River-ADCP-M9

Q: Why 9 beams? How does the dual-frequency array work?

The M9 uses two independent Janus arrays: 3.0MHz (4 beams) for high-resolution velocity profiling in the upper water column, 1.0MHz (4 beams) for deeper penetration and bottom tracking, and a 0.5MHz vertical beam for bathymetry. The instrument automatically selects the optimal frequency for each cell based on water depth and conditions — you get 3.0MHz resolution where the water is shallow and clear, 1.0MHz reach where it’s deeper or turbid. The 9th beam (vertical echo sounder) measures riverbed depth independently, so your bathymetry doesn’t depend on the oblique beams.

The River-ADCP-M9 is a 9-beam, dual-frequency acoustic Doppler profiler purpose-built for river discharge measurement. With two Janus arrays at 3.0MHz and 1.0MHz, plus a dedicated 0.5MHz vertical echo sounder, it simultaneously captures high-resolution velocity profiles, bathymetry, and riverbed topography — in a single pass across the channel.

Overview

At ≤1.5 kg with a Φ128mm POM housing, it is the most portable instrument in the Oceantek portfolio — designed for one-person deployment from small boats, cableways, and bankside rigs. GNSS input enables georeferenced moving-boat discharge measurements. Cell sizes down to 0.02m and ±0.25% ± 2mm/s accuracy make it the highest-resolution instrument we build.

Compact Oceantek ADCP optimized for SWaP constraints

Key Features

±0.25% ± 2mm/s Accuracy

The highest-accuracy instrument in the Oceantek portfolio. 1mm/s velocity resolution, ±20m/s range, 0–360° directional sensing at ±2° — built for official discharge records.

0.02m Cell Size

Finest cell resolution of any Oceantek product. Resolve velocity structure in water columns as shallow as 0.06m — critical for small streams, canal cross-sections, and near-bank flow detail.

≤1.5 kg · Single-Person Portable

Φ128mm × 168mm, POM housing rated to 50m. The lightest instrument in the Oceantek lineup. Carry it in a backpack, deploy from an inflatable boat, rig it on a cableway — one person, no crane.

Integrated Bathymetry

0.5MHz vertical echo sounder measures riverbed depth to 80m. Oblique beams cover 40m. Simultaneous velocity + bathymetry = complete discharge cross-section in one traverse.

70Hz Internal Sampling · 2Hz Output

70Hz raw sampling captures turbulent fluctuations. 2Hz output rate with configurable averaging. Up to 255 cells per profile — tune for resolution or range.

64GB Onboard Storage · RS-232/422

Records full-resolution data for days of continuous surveying. Standard serial output for real-time laptop/tablet connection during surveys. Compatible with major discharge software.

Specifications

Category	Technical Specification	Parameters
Velocity Measurement	Operation Mode	Direct Reading
	Profile Range	0.06-40m
	Typical Current Measurement Accuracy	±0.25% ± 2mm/s
	Velocity Resolution	1mm/s
	Velocity Range	±20.0 m/s
	Flow Direction Range	0-360°
	Flow Direction Accuracy	±2°
	Number of Cells	1-255
	Cell Size	0.02-4m
Transducer	Number of Beams	9 transducers; dual-beam 3.0MHz / 1.0MHz Janus; 1 x 0.5MHz vertical beam echo sounder
Transducer	Beam Angle	25°
Depth Measurement	Height Measurement Resolution	0.001m
	Height Measurement Accuracy	1% (0.02% with full water column sound speed correction)
	Height Measurement Range	0.2-80m
	Bottom Track Range	0.3-40m
Discharge Measurement	GNSS/GPS Range	0.3-80m, extrapolation above 40m
Discharge Measurement	Internal Storage	64GB
Bathymetric Measurement	Range	40m (oblique beams) - 80m (vertical beam)
Bathymetric Measurement	Velocity Profile Measurement Range	±10.0 m/s
Communication	Communication Interface	RS-232 or RS-422
	GNSS/GPS Communication	RS-232 serial input
	Max Data Refresh Rate (Output Rate)	2Hz
	Internal Sampling Rate	Up to 70Hz
Sensors	Temperature Sensor	Accuracy: ±0.1°C; Resolution: 0.01°C
	Pressure Sensor	Range: According to depth rating; Accuracy: ±0.25%; Resolution: 1mm
	Attitude Heading Reference Sensor	Range: Heading 0-360°; Accuracy (RMS): Roll ±1° \| Pitch ±1° \| Heading 0.8°; Resolution: 0.01°
Power Supply	Power Supply Interface	10-26V
Structure	Housing Material	POM
Environment	Operating Temperature	-5°C-45°C
	Storage Temperature	-40°C-70°C
	Pressure Rating	50m
Physical Properties	Weight (in Air)	≤1.5kg
Physical Properties	Dimensions	Φ128mm × 168mm
Optional	Available Options	-

