DK 4: Integrated water management in Odense City for improved risk assessment
Responsible beneficiary: Southern Denmark Region
The goal of the Odense pilot area is to illustrate how an integrated modeling approach can be used for management of water in urban areas. The tool will facilitate a more holistic administration of the water flow in the urban area, since the model can quantify how changes in one compartment (e.g. increasing infiltration of surface waters) affects the state of another compartment (e.g., groundwater). The city is threatened by inundation from increasing groundwater levels and flooding events from both the river, the fjord and flash floods caused by extreme precipitation.
The water cycle in urban areas in Northern Europe is faced by several challenges: (1) Climate induced increase in precipitation and extreme rain; (2) Adaptation measures to avoid flooding typically involves local infiltration of rainwater; (3) The population of the larger cities are expected to grow. All three factors affects the urban hydrological cycle, including groundwater levels, groundwater and surface water flow paths and the resulting migration of contaminants from landfills, and the interaction with the sewer system. Traditionally, each hydrological component has been treated separately where it is assumed that one unit do not significantly affect the other. However, in order to secure an optimal management of the urban water cycle in a future more extreme climate an integrated approach is needed that combines the individual components. It is believed that an integrated hydrological modelling approach is the most efficient way to quantify the impacts of both climatic changes, adaptation measures and changes in urbanization.
The objectives are:
• Initial start-up workshop with the stakeholders to focus the work on relevant aspects.
• Construction of a detailed geological model for the area with particular high resolution in the upper part of the soil, where the subsurface has been disturbed by human activities during centuries. The resulting “anthropogenic” geology is expected to impact groundwater flow significantly in areas with high groundwater level.
• Establishment of an integrated hydrological model of the urban water cycle including evapotranspiration, surface runoff on paved areas as well as infiltration on permeable and green areas, sewer flow, groundwater flow and the interaction between the individual hydrological compartments. Results from several climate models will be used and uncertainty will be quantified.
• Collect and imply transnational knowledge about groundwater level management (NL, D, B)
• The effect of alternative adaptation measures incl. e.g., intensive use of local infiltration trenches and increased evapotranspiration through green roofs will be investigated and elaborated with the stakeholders.
• If reasonable, new management practice will be innovated, described and implemented.
Stakeholders are the municipality, water utility South, region, citizens.