Frequently Asked Questions

Disclaimer

Use of this site is subject to the disclaimer on the Home page.

INTRODUCTION

The waterlevel.ie website provides you with real-time access to data that has been recorded by the Office of Public Works (OPW) hydrometric network. The primary focus of the site is the transfer of water level data, however, additional parameters such as water temperature are presented as a by-product of water level data collection. The OPW hydrometric network extends to approximately 380 surface water monitoring stations located on rivers, lakes and tidal locations throughout the Republic of Ireland. Many of these stations are presented on the website.

Processed archive hydrometric data can be accessed through the Hydro-Data website:

http://waterlevel.ie/hydro-data/

It is important that you read carefully all of the notes provided below.

If you have any queries or comments concerning the use of the site or the data, before contacting us please read the FAQs first.

Frequently asked questions (FAQ)

How reliable is the data presented on this website?
Why is the monitoring station I am interested in not displaying up to date data?
How often are monitoring stations maintained?
Why do some monitoring stations regularly stop and start working?
I can see what the water level is now but how does it relate to "normal" water levels?
What is a Hydrometric Area?
What are station numbers?
How do I view a monitoring station on the map?
How do I view a monitoring station in a list?
How are water levels recorded?
How is the water level data gathered and transmitted?
Why is water temperature recorded?
How accurate is the water temperature data?
Is flow data recorded on this site?
How can I get more than 5 weeks of data?
Can I reproduce data from this website?
Why are times recorded to UTC (GMT)?
How can I search for a specific monitoring station?
What datum are water levels relative to?
Why do some monitoring stations presented not have standard reference numbers?
What monitoring stations can be republished?

Q. How reliable is the data presented on this website?

Data is provisional, unchecked, and has not been validated to remove invalid or improbable values. Caution should be exercised in the interpretation and / or use of supplied data.
Data may be inaccurate due to instrument errors, malfunctions or physical changes at the monitoring station.
Data may be delayed due to telemetry issues or system malfunctions.
Data is provided on a best efforts basis - the OPW will endeavour to maintain data availability, but does not guarantee continuity of services.
It is the responsibility of the user to ensure that the data, if used, is accurate and fit for purpose.
The logger and telemetry equipment can malfunction or break down, and therefore gaps may occasionally appear in the records provided. These gaps must be considered when evaluating the data, and in particular peak or low water levels. It is also possible that sensors can display incorrect data due to a number of factors such as: faulty sensors, blocked stilling wells, build up of debris/silt, etc.

The operations of the Hydrometric Section of the OPW are quality assured and have been certified under ISO 9001:2008 by the National Standards Authority of Ireland. While the quality management procedures include quality control of data, this does not apply to data presented on the waterlevel.ie website as real-time provision of data does not facilitate application of normal quality processing procedures. The data presented on the site contains no guaranteed accuracy, and users must undertake independent quality control and verification procedures appropriate to any proposed use. To this end, calibration data is available for graphical presentation and download from the Hydro-Data website.

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Q. Why is the monitoring station I am interested in not displaying up to date data?

The Hydrometric Section operates several hundred remotely monitored stations around the country. Data from a station may be delayed due to telemetry issues or system malfunctions. When a station is late displaying data we operate on a best endeavours basis to resolve the problem as quickly as possible, however we give no guarantee of uptime or to fix the station within a given time frame.
 
Please do not contact OPW informing us of stations not displaying up to date data as we will already be aware of this.

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Q. How often are monitoring stations maintained?

Station visits are undertaken periodically to ensure the upkeep of the equipment. This visit is normally undertaken every 6 weeks. During this visit the Field Technician will check that the level displayed on the logger is the same as a staff gauge placed in the water, this is to ensure the logger is accurately representing the level of the water body. It should be noted that malfunctions can occur between these visits and all data displayed on www.waterlevel.ie is raw unchecked data, and has NOT been subjected to any quality processes. Caution should be exercised in the interpretation and / or use of supplied data.

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Q. Why do some monitoring stations regularly stop and start working?

All of our stations operate using remote telemetry. If there is an area with poor mobile phone network coverage a station can be irregular in the times that it sends its data in. There is nothing we can do to resolve this. Please do not contact OPW informing us of stations not displaying up to date data.

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Q. I can see what the water level is now but how does it relate to "normal" water levels?

If you are interested in seeing how the current water level relates to previous levels reached in the water body you can access our archive data website on www.opw.ie/hydro. Search for the monitoring station of interest and look for the “Annual Maxima” tab. This will give you a list of the maximum levels recorded at that station in each Hydrometric year for the duration of the record available.

http://waterlevel.ie/hydro-data/

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Q. What is a Hydrometric Area?

For the purposes of hydrological activities and by agreement between the various hydrological agencies in Northern Ireland and the Republic of Ireland, Ireland is divided into 40 Hydrometric Areas. Each Hydrometric Area comprises a single large river basin, or a group of smaller ones, and neighbouring coastal areas.  Each area is assigned a number from 01 to 40 beginning at the Foyle Catchment and proceeding in a clockwise direction (an exception to this general scheme is the catchment of the River Shannon and its tributaries which, because of its size, was divided into two hydrometric areas, 25 (Lower Shannon) and 26 (Upper Shannon)).

