Water Flow Monitoring

Application Notes

Application Background                                                                                                                                      Printer Friendly Version

Simply recording water depth does not provide a reliable measure of water flow, for example, depth may vary while flow remains constant. In such cases it is essential to measure depth and velocity and then determine the flow measurement.

Environmental waterflow monitoring

Unidata’s Starflow Ultrasonic Doppler System (Water Flow Monitoring System) is ideal for smaller open channel and pipe measurements as it is a complete hydrographic data collection system.

Starflow measures water velocity, depth, flow and temperature, enabling you to do a complete stream study with a single instrument.

Ultrasonic Doppler Instrument operates in a wide range of water qualities from fresh streams to primary sewerage channels. It measures both forward and reverse flows, and is particularly useful at sites where a stable stage/ velocity relationship does not exist.

For very small flow monitoring the Unidata tipping bucket flow gauge can be used.

Application Detail

Open channels, partly filled pipes, and natural streams have very complex velocity characteristics. Turbulence, waves, stream slope, bed and wall unevenness, rocks and debris, all combine to create an unpredictable velocity profile.

Unidata-Water Flow Measurement Open Channel
Starflow Ultrasonic Doppler System

To account for these effects Starflow analyses up to one thousand separate velocity measurements and statistically determines the mean velocity. This approach provides a good “average velocity” even under difficult conditions. Note, however, that Starflow is not a “current profiler”, that is, it does not record a detailed velocity profile.

Water Flow Monitoring System

The Starlog companion software allows a user to define the stream, channel or pipe profile, so that the velocity and depth readings can be converted to a true flow reading
Starflow contains a micrologger with 512kB of memory; enough for 250,000 measurements. It will acquire instantaneous, maximum, minimum and averaged readings. Furthermore, Starflow is equipped with the SDI-12 communications facility, intelligent battery supervision, and an interface to a telemetry system, such as Neon.

The unit also connects to an SDI-12 Data Recorder as a slave or it can be an SDI-12 Data Recorder master to which other SDI-12 instruments can be connected. You will generally mount the 6526 on (or near to) the bottom of the stream, pipe or culvert where you are measuring flow, however you can also mount it on the side of larger channels.

Water Flow and Velocity Measurement

A single cable connects the instrument to a 12VDC power source. The unit also provides a control output for initiating a water-sampling unit. The sampling control is fully programmable and can be based on flow, velocity, depth or a combination of these conditions. By connecting a rain gauge you can make a complete storm water monitoring system.

On top of this, Starflow can be paired up with the 6256LCD Starflow Liquid Crystal Display Module to display the values obtained from the most recent scan on demand. The 6526LCD is packaged in a compact weatherproof polycarbonate enclosure, fitted with pre-wired SQL type connectors.

Another accessory used with the Starflow is the 6702S-LCD. It consists of a polycarbonate enclosure containing battery mounting plate, three connectors and a LCD display. The display shows the current Starflow measurements. You can connect directly to an instrument and computer / external power supply (using a 6603D-SDI cable assembly) via these input/output connectors.
A Neon remote terminal or module can be housed within the enclosure as well.

application note sewer monitoring 5

Water Flow Measurement Starflow Instrument

Typical Configuration

Options for Application Specific Instruments / InputsUnidata Part NumberDescription
Ultrasonic Doppler Instrument - Velocity and Depth6526H-21Starflow Ultrasonic Doppler Instrument 0-2m
Ultrasonic Doppler Instrument - Velocity and Depth6526H-51Starflow Ultrasonic Doppler Instrument 0-5m
Tipping Bucket Flow Gauge6506GFlow Gauge 75ml
Tipping Bucket Flow Gauge6506HFlow Gauge 130ml
Options for Neon Telemetry - NRT / RTU / Field UnitsUnidata Part NumberDescription
Cellular RTU 3G2013F-AB03Neon Metering Module 3G with Antenna and Li Battery
Cellular RTU 4G2013F-AB04Neon Metering Module 4G with Antenna and Li Battery
Cellular RTU 3G - Industrial2016F-AB03Neon Remote Terminal 3G with Antenna and Li Battery
Cellular RTU 4G - Industrial2016F-AB04Neon Remote Terminal 4G with Antenna and Li Battery
Low Earth Orbit Satellite Globalstar2015E-AB0Neon Remote Terminal - Satellite Globalstar Modem with Antenna and three Li Batteries
Ethernet2017E-0B0-1 or 3NRT Ethernet with single or triple Ethernet Ports
with three Li Batteries
Equatorial Orbit Satellite - Inmarsat2018E-AB0-1 or 3NRT Ethernet with single or triple Ethernet Ports
with three Li Batteries
LCD Display2500ENRT LCD Display
NRT Field Termination Strip2103F2015E,2016F,2017E, and 2018E NRT FTS
NRT Firmware Option2303A-8M8M Extended Memory Option
NRT Firmware Option2303A-8M-CAM8M Extended Memory & Serial Camera Option
NRT Firmware Option2303A-CAMSerial Camera Option
Options for Neon Application Software - Customer ServerUnidata Part NumberDescription
Neon Application Software2302ANeon Server Software Licence Incl 5 NAL
Neon Application Software2302A-10Additional 10 NRT Access Licences
Neon Application Software2302A-20Additional 20 NRT Access Licences
Neon Application Software2302A-50Additional 50 NRT Access Licences
Options for Neon Application Software - Unidata ServerUnidata Part NumberDescription
Neon Application Software2301ANeon Data Initial Subscription Setup Fee
Neon Hosting Service2301A-01Neon Data Service Fee for 1-50 NRTs
Neon Hosting Service2301A-02Neon Data Service Fee for 51-100 NRTs
Neon Hosting Service2301A-10Neon Data Service Fee Metering
Options for Conventional Dataloggers / Field UnitsUnidata Part NumberDescription
Standards Starlogger6004D-11Red Logger 512K with Alkaline Battery
Display Starlogger6004D-21Blue Logger 512K with LCD and Alkaline Battery
Prologger7001D-11Green Logger 1M with LCD and Alkaline Battery
Micrologger8010C-EURMicrologger 512K
Starlogger Field Termination Strip6103E6004D FTS
Prologger Field Termination Strip7100E7001D FTS
Starlog V4 Management Software6308A-AUEStarlog V4 Full Licence Key