Inflow & Infiltration Pilot Study Project
Turkey Creek and Mission Main Watersheds
Johnson County, KS
Sewer system improvements within the Turkey Creek and Mission Main Watersheds are driven by the magnitude of wet weather flows. The wet weather flows are due to system defects and illicit connections that result in high rates of rainwater and groundwater entering the sewer system. The pilot study will fill a critical data gap that exists relative to the cost of system improvements necessary to meet both customer service goals and regulatory requirements.
Phase I – The purpose of the Phase 1 2009 Pilot Study was to identify, to the extent practical:
- All public and private sources of infiltration/inflow (I/I).
- To estimate the flow rate that each I/I source is contributing.
- To estimate the cost to remove each I/I source.
- To estimate the cost-effective sources that should be removed, and
- To develop the process and procedures for removal of public and private sector I/I sources.
TREKK completed 1,300 internal/external building and service lateral inspections, 107,000 lf of smoke testing and CCTV inspections, 494 manhole inspections, and 208 dyed water tests. Based on Studies conducted by WERF and confirmed through projects completed by TREKK, the results of the investigations correlate with the 60% to 80% of the identified I/I originating from the private sector.
Phase II – The purpose of the Phase II 2010 Pilot Study is to remove both private and public I/I within the pilot areas and evaluate the removal effectiveness. Lessons learned from the design of this project will be used to develop the process and procedures for future removal of private sector I/I sources throughout the entire watersheds. After construction is completed, JCW will be able to evaluate the effectiveness and costs of numerous I/I removal strategies and then determine how best to achieve I/I removal in the remaining watershed areas.
Nature of Firm’s Responsibility in Project
TREKK is responsible for:
- Providing assistance with public involvement as required
- Reviewing current private sector I/I policies and procedures and providing recommendations
- Assisting with private property contractor procurement
- Assisting with private sector building and inflow source/defect removal design
- Completing additional field activities to further identify I/I sources and evaluating the success of the rehabilitation program.