In response to a 2008 Administrative Consent Order aimed at eliminating sanitary sewer overflows (SSOs), the City submitted an I/I Reduction Plan prepared by a local firm. The plan identified 21 collection system projects totaling $21.6 million to be completed by 2019. However, the political challenges associated with implementing a broad home inspection and footing drain disconnection program prompted the City to reconsider its strategy. At the same time, the City faced major deficiencies at its Wastewater Treatment Plant (WWTP), including a non-functioning preliminary treatment system that negatively impacted downstream processes. Compounding the issue was the lack of reliable influent flow data during storm events, caused by years of deferred maintenance and nonfunctioning equipment. These factors led to highly variable effluent discharge volumes and inconsistent treatment performance.
To address these concerns, McClure partnered with the City and the Iowa Department of Natural Resources (DNR) to develop a comprehensive, data-driven strategy. The team focused on quantifying actual flow patterns entering the collection system and WWTP during storm events—critical for long-term planning and infrastructure design. This effort resulted in the Sanitary System Evaluation Survey and the establishment of an eight-year Sanitary Transportation and Elimination Program (STEP).
The STEP program introduced a phased, holistic approach aimed at reducing and ultimately eliminating SSOs, minimizing the risk of basement sewage backups, rehabilitating the aging collection system, and implementing substantial improvements at the WWTP. This strategy enabled the City to shift away from politically challenging residential programs and instead focus on measurable system-wide improvements to achieve regulatory compliance and enhance long-term operational resilience.