Soil Layer Development and Biota in Bioretention

Emily Mitchell Ayers,Patrick Kangas

doi:10.3390/w10111587

Emily Mitchell Ayers, Patrick Kangas

Open Access

https://doi.org/10.3390/w10111587

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Abstract

As bioretention comes into widespread use, it has become increasingly important to understand the development of bioretention soils over time. A field survey was conducted to investigate the development of bioretention soils and soil ecosystems. Sampling from 10 bioretention cells of various ages provides the first detailed descriptions of bioretention soil profiles. The study reveals much biological activity in bioretention and evidence of pedogenesis even in very young sites. The uppermost soil layers were found to be enriched with organic matter, plant roots, and soil organisms. This survey provides a first glimpse into the biological processes at work in bioretention soils. The research shows that soil organisms are ubiquitous in bioretention cells and suggests that their impact on bioretention performance may be significant.

Highlights

Bioretention cells are a stormwater best management practice (BMP) that are commonly used in low-impact development (LID) and green infrastructure designs
Soil organic matter was highest in the surface layer of the pits and declined with depth at all sites except for the Chesapeake Bay Foundation site (CBF), where it was low throughout the profile but showed a slight increase at the 20–30 cm depth (Figure 3)
This study has revealed the basic structure of the soil animal community

Summary

Introduction

Bioretention cells are a stormwater best management practice (BMP) that are commonly used in low-impact development (LID) and green infrastructure designs. Bioretention cells are essentially planted soil filters, and their performance during a storm event depends on the hydraulic conductivity and pollutant removal capacity of the soil medium These soil properties are influenced by the physical effects of storm events as well as the actions of the plants, microbes, and soil animals of the bioretention ecosystem. The bioretention soil medium can be expected to undergo pedogenesis as every soil does, beginning with the development of organically and biologically enriched horizons at the soil surface [2]. As this topsoil develops, it may change the soil media’s physical and chemical properties, and affect performance. The development of bioretention soils over time must be examined if the long-term performance of bioretention is to be understood

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