The City of Prospect Heights recently took over maintenance of a large portion of the sanitary sewer within the City formerly maintained by the Old Town Sanitary District. The service area encompasses approximately 75% of the City’s sanitary sewer. The only existing sanitary utility atlas for this area was a hand drawn map from 1980. Efforts had been made to convert the existing atlas into GIS features, but the positional accuracy was unreliable.
Before performing maintenance initiatives like smoke testing and televising, the City wanted to improve the positional accuracy of the data, as well as assign structure ID numbers to track maintenance efforts moving forward.
The unreliability of the existing data made locating the structures in the field difficult. A large portion of the sanitary sewer in this service area was installed in backyards rather than in the right-of-way, which also provided its own set of issues. Permission was required to enter private property, which added time to the data collection process. Since many of these structures were on private property, the landowners had installed landscaping or tried to disguise the structures, making many of them difficult to find.
After weeks of difficult data collection, GHA located roughly 775 sanitary manholes in the service area. Upon completion of the field work, GIS professionals updated the City’s atlas with the new structure locations and updated roughly 40 miles of sanitary sewer piping to match. After assigning new ID numbers to the structures, the City was ready to commence maintenance operations.