Comparison of Soil Health of Various Bioretention Systems within Morgan State University, Baltimore, MD

Abstract Submission: Comparison of Soil Health of various bioretention systems within Morgan State University, Baltimore, MD
Gift Ugochi Ugochukwu1, James G. Hunter2, Ph.D, AM.ASCE, Donghee Kang Ph.D ASCE, Nicholas Miwornunyuie
Morgan State University, Clarence M. Mitchell, Jr, School of Engineering
Department of Civil Engineering, Baltimore MD,21251
Abstract
This study evaluated soil health across bioretention systems at Morgan State University, established between 2012 and 2022, emphasizing seasonal variability and its impact on system performance. Key soil physical parameters texture, mean weight diameter (MWD), infiltration rates, and compaction were assessed across two distinct seasonal periods. The results highlighted a predominance of sand fractions, promoting high infiltration rates crucial for effective stormwater absorption. In contrast, systems with higher silt and clay contents improved water retention and pollutant filtration but reduced infiltration rates, increasing water logging risks during heavy precipitation. Significant seasonal variations in soil texture, particularly in silt fractions, indicated sensitivity to seasonal changes that could influence pollutant removal efficacy. Soil compaction exhibited spatial variability, with higher levels in high-traffic areas, potentially impeding root growth and water infiltration. Biological properties, including CO₂ respiration rates and microbial biomass, showed substantial seasonal variability, with a decline in microbial activity and a shift toward bacterial dominance in colder, drier seasons, potentially affecting nutrient cycling and pollutant degradation. Chemical properties, such as pH and organic matter content, remained stable across seasons, though a significant increase in organic matter was observed in one season, indicating enhanced fertility but potential nutrient imbalance risks. The study underscores the importance of accounting for seasonal fluctuations in soil properties, particularly compaction, in the design and management of bioretention systems, highlighting the need for continuous monitoring and adaptive strategies to maintain system efficacy under varying environmental conditions.

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