Curbing Sediment: Controlling Stormwater Pollution using a Novel Curb and Gutter Design
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Date
2024-08
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The Ohio State University
Abstract
As urbanization occurs, the increase in impervious surfaces, soil compaction, and removal of vegetation reduces the infiltration capacity of soils, reducing groundwater recharge. Urban runoff causes many water quality concerns and environmental issues, including stream erosion, pollutant transport, and flooding. With respect to water quality, transport of nutrients, metals, sediment, micropollutants, and emerging contaminants by stormwater is an urgent challenge in urban areas worldwide. Stormwater control measures (SCMs) are often implemented by municipalities to curtail these negative impacts on water quality; however, infiltration-based SCMs may become clogged with stormwater-borne sediment over time, greatly reducing their efficacy. Thus, pretreatment devices, such as forebays, filter strips, catch basin inserts, or hydrodynamic separators are implemented upstream of these SCMs to remove sediment and lengthen maintenance intervals. In the urban built environment, space constraints make retrofitting SCMs into existing development difficult and the installation of pretreatment measures even more challenging. Thus, new pretreatment systems need to be developed which fit within the existing road right-of-way. A modified curb and gutter system was designed and tested at laboratory scale; roughness was added to the curb and gutter, with varying degrees of spacing, shape, and depth of indentations, with the intention of reducing the water flow velocity and trapping sediment particles. The best performing designs removed >80% of sediment in simulated stormwater at the laboratory scale. In the current research, the most effective gutter roughness design was selected and implemented on a 60-meter section of Carmack Road on Ohio State University’s west campus. By using the standard curb and gutter on the opposite side of the street as a control for the experiment, we evaluated the performance of this modification. Effluent samples from both the treatment and innovative curbs were collected using automated samplers and tested for nutrients, metals, and total suspended solids (TSS) concentrations to understand real-world benefits of this novel pretreatment. Curbing Sediment provided no significant reduction in pollutant concentrations (TSS, nitrogen and phosphorous species, or trace metals); however, it is suspected that bare soil created by the construction process located adjacent to the treatment curb, impacted the results. Curbing Sediment tended to have lower concentrations of pollutants (compared to the control) in the final 4 months of the study, suggesting that a start-up effect may exist. Thus, continual site monitoring for an additional several months beyond what is presented in this thesis is recommended to holistically evaluate the effectiveness of Curbing Sediment.
Description
2024 CFAES Undergraduate Research Forum Poster Competition, Honorable Mention in Environmental and Plant Sciences
Keywords
Sediment, Urbanization, Stormwater control measures, Pretreatment, Trace metals, Nutrients