Assessment and Management of Stormwater Impacts on Sediment Recontamination

Dr. Danny Reible | Texas Tech University

ER-2428

Objective

In this project, a comprehensive set of laboratory, field, and modeling approaches will be used to characterize the role of urban stormwater in contamination of sediments and remediated sites. The research will focus on the development and application of techniques to assess the magnitude and characteristics of episodic distributed sources (i.e., stormwater) and the effects of these sources on sediments and benthos. The work will consider baseline conditions, loads of stormwater contaminants, relationship to other potential sources of sediment contamination, and the potential for recontamination following remediation. The bulk chemical contamination will be integrated with site-specific bioavailability, the potential for bioaccumulation, and identification of key stressors and ecological risk of stormwater and stormwater–related sediment contaminants. This will provide the foundation for a decision making framework for identifying stormwater sources and their consequences, designing effective source controls, and identifying the remedial goals realistically achievable without such controls.

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Technical Approach

Stormwater loads and the resulting impacts on surficial sediments will be characterized physically, chemically and biologically considering the spatial and temporal dynamics of the dominant stressors. The characterization of stormwater sources of contaminants will be informed via a review and summary of existing data on stormwater source characterizations and loadings (the International Stormwater BMP Database and the National Stormwater Quality Database) as well as targeted sampling of stormwater sources to complement existing databases and source characterization. Measurements will be used to calibrate a stormwater model that builds on previous DoD modeling efforts and coupled with measurements of receiving sediment impacts and ecological effects. Intensive field stormwater monitoring at one site or less intensive monitoring at two sites may be conducted, depending on data gaps.

The calibrated stormwater modeling will enable predictions of stormwater discharge as determined by specific drainage area characteristics and activities. These stormwater loading predictions, along with information affecting the fate of the discharged suspended and bedload sediments (e.g., particle size distributions and related settling rates) will be used to help quantify the recontamination potential of the sediments by stormwater discharges and to compare to the receiving sediment recontamination measurements. Contaminant dynamics in the receiving waters will be interpreted using models developed by SERDP project ER-1746 and ESTCP project ER-201031. Modeling and sediment recontamination monitoring is planned at up to three sites.

ER-2428_project_graphic

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Benefits

Linking and ranking stormwater inputs of specific stressor types (i.e., habitat and siltation, nutrients, anoxia, metals, and organic chemicals) with ecological impacts (e.g., site toxicity, food web contamination, degraded benthic macroinvertebrate communities) will allow for more effective assessment of recontamination and its consequences. This study of significantly different sediment environments will allow the development of broadly applicable tools for assessing the effect of stormwater loads and inputs on sediment recontamination and determining which stormwater-related stressors are most important. Results gained from this study and the methodology will support more effective source control and corrective action planning and advance the state of the practice for forecasting and quantifying sediment recontamination risk where continued long-term stormwater pollutant loading is present. (Anticipated Project Completion - 2018)

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Points of Contact

Principal Investigator

Dr. Danny Reible

Texas Tech University

Phone: 806-834-8050

Program Manager

Environmental Restoration

SERDP and ESTCP

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