SonTek FlowTracker2 Acoustic Doppler Velocity Meter
| Brand | SonTek |
|---|---|
| Origin | USA |
| Manufacturer Type | Authorized Distributor |
| Product Origin | Imported |
| Model | FlowTracker2 |
| Price Range | USD 13,500 – 40,500 (est.) |
| Technology | Acoustic Doppler Velocimetry (ADV) |
| Measurement Type | Point Velocity and Discharge |
| Key Performance | Low-velocity & shallow-water capability |
| Minimum Measurable Depth | 0.02 m |
| Velocity Range | 0.001–4.0 m/s |
| Resolution | 0.0001 m/s |
| Accuracy | ±1% of measured velocity or ±0.0025 m/s (whichever is greater) |
| Operating Temperature (Probe) | −20 °C to +50 °C |
| Operating Temperature (Display Unit) | −20 °C to +60 °C |
| Storage Temperature | −30 °C to +70 °C |
| Power Supply | 8 × AA batteries (alkaline, NiMH, or NiCd) |
| Weight | 1.55 kg |
| Display IP Rating | IP67 (1 m submersion for 30 min) |
| Integrated Sensors | Tilt, orientation, GPS, Bluetooth 4.0 |
| Memory | Non-volatile internal storage |
| Compliance | ISO 748, USGS TWRI 3-A17, ASTM D3858, SmartQC™ real-time quality assurance |
Overview
The SonTek FlowTracker2 is a field-deployable, handheld acoustic Doppler velocimeter engineered for high-precision point-velocity measurement and cross-sectional discharge computation in open-channel hydrometric applications. Utilizing broadband acoustic Doppler principles, the instrument transmits and receives ultrasonic pulses at 10 MHz to resolve instantaneous three-dimensional water velocity vectors at a single spatial point—enabling direct measurement of turbulent flow structures with minimal intrusion. Its design adheres to internationally recognized hydrometric standards including ISO 748 (measurement of liquid flow in open channels), USGS Techniques of Water Resources Investigations (TWRI) Book 3, Chapter A17, and ASTM D3858 (standard practice for measuring open-channel flow with acoustic Doppler current profilers). The FlowTracker2 is not a time-averaged averaging device; rather, it delivers raw, high-frequency velocity time series (up to 200 Hz sampling), supporting advanced analysis of turbulence intensity, Reynolds stress, and flow stability—critical for regulatory reporting, hydraulic modeling validation, and sediment transport studies.
Key Features
- True ADV architecture: Measures instantaneous velocity components (u, v, w) at a defined sampling volume (typically 5 mm diameter) using pulsed coherent Doppler processing.
- Ultra-low-velocity capability: Reliable operation down to 0.001 m/s—validated across shallow, low-gradient environments where conventional propeller or electromagnetic meters fail.
- Integrated inertial measurement unit (IMU): Real-time tilt and pitch compensation ensures accurate beam alignment and vertical/horizontal coordinate transformation—even on unstable platforms or sloped banks.
- Dual-mode GPS receiver: Supports both autonomous (±3 m CEP) and SBAS-enhanced (WAAS/EGNOS) positioning for georeferenced transect mapping and repeat-survey consistency.
- Ruggedized, IP67-rated display unit: Sealed against dust and immersion up to 1 m for 30 minutes; operational across −20 °C to +60 °C ambient conditions.
- SmartQC™ intelligent quality control: On-the-fly assessment of signal-to-noise ratio (SNR), correlation coefficient, and beam geometry validity—flagging marginal measurements before data export.
- Non-volatile flash memory: All raw velocity time series, metadata (GPS coordinates, tilt angles, battery status), and computed discharge values are retained without power loss or file corruption.
- Modular probe–handheld architecture: Interchangeable probes (including standard, shallow-water, and extended-cable variants) connect via ruggedized quick-disconnect interface; firmware and calibration profiles remain synchronized across units.
Sample Compatibility & Compliance
The FlowTracker2 is validated for use in natural and engineered open channels—including irrigation canals, drainage ditches, flumes, weirs, and low-flow urban streams—with minimum water depth of 20 mm. It complies with ISO 748:2010 for velocity-area discharge determination and supports automated calculation per USGS protocols (e.g., Q = Σ(Qi) where Qi = vi × Ai). Its embedded SmartQC system satisfies GLP-aligned data integrity requirements by logging sensor health metrics, operator inputs, and environmental context for full auditability. While not certified under FDA 21 CFR Part 11, its timestamped, immutable binary data files (in .FT2 native format) meet traceability benchmarks for third-party QA/QC review and regulatory submission (e.g., EPA Region 10 water rights reporting, California DWR compliance monitoring).
Software & Data Management
Data acquisition and post-processing are supported via SonTek’s FlowTracker Desktop software (Windows 10/11 compatible), which imports .FT2 files and exports ASCII, CSV, or Excel-ready tables containing velocity vectors, discharge integrals, uncertainty estimates, and SmartQC flags. The software implements ISO-compliant uncertainty propagation models (Type A and Type B) per GUM (JCGM 100:2008) and allows user-defined cross-section digitization with polyline-based area segmentation. Bluetooth 4.0 enables wireless download of field-collected datasets directly to laptop or tablet—eliminating physical cable handling in wet or muddy conditions. All firmware updates, calibration coefficients, and regional unit preferences (metric/imperial) are managed through the same interface, ensuring consistent configuration across multi-instrument deployments.
Applications
- Regulatory flow monitoring for water rights administration and drought response planning.
- Calibration and verification of flume/weir installations (e.g., Palmer-Bowlus, Parshall, Palmer-Bowlus).
- Turbulence characterization in ecological restoration projects—assessing habitat suitability for benthic macroinvertebrates.
- Validation of 2D/3D hydrodynamic models (e.g., HEC-RAS, SRH-2D) using high-resolution point-velocity boundary conditions.
- Low-flow measurement in ephemeral streams and agricultural return flows where traditional methods yield unacceptable uncertainty.
- Educational field hydrology instruction—supporting student-led discharge surveys with immediate visual feedback and error diagnostics.
FAQ
What is the minimum water depth required for valid measurement?
The FlowTracker2 achieves reliable acoustic backscatter and velocity resolution at depths as shallow as 20 mm—provided the probe is fully submerged and oriented perpendicular to flow direction.
Does the instrument support real-time telemetry or remote data transmission?
No—the FlowTracker2 operates as a standalone field recorder. Data are retrieved post-survey via Bluetooth or micro-USB; no cellular or LoRaWAN integration is available.
Can the device be used in saline or turbid water?
Yes. Its 10 MHz transducer frequency provides robust performance in suspended sediment concentrations up to 10 g/L and conductivity levels ≤ 50 mS/cm—typical of estuarine transition zones.
Is factory recalibration required annually?
SonTek recommends biennial verification against NIST-traceable flow calibration rigs; field-level zero-velocity checks using still-water immersion are advised before each deployment.
How is measurement uncertainty quantified and reported?
Uncertainty is calculated per ISO/IEC Guide 98-3 (GUM) using combined Type A (statistical scatter of velocity samples) and Type B (instrumental bias, tilt correction error, depth interpolation) components—displayed alongside each computed discharge value in FlowTracker Desktop.
