University of Technology, Sydney. Faculty of Engineering. / Although extensive worldwide literature on urban stormwater runoff exists, very few publications describe runoff development in terms of its basic building blocks or processes and their individual and accumulative significance in response to varying inputs and boundary conditions. Process algorithms should respond accurately to varying input magnitudes and characteristics as well as to changes in antecedent conditions. The present state of estimation errors involved in many current numerical simulation techniques has been reviewed in this thesis. A significant amount of errors that are presently encountered for have been explained in terms of undefined process response not explicitly included within many modelling methodologies. Extensive field monitoring of intra-catchment rainfall and runoff within an urban catchment at Giralang in Canberra, which is typical of Australian urban catchments, was carried out over a 3-year period to define and measure individual runoff processes. This monitoring work led to a greater understanding of the processes driving the aggregation of local runoff from many sub-areas into the runoff observed at full catchment scale. The results from the monitoring process prompted a number of approaches to potentially reduce standard errors of estimate from model-attributable errors based on improvements to definable catchment response mechanisms. The research isolated a number of basic building blocks associated with typical residential allotments, that can be grouped into roof drainage, yard drainage and adjacent road drainage. A proposed modelling approach was developed that allowed these building blocks at an allotment scale to be simply computed using storage routing techniques. This then aggregated via the total catchment’s public drainage system isochronal characteristics utilising a “process tree” approach to provide full catchment scale runoff response. The potential reduction in estimation errors utilising the developed procedure was assessed using a large number of recorded events from the Giralang catchment monitoring data. The proposed numerical modelling approach was found to provide significant improvements over current methods and offered a scale-independent and stormindependent methodology to model catchments of any size without the need for changes to any of the runoff routing parameters. Additionally the approach permits the flexible sequencing and inclusion of a wide range of different urban drainage structures within a catchment that are representative of the local characteristics. The developed procedure also includes a spatially varied water balance approach to infiltration estimation that is more suited to future continuous simulation models. The developed “flexible process tree” approach provides an important step forward in the numerical modelling of complex urban drainage systems. This can reduce errors of estimate by improving intra-catchment process representation.

University of Technology, Sydney. Faculty of Engineering. / Although extensive worldwide literature on urban stormwater runoff exists, very few publications describe runoff development in terms of its basic building blocks or processes and their individual and accumulative significance in response to varying inputs and boundary conditions. Process algorithms should respond accurately to varying input magnitudes and characteristics as well as to changes in antecedent conditions. The present state of estimation errors involved in many current numerical simulation techniques has been reviewed in this thesis. A significant amount of errors that are presently encountered for have been explained in terms of undefined process response not explicitly included within many modelling methodologies. Extensive field monitoring of intra-catchment rainfall and runoff within an urban catchment at Giralang in Canberra, which is typical of Australian urban catchments, was carried out over a 3-year period to define and measure individual runoff processes. This monitoring work led to a greater understanding of the processes driving the aggregation of local runoff from many sub-areas into the runoff observed at full catchment scale. The results from the monitoring process prompted a number of approaches to potentially reduce standard errors of estimate from model-attributable errors based on improvements to definable catchment response mechanisms. The research isolated a number of basic building blocks associated with typical residential allotments, that can be grouped into roof drainage, yard drainage and adjacent road drainage. A proposed modelling approach was developed that allowed these building blocks at an allotment scale to be simply computed using storage routing techniques. This then aggregated via the total catchment’s public drainage system isochronal characteristics utilising a “process tree” approach to provide full catchment scale runoff response. The potential reduction in estimation errors utilising the developed procedure was assessed using a large number of recorded events from the Giralang catchment monitoring data. The proposed numerical modelling approach was found to provide significant improvements over current methods and offered a scale-independent and stormindependent methodology to model catchments of any size without the need for changes to any of the runoff routing parameters. Additionally the approach permits the flexible sequencing and inclusion of a wide range of different urban drainage structures within a catchment that are representative of the local characteristics. The developed procedure also includes a spatially varied water balance approach to infiltration estimation that is more suited to future continuous simulation models. The developed “flexible process tree” approach provides an important step forward in the numerical modelling of complex urban drainage systems. This can reduce errors of estimate by improving intra-catchment process representation.

