1. Project Background & Challenge
Seoul, South Korea, a highly modernized metropolis, faces severe challenges with urban waterlogging. Its extensive underground spaces (subways, underground shopping centers), dense population, and high-value assets make the city extremely vulnerable to flood risks from heavy rainfall. Traditional contact-based water level and flow velocity monitoring equipment (e.g., pressure transducers, mechanical propeller meters) are highly susceptible to clogging from debris, sediment, and corrosion in sewer and stormwater pipes and drainage channels. This leads to data loss, accuracy degradation, and high maintenance costs.
The municipal authorities urgently needed a solution for real-time, accurate, and low-maintenance monitoring of hydrological data at key drainage points (e.g., culverts, weirs, rivers) to provide reliable input for urban flood models, enabling precise early warnings and scientific emergency response coordination.
2. The Solution: Integrated Radar Flow Sensor
The project selected the non-contact integrated radar flow sensor as the core monitoring device, deployed at critical weirs on urban rivers, main drainage culverts, and Combined Sewer Overflow (CSO) outlets.
- Technical Principle:
- Water Level Measurement: A radar water level gauge on the sensor emits microwave pulses towards the water surface and receives the echo. The water level height is calculated precisely based on the time difference.
- Flow Velocity Measurement: The sensor uses the Doppler radar principle, emitting microwaves at a specific frequency towards the water surface. The surface velocity of the flow is calculated by measuring the change in the frequency of the returned signal (Doppler shift).
- Flow Rate Calculation: Built-in algorithms use the real-time measured water level and surface velocity, combined with pre-input channel cross-section parameters (e.g., channel width, slope, Manning’s coefficient), to automatically calculate the real-time instantaneous flow rate and totalized flow volume.
3. Application Implementation
- Site Deployment: Sensors were installed under bridges or on dedicated poles, aimed vertically at the water surface without any physical contact, avoiding impact from floating debris and clogging.
- Data Acquisition & Transmission: The sensors operate 24/7, collecting water level, velocity, and flow data every minute. Data is transmitted in real-time to Seoul’s Smart Water Management cloud platform via 4G/5G networks.
- System Integration & Early Warning:
- The cloud platform integrates data from all monitoring points and links it with rainfall forecast data from the meteorological agency’s radar.
- When the flow rate or water level at any monitoring point rises rapidly and exceeds pre-set thresholds, the system automatically triggers a waterlogging alert.
- Alert information is displayed in real-time on a “digital twin” map at the city’s emergency command center, pinpointing high-risk areas.
- Coordinated Response: Based on the alerts, the command center can proactively execute responses:
- Issue Public Warnings: Send避险 (bì xiǎn -避险) notifications to residents in affected areas via mobile apps and social media.
- Activate Drainage Facilities: Remotely activate or increase the power of downstream pumping stations to pre-emptively create capacity in the drainage network.
- Traffic Management: Instruct traffic authorities to implement temporary closures for underpasses and low-lying roads.
4. Embodied Technical Advantages
- Non-Contact Measurement, Maintenance-Free: Completely solves the pain points of contact sensors being prone to clogging and damage, significantly reducing operational costs and data loss risks. Ideal for urban wastewater and stormwater with high debris content.
- High Accuracy & Reliability: Radar measurement is unaffected by water temperature, quality, or sediment content, providing stable and reliable data even during peak storm flows.
- All-Weather Operation: Unaffected by light or weather conditions (e.g., heavy rain, darkness), capable of capturing complete hydrological data throughout a storm event.
- Three-in-One Integration, Multi-Purpose: A single device replaces traditional separate water level gauges, flow velocity meters, and flow meters, simplifying system architecture and reducing procurement and installation costs.
5. Project Outcomes
The implementation of this system transformed Seoul’s flood management from a “passive response” model to “active prediction and precise prevention.”
- Improved Warning Timeliness: Provided a critical 30-minute to 1-hour lead time for emergency response.
- Reduced Economic Losses: Effective coordination and warnings significantly minimized major economic losses from flooded underground spaces and traffic disruptions.
- Optimized Infrastructure Investment: The accumulation of long-term, accurate flow data provided a scientific basis for upgrading, renovating, and planning the urban drainage network, making investment decisions more efficient and justified.
- Enhanced Public Sense of Security: Transparent warning information increased public trust in the government’s ability to handle extreme weather events.
- Complete set of servers and software wireless module, supports RS485 GPRS /4g/WIFI/LORA/LORAWAN
For more radar flow sensor information,
please contact Honde Technology Co., LTD.
Email: info@hondetech.com
Company website: www.hondetechco.com
Tel: +86-15210548582
Post time: Sep-11-2025