The City of Champaign has an estimated 1.3 million feet of sanitary sewer lines to maintain. This work is performed by the Public Works Department, Sewer Section. The annual goal for maintenance via televising is 80,000 linear feet. This televising work is completed using specialized equipment – first the lines are flushed, then vacuumed free of debris. Next a robotic camera is lowered into the sewer line, which is recorded on a closed-circuit television. Files are reviewed routinely by the Sewer Section and the Environmental Engineering Section.
On June 25, while conducting routine televising in the Downtown area, the sewer crew noticed a pipe with a severe blockage near the intersection of Neil and Clark Streets. Upon further investigation it was found that a portion of the pipe had been previously replaced with an iron pipe, which had now separated. This separation caused backfill from a previous excavation to move into the sanitary sewer. Not only would the backfill moving into the sanitary sewer cause the potential for blockages in the sanitary sewer pipe, it also created a void in the nearby soil causing the potential for a sinkhole to form. To safely make this repair over a potential sinkhole, also required the temporary removal of the traffic signal pole and mast arm at the southwest corner of the intersection. A contractor was brought in to excavate the area, complete the repairs to the pipe, refill in the backfill, and complete the concrete repairs.
