The Problem on Signal Mountain: The Hamilton County Water and Wastewater Treatment Authority (HCWWTA) faces increasing population and regulatory requirements under their Consent Decree on Signal Mountain, where they own a 42-mile sewer collection system in difficult terrain and shallow bedrock. Ten percent of this aging system sits along, or even in, creeks, making it prone to inflow and infiltration (I/I). As a result, the system experiences sanitary sewer overflows (SSOs) that contaminate creeks and popular swimming holes, and visibly disrupt the beauty of iconic hiking trails. During wet weather, the wastewater treatment plant also receives peak flows up to ten times the dry weather flow causing significant issues at the plant. Jacobs identified solutions for I/I removal including installing low pressure sewer systems throughout areas that contributed to the high I/I and installing two pump stations within a park to abandon the problematic sewers in the creek. These proposed solutions have been heavily scrutinized by the public over the last few years. Approach: Prioritization and Solution The system condition was scored and prioritized by processing existing SSES data such as CCTV, smoke testing and manhole inspections using Jacobs’ System Condition Risk-Enhanced Assessment Model (Argon) tool. The I/I distribution and hydraulic bottlenecks in the system were determined using a hydraulic model that was built with HCWWTA GIS data, calibrated from flow meter data at 16 strategic locations and validated against historical SSO events. Creeks were confirmed to be a significant contributor of I/I into the system. Two of the 10 sewer basins were identified as priority areas for action. The solution selected to eliminate SSO and reduce I/I was a combination of CIPP lining (45%) and new low-pressure sewer system (55%). The Challenges: Flattening the Curve of Inflow and Infiltration The HCWWTA implemented a two-part communication plan to educate the community on the benefits of removing I/I from the system with the proposed solutions. If the proposed solutions could not be implemented, then the alternatives would be highly disruptive to the community and to the creeks. The major message was that the HCWWTA wanted to avoid doing work in the creeks as to not disturb the natural beauty of Signal Mountain. The solution that seems the most likely, based on community feedback of the other alternatives, is to perform trenchless rehabilitation techniques such as using cured-in-place pipe and point repairs. HCWWTA and Jacobs are currently coordinating with TDEC to ensure that the proper permitting is executed for these solutions such as Aquatic Resource Alteration Permits (ARAP). The most difficult of these areas to access is only 2,500 lf, which will cost the WWTA millions of dollars to fix over several years. Let’s take a deep dive into how WWTA plans to repair these hard to access pipes efficiently and flatten the I/I curve. Fresh experience and lessons learned will be shared and discussed during this session.