Green Stormwater Infrastructure Effects on Pollutant Retention and Water Quality
Start Date
3-11-2024 11:10 AM
End Date
3-11-2024 11:19 AM
Abstract
In recent decades, green stormwater infrastructure (GSI) has gained prominence in urban planning and environmental management as a way to manage urban flooding, ameliorate water quality issues in receiving waters, and increase human well-being by creating green spaces for aesthetics and recreation. The benefits of peak flow attenuation through the widespread implementation of bioretention structures have been well documented, but the water quality improvements associated with GSI are not as well understood. Here, I report on several related projects in Portland, Oregon, that focused on the role of GSI in processing nitrogen, phosphorus, and metals.
In two studies, GSI soils were found to be potentially strong but quite variable nitrogen sinks, while soil phosphorus was vulnerable to release following repeated drying and flooding cycles. A third study focused on GSI impacts on water quality during storms showed that, while concentrations of total suspended solids and most metals decreased from inflow to outflow, concentrations of nitrate and phosphate increased substantially in effluent waters. Together, these results suggest that water quality improvements from GSI are not a foregone conclusion, and that more study of the mechanisms driving the variability of pollutant retention is needed to inform design processes and planning expectations.
Subjects
Land/watershed management, Soil science, Water quality
Persistent Identifier
https://archives.pdx.edu/ds/psu/41418
Creative Commons License
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License.
Green Stormwater Infrastructure Effects on Pollutant Retention and Water Quality
In recent decades, green stormwater infrastructure (GSI) has gained prominence in urban planning and environmental management as a way to manage urban flooding, ameliorate water quality issues in receiving waters, and increase human well-being by creating green spaces for aesthetics and recreation. The benefits of peak flow attenuation through the widespread implementation of bioretention structures have been well documented, but the water quality improvements associated with GSI are not as well understood. Here, I report on several related projects in Portland, Oregon, that focused on the role of GSI in processing nitrogen, phosphorus, and metals.
In two studies, GSI soils were found to be potentially strong but quite variable nitrogen sinks, while soil phosphorus was vulnerable to release following repeated drying and flooding cycles. A third study focused on GSI impacts on water quality during storms showed that, while concentrations of total suspended solids and most metals decreased from inflow to outflow, concentrations of nitrate and phosphate increased substantially in effluent waters. Together, these results suggest that water quality improvements from GSI are not a foregone conclusion, and that more study of the mechanisms driving the variability of pollutant retention is needed to inform design processes and planning expectations.