The hydrological conditions of natural rivers are complex, with problems such as uneven flow velocity distribution, variable cross-sectional morphology, sediment deposition, and interference from floating objects. Traditional single-point radar flow measurement is prone to errors in flow calculation due to monitoring blind spots or insufficient representativeness of flow velocity. The array radar wave flow measurement system, through the coordinated deployment of multiple radar units, achieves full-area flow velocity coverage and precise sampling of river sections. Combined with the core technical products of Wuhan Shuicejia Technology Co., LTD., it can effectively solve the flow monitoring problems in complex scenarios of natural rivers, providing high-precision data support for flood control and disaster reduction, water resource dispatching, and ecological protection.

I. Background of the Plan and Construction Goals
1.1 Background of the Scheme
At present, the flow monitoring of natural rivers is confronted with three core pain points: First, the flow velocity distribution in complex sections (such as curves, shallows, and branch sections) is uneven, and single-point monitoring is difficult to reflect the overall flow velocity field of the section, resulting in a flow calculation error of over 10%. Second, sections with high flow rates and high sediment content are prone to equipment wear or signal interference, and the maintenance cost of traditional contact equipment is high. Thirdly, it is difficult to conduct manual inspections under extreme weather conditions such as heavy rain and floods, and the continuity of data is hard to guarantee. The array radar wave flow measurement system, through the collaborative monitoring of multiple radar arrays, can achieve full coverage of the flow velocity at the cross-section. Combined with non-contact measurement technology, it is suitable for the complex environment of natural rivers and has become a key technical solution for improving the accuracy and stability of flow monitoring.
1.2 Construction Goals
All-domain precise monitoring: Through the deployment of array radar, the flow velocity at the monitoring sections of natural rivers is fully covered, with a flow velocity measurement error of no more than ±2% and a flow calculation error of no more than ±4%, meeting the first-level accuracy requirements of the "Hydrological Monitoring Data Compilation Specifications".
Dynamic adaptability: The system can adaptively adapt to changes in river cross-section (such as depth and width variations caused by erosion and siltation), support real-time adjustment of radar sampling strategies, and be compatible with a wide flow velocity range of 0-20m/s.
Real-time stable operation: The data sampling interval can be configured (5-60 minutes per time), the transmission success rate is ≥99.5%, and the end-to-end delay is ≤30 seconds. The equipment is adaptable to a temperature range of -30 ℃ to 70℃, has an IP67 protection rating, and its annual mean time between failures (MTBF) is no less than 10,000 hours.
Intelligent analysis and early warning: It integrates cross-sectional flow velocity field analysis and flow trend prediction functions. When the flow exceeds the threshold (such as warning flow and flood flow), it triggers multi-level early warnings and supports multi-channel information push.
Low operation and maintenance costs: By adopting non-contact installation and remote operation and maintenance technologies, the frequency of on-site maintenance is reduced, and the operation and maintenance costs are decreased by more than 40% compared with traditional flow measurement methods.

Ii. Overall System Architecture

The system adopts a three-layer architecture of "array perception layer - intelligent transmission layer - application layer", integrating technologies such as multi-radar collaborative monitoring, flow velocity field inversion, and terminal computing to achieve full-domain, precise and real-time monitoring of natural river flow.

2.1 Array Perception Layer: Core for multi-radar collaborative monitoring

The array perception layer is deployed at the monitoring section of the natural river course. By arranging multiple radar units according to specific rules, it achieves full coverage of the flow velocity at the section. The core equipment selected is the array radar current meter, flow meter and supporting equipment from Wuhan Shuicejia Technology Co., LTD.

Radar unit selection: Wuhan Shuichejia high-frequency radar flowmeter (24GHz) is adopted. Each radar has a monitoring Angle of 30°-60° (adjustable), a flow velocity measurement range of 0-20m/s, a resolution of 0.001m/s, and a distance measurement accuracy of ±3mm. The number of radars should be determined based on the width of the river: 2 to 3 for narrow rivers (< 20m), 4 to 6 for medium-wide rivers (20 to 50m), and 8 to 12 for wide rivers (> 50m). Ensure that the overlap rate of adjacent radar monitoring areas is no less than 10% and there are no blind spots in monitoring. The configuration can be adjusted according to the actual project construction situation.

Deployment method: The radar unit is installed on the outside of the guardrail of the cross-river bridge or on the special support for the steel wire rope cableway. The height of the support is 1.5 to 3 meters above the highest water level. The Angle between the radar beam and the water flow direction is 30° to 45° (to optimize the signal reflection efficiency). For river sections without Bridges, a combination of shore columns and transverse steel cables is adopted for installation to ensure the stable fixation of the radar unit.

Auxiliary perception equipment: Equipped with Wuhan Shuichejia radar water level gauge (measurement range 0-50m), it can obtain real-time water level data at the cross-section. Install meteorological sensors (rainfall, wind speed and direction) to assist in analyzing the causes of flow rate changes.

