City stakeholders in Springfield, Missouri develop and implement Early Action Plan to control wet weather-related sanitary sewer overflows. CH2M HILL’s Condition Assessment and Rehabilitation Services group helped conduct a pilot-scale study as part of the plan.

By: Dan Hegwald, Condition Assessment Services Operations Manager, CH2M HILL

Wastewater services are important to improving water quality, safeguarding public health and supporting development opportunities, especially in areas where water-related recreation and tourism account for a major portion of the state’s environmental and economic health. This is the case with Springfield, Missouri.

Over the last two decades, the City has made it a priority to upgrade its 1,200+ mile wastewater sewer collection and treatment systems. Following a consent judgment issued by the Missouri Department of Natural Resources to address wet weather-related sewer overflows, Springfield began focusing its efforts on sanitary sewer overflow (SSO) improvements for both public and private sectors in 2011. The resulting Early Action Program (EAP) and Overflow Control Plan (OCP) dedicated $50 million over seven years to provide adaptable and cost-effective long-range solutions to reduce stormwater induced overloads and wastewater discharges.

One part of the EAP included conducting a pilot-scale study in five basin areas, selected based on the severity of private defects identified during previous studies and leakiness of the basins, to identify and eliminate inflow-only sources from residential areas. CH2M HILL’s Condition Assessment and Rehabilitation Services (CARS) group was part of the project team that implemented the study.

Together, the project team and the City developed a multi-faceted Public Outreach Program under the Pilot-Scale Private Inflow and Infiltration (I/I) Abatement Program to involve and educate residents of the importance of this repair program. At no additional cost to property owners, the EAP’s goal was to fix a significant amount of deteriorated clay pipe sewer line and further address wet weather-related sewer overflows by working closely with private property owners to disconnect residential stormwater connections.

While most testing methods did not directly impact residents, success of the program depended on the coordination and participation of property owners in the pilot-scale area. CARS technicians required private access to identify which buildings had sump pumps discharging directly to the sanitary sewer system, as well as other types of connections (such as downspouts, driveway drains, area drains, cleanouts and stairwell drains, etc.) not easily verified using other testing methods. While completing their investigations, technicians heard directly from residents about complications they experienced during heavy rains, which enhanced the information obtained through traditional testing methods including: smoke testing, dye test and closed circuit television inspections.

To achieve optimal participation in the program, residents were encouraged to attend neighborhood association and public meetings; home builders, real estate associations and plumbing contractors were also targeted and encouraged to attend. A robust outreach and communications plan was activated to raise awareness and notify residents on the process for resolving issues and how to select qualified plumbers to correct defects found on their property.

Over the course of the study, CARS and the larger project team delivered a 92% inspection completion rate, successfully inspecting more than 1,500 homes and identifying 400 properties with inflow-only defects. The results of the pilot program will be used to evaluate the cost-effectiveness and efficiency of using alternative strategies to reduce private I/I flows and to support the City’s development of a sustainable City-wide Private I/I Abatement Program as part of its long-term OCP.

Dan Hegwald is a Principal Project Manager and Condition Assessment and Rehabilitation Services Operations Manager for CH2M HILL.  Mr. Hegwald has extensive experience in conducting sanitary sewer evaluation surveys (SSES), inflow and infiltration (I/I) investigations, wastewater collection system master planning, and in wastewater conveyance system issues associated with SSOs and CSOs.  His professional expertise also includes sewer system hydraulic modeling of more than 75 wastewater collection systems using several hydraulic modeling software packages. Currently, Mr. Hegwald is Project Manager for a multi-year Wastewater Overflow Control Program for the City of Springfield, Missouri.