Adaptive transformation of historic water works in Hamburg, Germany: from essential infrastructure and cornerstone of public health to valuable man-made ecosystems and designed public spaces

A lack of safe drinking water supply is the cause of a number of waterborne diseases such as cholera. Even nowadays, an estimated 100,000 people die from cholera each year. Since the early/mid-19th century relatively simple but highly effective engineering solutions were developed that helped provide clean drinking water. In 1892 the City of Hamburg, Germany was hit by a cholera epidemic and more than 8,000 people died within a few weeks. As a consequence, sedimentation and filtration systems to provide clean drinking water were built. They were in operation for nearly a century and subsequently became disused in recent decades. Since then, a number of proposals including large mixed-use developments were put forward and over time adapted to the changing needs to offer educational and recreational services, as well as enhancing natural assets. While the historic buildings of high heritage value were conserved, the sedimentation and filtration systems in their landscape setting transformed through natural succession combined with design interventions into attractive and valuable habitats. In addition, some of the former sedimentation basins were found to be the most suitable locations to compensate for the environmental impact of the highly disputed dredging of the Elbe River and were redesigned to provide a new habitat for a rare and endemic plant species.