Monitoring bioretention cell performance: A large-scale lysimeter study

Sustainable Drainage Systems (SuDS) are a widely adopted approach for managing excess urban runoff by intercepting, retaining and attenuating the flow of water through the built environment, playing a key role in reducing urban flood risk (Berretta et al. 2018). Vegetated bioretention cells (alternatively referred to as ‘rain gardens’) are one of the most simple, practical and commonly implemented of SuDS options and can be easily retrofitted into urban spaces to deal with surface water from paved areas. Although current UK and international guidance provide design recommendations for SuDS devices (e.g. Australian Government, 2015; Woods-Ballard et al., 2015), further quantitative indicators of hydrological performance based on monitored systems are required. The aim of this study is to provide an evidence base on the effectiveness of such systems to support the optimal implementation of vegetated bioretention cells for stormwater management. This paper presents the methodological approach using a series of large-scale lysimeter experiments based at the UKCRIC National Green Infrastructure Facility (NGIF), Newcastle University, UK.Lysimeter experiments were designed to provide long-term monitoring data of key hydrological variables todemonstrate the capacity and effectiveness of bioretention systems and improve future management and design.