Director UNH Stormwater Center, New Hampshire, United States
Abstract Submission: Polluted stormwater remains the largest threat to water quality nationwide. In recognition of this, permits issued by the EPA and state agencies require communities to adapt their approaches to managing stormwater to reduce the NPS pollution.
Complying with these requirements, however, is difficult and often beyond a community’s resources. More information is required on the long-term operation and functionality of stormwater control measures, particularly green infrastructure installations such as bioretention systems and engineered wetlands. The UNH Stormwater Center received funds to investigate and forensically research two common green infrastructure technologies (bioretention and subsurface gravel wetlands) to evaluate long term efficacy of system components.
While numerous publications on system design and performance are available there is limited information on the efficacy of long-term operations. The systems will be systematically deconstructed to access all surface and subsurface layers and analyses performed to assess long term function and operations. Investigations included the following:
Concentrations of typical pollutants associated with stormwater: • Total Solids • Total Nitrogen • Total Phosphorus • Fecal Indicator Bacteria • Total Petroleum Hydrocarbons
In addition to pollutants commonly associated with stormwater additional analyses will include: • Plant species investigation • Root penetration assessment • Comparisons with physical characteristics of in-situ material with virgin material (soil, gravel, etc) • Carbon sequestration assessment (blue carbon) • Pipe integrity • Hydraulic capacity of internal components
Analyses was conducted horizontally and vertically across each of the system segments including forebay, treatment areas and all cross-sectional components of each layer including soil, stone, and pipes. Results will be highlighted and discussed in this presentation.
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