This presentation, by Virginia Stovin, Reader, Department of Civil and Structural Engineering, University of Sheffield, UK, will explore how an understanding of the physical processes occurring within SuDS contributes to the development of fit-for-purpose, generically-applicable, modelling tools that are useful/practical for stormwater management purposes.
Our green roof hydrological research began in 2007, with the collection of rainfall/runoff data from a single representative extensive test bed. We have since constructed ten more test beds, which have allowed us to explore the relative influences of vegetation and substrate properties on observed hydrological performance. However, a green roof is not a black box; it is a system comprising multiple components. Understanding how key hydrological processes operate within each of these components is key to developing robust hydrological modelling tools. The presentation will focus on two specific processes: retention and detention. For retention, the critical process to model is moisture loss due to evapotranspiration. We have used climate-controlled chambers to quantify losses due to evapotranspiration and to determine the relationship between actual ET and substrate moisture content. We have used controlled rainfall simulator tests to establish how runoff detention depends on substrate physical characteristics. We have also employed X-Ray micro tomography to ‘see inside’ the green roof substrate (https://sites.google.com/a/sheffield.ac.uk/grr/).
The presentation will also briefly introduce a second project which focuses on the characterisation of residence time distributions in vegetated stormwater ponds (https://vpond.group.shef.ac.uk/#home). I will explain how laboratory mixing experiments with real vegetation are being used to develop a CFD-based modelling approach that will permit designers to model the three-dimensional and seasonally-varying impacts of vegetation on pond residence times and treatment capabilities.
Dr Virginia Stovin – biography
Dr Virginia Stovin has 19 years postdoctoral experience in the field of urban drainage engineering, focusing on stormwater management and Green Infrastructure. She is Reader in the Department of Civil and Structural Engineering at the University of Sheffield. She is a core member of the Sheffield-based Green Roof Centre, and is internationally recognised for her research aimed at quantifying the hydrological performance of green roof systems. She is also a member of the University’s EPSRC-funded Pennine Water Group and the Sheffield Water Centre. Dr Stovin initiated UK research into retrofitting SuDS (Sustainable Drainage Systems) within established urban areas to address existing stormwater drainage-related problems. She has led the development of Computational Fluid Dynamics (CFD)-based approaches to the modelling of flow and pollutant transport/sediment deposition within sewer ancillaries (Combined Sewer Overflows, storage tanks and manholes), with recent EPSRC-funded work focusing on stormwater ponds.