The City of Bend faces significant future growth and has an urgent need to plan long-term sewer system improvements. The collection system has nine major sewer basins covering some 35 square miles within the current Urban Growth Boundary and conveys sewage to the water reclamation facility.  Due to its varied topography and historical reliance on mechanical pumping systems, the Bend system has 86 regional lift stations and numerous other private and City pumping facilities within the existing primary sewer network.

Optimizer WCS was selected to assess and compare the alternatives identified for potential system improvements. Alternatives evaluated with the optimization included conveyance, storage, flow diversions, interceptor alignments, and satellite treatment.  Extensive sensitivity analyses were performed to test population growth scenarios, model calibration accuracy, and water conservation trends.  The team received input and advice from the City’s 18-member Sewer Infrastructure Advisory Group (SIAG) and City Council.  The transparent and defensible process led to unanimous approval of the CSMP by the SIAG.  The optimized solution has a total cost which is $40M lower than the Baseline Solution, representing a potential savings of 25%.

“In the water industry, the word “Optimization” has become a buzz word with many firms and people claiming to have both the knowledge and technology to either generate savings or make systems more efficient. We knew that optimization in the wrong hands would lead us to results that were no more helpful than using traditional hydraulic modeling tools.  We hired WCS Engineering to lead the optimization analysis for the City of Bend Collection System Master Plan (CSMP). WCS provided the very specific expertise in the use of optimization and was able to help guide us in generating new ideas for us to consider. WCS helped develop the confidence needed of our citizen committee, and more importantly produced very real and defensible results saving our community over $40M of capital investment. I would strongly recommend anyone considering undertaking an optimization project to engage WCS Engineering.” 

Tom Hickmann, P.E., Director of Public Works, City of Bend, Oregon

Figure 1 – Bend CSMP Optimized Solution – Prioritized Improvements