On October 5, 1992, Miami-Dade County’s Department of Regulatory and Economic Resources (RER) discovered free-floating product, characterized as synthetic oil, in an on-site monitoring well (MW-8) at the City’s Fleet Maintenance Facility (Attachment A). In a Site Assessment Report dated January 14, 1993, the City indicated that the discharge was associated with the on-site hydraulic lift pumps and detailed the results of the Non-Aqueous Phase Liquids (NAPL) analysis collected from MW-8. Recently conducted analyses confirm the discharge has remained localized at its source since it was first discovered and that it is not migrating within or off the site.
On January 23, 2012, RER requested that the Florida Department of Environmental Protection (FDEP) consider the site’s eligibility in the Petroleum Cleanup Participation Program for the October 5, 1992 discharge. However, in a letter dated January 27, 2012, FDEP stated that the discharge was not eligible because hydraulic lift pumps are not considered petroleum storage systems. Therefore, FDEP requested that the City submit a Site Assessment Report Addendum.
On October 30, 2013, City staff met with the Environmental Code Enforcement Section of RER to discuss the next steps for achieving regulatory closure of this facility. RER provided a proposed scope of work which included visual and Organic Vapor Analysis (OVA) screening of four soil borings and testing of the existing monitoring wells on-site. In FY 2013/14, the City filed a Risk Management Damage Claim Form for this property in order to use $25,000 of Risk Management funds to initiate the required investigation.
In May 2014, soil and groundwater samples that were collected from the site confirmed the presence of free product in MW-8 and of hydrocarbon derivatives in the surrounding soil. It must be noted that presence of the Fleet Management office building restricted the ability to collect samples to the north of MW-8. Based on the results of the limited assessment and subsequent groundwater sampling events, the presence of free product is localized in the immediate vicinity of MW-8, is residual in nature, and is not currently migrating off-site.
Due to the localized nature of the plume, the frequency of sampling was reduced from quarterly events to semi-annual events in November 2016. However, RER has required the City to continue the site assessment activities, submit an Addendum to the Site Assessment Report, and pursue regulatory closure of the site due to the property’s prior compliance issues.
The City is considering redeveloping the site in the near future. If the remediation work is incorporated into the site’s redevelopment rather than performed as a stand-alone project, the City can lower project costs, reduce unnecessary site disturbance, and facilitate the assessment and removal of contaminated soils near or under the existing building. Staff has requested a thirty month extension from RER to complete the remediation activities either as part of a site redevelopment effort or a stand-alone project.
The County approved the City’s request and granted a 30 month extension contingent upon the City approving and executing a consent agreement with progressive milestones, including the development and implementation of an interim groundwater monitoring plan (Attachment B). The City executed a consent agreement in January 30, 2015, which expires and requires the City to submit the Addendum to the Site Assessment Report in July 2017. The City is still in discussions regarding the potential redevelopment of the site. As such, RER has agreed to grant the City an additional 24 month extension to the consent agreement, postponing the remediation of the existing hydrocarbon discharge for a total of 54 months from the consent agreement effective date.