Portfolio Sewer Rehabilitation Planning through Interactive Decision Tree Framework

• Framework Development: The City of Bothell, Washington, collaborated with WithersRavenel to create the Pipes Underground Evaluation Tool to reduce infiltration and inflow in its sanitary sewer system, enhancing long-term efficiency and capacity.
• Advanced Assessment Techniques: The tool integrates various data sources, including AI-generated CCTV ratings, SL-RAT scores, GIS attributes, and flow monitoring, to identify and prioritize sewer pipes needing repair, replacement, or further assessment.
• Strategic Planning and Cost Estimation: The tool aids in future condition assessment planning by considering factors like pipe age and material, and includes cost estimates for projects, ensuring informed and efficient infrastructure management.

Reducing Inflow and Infiltration

Many utilities deal with the challenge of aging sewer infrastructure. Consequently, they face 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. This aimed to improve long-term efficiency and capacity. In addition, the effort targeted 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).

Sewer assessment

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. These include AI-generated CCTV ratings, SL-RAT scores, GIS attributes, Rootsaw data, and I&I severity rankings.

Pipe inspection data storage

The City was also interested in pipe inspection data storage. Moreover, it wanted to explore streamlining its inspection process. WithersRavenel not only demonstrated the functionality of AI-coded CCTV but also provided advanced metrics. These metrics allowed comparison 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. Therefore, it automates the pipeline for enhanced efficiency.

Future flow monitoring

Finally, WithersRavenel provided a strategy for future flow monitoring. As a result, this refines the spatial resolution of future PUGET updates for intelligent targeting of I&I.