The City of Fort Wayne utilized Optimizer™ to achieve multiple mandated levels-of-control and to meet its consent decree requirements for its combined sewer system and separate sanitary sewer systems.
The City of Fort Wayne had focused the last 10 years on planning and completing Long Term Control Plan (LTCP) and Sanitary Sewer Discharge (SSD) elimination projects required in its consent decree. The City decided to undertake an optimization effort to confirm or modify the remaining planned projects (approximately one-third of the initial plan) while achieving multiple levels-of-control at minimum project costs.
City of Fort Wayne, Indiana
Optimization to meet consent decree requirements
- Careful preparation of the options model and multiple levels-of-control performance criteria
- Exhaustive consideration of improvement options for both combined and separate sanitary sewer areas
- Careful weighting of penalties to achieve elimination of overflows and flooding
“This project highlights the significant value provided by the unbiased decision support approach enabled by Optimizer – in terms of defensible, near-least cost solution that meets the City’s specified performance levels.”
Brian Desharnais, PhD
Commonwealth Engineers Inc.
The system hydraulic models were reviewed and modified to achieve faster simulation run times while maintaining accuracy of the hydraulic results. Approximately 150 improvement options were developed, each with multiple variables to be optimized such as conduit size, storage volumes, pumping rates, treatment plant capacities, I/I reduction and targeted sewer separation.
The performance criteria centered around four levels-of-control, namely the 5-yr 6-hr design storm event with no flooding for the separate sanitary areas and 3 different performance requirements for the combined sewer system. The project was particularly challenging due to the multiple levels of control to be met and the model simulation run times for the different design events. Extensive testing and refinement were carried out to confirm the recommended optimized solutions fully met the City’s requirements.
Location Map of Improvement Options
With so many levels of control to be considered, the optimization runs had to be completed numerous times to assure the City was meeting all of its needs. Out of nearly 150 developed options, each with numerous variables to consider, the city was able to streamline its improvement schedule.