The discussed paper states that the rigid column model is applied for a single air pocket and the nature of the used equations makes it difficult to be employed in case of several air pockets. The discussers do not agree with this assertion.In fact, other authors also use the rigid model approach. Liou and Hunt (1996) proposed a rigid column model of flow start-up in empty pipelines with undulating elevation profiles assuming a vertical interface between the air and water phases. They proposed a velocity-based criterion to justify the application of the rigid-column approach. Zhou et al. (2002) presented an experimental and numerical investigation on the description of the rapid filling of an empty horizontal pipe with limited ventilation. The numerical model was constructed using a lumped inertia approach and assumed a vertical interface separating the advancing waterfront and the air that initially filled the pipe.The discussers have developed a general model for the simultaneous analysis of entrapped air pockets within a pipeline with irregular profile (Fig. 1). Previous papers have paid attention to this problem from both theoretical (Fuertes et al. 1998;Izquierdo et al. 1999;Fuertes 2001) and experimental (Fuertes et al. 2000;Fuertes 2001) approaches. Moreover, and in order to identify the most significant parameters of the

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Pour inciter les professionnels québécois engagés dans la gestion durable et optimale des eaux pluviales à cibler des objectifs clairs, huit propositions d’action publique, de même qu’une démarche méthodologique sommaire pouvant aider à utiliser ces propositions de manière avisée et responsable, ont été suggérées dans l’article complémentaire. Le présent article traite d’une étude de cas où les huit propositions ont été appliquées dans un secteur en développement résidentiel d’une municipalité québécoise, en suivant la méthodologie proposée. L’objectif principal du présent article est de montrer la faisabilité d’utiliser de nouvelles pratiques de gestion optimale (PGO) des eaux pluviales au Québec. L’analyse économique sommaire, décrite seulement à titre indicatif dans cet article, montre que l’implantation de quelques PGO applicables au Québec sur la base d’objectifs précis de gestion intégrée et durable, est réalisable et même rentable. Une analyse technique poussée reste toutefois nécessaire pour identifier toutes les PGO susceptibles d’améliorer les conditions de drainage urbain au Québec, de même qu’une analyse économique approfondie reste indispensable pour préciser les véritables coûts liés à l’investissement dans les nouvelles techniques.

Drainage systems are designed to quickly convey rainwater from urban areas to areas of natural flow (rivers, streams, lakes, etc). Hence, they are sized with the assumption of steady free surface flow. With the frequent flooding of storm sewers and corresponding damage to public and private infrastructure (Schmitt et al. 2004), numerical modeling of transient flow has now become unavoidable. Several models of transient flow are available, each with its advantages and limitations. This chapter examines the impact of the inclusion of manhole size on the filling celerity of urban drainage systems. It is assumed that the pressurization of the drainage network starts with the rapid filling of a manhole, i.e. as soon as the water level in the manhole reaches the crown of the pipe being filled. Based on this assumption, a filling model is built to analyze the influence of manhole capacity on the propagation of the surge wave. This model uses the method of characteristics within the conduit and an innovative method based on gravity waves. To evaluate the impact of manhole size on the filling speed of the Storm Water System (SWS), the proposed methodology is applied to a theoretical case study. Results show that manhole size can accelerate or reduce the filling speed of connecting conduits.