As part of the Combined Sewer Overflow (CSO) Long Term Control Plan, the City of Indianapolis Department of Public Works (DPW) proposes to construct a wet weather conveyance tunnel that will provide a connection and gravity flow conveyance from CSO 008, CSO 117 and CSO 118. The proposed 9.8 mile tunnel will provide a minimum storage capacity of 54 million gallons and convey wet weather flows through a minimum diameter of 18-feet to the Southport AWT facility.Shrewsberry & Associates (Shrewsberry) conducted environmental investigations for each proposed access shaft location (impact area) to assess potential impacts to residents, businesses, historically significant sites and districts. These investigations assisted in the selection of the appropriate alignment as part of the advanced facility plan.
Environmental investigations included Phase I Environmental Assessments, a Historic Property Report, a Phase 1a Historical Investigation, a Phase 1a Archaeological Field Reconnaissance Survey, a Phase 1c Archaeological Investigation, and Phase II Limited Subsurface Investigations at areas of concern. The Phase II Investigations included soil and groundwater sampling and corrective action planning. A Socio-Economic Evaluation was conducted to access potential impacts on Environmental Justices populations. Furthermore, Shrewsberry assisted with required documentation for the project State Revolving Fund (SRF) application and is assisting the project design team with project permits and regulatory compliance