Data and Evidence Show the Way

Topeka is the capital of Kansas and the seat of Shawnee County. The city is located on the Kansas River in the northeast of the state. The city’s reported 2020 U.S. Census population was 125,310, making it the fourth largest city, by population, in Kansas.

At the end of 2017, the city with the assistance of Bartlett & West (Topeka, Kansas) completed updating their combined sewer overflow (CSO) long-term control plan (LTCP). As part of that work, early action projects were identified, and projects were initiated to clean and rehabilitate major sewers to ensure their structural integrity and improve their hydraulic capacities to enhance peak wet...

The program will augment the city’s existing cleaning and maintenance work activities with the collection and analysis of extensive and detailed inspection data. The detailed analyses enable repeatable processes for defensible decision-making, capital planning, and prioritization of recommended improvement projects.

To date, program work has been performed as a series of stand-alone projects comprised of city quarter sections — 64.7 ha (160 ac) each — or groups of contiguous quarter sections. In the first 18 months of the program, which sections to inspect and assess were based on past maintenance history and to coordinate with other known, planned street or utilities improvement projects to...

Inspectors compile condition scores for each pipe. These scores are comprised of various pipe defects and observations such as roots, cracks, holes, sags, grease and debris deposits, lateral connections, inflow and infiltration, and joint condition. NASSCO ratings for each type of defect were assigned weighting factors. The total pipe score (TPS) for a pipe is computed by adding up the weighted...

Pipes in each section then are prioritized for initial improvement recommendations based on normalized structural condition scores. Planning level cost estimates are developed for recommendations based on a cost tool that provides standard unit costs for

To date, approximately 104,000 m (340,442 ft) of inspected pipes have been assessed. Improvements have been recommended for 44,871 m (147,213 ft) of pipe. Of the pipes recommended for improvements, approximately 9% — 3,957 m (12,983 ft) — were intermediate pipes and pipes with excessive sags.

After recommended improvements were developed for each quarter section and quarter section group, the next step was to prioritize the implementation of improvements. Prioritization is performed using consolidated business risk exposure (BRE) scores and overall quarter section defect ratings. The consolidated BRE score is the sum of the pipe BREs in each quarter section. The overall defect rating...

The methodology outlined here provides Topeka with powerful tools. They enable to city to make methodical analyses and defensible prioritized improvement recommendations that can be implemented in a financially sustainable fashion while maintaining regulatory requirements and level of service standards.