Les Rejets Urbains par Temps de Pluie (RUTP) représentent une pollution très complexe et variable de par la diversité des évènements pluvieux et des bassins versants lessivés. Les RUTP sont, dans la majorité des cas, rejetés dans des milieux récepteurs aquatiques péri-urbains tels que les lacs, rivières ou eaux souterraines, sans traitement d’épuration. La pollution déversée, qui peut être très diluée, est le plus souvent liée à des évènements relativement courts et difficiles à prévoir. L’impact écotoxique des RUTP peut donc s’avérer difficile à évaluer, en particulier par des mesures directes in situ. Parmi les organismes utilisés en écotoxicologie, les microalgues sont extrêmement intéressantes. En effet, elles constituent la base des réseaux trophiques, sont sensibles à une large gamme de polluants et sont très sensibles à la présence de substances exogènes. C’est la raison pour laquelle nous avons développé dans un premier temps une batterie de biomarqueurs cellulaires sur microalgue (perturbation de la physiologie (comme la photosynthèse) de Chlorella vulgaris), afin de montrer leur intérêt pour détecter rapidement et sensiblement l’impact toxique d’échantillons de RUTP collectés sur la région Lyonnaise. La réponse de ces biomarqueurs a été comparée en laboratoire à une batterie de bioessais écotoxicologiques monospécifiques classiques sur microalgues et microcrustacés (e.g. essais de croissance, reproduction). Dans un second temps, nous avons travaillé à l’adaptation de ces biomarqueurs afin de créer des outils de détection in situ. Des biocapteurs à cellules entières, basés sur une mesure de la perturbation de la photosynthèse (fluorescence chlorophyllienne) de microalgues, ont été développés. Pour leur création, deux techniques de mise en contact bio-récepteur/transducteur ont été testées : (i) la double encapsulation des microalgues dans des hydrogels alginate/silice utilisant un procédé sol-gel, et (ii) l’inclusion des microalgues dans des puces microfluidiques fabriquées par xurographie. Une station portative autonome de terrain a été élaborée et testée avec efficacité pour effectuer des mesures in situ de la toxicité des RUTP, et des milieux aquatiques urbains contaminés. Ce travail de thèse présente de nombreuses perspectives concernant une meilleure connaissance de l’impact des RUTP sur les organismes aquatiques. Il apporte également des réponses à la problématique du développement des biocapteurs à cellules algales entières pour la surveillance environnementale. / Urban Wet-Weather Discharges (UWWD) represent a very complex and variable pollution due to the diversity of the rainfall events and leached watersheds. In most cases, UWWD are released without, or after very low treatments only, in suburban aquatic environments such as lakes, rivers or groundwaters. Spilled pollution is often linked to relatively short and difficult to predict events, and can be very diluted. Thus, it may be complicated to assess the ecotoxic impact of UWWD, and particularly in situ. Among the organisms used in ecotoxicology, microalgae are particularly interesting because they are the basis of trophic networks, are sensitive to a wide range of pollutants found in UWWD and can react very quickly to their presence. It’s why, first, we developed and used a battery of microalgae (Chlorella vulgaris) cellular biomarkers (e.g. photosynthesis disturbance) to demonstrate their utility in detecting the toxic impact of UWWD samples collected in the Lyon city area in a rapid and sensitive way, in comparison with a battery of monospecific bioassays on microalgae and microcrustaceans (e.g. growth or reproduction inhibition assays). In a second phase, we worked on the adaptation of these biomarkers for the creation of ecotoxicological field tools, biosensors. We developed two types of whole-cell biosensors based on the microalgal photosynthesis (chlorophyll fluorescence) disturbance. We particularly worked on the microalgal immobilization processes in the aim to design biosensors, using mainly two techniques: a double-encapsulation in alginate/silica hydrogels using a sol-gel process and an inclusion in microfluidic chips created by xurography. Finally, we were able to create an autonomous portative biosensor able to conduct in situ measurements of UWWDs toxicity and contaminated urban aquatic environments in general. This thesis project presents many perspectives concerning the deeper understanding of the UWWDs impact on aquatic organisms, and also on the development of whole-cell biosensors for the environmental monitoring.

Extreme rainfall statistics are important for the design and management of the water resource infrastructure. The standard approach for extreme rainfall event severity assessment is the Intensity-Duration-Frequency (IDF) method. However, this approach does not consider the spatial context of rainfall and consequently does not properly describe rainfall storm severity, nor rarity. This study provides a critical account of the current standard practice and presents an approach that takes into consideration both the spatial context of rainfall storms, and indirectly incorporates runoff to produce a representative approach to assessing urban rainfall storm severity in terms of flood potential. A stepwise regression analysis was performed on a dataset of individual rainfall storm characteristics to best represent documented basement floodings in the City of Edmonton. Finally, the urban rainfall storm flood severity index was shown to be most representative of the documented basement floodings' severity when compared to that of the IDF method.

Extreme rainfall statistics are important for the design and management of the water resource infrastructure. The standard approach for extreme rainfall event severity assessment is the Intensity-Duration-Frequency (IDF) method. However, this approach does not consider the spatial context of rainfall and consequently does not properly describe rainfall storm severity, nor rarity. This study provides a critical account of the current standard practice and presents an approach that takes into consideration both the spatial context of rainfall storms, and indirectly incorporates runoff to produce a representative approach to assessing urban rainfall storm severity in terms of flood potential. A stepwise regression analysis was performed on a dataset of individual rainfall storm characteristics to best represent documented basement floodings in the City of Edmonton. Finally, the urban rainfall storm flood severity index was shown to be most representative of the documented basement floodings' severity when compared to that of the IDF method.