Bioretention Performance – Multi-year Analysis of Hydrological and Water Quality Performance
Date
2023-05-09
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Abstract
Low Impact Development (LID) aims to mitigate and prevent the negative impacts of urbanization on the hydrology and water quality of the natural water bodies. Bioretention systems are some of the most popular LID systems that offer various benefits, including reduction of peak runoff, attenuation of excess runoff volume, retention of various pollutants, as well as aesthetic and habitat benefits. This research provides a comprehensive investigation of bioretention performance using mesocosms and controlled runoff application. The research site for this project was constructed in the Town of Okotoks, Alberta, in 2016/2017. The site consists of 24 lined mesocosms that were designed to receive no natural runoff and were drained by pumping through a perforated standpipe. There were three different bioretention media and three different vegetation types. Among the media, there was a unique mix of clay-loam and wood chips, as an alternative to the conventional sand-based bioretention media. The mesocosms were analyzed for their hydrologic and water quality performance using 72 simulated runoff events over four growing seasons. The mesocosms with different media exhibited significant differences in water retention at the onset of the study period yet became increasingly similar over time, whereas the differences in vegetation impacts increased over time. The water quality analytes include Total Phosphorus (TP), Reactive Phosphorus (RP), Total nitrogen (TN), Nitrate-Nitrogen (NO¬¬3-N), and Total Organic Carbon (TOC). The research revealed significant leaching of nutrients and organics over four years. The leaching of nitrogen and organic compounds decreased over time, whereas phosphorus leaching persisted. This research also monitored the infiltration rate of the mesocosms, and an overall increasing trend in the infiltration rate was observed. Among the three media types, the clay-loam media had the highest infiltration rates, showing promise for future implementation. Soil respiration was measures as an indirect method of quantifying root activity, where the greatest respiration was associated with the clay-loam media. This research showcased the variability and changes in bioretention performance over time, as well as highlighted the role of the media and vegetation in various aspects of performance.
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Keywords
bioretention, green infrastructure, nature-based solutions, low impact development, stormwater management, urban hydrology, water resources
Citation
Skorobogatov, A. (2023). Bioretention performance – multi-year analysis of hydrological and water quality performance (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.