Temporary urban floodways – when multiple perspectives must work together

One approach to managing large volumes of stormwater is to allow parts of the existing infrastructure to function as temporary floodways—that is, to direct water along designated routes where it causes the least damage.

Although no universal definition exists, a temporary floodway in urban environments can be described as a reinforced natural open flow corridor that is activated only during extreme rainfall events. It collects and conveys water in a controlled manner and may consist of streets, parks, pedestrian and cycling paths, or ditches that together form a continuous route for the water. The urban floodway is designed to ensure that water levels and flow conditions remain safe and passable.

In Sweden, the interest in urban floodways is growing, but knowledge remains limited. Several issues require further investigation, including accessibility, safety, long‑term performance, environmental impacts, and the distribution of responsibilities. Also, barriers and conflicts of interest need to be clarified and addressed.

Purpose

The pre-study aims to provide an overview of the potential and societal benefits of urban floodways as a climate adaptation measure, identify knowledge gaps and lay the foundation for subsequent research and demonstration projects.

The pre-study aims to examine the following questions:

1. What technical and physical consequences do urban floodways entail for state owned infrastructure and the facilities of other road operators?
2. What key legal obstacles arise in the planning, construction and operation of temporary floodways?
3. How can urban floodways be integrated with other types of climate adaptation measures to optimise societal benefits and reduce risks?
4. What forms of collaboration are required between national authorities, municipalities and other stakeholder for the effective and sustainable implementation of urban floodways?