Tonino Liserra

Short communication: Simulation of a storm sewer network in industrial area: Comparison between models calibrated through experimental data

The purpose of this article is to test the performance of two commercial models for the simulation of sewer systems (InfoWorks, developed by Wallingford Ltd and Mouse, developed by DHI), basing on the experimental data sampled in a 1.15ha watershed located near Bologna, Italy. The experimental catchment is part of a truck transit and parking area, completely asphalt paved and drained into a first flush tank. Hydrologic and water quality data collected for almost 8 months inside the tank have been used to calibrate the models through a trial and error procedure for both quantity and quality aspects. A sensitivity analysis for the most relevant quality-quantity parameters has also been performed, testing therefore the behaviour of these models in a small impervious watershed and their reliability as a support tool in the design phase.

Evaluation of Reliability Indicators for WDNs with Demand-Driven and Pressure-Driven Models

Reliability of water distribution networks (WDNs) has received much attention in recent years due to progressive aging of infrastructures and climate change. Several reliability indicators, focusing on hydraulic aspects rather than water quality, have been proposed in literature. Reliability is generally assessed resorting to well established methods coupling hydraulic simulations and stochastic techniques that describe the WDNs hydraulic performance and component availability respectively. Two main algorithms are employed to simulate WDNs: the demand driven approach (DDA) that disregards the physical relationship between actual water demand and nodal pressure, and the pressure driven approach (PDA) that explicitly incorporates it. In this paper, we show how the choice of hydraulic solver may affect reliability indicators. We modify existing quantitative indicators at nodal and network level, and define novel indicators to consider water quality aspects. These indicators are evaluated for three example WDNs; discrepancies between results obtained with the two approaches depend on network size, feeding scheme and skeletonization. Results suggest to use with caution the DDA for reliability assessment at both local and global level.

WASTEWATER NETWORK CHALLENGES AND SOLUTIONS

Sewer and storm water systems in cities worldwide suffer from ageing and inappropriate wastewater networks. This challenge has to be met by systematic upgrading and preventive maintenance. It is necessary to analyse the current performance of the wastewater networks, to determine the system bottlenecks that cause system vulnerability on floods in city areas and pollution of receiving waters. The next task is then to use this information for selecting and ranking upgrading projects to improve the situation. CARE-S is a computer based system developed to meet this challenge. It is designed for sewer and storm water network rehabilitation planning. It provides fundamental instruments for estimating the current and future condition of sewer networks, ______ * Sveinung Saegrov, SINTEF, Dept. Water and Wastewater, Klaebuveien 153, NO-7465 Trondheim, Norway, phone +47-73592349, fax +47 73592376, e-mail: sveinung.sagrov@sintef.no

Uncertainty in Design and Management of Sewer Systems

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