GIS-Mapping Sewer Cleaning Areas

Many different towns in Kentucky are experiencing a rise in the number of sanitary sewer overflows and stoppages. The reason for the problem is evident––most towns have thousands of manholes and hundreds of miles of sanitary sewer main lines, but only a very small percentage of the infrastructure was constructed in the last twenty years. Many of these towns’ populations have doubled and even tripled during this time, putting more strain on the aging sanitary sewer system.

Recently, a small municipality in North Carolina worked in conjunction with their state’s division of water quality to locate the town’s distressed spots in order to more strategically and effectively clean and maintain their system.  The local engineering division assisted the municipality by pinpointing these locations on a map and assigned dates for when the sewer feature (manholes, sewer mains, etc.) were last cleaned. They were able to review this data by going through the monthly reports from August 2009 to January 2011, showing where and when sewer cleaning had occurred. This data was transferred into a spreadsheet that contained the cleaning data for that month, as well as a unique identifier, Manhole ID (MHID), to capture the location. They then began joining the data to the town’s ArcGIS SDE dataset and were able to interpret which area of the system could be the problem area with the SSOs.

By using ArcGIS, it was easy to display all of the cleaning data for this period of time. The ability to map where the sewer cleaning occurred and how often it occurred yielded some interesting results. There were over a dozen separated areas where the sewer mains had been cleaned 7-12 times in an 18-month span. This information showed that there needed to better communication between the municipality and the local fats, oils and grease (FOG) department because of the amount of restaurants in the specific area. They were able to conclude that some of these restaurants had issues with their grease traps and interceptors and needed to be fixed properly to prevent further issues.

Without properly mapping these problematic areas, the municipality and FOG Department may have never concluded how to correct the problems they were having.  As of today, the town continues to map the sewer cleaning using the ArcGIS app, and workers can now use iPads to log cleaning data directly into the system from the field. The sewer cleaning crew can instantly view where the cleaning truck has been in the past two years and be strategic in cleaning by maximizing the route of the cleaning crew and migrating to areas that may need attention.

For further information about the capabilities of ArcGIS, you can visit the ESRI website at

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