Basin-wide integrated modelling via OpenMI considering multiple urban catchments

Integrated modelling is currently receiving a lot of attention in the field of urban hydrology. This paper describes a method for carrying out integrated modelling of sewer systems and rivers, where the constituent models are linked to each other using the European OpenMI interface. This has the advantage that, once the necessary software extensions have been carried out, the data sets describing the subsystems can be used as they are without any need for adaptation.</jats:p

Effect of seasonal climatic variance on water main failure frequencies in moderate climate regions

The yearly water main failure frequency is a central performance indicator to describe the structural quality of a water distribution network. Besides age related deterioration, events such as severe climatic conditions or intensified third party construction may cause sudden seasonal increases in failure frequency trends. For the cold regions of Canada and the dry regions of Australia, several studies exist describing the impacts of climatic failure frequencies on water main failure variations. Failure prediction modelling applied to Austrian supply systems have shown that irregularities in overall failure trends were not explainable with commonly used model covariates like material, vintage, diameter or the number of previous breaks. Analysing the monthly failure frequencies of several Austrian utilities, seasonal differences and variations in failure frequencies are recognizable. The research described in this paper therefore focused on analysing if climatic impacts are responsible for these variations. In a first step, climatic indicators, which are able to describe seasonal climatic variations in moderate climate regions, were derived. In a next step the correlation between summer and winter failure frequencies to these climatic indicators was analysed. The indicators taken into account were, e.g. the decisive freezing index (DFI), the summer rain deficit (RDs) or the amount of successive hot days (AHD). The research has shown that in all investigated climatic zones of Austria, the severity of the winter season influences failure frequencies. A dependency between winter failure frequency and the DFI was significant especially for rigid material types and for diameters up to 200 mm. So far, soil moisture effects have only shown a slight significance. Nevertheless, the indicator AHD has shown a correlation to failure frequencies in the dryer climate zones of Austria. This is of further interest as it is very likely that the AHD is going to increase due to climate change.</jats:p

The HSG Guideline Document for Modelling Integrated Urban Wastewater Systems

ABSTRACT The importance of integrated modelling of urban wastewater systems is ever increasing, also due to the European Water Framework Directive. In order to facilitate its practical application, the Central European Simulation Research Group (HSG) has prepared a guideline document, suggesting a seven-step procedure to integrated modelling. Findings of recent research and application projects in Central Europe have been integrated in the guideline. The present paper outlines this guideline document. The full guideline will be made available on the Internet

The HSG procedure for modelling integrated urban wastewater systems

Whilst the importance of integrated modelling of urban wastewater systems is ever increasing, there is still no concise procedure regarding how to carry out such modelling studies. After briefly discussing some earlier approaches, the guideline for integrated modelling developed by the Central European Simulation Research Group (HSG - Hochschulgruppe) is presented. This contribution suggests a six-step standardised procedure to integrated modelling. This commences with an analysis of the system and definition of objectives and criteria, covers selection of modelling approaches, analysis of data availability, calibration and validation and also includes the steps of scenario analysis and reporting. Recent research findings as well as experience gained from several application projects from Central Europe have been integrated in this guideline.</jats:p