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Phone: 913-715-8500

11811 S. Sunset Drive, Suite 2500, Olathe, Kansas 66061

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Engineering Public Projects: I/I Study Overview

Current Project Status

All construction phase work was completed in May 2013. Johnson County Wastewater will conduct post-construction flow monitoring, data analysis, and evaluation of the effectiveness of the completed construction through 2014. As part of the post-construction evaluation, Johnson County Wastewater is also evaluating the costs of numerous infiltration and inflow (I/)I removal strategies and will then determine how best to achieve I/I removal in the remaining watershed areas. Ultimately, Johnson County Wastewater's concern is to provide more dependable, cost-effective, and environmentally sound wastewater service to our customers. Please call Johnson County Wastewater's Project Manager at 913-715-8544 with any questions.

Project Description and Objectives

Sanitary sewer system performance within two watersheds, Mission Township Main (MTM1) - located in Prairie Village and Shawnee Mission Turkey Creek (SMTC) -  located in Shawnee, is impacted by the magnitude of wet weather flows (I/I) that enter the sanitary sewer system through cracked or broken pipes, root penetrations, illicit connections, and other deficiencies within the system. The wet weather flows are also the result of illicit connections. This pilot study is needed to fill a critical gap in the data that exists relative to the system improvements necessary to adequately manage I/I, and in so doing meet both customer service goals and respond to evolving regulatory requirements established by the Environmental Protection Agency (EPA). The project included the construction phase which involved repair of the sanitary sewer system to remove I/I.

Lessons learned from the study and construction phases of this project will be used to develop the process and procedures for future removal of public and private sector I/I sources throughout the entire MTM1 and SMTC watersheds.

Study Phase (2009)

The Pilot I/I Project was initiated in March 2009 as a result of ongoing efforts by Johnson County Wastewater to effectively manage wet weather flows in the Nelson service area and is part of the most recent permit renewal process for the Nelson Treatment Complex. The study phase was completed in April 2010. The study involved a series of inspections, including televising of sewer lines and house service laterals, visually inspecting homes and businesses (including internal basement plumbing), manhole inspections, smoke testing, and various other inspections. The project took place in three (3) selected areas suspected of having high I/I:

Turkey Creek
(Shawnee - Vicinity of Quivira Road from Johnson Drive to 50th Street)

  • 677 buildings
  • 50,000 feet of sanitary sewer pipe      
  • 203 manholes

Mission Main
(Prairie Village - Vicinity of Roe Avenue from 75th Street to 79th Street)

  • 288 buildings
  • 20,000 feet of sanitary sewer pipe
  • 111 manholes

(Lee Boulevard to State Line Road and 80th Street to 87th Street)

  • 327 buildings
  • 35,000 feet of sanitary sewer pipe
  • 170 manholes

Construction Phase (2011)

The construction activities on this project included rehabilitation and repair of existing sanitary sewer mains and private service lines, and disconnection of sources within buildings and on private property. Construction was completed in May 2013. The two links above to the project study maps show not only pilot I/I rehabilitation areas, but also where the strategies listed below were used:

  • Everything – rehabilitate all main sewers, manholes, service line connections, and service lines; and remove all identified building and inflow sources/defects
  • Private Only – rehabilitate all service line connections and service lines; and remove all identified building and inflow sources/defects
  • Public Only – rehabilitate all main sewers and manholes
  • Typical Comprehensive – rehabilitate main sewers and manholes that are contributing significant amounts of I/I; and remove all identified building and inflow sources/defects
  • Typical Comprehensive + LL – rehabilitate main sewers and manholes that are contributing significant amounts of I/I; remove all identified building and inflow sources/defects; and rehabilitate all service line connections and lower laterals (i.e., service line between main sewer connection and a point between three (3) and 10 feet from main sewer)
  • Control – no rehabilitation work will occur

This project included three (3) general types of construction:

  1. Rehabilitation of Johnson County Wastewater's or public main sewers and manholes
    • Construction of four (4) manholes
    • Rehabilitation of 123 manholes
    • Main sewer open cut excavation replacement (250 ft)
    • Main sewer trenchless (pipe bursting) replacement (274 ft)
    • Main sewer trenchless (CIPP lining) rehabilitation (28,585 ft)
  2. Rehabilitation of private service lines (the pipe that connects private buildings to the main sewer)
    • Cleanout Installations (203)
    • Service line open cut excavation replacement (11 properties)
    • Service line trenchless (pipe bursting) replacement (2 properties)
    • Service line trenchless (CIPP lining) rehabilitation (377 properties)
  3. Remove building and inflow sources/defects. For example, removal of sump pump discharge connections to the sanitary sewer. In some cases, this construction required access inside the home.