From Technical Challenges to Successful Implementation: An Account of the Urban Pipeline Network Project

Introduction: Drainage Network Monitoring Becomes the "Front-End Sensor"

As a concealed underground infrastructure, the operational status of the drainage network has long been difficult to monitor in real time. A rapid rise in water level, abnormal flow changes, or localized backwater in pipe sections often indicate the formation of surface waterlogging risks. Therefore, multi-source monitoring data such as water level, flow rate, and rainfall are becoming the fundamental support for urban flood prevention efforts.

This article takes the drainage network monitoring and flood prevention early warning project in the central urban area of a city in East China as an example. The project covers approximately 48.6 square kilometers of the old urban area, serving a population of about 680,000. Through continuous monitoring of key indicators such as water level and flow rate, the project formed a relatively stable early warning and response closed-loop during the 2024 flood season.

Project Background: The Drainage System in the Old Urban Area Faces Multiple Pressures

The central urban area features low-lying terrain and a dense river network, significantly affected by the backwater effect of the outer river water level during the flood season. The local multi-year average annual rainfall is about 1,320 mm, with short-duration heavy rainfall occurring frequently. Under heavy rainfall conditions, mismatches often occur among the drainage capacity of the stormwater network, the pumping capacity of pump stations, and the receiving capacity of the rivers.

Previously, drainage management relied mainly on manual patrols and hotline feedback. Due to the lack of real-time data on network water levels and flow rates, dispatchers found it difficult to determine whether waterlogging was caused by excessive rainfall intensity, network blockage, external water backwater, or delayed pump station operation. Based on this, the local drainage authority launched the "Central Urban Area Drainage Network Operation Monitoring and Flood Prevention Early Warning Project," hoping to shift the flood prevention focus forward through online monitoring and model analysis.

Technical Challenges: The Triple Challenge

Implementing this system faced three distinct hurdles:

Solution: Integrated Monitoring System Architecture

The project is built on a four-tier architecture of "perception, transmission, platform, and application."

Perception Layer Deployment

• Water Level: 186 points (152 radar transmitters, 34 pressure transmitters). Range: 0-6m, Accuracy: ±3mm.
• Flow Rate: 68 points (Doppler flow meters). Covers DN300-DN2000 pipes. Velocity range: 0.03-5 m/s.
• Rainfall & Video: 46 automatic rain gauges, electronic staff gauges at 12 underpasses, and smart manhole covers.

Platform & Algorithm Logic

The platform integrates GIS-based network topology with a simplified hydraulic model. It calculates three critical indicators:

1. Pipe Fullness Degree: Determines proximity to full-pipe flow.
2. Key Section Flow Capacity: Identifies bottleneck pipe sections.
3. Waterlogging Risk Index: Predicts timing and depth of potential flooding.

Hierarchical Warning Rules:
• Operation Prompt: Manhole water level reaches 80% of pipe crown.
• Level 2 Warning: Water level 0.3m below ground + rising >0.05m/15min.
• Level 3 Alarm: Water level near ground + Rainfall >30mm/h + Underpass gauge >0.10m.

Implementation Process: From Survey to Calibration

Launched in March 2023, the project followed a rigorous implementation path:

In May 2024, a joint drill involving drainage, emergency management, urban management, and traffic police departments successfully simulated underpass waterlogging and pump station failure scenarios under intense rainfall (70 mm/h).

Operational Results: Earlier Warnings, Faster Response

During the 2024 flood season, the system handled 17 heavy rainfall events effectively.

Case Study: June 24 Heavy Rainfall Event

On June 24, with maximum hourly intensity reaching 86.5 mm, the system detected a rapid water level rise at a key underpass upstream pipe (0.62m to 0.94m) at 16:12. A Level 2 warning was issued at 16:14, upgrading to Level 3 at 16:21.

The drainage dispatch center immediately activated 3 pump station units and dispatched 2 mobile pump trucks. By 16:48, waterlogging reached 0.27 meters but did not exceed the 0.30-meter control value. Traffic was never interrupted, demonstrating the effectiveness of the "predict-and-preempt" strategy.

Outlook: Moving from Point Monitoring to Systematic Management

This case demonstrates that drainage network monitoring requires completing point layout, data governance, model calibration, and dispatch process reengineering around business objectives. Only when water level changes, flow rate anomalies, rainfall intensity, pump station operations, and on-site response form a closed loop can monitoring data truly be transformed into urban safe operation capabilities.

Looking ahead, local authorities plan to expand the monitoring scope from 2025 to 2027, adding ~120 water level points and ~30 flow rate points. The system will incorporate sponge city facilities, detention basins, and newly built pump stations. Furthermore, integration with emergency management, traffic management, and meteorological radar data will promote the transformation of drainage and flood prevention from "post-event response" to full-process management of "pre-event prediction, in-event dispatch, and post-event evaluation."