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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 is vital to manage damage during 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 more difficult in waters with sediment.
The water level above the low point of the flume or weir is measured and the flow is calculated based on the shape / size of the flume or weir and the level of water passing through that flume or weir. When large / wide rivers need to be measured, there is a manual river gauging process undertaken where the flow and velocity and level at several points and depths are measured by hydrographers (this is called a river gauging) and a set of relationships is determined such that the flow at a certain point in the river can be determined based on the level at a certain point in the river (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 use that date for immediate use purposes. 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:
There are also emerging technologies such as radar and ultrasonic which can be used to measure water depth.
While there are many methods / technologies available, the most common and the most stable method is the shaft encoder float and wheel system. This method required a large well or a smaller pipe to be installed on the stream or river bank or on a bridge structure to provide a stable / not disturbed by flow or wind measurement environment for a small float, a float line and a counter weight so the movement in stream / river level can be measured by rotation of the shaft of a wheel. Typically the shaft rotation is measured very accurately by light or laser encoder, and the data is shown on the display and is recorded in the data logger within the instrument.
The Unidata 6541C Precision Water Level Instrument is a very accurate shaft encoder instrument, which has an LED display for the water level, as well as an internal data logger so water level readings can be recorded every 1, 5 or 10 minutes as required.
When a Neon Remote Terminal or Module is added, the water level information can be transmitted over the internet to a central Neon server to allow authorities view the data on the web in near real time.
|Options for Application Specific Instruments / Inputs||Unidata Part Number||Description|
|Ultrasonic Doppler Instrument - Velocity and Depth||6526H-21||Starflow Ultrasonic Doppler Instrument 0-2m|
|Ultrasonic Doppler Instrument - Velocity and Depth||6526H-51||Starflow Ultrasonic Doppler Instrument 0-5m|
|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 - NRT / RTU / Field Units||Unidata Part Number||Description|
|Cellular RTU 3G||2013F-AB03||Neon Metering Module 3G with Antenna and Li Battery|
|Cellular RTU 4G||2013F-AB04||Neon Metering Module 4G with Antenna and Li Battery|
|Cellular RTU 3G - Industrial||2016F-AB03||Neon Remote Terminal 3G with Antenna and Li Battery|
|Cellular RTU 4G - Industrial||2016F-AB04||Neon Remote Terminal 4G with Antenna and Li Battery|
|Low Earth Orbit Satellite Globalstar||2015E-AB0||Neon Remote Terminal - Satellite Globalstar Modem with Antenna and three Li Batteries|
|Ethernet||2017E-0B0-1 or 3||NRT Ethernet with single or triple Ethernet Ports|
with three Li Batteries
|Equatorial Orbit Satellite - Inmarsat||2018E-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||2015E,2016F,2017E, and 2018E 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|
|Standards Starlogger||6004D-11||Red Logger 512K with Alkaline Battery|
|Display Starlogger||6004D-21||Blue Logger 512K with LCD and Alkaline Battery|
|Prologger||7001D-11||Green Logger 1M with LCD and Alkaline Battery|
|Starlogger Field Termination Strip||6103E||6004D FTS|
|Prologger Field Termination Strip||7100E||7001D FTS|
|Starlog V4 Management Software||6308A-AUE||Starlog V4 Full Licence Key|