant ». / Ecological and digital transitions, along with concerns over social inequalities, signal the advent of complex new challenges for contemporary cities. These changes raise the issue of the dynamic capability of urban planners: more specifically, their ability to review their tools and planning routines in urban projects in order to explore the potential of new paradigms of collective action and foster innovative transition paths for cities. European companies, especially in public transportation, have responded to this challenge, with convincing results, by developing tools based on innovative design theories. One of these methodological tools, the Definition-Knowledge-Concept-Proposition (DKCP) process, was used to generate a new range of planning options for three urban districts in Montreal, Canada. The traditional planner’s routine generally focuses on a single activity in the process, the formulation of propositions (Phase P), by slightly adapting former projects to the local context and rules. However, the future urban planners’ routine should include new capabilities for managing upstream stages of projects in the form of a succession of DKCP phases. The need to tackle the complex challenges of the 21st century city opens the way to a new professional identity: the “innovative urban planner”.