The 92,000 water and sewer customers in Greensboro, N.C., are receiving more efficient and timely service thanks to a digital mapping project. In September 2004, the city’s water resources department (WRD) converted its paper-based water and sewer mapping system to a GIS-based digital process.
The digital system will enable field personnel to respond more quickly to service calls, accurately inventory approximately 80,000 water and sewer features and eventually eliminate 6,000 paper maps.
The team of McKim & Creed, an engineering and surveying firm headquartered in Wilmington, N.C., and Geographic Technologies Group (GTG), GIS specialists based in Goldsboro, N.C., worked with the WRD to plan and design the $1.3 million digital system, which incorporates state-of-the-art software and hardware.
A phased approach
Converting from paper to a fully digital geodatabase involved design, data collection, features connectivity, attribution, data migration and system integration. The team conducted four phases: 1) needs assessment, 2) prototype system development, 3) full-scale system implementation and 4) hydraulic model development.
One of the most unique aspects of the project occurred during phase 2, when the team applied its proposed digital mapping process to a nine-block prototype area. This introduced future users to the system and allowed them to test and provide feedback prior to full implementation.
The WRD asked the team to complete the full-scale implementation by Sept. 30, 2004.
Collecting the data
To expedite the data collection process, the team divided the city into five sections, with a technical team assigned to each. Surveyors collected data on approximately 32,000 water features, which they maintained in personal geodatabases.
The team also used nearly 27,000 scanned maps and drawings, including hand-drawn block sheets, water strip maps and individual record drawings. To track these documents, McKim & Creed developed a customized database and index to identify the type of infrastructure on each drawing.
After the scanned paper maps were geo-referenced, GIS technicians established pipeline connectivity and feature attribution using county parcels, road centerline and aerial photography from the city’s management and information systems (MIS) department as background data. The personal geodatabases established by the technical teams were merged into the enterprise geodatabase, and features along the boundaries were connected, attributed and rechecked for quality control. Once the entire distribution network was connected, the team created a geometric network with nodes and connections suitable for subsequent hydraulic modeling.
To save money, the WRD worked with the city’s MIS department to direct-purchased all hardware and software. Hardware included a phased purchasing of ruggedized mobile tablet PCs to be used by field crews. Proprietary software included GTG’s customized GISmo Web intranet data browser for office applications, GTG’s customized field GIS data browser and McKim & Creed’s steady-state hydraulic modeling application, FORCEMAIN.
The digital mapping system was completed and fully implemented on Sept. 30, 2004.
System benefits
The new digital-mapping system enables the WRD to accurately and efficiently maintain water and sewer infrastructure’s spatial and tabular data. It also provides a means for tracking locations and conditions of all water and sewer features within its system. Digital mapping provides a strong link between the physical data, analytical results and the technical basis for management decisions.
In a phased approach, the WRD is installing the tablet computers in every service vehicle. The computers enable field crews to instantly locate every feature in the city’s water and sewer system, which in turn allows them to provide more timely service to customers. The WRD’s mapping section personnel will have field computers complete with GPS chips, allowing them to pinpoint their exact location in relation to each feature. Additional benefits include: eventually eliminating approximately 6,000 paper maps; reducing dependence on 15,000 digital water and sewer record drawings; facilitating GASB 34 and CMOM compliance; conducting technical, administrative and financial queries; performing hydraulic modeling; and rapidly reflecting infrastructure revisions.
Greensboro is one of the largest cities in the U.S. to digitally convert its entire water and sewer system.
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