Wastewater collection systems can be simple or complex in their location, type, or connectivity and inspecting them as part of a good operation and maintenance (O&M) program often requires exploring innovative techniques to get the answers needed. Did you know, geographic information systems (GIS) can be used to improve traditional approaches to wastewater collection system O&M? Three techniques are shared below.
Night Flow Isolations via CCTV Inspections
The traditional approach for selecting pipes to perform closed-circuit television (CCTV) inspections when trying to identify defects that contribute to inflow and infiltration (I/I) to the sewer collection system has been to perform night flow isolations. This involves blocking flow to segments of the sewer and determining if any flow originates from the pipe itself. In drought conditions, this method is not effective because there is little or no groundwater to enter the pipes through existing defects.
When this situation occurred in the City of Greenfield, MA, Wright-Pierce used GIS to determine the most likely places for I/I. Utilizing the City’s pipe database and topographic data, pipes were selected for inspection based on age, pipe material, and proximity to drain lines, wetlands, and streams. These criteria were used to determine the most appropriate pipes for inspection and ultimately found just over 50% of those selected needed repair or immediate corrective action.
Mobile GIS Applications
Using mobile GIS applications, like Esri’s Collector and Survey123, on tablets can improve efficiency when conducting smoke testing and dye testing activities in the field. With customized, automated applications for these tasks, not only can field crews collect data more quickly, but the data is also available immediately to assist with coordination between crews, owner-operators, and managers for analysis.
GIS for Tracking OSHA Compliance
Another innovative application includes using GIS for tracking compliance with organizational safety policies and federal regulations such as those of the Occupational Safety and Health Administration (OSHA). By using a mobile GIS application, crews can complete and store required confined space entry forms online from the job site in a quick and accurate manner, with automated location information included. Staff and managers can easily see where and when confined space entry has occurred, track progress on a project, and monitor compliance. Individual forms can be reviewed online, viewed on a map, or printed for documentation in a hard copy if needed.
Wright-Pierce has an in-house infrastructure assessment group and GIS team that can work with you to implement these techniques to help improve your collection system O&M. When applied properly, these methods reduce time and effort, increase efficiency, and lower cost for municipalities. Contact us today to learn more.