Conference Agenda

Drainage systems in many cities are unintentionally loaded by groundwater infiltrating through damaged or non-watertight pipes, as well as by groundwater from forced underground drainage. With anticipated climate changes, this problem is expected to worsen, particularly in cities with dynamic shallow groundwater tables. Addressing the problem requires comprehensive mapping of a potentially very heterogeneous system. This involves understanding the local groundwater table’s level and dynamics, soil types and characteristics, as well as the condition of the drainage infrastructure.

Monitoring at an experimental site in Denmark shows great variability in the shallow groundwater table caused by capillary forces in the soil causing significant increases in groundwater levels posterior to rainfall events. Groundwater levels are observed to increase tenfold in response to the rainfall depths for example meaning a 50 cm increase in the water level in response to 50 mm of rain. Areas where the drainage system is located in this dynamic zone of shallow groundwater therefore experience a great variability in infiltration. In this study, the hydrological processes in the soil are modelled and compared to estimated flow rates based on a decomposition of flow from drainage system pumping stations.