The Summer Street Housing Limited Partnership, a partnership between the Central Vermont Community Land Trust (CVCLT) and the non-profit Housing Vermont, sought to redevelop a brownfields (with certain legal exclusions and additions, the term "brownfield site" means real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant) site in Barre, Vermont. The site was the former location of an automobile servicing station and a paint shop, and previously contained several underground petroleum storage tanks.
To guide the redevelopment efforts, the Partnership conducted an Analysis of Brownfields Cleanup Alternatives. As part of its analysis and to build in climate resilience and adaptation, the Partnership used available regional climate projections to anticipate current and future risks, namely flooding and extreme temperatures. The partnership then considered the vulnerability of potential cleanup remedies to the identified climate risks.
By including current and future climate threats in its analysis, the Partnership was better able to understand potential vulnerabilities associated with its planned brownfields investment. For example, the increasing frequency and intensity of storms projected for the region may lead to flooding that could compromise potential remediation fixes such as engineered caps. By its explicit consideration of projected climate threats, now and in the future, the Partnership's final remedy selection is designed to safeguard public health even as the climate changes.
How Did They Do It?
First, the Partnership identified regional climate risks by reviewing the NOAA Technical Report Regional Climate Trends and Scenarios for the United States National Climate Assessment: Climate of the Northeast United States After identifying anticipated climate risk, the partnership used local knowledge of the site to determine primary climate vulnerabilities. Specifically, more frequent and intense storms may lead to flooding which could result in potential contamination releases beyond the site. More extreme temperatures could also exacerbate the risk of soil gas exchange and maintaining healthy indoor air quality.
Next, the Partnership considered climate risks and vulnerability when evaluating cleanup alternatives. The site's Analysis of Brownfield Cleanup Alternatives stated, "Climate change concerns for site-wide soil gas contamination include: drought conditions could lower the surficial groundwater table, leading to a larger vadose zone for soil gas migration; and the loss of a winter frost layer could alter soil gas contaminant migration pathways to indoor air in unknown ways."
- Applicable Tool - For more on Vadose Zone Leaching see USEPA VLEACH.
While several cleanup options were identified, several were rejected because they would not have reduced climate vulnerability. (E.g capping the contaminated soil was not selected because while it may have reduced current exposure, it would have been vulnerable to future flooding events anticipated as a result of projected increased precipitation).
Finally, the Partnership selected a brownfield cleanup alternative that they identified as having adaptive benefits. A cleanup that included a soil management plan and targeted excavation was adopted. Excavation was selected due to the level of uncertainty on how climate change could "alter soil gas contaminant migration to indoor air in unknown ways" (as identified in the Analysis of Brownfield Cleanup Alternatives). For additional safety, a "sub-slab depressurization system and vapor barrier to mitigate exposure to indoor air via the vapor intrusion pathway in the future buildings" was included in the Corrective Action Public Notice in order to attain "land use restrictions to protect any potential future construction/utility workers or new property owners from exposure to site contaminants.