SonTek®-SL Series


SonTek-SL500, Brazil

SonTek-SL1500, UK




NEW SL1500/3000 3G MODELS! Inspired by the need for a SIMPLE way to measure water velocity and level in open channels, the SonTek-SL (affectionately known as the Side-Looker or "SL") has earned worldwide acceptance as a long-term monitoring solution. Now, with two new (3G) models turbo-charged by our proprietary SmartPulseHD®, the SonTek-SL features  accessories, mounting options, software, and a variety of integration formats to ensure it fits your application. [View online webinar - Recorded version]

Designed specifically for side mounting on bridges, canal walls, or riverbanks, the SL's SLEEK, low-profile housing makes installation easy.  With three models to choose from, the SL can be used in channels as small as you can jump across to rivers as wide as the Amazon. Ultra narrow beam widths combined with unmatched side lobe suppression provide the SUPERIOR acoustic directivity necessary for achieving maximum horizontal range free of interference from surface or bottom boundaries.

  • Features
  • Specifications
  • Software

First time users can collect test data within minutes of receiving the SonTek-SL. Deployments require only a few minutes to configure the SL and start collecting data. This system provides the highest quality Doppler velocity data without requiring the user to become an expert on Doppler technology.

SonTek-SL in a CanalFeatures

Water Velocity and Level: Water velocity, level, flow, and total volume-multiple parameters from one easy-to-use instrument. Acoustic Doppler profile of velocity data and acoustic water level offer the most accurate, reliable measurements.

SmartPulseHD®*: An intelligent algorithm that looks at water depth, profiling range, velocity, and turbulence, and then acoustically adapts to those conditions using pulse-coherent, broadband, and incoherent techniques.  Best data possible under any condition.  High-def cell sizes down to 4 cm.

Compact, Hydrodynamic Design: Incredibly lightweight and easy to transport and mount.  Slim shape is easy to maintain, stays clean, increases available sample area, and fits into more places.

Water Velocity Profiling: Customizeable, flexible setup options to suit a variety of applications. 3G models offer 128-cells for high-resolution and detailed profiles.

Acoustic-Pressure "Duo" Water Level (3G models only): Not only redundant sources of water level, the acoustic vertical beam and pressure sensor continually self-check, and pressure data are auto-corrected to keep atmospheric offset negligible.

Versatile, Easy Mounting:  Easy-access side mounting reduces concerns over personnel safety, lowers operational cost by avoiding divers and boats, avoids interruption in facility operations, and avoids interruption in data and water delivery to clients and stakeholders. 

Wave Spectra Option: Integrated pressure sensor calculates and outputs wave-height and period, in real-time.

*SL1500/3000 3G models only. Patent pending.

