A few weeks ago, our team at Public Works presented an update on the City’s sewer system to the City Council.
As a bit of backstory, the City manages 72 miles of gravity sewer lines with 1,350 manholes and one lift station. Due to the City’s aging sewage infrastructure, the City has suffered several sewage overflows. Back in March 2016, the City was issued a consent judgement and settlement agreement with a goal to eliminate sanitary sewer overflows and improve the maintenance and management of sewer systems.
The consent judgement comes with five requirements which the City needs to abide by:
- The City must clean and inspect the entire sanitary sewer system via video and create a geographic information system to help document the current condition of all the City’s lines.
- The City contracted with Pro-Pipe to help video-inspect the lines. The City also implemented a new sanitary sewer system mapping layer with the assistance of Steel Co.
- Upon completing a holistic inspection, the City must initiate a routine maintenance program based on the results of the inspection.
- This maintenance program included the purchase of a vacuum truck that can clean sewer mains and pump out blockages. The City also purchased and installed ten manhole covers with sensors to detect a potential overflow.
- As part of the program, the maintenance team cleans and inspects about 20 miles of sewer pipe per quarter. Over the past year, the maintenance team has cleaned the entire sewer system in addition to multiple cleanings at known trouble spots.
- To combat the buildup of grease, the City contracted with CWE to perform inspections of fats, oils and grease and to educate local restaurants about their required disposal practices.
- The City must create a mapping and asset management system for its sewage lines.
- To address this, the City uses three programs: ESRI (which helps create a mapping layer), CityWorks (which helps track work orders) and Innovyze (an asset management software that takes data detailing the condition of lines, the amount of flow and overall capacity into an algorithm that allows the City know what sewer lines to prioritize for rehabilitation or replacement or upsizing).
- The City must prepare an asset management program to prioritize repairs based on the condition and the capacity of the sewage system.
- To address this, the City has issued a request for proposal for firms to review the previous inspections and videos, conduct limited additional inspections and flow monitoring tests, enter all the data into our management system, evaluate the results with a rank for every sewer main and manhole with the ultimate goal of producing a capital improvement program for upgrading the sewer system with cost estimates and schedules for corrective work.
- Finally, the City must complete repairs for sewer segments in the worst condition within a specified amount of time.