Aquatic sediments are often the ultimate repository of discharged contaminants. According to an estimate by the U.S. Environmental Protection Agency (U.S. EPA), approximately 10% or 1.2 billion cubic yards of the sediment underlying the country’s surface water is sufficiently contaminated with toxic pollutants to pose potential risks to fish and to humans and wildlife that eat fish (U.S. EPA, 1998). Contaminated sediments can pose a threat to human health when pollutants in sediments accumulate in edible aquatic organisms (U.S. EPA 1998 and references therein).
Quantification of the source and rate of change in remediated sediment surface chemical concentrations remains a critical priority research need. Uncertainties still exist in defining and quantifying connections between stormwater-associated sediment load, dissolved-phase contaminant concentrations, and contaminant-induced benthic impairment. Tools or approaches that improve the understanding of the incoming particulate load, chemical concentrations in those loads, rates of sediment accumulation, and potential impacts to benthic organisms at the contaminated surface would facilitate both remedy decision-making and setting long term monitoring (LTM) objectives.
New and innovative approaches that improve stormwater control processes are needed to minimize sediment recontamination. In-storm hydraulic management that could selectively promote or limit transport of specific chemical contaminants of concern in stormwater are of interest. Stormwater control processes are typically based on standard specifications and designs. Termed “best management practices (BMPs),” these designs are intended primarily to be protective of water quality, but are not well-validated in terms of hydraulic performance, management of particulate-bound contaminants, long term performance, or specifically with respect to sediment contamination. To this end, it is often unclear whether the adopted BMPs are effective at managing water and sediment quality.
Benefits of this work would include linking improved control practices to reduced infrastructure and cost for sediment quality protection compared to current practice. By preventing the contamination of stormwater or treating stormwater, the loading of contaminants to sediments can be more effectively managed. Such a designed system that may also offer the potential to manage stormwater as a resource by harvesting, treating, and repurposing the water for reuse, aquifer recharge, or ecological restoration.
