Johnson County, KS
I/I Detention Study Overview

Wade and Associates, Inc. is assisting Johnson County Wastewater (JCW) in implementing an Inflow/Infiltration (I/I) Impact Study to identify and measure I/I the impact on the JCW sanitary sewer system.

Field investigations in the study area will include smoke testing of sanitary sewers in relation to Detention/Retention Ponds throughout the Johnson County Sanitary Sewer System.

Door hanger notification for smoke testing of sanitary sewer lines will be distributed 2-7 days before tests in your area begin. Field crews will carry identification and use JCW or Wade vehicles. We will make every effort to coordinate these activities with city officials, citizens, and business owners in the area to limit traffic disruption and to avoid interference with community-wide events. 

Our goal is to find and reduce defects in your wastewater collection system to eliminate future sanitary sewer overflows and backups, and to control wet-weather flows.  Inflow & Infiltration reduction also reduces costs of excessive relief sewer construction.  We would like to thank the citizens of Johnson County for their efforts in making this project a success!

Check our Work Schedule link for a map of our study area.  Visit our SSES links to learn more about Wade's other field investigations.

In general, an SSES may consist of all or some of the following parts:

Flow Monitoring: In order to determine the volume of water flowing through a sewer pipe, the flow must be monitored and measured. Once this is done, data analysis is completed to determine relationships between flows and rainfall data. The resulting data may also be used to build a computer model of hydraulic flows throughout the entire sewer system. This hydraulic model is highly useful in determining areas of stress, addressing capacity issues, and diagnosing problems in the sewer system.  A hydraulic model is also useful as a tool for future planning and development.

Manhole Inspections: Fifty percent or more of water entering into the sewer system, and overloading the sewer pipes, enters through manhole structures. During these inspections, our trained field inspectors survey all manhole structures and components for defects, as well as incoming and outgoing sewer lines.

Visual Pipe Inspections: Commonly called 'lamping,' this is the process of entering a manhole and using a light and mirror to visually examine all sewer pipes entering and exiting the manhole to identify early signs of pipe deterioration, root intrusion, deposition and other defects.

Smoke Tests: Smoke testing is used to augment the manhole and visual pipe inspections. Smoke testing (often referred to as a rainfall simulation test) is used to detect I/I sources in both the private and public sectors. Smoke testing is performed by placing a smoke generator into the intake chamber of a high-capacity blower placed over an isolated sewer pipe. Field crews monitoring the area document locations where smoke escapes the system at some defect or I/I source. Although not a defect, one common escape route for smoke is the vent pipe: this is the pipe emerging from the roof of a private dwelling that allows the escape of sewer gasses before they enter the residence.  The smoke that can be seen coming from vent pipes or rising from areas in the ground is: 

NON-TOXIC, HARMLESS, ODORLESS, AND CREATES NO FIRE HAZARD.

Building Surveys: Smoke testing alone cannot confirm every possible I/I defect on a property. For this reason building surveys are conducted to detect and/or confirm potential I/I sources. During a building survey, crews examine private property for evidence of defects in the sewer line connections, called 'service laterals.' Such defects can lead to unwanted and potentially dangerous influx of gasses into residences. Such surveys are conducted with minimal disturbance to building residents and owners; special provisions are made to assure homeowners and occupants of the legitimacy of the survey and to communicate the importance of the information needed.

TV Inspections: This process involves transporting a closed-circuit TV camera through a sewer pipe. Engineers and technicians view the resulting footage and glean valuable data on conditions of the sewer pipe.

Dyed-Water Testing: Sometimes a simple visual inspection of a suspect I/I source cannot confirm if the source is connected to the sewer system. In this case, crews will introduce dyed-water into the suspect source. If dyed water shows up in the sewer system, the leak will be confirmed. This makes identifying leaks and breaks in the pipe much easier to identify.