A discharge monitoring system (ADMS) is a non-contact radar flow solution that continuously measures river/canal discharge, water level, and flow velocity with built-in data logging and cellular telemetry. The RQ-30 is a compact all-in-one discharge radar (logger + 2G/3G/4G) ideal for bridges and canals; the RQ-30d is a multi-point radar for very wide rivers or sections with inhomogeneous velocity. Both are maintenance-free, flood-proof, solar-ready, and deliver high accuracy for regulatory reporting, hydrology, irrigation, and compliance. If you’re planning or procuring ADMS, this guide explains use cases, specifications, installation, integration, ROI—and how AAXIS NANO can size, supply, and install the right system for your site.
What is a Discharge Monitoring System (ADMS)?
A Discharge Monitoring System (also known as an open-channel flow meter or river discharge meter) measures discharge (Q), water level (h), and flow velocity (v) in rivers, canals, storm drains, and industrial outfalls. Unlike submerged sensors, non-contact radar ADMS mounts above the water on a bridge or gantry, so it avoids fouling, corrosion, weed entanglement, and flood damage. The result is reliable, continuous open-channel monitoring with minimal OPEX and high uptime. For a site assessment and proposal, AAXIS NANO can help—/contact-us.
Why Choose Non-Contact Radar for Discharge Monitoring?
- Maintenance-free & flood-proof: Mounted above water, no contact with debris or weeds.
- Accurate & repeatable: Millimetre-level water level resolution and precise Doppler surface velocity, stable even in turbidity and backwater.
- Safe installation: Bridge/gantry mounting, IP66/IP67 enclosures, surge and lightning protection.
- Ready for remote locations: Low power draw, battery + solar operation, cellular telemetry.
- Easy integration: SDI-12 and RS-485/Modbus to PLC/RTU/SCADA, optional 4–20 mA for legacy systems.
Product Overview
RQ-30 Discharge Radar (Compact ADMS)
Best for: Bridges, canals, stormwater outfalls, uniform river sections where a single velocity point represents the cross-section well.
Integrated in one compact housing:
- Water level radar (26 GHz, K-band)
• Measuring range: 0–15 m (standard), 0–35 m (extended)
• Resolution: 1 mm | Accuracy: ±2 mm | Opening angle: 10° - Velocity radar (24 GHz, K-band)
• Measuring range: 0.08–16 m/s (flow-dependent)
• Resolution: 1 mm/s | Accuracy: ±0.01 m/s; ±1 % FS
• Opening angle: 12° | Distance to water: 0.50–35 m - Data logger: Up to 500,000 values; measurement duration 5–240 s; interval 8 s–5 h
- Telemetry: Quad-band EGSM 850/900/1800/1900 MHz; 2G/3G/4G (transparent up to 14.4 kbps; non-transparent 9.6 kbps); FTP/HTTP data push; MDS server option (database + station/user management + web visualization)
- Power & enclosure: IP66; 24 Ah/12 V battery; 20 W solar recommended (mid-latitude)
• Power consumption (total system): 150 mA active / 3 mA standby
• Operating temperature: –20 … 60 °C
• Protections: over-voltage, reverse power, lightning - Total weight: ~19.5 kg
RQ-30d Discharge Radar Sensor (Multi-Point for Very Wide Rivers)
Best for: Very wide rivers, river bends, near tributary confluences or gates, and any site with inhomogeneous velocity across the width.
How it improves accuracy:
A master device measures water level and shares it with up to seven slave devices. Each device measures local surface velocity for its section. The system sums the partial discharges (vᵢ × Aᵢ) across sections to compute total discharge continuously—without contacting the water. Direction recognition and hysteresis handling ensure stable readings in tidal and backwater conditions.
Key technical details:
- Enclosure & power: IP67; 6–30 V supply; ~1 mA standby / ~140 mA active @ 12 V; –35 … 60 °C; surge, reverse power, and lightning protection
- Form factor: Master 338×333×154 mm (5.4 kg); Slave 175×154×246 mm (2.7 kg)
- Water level radar (master): 26 GHz; 0–15 m (std) / 0–35 m (ext); 1 mm resolution; 10° beam
- Velocity radar (all devices): 24 GHz; 0.08–16 m/s; 1 mm/s resolution; ±0.01 m/s; ±1 %FS; 12° beam; 0.50–35 m standoff; minimum surface swell: 3 mm
- Automatic vertical angle compensation: ±1° (resolution ±0.1°)
- Interfaces: 1× SDI-12; 1× RS-485/Modbus; 1.2 to 115.2 kBd; diverse ASCII protocols
- Outputs: Discharge rate, flow velocity, water level, quality parameters; optional 4–20 mA
Buying highlights: Multi-point velocity sampling yields higher accuracy in complex hydraulics, section count is modular (up to seven slaves). For a layout and bill of materials tailored to your river width, use /contact-us.
Measuring Principle (Discharge = Velocity × Area)
- Water level scan determines stage and cross-section/area (based on known channel geometry or rating).
- Velocity measurement uses Doppler radar at the water surface—single point (RQ-30) or multiple points (RQ-30d).
- Discharge calculation sums partial flows to a site total.
- The system logs the data and transmits it to SCADA/cloud in near real-time.
