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NOVATECH 2013 Connection between geological heterogeneity and hydrological performance of SUDS in a peri-urban area in Denmark Connecter l'hétérogénéité géologique et les performances hydrauliques de SUDS dans un secteur péri-urbain du Danemark Britta Bockhorn, Knud Erik Klint, Marina Bergen Jensen Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark ([email protected]) ABSTRACT Climate change, urban densification and a growing concern of eco-environmental issues call sewerbased urban drainage systems into question. Infiltration of stormwater runoff into the soil can be an alternative to a cost-intensive enlargement of the existing sewer system. Most Danish cities are located on low water-permeable glacial deposits where infiltration of stormwater runoff poses a major challenge (Hermansen et al. 2000). The objective of this project is to investigate non-destructive infiltration methods for stormwater runoff into low permeable glacial sediments. The Danish city Mårslet, 10 km South of Århus, is located on a clay till site and serves as the experimental area for this study. Geophysical investigations and field studies on fractures and biopores which serve as hydraulic flow-paths through an otherwise impermeable clay (Fredericia 1990; Hendry 1982; Klint et al. 2001) show a vast geologic variability for the site. The results give different options for infiltration strategies of stormwater runoff. The hypothesis is that the infiltration rate can be enhanced by the exploitation of the site specific geologic and hydraulic variability. In that way the efficiency of water sensitive urban designs can be increased significantly. Identifying the optimal location for the installation of infiltration trenches, as well as more advanced technologies to stimulate the hydraulic performance of the subsurface will be investigated, thus facilitating optimal conditions for the infiltration of surface water. References: Fredericia, J (1990): Saturated hydraulic conductivity of clayey tills and the role of fractures. Nord Hydrol 25:119– 132. Hendry, MJ (1982): Hydraulic conductivity of a glacial till in Alberta. Ground Water. 20(2):162–169. Hermansen, B.; Jakobsen, P.R. (2000): Danmarks digitale jordartskort 1:25 000. Danmarks og Grønlands Geologiske Undersøgelse, version 2,0, GEUS rapport nr. 81, 2000. Klint, K.E.S.; Abildtrup, C.A.; Gravesen, P.; Jakobsen, P.R.; Vosgerau, H. (2001): Sprækkers oprindelse og udbredelse i moræneler i Danmark. Vand og Jord 8, 3, 111-119. KEYWORDS Glacial deposits, infiltration, stormwater management, SUDS 1 A7 - OUTILS AMÉNAGEURS & DD / PLANNER TOOLS & SD In what aspects does this case study: Integrate stormwater? Objective of this study is to investigate techniques for an enhanced infiltration of stormwater run-off into low permeable soils. Has a sustainable approach? The outcome will give an important contribution to an improved work efficiency of green technologies for stormwater infiltration and consequently be beneficial for climate change adaption. Is innovative? The case study takes the geological variability of a clay soils into account to enhance infiltration of stormwater run-off. Is applicable to other projects? The case study can be transferred to regions which are covered by low permeable clay sediments and where the infiltration of stormwater run-off consequently poses a challenge. 2