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Flow & Discharge

Measuring water flow and discharge to determine the amount of water flowing through an open channel is critical for predicting water availability and flood events, allocating watering, and more.

OTT Hydromet has been a leader in flow meter technology for over 100 years, from the first mechanical current meters to advanced acoustic Doppler technology used today, and offers a variety of technologies to measure flow and water discharge, from portable in-stream current meters and acoustic profilers, to side looking Doppler technology for continuous discharge measurement.

Acoustic Digital Current Meter

OTT ADC - Acoustic Digital Current Meter

Handheld, acoustic water flow, velocity meter for in-stream point velocity measurements

The OTT Acoustic Digital Current meter (ADC) delivers consistently accurate results with the most advanced acoustic technology available for point velocity measurement.

  • Spot
  • Acoustic
  • Flow velocity, depth
  • Latest state of the art ultrasonic Doppler technology for high accurate velocity measurements. Maintenance free sensor with integrated depth measurement, graphical step by step user guidance and discharge calculation according to ISO 748 and USGS standard
  • -0.2 … 2.4 m/s
  • ± 1% of measured value ± 0.25 cm/s
Non-contact bubbler in water level sensor for surface water monitoring

OTT CBS - Compact Bubbler Sensor

Non-contact, bubbler sensor for longterm surface water level monitoring

The OTT CBS is a compact, accurate, and low power bubbler sensor for surface or groundwater level monitoring.

  • Surface water Groundwater
  • Bubbler-in
  • Drift-free water level measurement - no pressure sensor or electronics in the water
  • 0 to 15 m or 0 to 30 m
  • ± 3 mm (high accuracy version); ± 5 mm (standard and 30 meter versions)
  • No
  • SDI-12, RS-485 (using SDI-12), or 4 ...20 mA
Integrated pressure level transducer and datalogger

OTT Orpheus Mini Water Level Logger

Pressure level transducer with datalogger for longterm groundwater monitoring

The OTT Orpheus Mini is an integrated pressure sensor and datalogger for level measurement in surface and groundwater applications.

  • Surface water Groundwater
  • Vented pressure cell
  • Waterlevel/Pressure, Water temperature
  • Measures and stores water level and temperature data
  • 0 … 4, 10, 20, 40, and 100 m
  • ± 0.05% FS
  • Yes
Small - Mini Current meter for discharge measurements OTT C"

OTT C2

Small - Mini Current meter for discharge measurements OTT C"

The OTT C2 small current meter for discharge measurements for shallow waters in small rivers, channels, laboratories and river models.

  • Spot
  • Mechanical
  • Flow velocity
  • OTT C2 - the original for wading rod measurements in shallow streams, applicable from 4 cm water depth.
  • 0.025 ... 5 m/s
  • ± 2%
Universal current meter OTT C31

OTT C31

OTT C31 Universal Current Meter for discharge measurements

OTT C31 Universal current meter for flow velocity measurement in rivers and open waterways. Rod-mounted or as cable-suspended current meter from a bridge, boat or on cable ways.

  • Spot
  • Mechanical
  • Flow velocity
  • C31 - the original. Taditional hydrometric current meter with proved quality for use with wading rods, from bridges and at cable-way installations
  • 0.025 ... 10 m/s
  • ± 2%
Handheld electromagnetic stream flow meter with automatic discharge calculation

OTT MF pro - Water Flow Meter

Handheld electromagnetic water flow meter with automatic discharge calculation

The OTT MF Pro is a user-friendly, low maintenance electromagnetic current meter for cost-efficient in-stream discharge measurement.

  • Spot
  • Electro-magnetic
  • Flow velocity and water depth
  • Low maintenance magnetic - inductive probe with level measurement for reliable flow measurements. Works well in low flow and turbulent conditions, cross - sections with weed growth and pollution. Applicable in streams and conduits.
  • 0 … 6 m/s
  • ± 2% of measured value ± 0.015 m/s ( 0 … 3 m/s ) and ± 4% of measured value ± 0.015 m/s ( 3 … 5 m/s )
Fixed installation of water flow sensor

OTT SLD - Side Looking Doppler Sensor

Water flow meter for longterm data collection of velocity and discharge measurements

The OTT SLD uses acoustic Doppler technology for continuous measurement of water velocity and level in streams, rivers, and canals.

  • Fixed installation
  • Acoustic
  • Flow velocity
  • Side-Looking-Doppler for continuous discharge measurement in rivers and open channels. Discharge calculation based on velocity - index - method. Integrated vessel filter algorithm, Modbus interface and output of total volume of flow (max. interval 1 day).
  • ± 10 m/s
  • ± 1 % of measured value ± 0.5 cm/s
Zählgerät für die Abflussmessung mit Messflügel

OTT Z400

Counterset for current meter flow measurements

The counter OTT Z400 is a useful tool for flow measurements with hydrometric current meters. It records the number of propeller revolutions and, if required, calculates the velocity of flow.

  • Spot
  • Numbers of pulses
  • Compact handy counter for mechanical current meters with optional display of velocity of flow and integrated user software for the management of calibration tables
  • 50 Hz (680 Ohm), 100 Hz
  • ± 0,01 s / ± 0,5 Impulse
OTT MF pro Video - EN
OTT ADC Video - EN
Discharge Sensor Selection Guide
Surface Water Level Sensor Guide
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