Drainage pipes are like the "capillaries" of a city, playing a vital role in urban drainage and flood prevention. To prepare for the flood season, since April, Jiangsu, Beijing and other places have carried out pipe-cleaning campaigns to "dredge the meridians" of drainage pipes, ensure their safe and smooth operation, and build a solid barrier for flood control.

Yangzhou City, Jiangsu Province, organized municipal workers to dredge drainage pipes according to plan, building on earlier centralized cleaning. During the dredging, municipal workers cleared silt, leaves, garbage and other blockages from rainwater grates, and focused inspections on rainwater wells and grates in key areas such as sections with dense restaurants, areas around construction sites, and low-lying flood-prone areas. Dredging trucks and cleaning trucks worked in coordination. For pipe sections with accumulated silt, municipal workers first blocked one end of the pipe with an inflatable plug, then pumped out the water in the pipe, used the dredging truck to drive the water-jet nozzle to the next well and pull it back, flushing silt, leaves, garbage and other debris in the pipe to the well mouth, and then dredged and cleaned the entire pipe, leaving no dead corners and ensuring thorough cleaning so that the pipe drains smoothly. So far, 80% of the drainage pipe cleaning work has been completed. The relevant person in charge said that tracking and supervision of pipe dredging will be strengthened, and silt removal will continue at waterlogging-prone points and sections to improve the drainage and flood prevention capacity of the underground pipe network in the jurisdiction.

In the pipe-cleaning campaign carried out in Yanqing District, Beijing, to help drainage pipes and supporting facilities operate normally and keep the area around rainwater inlets clean and pollution-free, municipal workers opened roadside rainwater grates and, using shovels, long-handled tongs and other tools, cleared branches, leaves, various types of garbage and other debris accumulated in the rainwater inlets one by one. They then used high-pressure washing trucks to carry out "water-jet" operations on the drainage pipes. Municipal workers fed the flushing hose into the pipe and used the reaction force generated by the high-pressure water to carry sand and silt in the pipe to the next work well mouth, where manual and mechanical work were combined for centralized cleaning.

Because time is short and the task is heavy, Yanqing District adopted a mode of two work groups operating simultaneously to advance the pipe-cleaning campaign and make full preparations for drainage and flood prevention during the flood season. According to the relevant person in charge, after autumn and winter, large amounts of fallen leaves, mud and dust settle in rainwater wells and drainage pipes, which can easily cause blockages; these are the main targets of the pipe-cleaning campaign. In addition, cigarette butts, plastic bags and other garbage are found in rainwater inlets, and municipal workers sort the garbage cleared out and send it to professional waste disposal stations for treatment.

On a road section near Enan High School in Xianning City, Hubei Province, municipal workers opened rainwater and sewage wells, checked cable distribution and pipe blockage conditions, removed old cables and laid new cables. This was a scene from the weak-current cable rectification of the rainwater and sewage pipe network on Xianning Avenue, carried out by the Xianning City Urban Management and Law Enforcement Committee together with telecommunications operators. Why carry out the rectification? The relevant person in charge said that in urban areas there are many cases of weak-current cables occupying drainage pipes; in some pipes, weak-current lines have been drilled through, and surplus and waste lines have accumulated, causing blockages and causing the pipes to lose their normal drainage function.

To this end, the Xianning City Urban Management and Law Enforcement Committee took the lead in establishing a special work team to comprehensively rectify the problem of pipe siltation and blockage. The rectification focused on waterlogging-prone points in the main urban area identified in earlier surveys. The main tasks were to clear abandoned lines and tidy accumulated surplus lines, relocating them where possible and sorting them by category where relocation was not possible. So far, the rectification of pipe network cables at 19 waterlogging-prone points and 71 problem wells in the main urban area has been completed, and 23,300 meters of abandoned cables have been removed.

Only by "prescribing the right medicine" can the "disease be cured." Branches, leaves, deposited mud and the like seeping into rainwater inlets, rainwater wells, branch pipes and other drainage facilities are also one of the causes of blockages in some drainage pipes. The Xianning City Urban Management and Law Enforcement Committee organized personnel to clean and dredge rainwater inlets, rainwater wells and branch pipes along 65 main and secondary roads and back streets and alleys in the urban area. So far, 8,643 rainwater grates and 3,842 rainwater wells have been dredged, and silt removal has been completed for drainage pipes at 29 waterlogging-prone points.

Some cities have applied new technologies and new equipment to quickly and accurately complete drainage pipe inspection tasks, fully grasp the siltation and blockage conditions inside pipes, and better carry out pipe cleaning and dredging work.

At a drainage pipe cleaning and dredging site on Erhuan Road, Lihu Street, Zengcheng District, Guangzhou City, Guangdong Province, workers were using a QV (wireless pipe) periscope to inspect drainage pipes. According to reports, the QV periscope has the advantages of being easy to carry, simple to operate and fast in imaging, and can clearly observe whether a pipe has serious blockages, misalignment, leakage and other problems. Through the real-time inspection images, the workers saw that a considerable amount of accumulated garbage, gravel and the like was present in the pipe; if not cleaned in time, this could lead to pipe blockage and poor drainage. After fully grasping the conditions inside the pipe, the workers quickly formulated a plan and used a combined jetting and suction truck to carry out pipe cleaning and dredging.

One worker said that the combined jetting and suction truck is fast, has a large capacity and is convenient to transport, and has the functions of high-pressure water flushing to clear blockages and high-suction garbage removal; it can be used for pipe dredging before, during and after rain, and during continuous rainfall it can operate continuously to ensure smooth pipe drainage. In less than half an hour, under the powerful operation of the combined jetting and suction truck, the pipe was cleaned and dredged. Through the images from the QV periscope inspection, it could be seen that the silt and garbage in the pipe had been washed away.

Jieshou City, Anhui Province, used robot technology to conduct detailed and comprehensive inspections of urban drainage pipes, identifying problems such as blockages, cracks, deformation and undulation in the pipes, and providing designers with accurate data to treat the "diseases" of urban drainage pipes. The relevant person in charge said that to ensure completion of the inspection task before the flood season, Jieshou City invested more than 20 sets of inspection equipment and vehicles and divided nearly 50 technical personnel into 9 teams to conduct comprehensive inspection of 232 kilometers of drainage pipes in the urban area, with inspection expected to be completed in the middle of this month.

Technical personnel first conducted on-site surveys and collected data, and prepared inspection plans based on the survey results. After the preliminary preparations were completed, technical personnel operated pipe robots to carefully inspect the pipes and collect image data, analyzed the data on site, issued inspection reports, and after the on-site person in charge accepted and verified the accuracy of the data, summarized the inspection results and submitted the assessment report to the design unit, providing first-hand on-site data for dredging drainage pipes.

During construction, the project unit adopted strict safety measures and, according to the project characteristics, formulated safety rules and regulations and emergency response plans, listing in detail the identification of safety hazards and preventive measures. Before work, safety technical briefings were given to all personnel. Each team was equipped with a full-time safety officer to supervise the entire construction process, and construction personnel were required to work strictly in accordance with the safe construction plan. At the same time, relevant departments also arranged staff to inspect safe construction conditions every day and promptly require the project unit to rectify any problems found, so as to avoid safety accidents.