All radar units are equipped with synchronous sampling function, with a sampling frequency of ≤1Hz, ensuring the consistency of flow velocity field data.

2.2 Intelligent Transport Layer: Stable and efficient data link

In view of the wide distribution of monitoring points in natural rivers and the weak signal in some areas, a hybrid transmission mode of "wireless as the main and wired backup" is adopted to ensure real-time data upload.

Main transmission link: 4G/ Beidou data transmission is adopted to ensure transmission stability. Data transmission adopts the MQTT protocol and combines the national encryption algorithm SM4 to prevent data leakage or tampering.

Backup transmission link: LoRa self-organizing network relays (transmission distance 1-5km, strong anti-interference ability) are deployed in remote river sections or signal blind areas. In extremely no-signal areas, Wuhan Shuichejia Beidou satellite transmission modules (supporting short message and data transparent transmission) are provided to ensure uninterrupted data.

2.3 Edge Computing Layer: Flow Velocity field Inversion and flow rate calculation

The edge computing layer is deployed at the on-site telemetry terminal, undertaking core tasks such as multi-radar data fusion, flow velocity field inversion, irregular section model algorithm, and flow calculation, thereby reducing the pressure on cloud data transmission.

Flow calculation: Based on the flow velocity field data and real-time water level data, the cross-sectional calculation units are automatically divided, and the total flow is calculated by accumulating the "unit flow velocity × unit area". Support the automatic selection of the appropriate cross-sectional area calculation model (such as trapezoidal formula, Simpson's integral method) based on the cross-sectional type (rectangular, trapezoidal, irregular shape) to ensure the accuracy of flow calculation.

Edge early warning: The edge terminal is preset with multiple levels of traffic early warning thresholds. When the real-time traffic exceeds the threshold, a local audible and visual alarm is triggered (on-site alarm lights can be optionally equipped), and the early warning information is simultaneously pushed to the cloud platform, achieving dual early warning of "local + remote".

2.4 Application Layer: Multi-scenario management and analysis functions

The application layer is deployed in the cloud or local hydrological data centers, providing diverse functional modules for hydrological management departments, emergency command personnel, and operation and maintenance personnel. It supports access from PC (Web platform) and mobile (APP/mini-program) terminals.

Real-time monitoring module: It displays the location of the monitoring section and the deployment status of the radar array through GIS maps, visually presenting real-time water level and flow data. Dynamically display the changing trend of flow velocity distribution; View the real-time flow velocity and historical change curve at this point.

Data analysis module: Automatically generate traffic statistics reports; Support the analysis of flow velocity field characteristics, such as the position of the maximum flow velocity at the cross-section and the average flow velocity distribution.

Early Warning management module: Supports custom traffic early warning thresholds (such as daily alert traffic, flood traffic, and dry water traffic). When the traffic exceeds the threshold, early warning information will be pushed through platform pop-up Windows, APP push notifications, text messages, emergency broadcasts, etc. Record the entire process of early warning and handling (receiving time, handling personnel, measures, feedback results) to form a closed-loop management. Support the linkage with surrounding water conservancy projects (such as gates and pumping stations), and automatically push dispatching suggestions.

Data sharing module: It provides communication protocols and supports integration with third-party systems such as basin hydrological monitoring systems, flood control command systems, and water resources management platforms. Supports data export function to meet the requirements of hydrological data compilation and report submission.

 

Iii. Core Technologies and Scenario Adaptation

3.1 Core technological advantages

Multi-radar collaborative monitoring technology: Through array layout and spatio-temporal synchronous calibration, it achieves full coverage of cross-sectional flow velocity and solves the problem of blind spots in single-point monitoring. The "signal strength weighting algorithm" is adopted to enhance the inversion accuracy of complex flow velocity fields (such as secondary flow in curves).

Dynamic section adaptation technology: By integrating real-time data from radar water level gauges with historical section shape data, the section area calculation model is automatically updated. The irregular section algorithm ensures good accuracy in flow calculation.

Anti-interference technology: The radar unit adopts the "narrow beam + adaptive gain control" technology to reduce the interference of water surface waves and floating objects on the signal.

3.2 Adaptation to Different Natural River Course scenarios

Mountainous river channels (high flow rate, multiple reefs) : Select the Wuhan Shuicejia high anti-interference radar flowmeter (with enhanced signal filtering function), and increase the array layout spacing to 5-8m, focusing on covering the areas with disorganized flow rate around the reefs.

Plain river channels (wide cross-section, gentle flow rate) : Adopt a "sparse array" combination, with radar deployment intervals of 10-15 meters, reducing the number of devices. Through "flow velocity field uniformity analysis", the main flow area and reflux area of the cross-section are automatically identified, the weight of flow calculation is optimized, and it is adapted to the gentle water flow scenario with a flow velocity of ≤0.5m/s.

