The maintenance of the city’s infrastructure is an important factor in the aforementioned priorities. Particularly, the inspection and repair of the sanitary sewer system have been a continuous effort. The system contains 122 miles of gravity mains, which were installed beginning in the 1920s. That means the system is close to 100 years old, which makes it vulnerable to infiltrations and breaks.
This year, the Public Works Department has decided to take the lead in the coordination of the Sanitary Sewer Evaluation Survey (SSES) Phase III, which previously was subcontracted to external companies. This will not only save the City a significant amount of resources, but will result in the update of information directly to the Geographic Information System (GIS) data, which is widely used by the department.
The project is coordinated by the Engineering and Operations Divisions. The City contracted an experienced company to do the closed-circuit television (CCTV) inspections. After the data is collected in the field, the City’s engineers use the inspection videos to create necessary revisions to the GIS and recommendations for spot repairs or sewer lining.
The GIS Division supports the project in different ways. First of all, nine maps were created for the sewer basins identified as having serious infiltration problems in the sanitary sewer collection system. Those maps are used by the EnviroWaste field crew to create the inspections from manhole to manhole. The results of those inspections are later reported to the City in a document along with a CD that contains the digital information.
The main role of the GIS Division has been to provide support to the city’s engineers during the revision and update process of the sanitary sewer utility system. That task is done in two parts. The first part is through the existing GIS-based asset management system, Cityworks. This application allows the engineers to do internal revisions of the work performed in the field and provide a final resolution.
After the inspection is completed, automated reports are generated based on the different recommended solutions of each sewer line. This allows the engineers to keep track of the work and decide what will be the next steps in the process. Also, the map displays the pipes in different colors, corresponding to the next action needed, which gives quick information about the status of the area.
The other part of the GIS update process is to ensure that all the digital data contained in the CDs is transferred to the GIS system. Each CD has an access database and the CCTV videos related to the inspections of the day. That data is saved in a centralized folder in the network. Because the inspections related to the gravity mains are identified by the upstream and downstream manholes, the update could not be done using the pipe identifier. The solution was to create a spatial query with the direction of the line, which allows us to identify the upstream and downstream manholes and the line between them. Other SQL queries were created to identify any errors, fix them, and update the GIS features. After the creation of all of these elements for the updates, the process has been very easy and efficient.
The main challenge of the project has been in those areas where GIS data is not correct. When that happens, the crew goes to the field and finds that the manholes are located in places different from what the GIS map shows. At that time, new manhole numbers are assigned using a reference manhole plus a letter, and the inspection is performed using those identifiers. The steps for that process include gathering the data by the City’s surveyors, updating the GIS using that information, and finally creating the inspections in Cityworks. When the digital information is received, the inspections are also updated using the new GIS manhole identifiers.
New projects are always a challenge and they leave us with experiences to make the next one better. This is the first time that the City of Miami Beach is coordinating the SSES inspections and repairs, and it has been a success. From before the inspections are started to after they are done and the GIS updates are made, using GIS data throughout the process has made better use of that data and put the City in charge of its information. The use of GIS, Cityworks, and SQL spatial queries has made this an easy process with very transparent and truthful results. For those reasons, Public Works is looking to continue doing SSES projects in the future.