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Modeling and Assessing Opportunities for Stream Restoration to Address PFAS and other Emerging Contaminants of Concern
Brandon Alderman
AECOM
Roanoke, VA
Stream restoration and other low-impact development best management practices have become widely accepted and celebrated approaches to using natural approaches to address TSS, TN, and TP contamination issues in surface water. While these contaminants have been the primary focus of regulatory efforts in states like Maryland, emerging contaminants of concern, such as PFAS are quickly moving to the forefront of regulatory and mitigation efforts due to their persistent and associated negative health effects.
PFAS chemicals are showing up in benthic macroinvertebrates and fish tissues, as well as surface water and soils around rivers and streams. PFAS is known to bioaccumulate and is believed to cause long-term health consequences that are not yet widely understood. MDE recently issued the 20-SW permit, which includes a requirement to document and monitor sources of PFAS on industrial sites. Many states are beginning to develop TMDLs to address these emerging pollutants, and Maryland is expected to join them.
PFAS modeling is possible through PCSWMM and other H&H software programs that can simulate pollutant transport. With this kind of software, the user can determine pollutant loads accumulating in a drainage area and potential locations of pollutant origin. In the case of PFAS, treatment systems like GAC, ion exchange, and high-pressure membranes are often used to remove pollutant accumulation. Though these methods are highly effective, more natural approaches such as stream restoration should be investigated, as they can provide aesthetic, cost, and longer-term benefits in addition to pollutant removal benefits. Studies conducted on plant uptake of PFAS chemicals point to the potential for plant use as treatment. Surface water and aquatic life tissue sampling can also be used to evidence the use of these natural best management practices to remove emerging chemicals of concern.
About Brandon Alderman
Brandon Alderman has over 15 years of experience designing, assessing, monitoring, and implementing various stream and wetland restoration projects. As AECOM’s National Practice Leader for stream restoration, he leads stream and wetland design of ecosystem restoration, stream bank stabilization, dam removal, outfall restoration, and mitigation banking and permittee responsible mitigation projects. He also provides construction oversite and management of implementation of ecological restoration projects. Brandon has received extensive training in natural stream channel design and has completed all four levels of Dave Rosgen’s natural stream design courses. Brandon has been involved in the design and construction of over 350,000 linear feet of stream restoration activities and establishment of over 250 acres of wetlands in 11 different states throughout the Eastern United States and Midwest Regions.
