Bioretention and its influence on the flow of effluent in rainwater drainage systems

Equipment for local rainwater management classified as LID (Low Impact Development), including bioretention systems (i.e. rain gardens, green roofs, infiltration ditches, etc.) helps reduce the volume and flowrate of water in drainage systems. Such systems are being increasingly taken into consideration when designing water drainage systems in urban areas to relieve such systems, while increasing rainwater retention in a given area and using this precious natural resource. To be able to assess the impact of this type of systems, hydrodynamic modelling software is used with the option to include an LID module.


  • Benefits:
    Possibility to assess the impact of bioretention equipment on the flow dynamics of rainwater guided in a rainwater system for various rainfall events and surface retention.



  • Water supply


Projects completed:

A hydrodynamic model was developed for the catchment located in the area of one of the residential and industrial districts in Wrocław. An interpretation was performed of the reduction of rainwater flowing into the rainwater drainage system for the use of a green roof in place of a conventional roof cover on a large-area industrial building. The model was calibrated based on flowrate intensities recorded by measuring equipment installed on the rainwater drainage system at the outlet from the catchment.

The project was executed for scientific rather than commercial purposes, but based on actual data from flow monitoring by the Water Supply and Sewage Company in Wrocław.