Water and Wastewater Management in Megacities

Water management of metropolitan urban regions represents an ever challenging task, particularly under the increasing pressures of climate change and population growth. Lima/Peru, with an annual precipitation of only 9 mm, is a city with particularly adverse boundary conditions. This article illustrates the current situation and presents a methodology and tools developed for and applied for sustainable water and wastewater management in Lima/Peru. Techniques of scenario building are feeding into simulations using a water system simulator, covering the entire water and wastewater system of Lima. Modelling serves as an integral part of stakeholder involvement and participation and, thus, contributes to informed discussions and participatory decision finding.