SPU Wastewater System Analysis

Dubin Environmental was part of a large team that evaluated Seattle’s separated and combined sewer systems citywide to identify areas with insufficient capacity and moderate-to-high risk of basement backups and sewer overflows. For three regions of the city, Dubin Environmental performed SWMM model updates, real-time control updates near CSO facilities, flow and depth calibration, capacity analysis, prioritization of problem areas, and also provided mentoring for staff engineers across the consultant team and QC oversight for different regional models. 

The calibration results were presented across a series of workshops with SPU staff. In each case, Dubin Environmental emphasized the story each model could tell by comparing different rain gauges and flow responses, discussing data quality, and highlighting complex phenomena, like hydraulic jumps. This effort provided SPU with the context needed to make decisions based on the model results. 

The calibrated models were used to identify capacity-limited clusters and flooding locations within the city and describe likely reasons for the capacity problems (e.g., pipe diameters, gate settings). Different climate scenarios were examined to determine the likely extent and magnitude of future problem areas. The results prepared by Dubin Environmental are currently being used to SPU staff to help guide its integrated planning process, which seeks to jointly manage wastewater and storm drainage infrastructure in a customer-focused manner.

Services: Modeling