Coordinated and holisticised climate adaptation creates new opportunities

EnviDan  A/S is currently investigating the possibilities for climate adaptation in the area around Egåen at Vejlby/Risskov north of Aarhus.

Today, the area is threatened by rising groundwater levels as well as floods from streams, oceans, lakes and cloud bursts, therefore there is a need for a coordinated and holistic climate adaptation.

The project area extends from Engsøen (the lake) in the west to Egåens (the stream) outlet in Aarhus Bay to the east.

EnviDan's role in the first instance includes collecting all available knowledge of the urban drainage system, the sluice at the stream outlet in Aarhus Bay and the history of the stream system.

A statistical analysis of the effluent in Egå stream has been performed, including an analysis of the likelihood of simultaneous floods from sewers, watercourses and seas, as inputs for modelling and dimensioning the best climate adaptation solutions.

Subsequently, the collected knowledge is incorporated into hydraulic models that are used to map the areas that will later adapt to climate change.

As part of the project, EnviDan has set up a Mike Urban model for the sewer system, and updated the existing Mike 11 waterway model for Egåen (the stream).

The two models are connected to the surface model in Mike Flood, and the entire project area is modeled simultaneously and dynamically.

In addition, injury modeling (EAD - expected annual damage) has been performed as a result of floods from cloudbursts, rivers and storms, followed by cost-benefit analysis for climate adaptation solutions.

The results of the surveys are a detailed mapping of the problems as well as a catalogue of tools where the various efforts are prioritised in terms of robustness and cost-effectiveness. Later, the best solutions will be realised.

Sten Kisum  Nielsen