The forgotten blue-green passages and their potentials for climate change adaptation with multiple benefits in urban landscapes

18:00 Tuesday 28 May




Katrina Marstrand Wiberg (Denmark) 1

1 - Aarhus School of Architecture

More surface water from cloudburst events is a key issue in Danish climate change adaptation (CCA) projects. The objective of this PhD-research was to explore potentials for creating multiple benefits in urban landscapes through CCA.

This was studied in three on-going case studies in Aarhus Municipality, Denmark. The departure was landscape architectural methods, with mapping and field trips at its core together with action research in a transdisciplinary context.

The case studies revealed a correlation between historical blue-green passages and projected flow paths forming flood risk. The urban landscape of the present provided detours to waters flow, causing further flooding of human interests.

One of the findings was that flood risk caused by cloudbursts was enforced through contemporary planning and urban development, due to the neglect of the landscapes deep structures.

Furthermore, the case studies showed how public schools, senior homes, nurseries, allotment gardens and sports fields, to a considerable extent were located within the historical blue-green passages.

In Denmark, these public and semi-public functions are mostly provided with open, green spaces, providing an opportunity to delay and retain water on the surface for CCA. The study of the historical the blue-green passages in relation to the contemporary city and urban landscape showed that re-connecting these passages could too facilitate walking and bicycling, while also connecting schools, neighbourhoods, sportsfields, and different age- and income groups as well as connecting waters flow. The finding of the forgotten blue-green passages implied a local and feasible opportunity to provide low-cost CCA while also promoting biodiversity, recreation and social cohesion of the city.

A key finding was that the physical landscape properties of Aarhus were seemingly forgotten in the urban development after WWII. The city of Aarhus had a forgotten opportunity beneath the asphalt. The historical and present landscape offered hidden but feasible, opportunities to re-connect for blue-green passages as nature-based CCA solutions with considerable potentials for multiple benefits at different levels.

The correlation between the historical and future flow paths is possibly transferable to other alike landscapes in Eastern Jutland. The method of connecting the landscapes and waterscapes of the past, present and future through the agency of mapping and field trips could too be employed in CCA-processes in other Western European cities.