Branch channels (multi-flow branches) : Monitoring sub-sections are divided according to the number of branches. Each sub-section is independently equipped with a radar array. The terminal computing layer calculates the flow of each sub-section separately and then accumulates the total flow.

IV. Implementation Process and Schedule Plan

4.1 Implementation Process

On-site investigation and scheme design

Conduct a detailed investigation of the monitoring section of the natural river course, measure the section morphology (width, depth, slope), flow characteristics (flow velocity range, mainstream position), and surrounding environment (topography, communication signal strength, installation conditions);

Based on the exploration data, determine the radar array layout plan (quantity, spacing, Angle), installation method (bridge/support/steel cable), and transmission link selection.

Prepare a detailed implementation plan, including equipment list, installation drawings, technical parameters and commissioning plan, and have it reviewed and confirmed by the hydrological management department.

Equipment procurement and on-site inspection

According to the plan, purchase core equipment such as Wuhan Shuichejia array radar flowmeter, radar water level gauge, edge computing terminal, and transmission equipment, as well as auxiliary materials such as brackets, waterproof boxes, and cables.

After the equipment arrives at the site, it undergoes unpacking inspection to verify the model, parameters, and certificate of conformity. The radar signal strength, flow velocity measurement accuracy, and edge computing function are tested to ensure compliance with the design requirements. Pre-calibrate the radar unit to ensure the consistency of parameters across multiple devices.

Array Installation and debugging

Foundation construction: Pour the concrete foundation of the support (strength C30) or install the steel cable fixing device to ensure that the load-bearing capacity is ≥50kg (the weight of a single radar unit is ≤10kg).

Equipment installation: Install the radar unit, water level gauge and video camera at the designed position, adjust the radar Angle and height to ensure that the monitoring range covers the target area. Install edge computing terminals (with protection grade IP65) and transmission equipment, and complete the wiring of the equipment (power lines and signal lines are separately laid out with clear markings).

System debugging: Perform spatio-temporal synchronization calibration for multiple radars (timestamp error ≤1ms), and test the stability of data acquisition for each radar unit. By comparing and calibrating the flow velocity field with the flow data through manual flow measurement (such as an ADCP flow meter), adjust the parameters of the edge computing algorithm to ensure that the flow error is ≤±4%. The test transmission link shows that the success rate of continuous 24-hour data transmission is ≥99.5%.

Platform Deployment and integration

Deploy the cloud application platform, configure the database (time series database + relational database), flow velocity field visualization module, and early warning algorithm;

Realize the data connection between edge computing terminals and cloud platforms, and debug real-time monitoring, data analysis, and early warning push functions.

Connect with third-party systems (such as basin hydrological systems), open API interfaces, and complete data sharing tests.

Trial operation and acceptance

The system has been in trial operation for 8 weeks, monitoring the stability of the equipment, data accuracy and early warning response speed under different hydrological conditions (such as normal water period, high water period and low water period).

Organize hydrological experts to conduct acceptance, including on-site tests (accuracy of flow velocity field inversion, accuracy of flow calculation), platform function verification, and anti-interference capability tests; After the acceptance is qualified, sign the acceptance report and deliver the operation manual, maintenance manual, calibration records and other technical materials.

V. After-sales Operation and Maintenance and Quality Assurance

5.1 Operation and Maintenance Service System

Service team configuration: Configure a hydrological technology director + regional operation and maintenance engineers; Establish a 7× 24-hour service hotline and online support platform, with a response time of no more than 30 minutes.

Hierarchical operation and maintenance strategy

Remote operation and maintenance: Real-time monitoring of equipment status through the cloud platform, remote diagnosis of faults (such as weak radar signals, abnormal algorithm parameters), and over 80% of faults can be resolved remotely.

On-site operation and maintenance: Conduct one on-site inspection every quarter, clean the radar lens, check the stability of the bracket, and calibrate the radar accuracy. Comprehensive maintenance should be carried out before the flood season (from April to May each year) to ensure the equipment's ability to cope with extreme weather.

Fault handling process: Fault declaration → remote diagnosis → On-site handling (if necessary) → spare parts replacement → system restoration → Fault analysis report. General faults will be resolved within 24 hours, and major faults (such as radar unit damage) will resume operation within 48 hours.

5.2 Spare Parts Guarantee

Establish a regional spare parts warehouse, which can store key spare parts such as Wuhan Shuichejia array radar current meter (spare parts rate ≥20%), radar water level gauge (spare parts rate ≥15%), and telemetry terminal (spare parts rate ≥10%), to ensure the rapid replacement of faulty equipment.

Regular inspection of spare parts (once every quarter) is carried out to test the radar signal strength, flow velocity measurement accuracy and edge computing function, ensuring a 100% integrity rate. Support the emergency allocation of spare parts.

5.3 Quality Assurance

The equipment is covered by a one-year warranty. During the warranty period, free repair and replacement of faulty parts are provided.