This deterministic scan cycle ensures stable, repeatable open-channel discharge measurement suitable for compliance and operations.
Typical Use Cases
- River gauging and hydrology networks (basin studies, flood forecasting, water accounting)
- Irrigation and canal automation (equitable distribution, gate optimization, loss assessment)
- Urban stormwater and drainage (outfall monitoring, event capture, CSO management)
- Tidal and backwater zones (direction-aware velocity with hysteresis handling)
- Industrial/STP/ETP discharges (continuous evidence for audits and regulatory compliance)
- Dams and barrages (gate operation, downstream releases, O&M optimization)
AAXIS NANO can match the right sensor configuration to your hydraulic conditions. Share site details at /contact-us.
Connectivity, Telemetry, and SCADA Integration
- Cellular telemetry: 2G/3G/4G, quad-band EGSM; FTP/HTTP data push to server/cloud
- Local control: SDI-12 and RS-485/Modbus for PLC/RTU/SCADA connectivity; optional 4–20 mA outputs
- Server stack: MDS server with built-in database, station/user management, and browser-based visualization
- Security & reliability: Hardened enclosures, surge and lightning protection; private APN/VPN options via your carrier
Need integration with existing PLC/SCADA or cloud dashboards? Our engineering team can provide templates and drivers—reach out to us.
Installation, Power, and Environmental
- Mounting: 0.50–35 m above water; bridge parapet/gantry brackets; no in-water works
- Power: 12 V battery (e.g., 24 Ah) with 20 W solar (mid-latitude recommendation)
- Protection: IP66/IP67, over-voltage, reverse power, and lightning protection
- Operating temperatures: RQ-30: –20 … 60 °C | RQ-30d: –35 … 60 °C
- Maintenance: Non-contact design minimizes site visits—occasional lens/aim checks per SOP
For mounting kits, solar sizing, and cabinet layouts, AAXIS NANO provides drawings and a site-specific boQ—/contact-us.
Accuracy and Reliability in Challenging Conditions
- Water level: Resolution 1 mm, accuracy ±2 mm
- Velocity: Resolution 1 mm/s, accuracy ±0.01 m/s; ±1 % FS
- Hydraulic challenges: Operates in turbidity, weed growth, tidal or backwater conditions; directional recognition and quality flags improve data reliability
How to Choose Between RQ-30 and RQ-30d
- Choose RQ-30 when the cross-section is relatively uniform (canals, straight river reaches), and you want fast, all-in-one deployment with logger + telemetry and solar power.
- Choose RQ-30d for very wide rivers or complex sections (bends, confluences, gates) where multi-point velocity is required to capture inhomogeneous profiles and improve total discharge accuracy.
Procurement & Tender Checklist (Copy-Ready)
- Non-contact radar discharge monitoring system (level radar 26 GHz; velocity radar 24 GHz)
- Level range 0–15 m (std) / 0–35 m (ext); resolution 1 mm; accuracy ±2 mm; beam 10°
- Velocity range 0.08–16 m/s; resolution 1 mm/s; accuracy ±0.01 m/s; ±1 % FS; beam 12°; standoff 0.50–35 m
- Data logger ≥500,000 records; configurable measurement duration 5–240 s and interval 8 s–5 h
- Telemetry via 2G/3G/4G (quad-band), FTP/HTTP push; optional server with database, user/station management, web visualization
- Local interfaces: SDI-12, RS-485/Modbus; optional 4–20 mA outputs
- Environmental: IP66/IP67; –20/–35 … 60 °C; surge, reverse power, lightning protection
- Power: 12 V battery; solar-ready (≥20 W recommended at mid-latitudes)
- For wide rivers: multi-device system (1 master + up to 7 slaves), automatic vertical angle compensation (±1°, 0.1° resolution)
ROI and Total Cost of Ownership
- No submerged parts → fewer site visits, no de-silting/de-weeding, longer service life
- Solar + low power → off-grid operation with minimal energy costs
- Minimal civil work → faster commissioning from bridge parapets/crossings
- Better data → optimized gate control, equitable irrigation, flood warnings, audit-ready compliance
Frequently Asked Questions
Does radar ADMS work in turbid water or with heavy weed growth?
Yes. The non-contact radar principle is unaffected by turbidity and weeds; the system requires only minimal surface disturbance (RQ-30d needs ~3 mm swell) which is typically present.
Can the system integrate with my PLC/SCADA?
Yes. SDI-12 and RS-485/Modbus are standard, and 4–20 mA outputs are available. Cellular telemetry pushes data to cloud/servers; an MDS server option provides ready-to-use dashboards.
How is it powered at remote sites?
With a 12 V battery (e.g., 24 Ah) and a 20 W solar panel (mid-latitude). Ultra-low standby current extends autonomy.
Which model should I buy?
RQ-30 for compact, uniform sections with quick deployment; RQ-30d for wide or hydraulically complex sites requiring multi-point velocity.
Why AAXIS NANO?
AAXIS NANO specializes in design, supply, and commissioning of discharge monitoring systems—complete with site surveys, mounting and solar design, PLC/SCADA integration, dashboards, documentation, and ongoing support. We deliver tender-ready specs, drawings, and BoQs, then install and commission on site.
Ready to evaluate, price, or deploy ADMS? Share your site details and get a tailored proposal.
