Many utilities deal with the challenge of aging sewer infrastructure and the consequential infiltration and inflow (I&I) issues stemming from rain or groundwater. The City of Bothell, Washington, partnered with WithersRavenel to develop a framework to reduce I&I in its sanitary sewer system to improve long-term efficiency and capacity, while also targeting related rehabilitation of its system’s infrastructure. Given an overarching desire to protect the environmental health of the Puget Sound, the deliverable was titled Pipes Underground Evaluation Tool (PUGET).
The assessment of sewer system conditions, facilitated by technologies such as closed-circuit television (CCTV) inspection and flow monitoring, is pivotal in pinpointing aging sewer pipes in need of repair or replacement. While some assessments, like CCTV, provide crucial insights into the condition of concealed pipes, the data is confined to the assessed assets. Conversely, flow monitoring offers an overview of I&I severity across the entire subbasin but lacks detailed information for individual assets. To address this, PUGET, amalgamates diverse inputs, including AI-generated CCTV ratings, SL-RAT scores, GIS attributes, Rootsaw data, and I&I severity rankings. The City was also interested in pipe inspection data storage and wanted to explore streamlining its inspection process. WithersRavenel not only demonstrated the functionality of AI-coded CCTV but also provided advanced metrics to compare against human-created PACP scores.
PUGET identifies pipes necessitating replacement, repair, root control, or recurring condition assessments. Prioritization for future condition assessment planning is determined by factors such as pipe age, material, and known condition scores. Opinion of probable cost for each project was also included. This tool confirms that past efforts inform future planning endeavors, thereby automating the pipeline for enhanced efficiency. Lastly, WithersRavenel provided a strategy for future flow monitoring, therefore refining the spatial resolution of future PUGET updates for intelligent targeting of I&I.