Is there a limit to bioretention effectiveness? Evaluation of stormwater bioretention treatment using a lumped urban ecohydrologic model and ecologically based design criteria

Abstract

In this study, we developed the urban ecohydrology model (UEM) to investigate the role of bioretention on watershed water balance, runoff production, and streamflow variability. UEM partitions the land surface into pervious, impervious, and bioretention cell fractions. Soil moisture and vegetation dynamics are simulated in pervious areas and bioretention cells using a lumped ecohydrological approach.Bioretention cells receive runoff from a fraction of impervious areas. The model is calibrated in an urban headwater catchment near Seattle, WA, USA, using hourly weather data and streamflow observations for 3 years. The calibrated model is first used to investigate the relationship between streamflow variability and bioretention cell size that receives runoff from different values of impervious area in the watershed. Streamflow variability is quantified by 2 indices, high pulse count (HPC), which quantifies the number of flow high pulses in a water year above a threshold, and high pulse range (HPR), which defines the time over which the pulses occurred. Low values of these indices are associated with improved stream health. The effectiveness of the modelled bioretention facilities are measured by their influence on reducing HPC and HPR and on flow duration curves in comparison with modelled fully forested conditions. We used UEM to examine the effectiveness of bioretention cells under rainfall regimes that are wetter and drier than the study area in an effort to understand linkages between the degree of urbanization, climate, and design bioretention cell size to improve inferred stream health conditions. In all model simulations, limits to the reduction of HPC and HPR indicators were reached as the size of bioretention cells grew. Bioretention was more effective as the rainfall regime gets drier. Results may guide bioretention design practices and future studies to explore climate change impacts on bioretention design and management.

The role of landscape morphology on soil moisture variability in semi‐arid ecosystems

“…We utilize an ecohydrological model (the Bucket Grassland Model [BGM]) (Istanbulluoglu et al, 2012; Yetemen, Istanbulluoglu, Flores‐Cervantes, et al, 2015), to understand the roles of geographical, climatological, soil, and vegetation factors affecting SMV on two different landform shapes. BGM has been extensively used in ecohydrological studies (Caracciolo et al, 2014; Naseem et al, 2016; Srivastava et al, 2019; Tang et al, 2019; Wright et al, 2018; Yetemen et al, 2015,b; Zhou et al, 2013) and was found to represent SMV accurately. In particular, Yetemen et al (2015,b) applied the BGM model to the SNWR site that we use as a guide to setup our experiments, and were able to successfully reproduce daily runoff and soil moisture observations (Nash‐Sutcliffe efficiency of 0.76) as well as vegetation extent and seasonality.…”

Effects of Design and Climate on Bioretention Effectiveness for Watershed-Scale Hydrologic Benefits

“…The literature has similar variability in DARs analyzed. For studies that reported this metric, values ranged from 1% to 25% (Boancă et al 2018;Li et al 2009;Stander et al 2010;Wright et al 2018). More commonly, design standards are based on depths of runoff that should be captured and/or treated by a stormwater control measure (McPhillips et al 2020).…”

“…These practices can also improve water quality (Johnson and Hunt 2019), but the focus of this paper is the hydrologic benefits. Research using either field monitoring (Li et al 2009;Stander et al 2010;Winston et al 2016) or numerical modeling (Jennings 2016;Olszewski and Davis 2013;Sun et al 2019;Wadzuk et al 2017) has shown that, when properly designed and maintained, bioretention areas can reduce runoff volumes and peak flow rates, potentially improving stream integrity (Wright et al 2018). A number of factors affect bioretention performance, including design choices (e.g., surface area, soil depth, infiltration capacity) (Jennings 2016;Lewellyn and Wadzuk 2019) and climate (Cook et al 2019;Hung et al 2020;Jennings 2016).…”

“…Despite substantial research on the effectiveness of individual bioretention areas, it is still unclear how to best implement these practices to achieve watershed-scale benefits (Golden and Hoghooghi 2017; Jefferson et al 2017). Monitoring (Hopkins et al 2019;Loperfido et al 2014;Woznicki et al 2018) and modeling studies (Avellaneda and Jefferson 2020;Fry and Maxwell 2017;Wright et al 2018) have shown that extensive systems of GSI can have measurable watershed-scale benefits. However, some found relatively minor benefits (Avellaneda et al 2017;Hoghooghi et al 2018), while others found more impressive GSI performance (Fry and Maxwell 2017;Wright et al 2018).…”

“…Monitoring (Hopkins et al 2019;Loperfido et al 2014;Woznicki et al 2018) and modeling studies (Avellaneda and Jefferson 2020;Fry and Maxwell 2017;Wright et al 2018) have shown that extensive systems of GSI can have measurable watershed-scale benefits. However, some found relatively minor benefits (Avellaneda et al 2017;Hoghooghi et al 2018), while others found more impressive GSI performance (Fry and Maxwell 2017;Wright et al 2018). In some cases, stormwater controls may have no discernable benefit at the watershed scale (Miller et al 2021).…”