Specification SL3000 (3G) SL1500 (3G) SL500
Sampling range 0.1 to 5m | 0.3-17 ft 0.2 to 20m | 0.7-66 ft 1.5 to 120m | 5-400 ft
Minimum Channel Width 0.5m | 1.6 ft 1.0m | 3.3 ft 6.5m | 21 ft
Acoustics — Horizontal Beam Width•• 1.4° 1.4° 1.4°
Acoustics — Vertical Beam Width•• 1.4° 2.9° 3.8°
Acoustics — Side Lobe Suppression >60dB >60dB >60dB
Multi-cell Velocity Profiling Up to 128 cells Up to 128 cells Up to 10 cells
SmartPulse HD® Yes Yes n/a
SonTek Compass/Tilt Tilt Tilt Compass/Tilt
Internal Nonvolatile Memory 4GB 4GB 4MB
Water Velocity — Range ±7 m/s | 23 ft/s ±7 m/s | 23 ft/s ±6 m/s | 20 ft/s
Water Velocity — Resolution 0.0001 m/s | 0.0003 ft/s 0.0001 m/s | 0.0003 ft/s 0.001 m/s | 0.003 ft/s
Water Velocity — Accuracy ±1% of measured velocity;
±0.005 m/s | ±0.015 ft/s
±1% of measured velocity;
±0.005 m/s | ±0.015 ft/s
±1% of measured velocity;
±0.005 m/s | ±0.015 ft/s
Water Level — Vertical Beam Range 0.1 to 5m | 0.3 to 17 ft 0.15 to 10m | 0.5 to 33 ft 0.2 to 18.0m | 0.7 to 59 ft
Water Level — Vertical Beam Accuracy Depth <3m: ±0.3cm | 0.01 ft
Depth ≥3m: ±0.1%
Depth <3m: ±0.3cm | 0.01 ft
Depth ≥3m: ±0.1%
Depth <6m: ±0.6cm | 0.02 ft
Depth ≥6m: ±0.1%
Pressure Sensor — Range 30 m 30 m 20 m
Pressure Sensor — Accuracy FS 0.10% FS 0.10% FS 0.25% FS
Wave Height Spectra Optional Optional Optional
Temperature Sensor — Resolution ± 0.01º C ± 0.01º C ± 0.01º C
Temperature Sensor — Accuracy ± 0.2º C ± 0.2º C ± 0.1º C
Power Input 9-15 VDC 9-15 VDC 7-15 VDC
Power Consumption§ 0.8 W 1.0 W 0.7 to 1.0 W
Weight in Air 0.45 kg | 1.0 lb 0.90 kg | 2.0 lb 6.0 kg | 13.2 lb
Weight in Water 0.15 kg | 0.3 lb 0.2 kg | 0.5 lb 1.1 kg 2.5 lb
Pressure Rating & Maximum Depth 30 m | 98 ft 30 m | 98 ft 30 m | 98 ft (20 m sensor)
Mounting Plate Dimensions 25 x 17 x 1 cm | 10 x 6.7 x 0.4 in 25 x 17 x 1 cm | 10 x 6.7 x 0.4 in 35.5 x 22.9 x 1.5 cm | 14 x 9 x 0.6 in
Operating Temperature -5° to 60°C | 23° to 140°F -5° to 60°C | 23° to 140°F -5° to 60°C | 23° to 140°F
Storage Temperature -10° to 70°C | 14° to 148°F -10° to 70°C | 14° to 148°F -10° to 70°C | 14° to 148°F
Communications — Standard Protocols RS232/SDI-12/Modbus RS232/SDI-12/Modbus RS232/SDI-12
Communications — Software SonTek-SL: Intelligent Flow SonTek-SL: Intelligent Flow ViewArgonaut
Communications — Modbus Interface Module n/a n/a Required for Modbus
Communications — Analog Output Option Integrated on Flow Display Integrated on Flow Display Separate AO module
Communications — Flow Display Type SonTek Flow Display SonTek Flow Display Argonaut®

Actual maximum range depends on environmental conditions.
••Beam width reported at half power level (-3dB).
Side lobe suppression improves the aspect ratio of the instrument enabling greater measurement range in shallower water.
FS = Full Scale.
§ Power consumption will be higher is Flow Display is enabled.

Options & Accessories

SonTek Flow Display (IQ and SL 3G systems)

SonTek-IQ/SL 3G Flow Display

Allows for full tabular data display in the field without the need for a computer. Includes option for up to four 4-20 mA outputs. Read more.

SonTek-IQ/SL Adaptor Cable

SonTek-SL or IQ Adaptor Cable

1m adapter cable to connect a SonTek-IQ or SonTek-SL 3G system to an existing G2 Argonaut-SW or Argonaut-SL style cable.

Argonaut Flow Display

Real-time Flow Display

Provides an easy-to-use interface for monitoring both output data and the system status.

FlowTracker Bubble Level

Wading Rod and Bubble Level

The SonTek deluxe wading rod, featuring a sturdy grip and bubble level.

SonTek-SL Canal Mount

Canal Mount

An easy solution for installation in open channels.


Narmada Main Canal, India

Automated Gaging of the Narmada Main Canal

India is emerging as a world leader in irrigation schemes, and the 458-km Narmada Main Canal – the largest concrete-lined irrigation canal in the world – stands as a monument to the opportunities and challenges that face water providers.  The scale of the SSNNL canal system, velocity changes due to volume and management, and the constant battle against siltation illustrate the importance for accurate measurement of flow and discharge.