From Highway to High-Way—Challenges and Opportunities for Wastewater Design along the I-35 Corridor in Austin

This paper presents a case study of how Austin Water (AW) seized the opportunity to overhaul the Austin, Texas, wastewater system along a densely urbanized corridor in a fast-growing city. The catalyst for this project was the Interstate Highway 35 (I-35) project by Texas Department of Transportation (TxDOT). The roadway improvements include depressed main lanes, significant retaining walls, and limited right-of-way (ROW). While the limitations of the roadway project are difficult for all utilities, they are particularly constraining for the existing gravity sewer system. The project team evaluated alignments, redefined sewershed boundaries, and developed a strategic plan to meet the current and future needs under two different design conditions. The paper discusses how the project strengthened the infrastructure, prepared for population growth by allowing redevelopment along the corridor, and addressed the challenges and opportunities of wastewater design in the context of a highway utility relocation project.