METAS runs one of the oldest tow tanks for hydrometric instruments in the world.

The tank has a length of 140 m, a width of 4 m and a depth of 2.4 m. It is used to calibrate or test instruments that measure water flow speed.

The laboratory has built up considerable experience and its expertise is accepted worldwide. Its customers are distributed on all continents.

The laboratory’s quality system is based on the ISO/IEC 17025 standard and its certificates are internationally accepted and recognised.


The powered carriage can tow instruments up to 10 m/s and can accommodate passengers for viewing purposes. Depending on towing speed, up to 3 instruments can be calibrated simultaneously.

Tow tests to evaluate or assess prototypes can also be conducted.


Instrument type

Speed range

Mechanical current meter mounted on a circular or profiled rod

(0.02 … 10.0) m/s

Mechanical current meter on weight

(0.02 … 7.0) m/s

Magneto-inductive instrument

(0.02 … 5.0) m/s

Acoustic-Doppler instrument

(0.02 … 5.0) m/s

Any instrument with a display, impulse or analogue output

(0.02 … 10.0) m/s

Research and development

We are continuously improving our installations and procedures to fulfil our customer’s needs and extend our measurement services. This Research and Development effort is conducted internally as well as with other tow tanks over the world and manufacturers of hydrometric instruments.

Our current research axis focus on:

• Optimisation of waiting times between runs (reduction of residual currents in the tank)
• International harmonisation of the calibration procedures for acoustic Doppler instruments
• Development of testing and calibration procedures for ADCPs

Last modification 05.01.2023

Top of page


Federal Institute of Metrology
Laboratory Flow and Hydrometry
Lindenweg 50
CH-3003 Bern-Wabern
T +41 58 387 01 11

Print contact