Careful measurement and monitoring of streams and rivers is vital to manage water resources throughout the world. Rivers also flood so the careful measurement of river levels can help mitigate damage caused by floods. River flow measurements are calculated by hydrographers and are analysed by hydrologists and other scientists. To calculate flow, the river level is measured accurately at a certain point in the river, typically at a flume or weir which has known dimensions / has been constructed to a known standard. There are different types for different conditions, for example a flume type generally passes sediment more easily, while a V notch type is not suitable for use in waters with lots of sediment.
The water level above the low point of the flume / weir is measured and the flow is calculated based on measurement results and the shape and size of the flume / weir. For measuring flow of large / wide rivers, manual river gauging process is undertaken. Hydrographers record level and velocity at different depths along the slope of the river bank. From these measurements a set of relationships is determined such that the flow at the certain point in the river can be determined based on the water level at a certain point in the river, so called stage to flow relationship.
There are several different methods used to measure streams and rivers, and these methods will be summarized below. The
measurement of rainfalls is often associated with river measurement stations as local rainfall is a key factor especially in hills or mountainous areas.
Regular reporting of river levels to a central server allows authorities to monitor stream and river flows across a country or region and
to use that data immediately if required. For example: flood alerts / flood warnings as well as longer term analysis by hydrographers and hydrologists to manage the rivers / catchments in the long term.
The measurement methods include:
• Method 1 – a still well or still pipe with a shaft encoder with a float and beaded float line system
• Method 2 – a pressure sensor which is immersed into the stream or river
• Method 3 – the more complex pressure bubbler system which allows for a small open tube to be immersed into the stream or river with a gas pump or gas cylinder to inject small bubbles into the open tube and measure water depth by measuring the back pressure required to force bubbles out of the tube in the water.
• Method 4 – Measuring depth using Ultrasonics Doppler Instrument
• Method 5 – Measuring depth using Radar
There are many measuring methods available, but still the most common method is shaft encoder float and wheel system. This method requires a large well or a smaller pipe to be installed on the stream, river bank or on a bridge structure, to provide a stable, not disturbed by flow or wind, measurement environment.
A small float, a float line and a counter weight system will respond to depth / level changes in stream or river. That response causes rotation of the shaft of a wheel. Shaft rotation is measured very accurately by optical encoder and the data is simultaneously displayed and recorded in the data logger within the instrument.
The Unidata 6541 Precision Water Level Instrument is a very accurate shaft encoder instrument. 6541 integrates both an LED display for displaying water level instantaneously and a data logger for recording / storing water level readings as required.
When a Neon Remote Logger is added, the water level information can be transmitted over the internet to a central Neon server to allow authorities to view the data on the web in near real time.
|Options for Application Specific Instruments / Inputs||Unidata Part Number||Description|
|Ultrasonic Doppler Instrument - Velocity, Depth & Flow||6526J-21||Starflow Ultrasonic Doppler Instrument 0-2m|
|Ultrasonic Doppler Instrument - Velocity, Depth & Flow||6526J-51||Starflow Ultrasonic Doppler Instrument 0-5m|
|Ultrasonic Doppler SDI-12 Instrument - Velocity & Depth||6527A||Starflow QSD|
|Water Level Instrument||6541C-11||WLI with 500mm Pulley & Alk Batt Metric (Imperial version available)|
|Float||6541F-115||WLI Float - Cylinder 115mm (other options available)|
|Float Line||6541D-M||WLI Beaded Floatline Metric (Imperial version available)|
|Options for Neon Telemetry - NRL / NRT / RTU / Field Units||Unidata Part Number||Description|
|Neon Remote Logger 16 Channels||3016A||Options Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa|
|Neon Remote Logger 8 Channels||3008A||Options Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa|
|Neon Remote Logger 4 Channels||3004A||Options Available: 3G/4G Cellular|
|Neon Remote Logger 4 Channels M Series||3004A-M||Options Available: 3G/4G Cellular, Ethernet, Microsatellite, Iridium SBD and LoRa|
|Cellular RTU 3G/4G||2013F-AB03 / 2013F-AB04||Neon Metering Module 3G/4G with Antenna and Li Battery|
|Cellular RTU 3G/4G - Industrial||2016F-AB03 / 2016F-AB04||Neon Remote Terminal 3G/4G with Antenna and Li Battery|
|Low Earth Orbit Satellite Globalstar||2015F-AB0||NRT Satellite Globalstar Modem with Antenna and three Li Batteries|
|Ethernet||2017F-0B0-1 or 3||NRT Ethernet with single or triple Ethernet Ports with three Li Batteries|
|Equatorial Orbit Satellite - Inmarsat||2018F-AB0-1 or 3||NRT Ethernet with single or triple Ethernet Ports with three Li Batteries|
|LCD Display||2500E||NRT LCD Display|
|NRT Field Termination Strip||2103F||2015F,2016F,2017F, and 2018F NRT FTS|
|NRT Firmware Option||2303A-8M||8M Extended Memory Option|
|NRT Firmware Option||2303A-8M-CAM||8M Extended Memory & Serial Camera Option|
|NRT Firmware Option||2303A-CAM||Serial Camera Option|
|Options for Neon Application Software - Customer Server||Unidata Part Number||Description|
|Neon Application Software||2302A||Neon Server Software Licence Incl 5 NAL |
|Neon Application Software||2302A-10||Additional 10 NRT Access Licences|
|Neon Application Software||2302A-20||Additional 20 NRT Access Licences|
|Neon Application Software||2302A-50||Additional 50 NRT Access Licences|
|Options for Neon Application Software - Unidata Server||Unidata Part Number||Description|
|Neon Application Software||2301A||Neon Data Initial Subscription Setup Fee|
|Neon Hosting Service||2301A-01||Neon Data Service Fee for 1-50 NRTs|
|Neon Hosting Service||2301A-02||Neon Data Service Fee for 51-100 NRTs|
|Neon Hosting Service||2301A-10||Neon Data Service Fee Metering|
|Options for Conventional Dataloggers / Field Units||Unidata Part Number||Description|
|Neon Remote Logger 16 Analog Channels / Touch Screen Display||3016A-000||16 Ch NRL (Superseded Prologger 7001D)|
|Neon Remote Logger 8 Analog Channels / Touch Screen Display||3008A-000||8 Ch NRL (Superseded Stalogger 6004D)|
|Neon Remote Logger 4 Analog Channels / Touch Screen Display||3004A-000||4 Ch NRL (Superseded Micrologger 8010C)|
|Starlog V4 Management Software||6308A-AUE||Starlog V4 Full Licence Key|