Applications

Why Choose the River-ADCP-M9

Three reasons hydrological agencies choose the M9 for their field teams.

Carry It Anywhere

≤1.5 kg. Φ128mm. One person carries it in a backpack to a remote gauging site, deploys from an inflatable boat or cableway, and completes the survey alone. No boat crew, no crane, no vehicle-mounted rig. For hydrological agencies covering dozens of stations across difficult terrain, this portability is not a luxury — it’s operational necessity.

Resolution That Matches the Shallowest Rivers

0.02m cell size and 0.06m minimum profile depth. Most ADCPs — even river-specific ones — bottom out at 0.25m cells and ~0.5m minimum depth. The M9 profiles water columns that other instruments can’t even measure, making it indispensable for small-stream gauging networks and irrigation canal monitoring.

One Pass, Complete Cross-Section

9 beams, 3 frequencies, 1 traverse. Velocity profile, bathymetry, and discharge computed in real time as you cross the river. No separate echo sounder needed. No post-processing to merge velocity and depth data. One instrument, one survey, one complete discharge measurement — compliant with ISO 748.

Frequently Asked Questions

Quick answers about the Ocean-ADCP-600-FA4

Why 9 beams? How does the dual-frequency array work?

The M9 uses two independent Janus arrays: 3.0MHz (4 beams) for high-resolution velocity profiling in the upper water column, 1.0MHz (4 beams) for deeper penetration and bottom tracking, and a 0.5MHz vertical beam for bathymetry. The instrument automatically selects the optimal frequency for each cell based on water depth and conditions — you get 3.0MHz resolution where the water is shallow and clear, 1.0MHz reach where it’s deeper or turbid. The 9th beam (vertical echo sounder) measures riverbed depth independently, so your bathymetry doesn’t depend on the oblique beams.

What software is compatible with the M9 for discharge measurement?

The M9 outputs standard PD0 binary format, which is directly compatible with WinRiver II, QRev, VMT, and most hydrological data processing packages. GNSS data is embedded in the PD0 stream — no separate GPS file to synchronize. If your agency uses proprietary discharge software, contact our support team with your format requirements — we can provide a data conversion utility.

How does moving-boat discharge measurement work?

The M9 is mounted on a small boat or tethered platform. As you traverse the river from bank to bank, the ADCP measures water velocity along the beam paths while the GNSS receiver tracks the boat’s ground speed and position. The instrument subtracts boat velocity from water velocity to compute true current speed and direction at each depth cell. The result is a full discharge cross-section — velocity, depth, and computed discharge — from a single traverse. This is the standard moving-boat method per ISO 748 and USGS protocols.

Can the M9 be used in very shallow water (less than 0.5m)?

Yes — with a minimum profile depth of 0.06m and cell size down to 0.02m, the M9 can measure flow in water depths where most ADCPs cannot operate at all. For extremely shallow conditions (<0.3m), the Self-Contained configuration with a fixed mount and the smallest cell size is recommended. For moving-boat surveys in very shallow rivers, a tethered deployment (rather than a boat) keeps the transducer stable and submerged.

Get a Quick quote

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Also HADCP for Fixed-stations

HADCP-600

600kHz horizontal side-looking ADCP for fixed-station discharge monitoring. 3-beam, 90m cross-channel coverage. 24/7 unattended flow data for hydrological networks and flood warning. DR model only