August Mack and and its subsidiary collaborated to design and build an interim Measure (IM) to protect and improve a local Indianapolis waterway, Pleasant Run Creek (PRC). The primary objectives of the project were to identify, evaluate and remediate areas within a former manufactured gas plant (MGP) site that were impacting or had the potential to adversely impact the creek ecology.
The site was subject to Resource Conservation and Recovery Act (RCRA) regulations and was enrolled into the Indiana Department of Envrionmental Management’s (IDEM) Voluntary Remediation Program (VRP) in 2005. As part of the Voluntary Remediation Agreement, the client and IDEM agreed to address RCRA obligations under the framework of IDEM’s VRP. Since 2008, August Mack has worked with the IDEM VRP to conduct investigations of soils, sediment and groundwater at the site to further assess environmental conditions. A holistic site-wide approach for investigation and remediation efforts consistent with U.S EPA and IDEM guidance was utilized to identify and delineate impacts associated with the site. Investigation activities conducted within the creek included a qualitative habit assessment of approximately 4,300 linear feet of the creek, quantitative sediment and pore water sampling at 43 transects, performance of a Human Health Risk Assessment based on sediment and surface water data, and qualitative and quantitative sediment and underlying soil investigations in areas of potential ecological risk.
As site investigations were completed and exposure pathways were evaluated, multiple interim measures (IMs) were conducted in order to expediate the remediation process.
August Mack performed three excavation IMs associated with the creek. Army Corps of Engineers (ACOE) and Indiana Department of Natural Resources (IDNR) permitting was required for each phase of work including significant surface water modeling and restoration planning for the 3rd and final IM within the creek. Approximately 2,200 linear feet of the creek was excavated to depths ranging from 2-4 feet, a low permeability liner was installed, and the area was restored. Surface water features consisting of alternating pools and riffles were installed to assist with high flow conditions and minimize erosion and a low head dam and retaining walls, installed during plant operation, were removed. Overall, approximately 45,000 tons of impacted material was removed from the creek during the IMs. A groundwater recovery and oil collection system was also installed along the east bank of the creek to help mitigate the potential for contaminant migration in shallow groundwater.
August Mack, the client, and IDEM met on a bi-weekly basis for several months to discuss the site and address concerns regarding nature and extent of impacts and remedial objectives. This intense regulatory interaction culminated in the submittal of a site wide Remediation Work Plan (RWP). The RWP presented a site-specific, non-default risk-based remedial strategy consistent with non-residential land use at the site. Plume stability monitoring, groundwater system operations, excavation activities, surface covers, and environmental restrictive covenants were proposed to limit potential future exposures. Additional meetings with IDEM in September and October led to the client and August Mack satisfactorily addressing IDEM comments on the RWP and IDEM approved the RWP.
During the project lifetime, August Mack and the client regularly engaged, updated, and consulted community, non-profit, regulatory, and government stakeholders. In addition to the HBUS process, August Mack worked with the client to complete an Economic Development Administration Grant evaluation to develop a comprehensive strategy to redevelop the site. In 2017, the site was chosen by the City of Indianapolis as the location for their Community Justice Campus, a $571 million project which will result in the City’s courts buildings, a sheriff’s office, a medical assessment center, and adult detention center being built on the site. Construction for the Community Justice Campus commenced in May 2018 and August Mack is currently engaged as the client’s representative during construction. Activities include design review and construction supervision at the site. The project has recently received an Honor Award in the American Council of Engineering Companies of Indiana’s 2019 Engineering Excellence Awards Competition.