Into the Matrix: Sewer Trunk Main Study and Multi-Alignment Decision Visualization

Through its capital improvement program, the City of Richardson identified the Cottonwood Creek sewer interceptor as a line for replacement due to high wet weather peaking, the age of the system, and its location within Cottonwood Creek. With the overall basin nearing its ultimate buildout, city staff recognized the need to explore the best options for replacing or realigning the sewer trunk main. BGE conducted a conceptual study of the existing system, which included model analysis of the existing main, inflow, and infiltration studies to determine critical subbasins that contributed especially high peaking factors, and future maintenance and cost assessments to determine the city's best options moving forward. This report will cover how we assisted the City of Richardson staff on the preferred alignment decision and how personal biases were removed from the decision process via a multi-alignment decision scoring system and visualization app. This same system would be beneficial to other projects as it can be tailored specifically to the necessary criteria of the project and owner.