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Q. What are station numbers?

Each individual hydrometric station number is made up of five digits where the first two digits indicate the Hydrometric Area in which the monitoring station is located and the final three digits the unique station number within the Hydrometric Area. Thus the first two digits of a station number is a general indication as to where the station is located. The fourth digit in the station number also has a special significance. If the value of the fourth digit is between 0-5 then the station is on a river, 6 denotes a station on a tidal channel or sea and 7- 9 indicates a station on a lake, reservoir or a location affected by backwater.

For example: The station number for Station 12002 Enniscorthy is made up as follows:

12 denotes that it is in Hydrometric Area 12 (Slaney and Wexford Harbour), and

002 is the unique station number within the Hydrometric Area.

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Q. How do I view a monitoring station on the map?

A stations map is presented on the left of the homepage. Each station is represented by a station node on the map, and by placing the cursor over an individual node, the station name is presented to the bottom right of the map. Zoom functions are available to the top right of the map.

In order to view available station data, simply click on the node. This produces a range of parameter options. Click on the desired parameter to view the associated data.

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Q. How do I view a monitoring station in a list?

The stations are also presented in a list to the right of the map. The stations are listed by station name or station number. To select a station, simply click on the desired station to view the range of parameters available. Click on the desired parameter to view the associated data.

To list the stations by any of the list headings, i.e. alphabetically, numerically or otherwise, simply click on the desired heading and the stations will sort accordingly.

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Q. How are water levels recorded?

Water level data is collected using data loggers. A data logger digitally records the water level at set time intervals using a pressure transducer immersed into the water body, or by using an ultrasonic receiver.

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Q. How is the water level data gathered and transmitted?

The data recorded on the data logger is transmitted using telemetry. The telemetry systems utilise Global Packet Radio System (GPRS) to transfer data from the station logger to a web server, where it is configured and presented on the waterlevel.ie website.

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Q. Why is water temperature recorded?

Water temperature is collected as a by-product of the water level collection process. This is to provide greater accuracy of water level recording through application of temperature compensation within the pressure transducer sensor.

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Q. How accurate is the water temperature data?

It should be noted that water temperature data presented on the website has not been calibrated or been subjected to any quality processes. Caution should be exercised in the interpretation and / or use of supplied data. Sensors are deployed in a variety of ways aimed at recording accurate water levels, e.g. within stilling wells, within conduits laid on the river bed, etc. The deployment will greatly affect how well the temperature recorded reflects the ambient temperature of the water body. Caution should be exercised when evaluating temperature data displayed on waterlevel.ie.

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Q. Is flow data recorded on this site?

A number of hydrometric stations are fitted with side looking acoustic doppler profiler (ADP) devices. These instruments continuously monitor water velocity as well as a number of other operational parameters. These instruments make it possible to present flow data in real-time as the flow estimation calculation is undertaken at the point of data collection. It should be noted that flow data and associated by-product parameters presented on this website have not been subjected to standard quality processes. Caution should be exercised in the interpretation and / or use of supplied data.


To view flow data for OPW hydrometric stations, the full hydrometric archive containing processed flow data is available on the Hydro-Data website, see link below.

 

http://waterlevel.ie/hydro-data/

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Q. How can I get more than 5 weeks of data?

The data presented on the waterlevel.ie website is limited due to the primary operational data transfer function of the website. A 5 week rolling window of data is presented. The full hydrometric archive of processed data is available on the Hydro-Data website, see link above. The Hydro-Data website presents a range of data types including station meta-data, mapping, instantaneous data, sub-daily data series, summary statistics, and annual maxima series.

http://waterlevel.ie/hydro-data/

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Q. Can I reproduce data from this website?

Re-use of data from this website is subject to licence under DIRECTIVE 2003/98/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the re-use of public sector information. Full details of this licence can be found at http://circulars.gov.ie/pdf/circular/per/2016/12.pdf

http://www.per.gov.ie/en/open-data/

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Q. Why are times recorded to UTC (GMT)?

It is common practice when recording Hydrometric data that the changes for British Summer Time are ignored and the clock stays constant throughout the year. This is to avoid the complication of losing and gaining an hour twice a year. All data available on waterlevel.ie will always be to UTC (GMT).

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A quick search / filter option is available to the right of the map, in the search / filter box above the station list. Stations can be filtered by various criteria including station number, station name, river, catchment, River Basin District (RBD) or Hydrometric Area.

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Q. What datum are water levels relative to?

The water levels are recorded as water depth (stage) above the zero level on a local staff gauge. The zero levels of the staff gauges have been surveyed to either Poolbeg or Malin Head Ordnance Datum levels, and in some cases, these heights are added to the recorded levels (stage) to provide water levels to an Ordnance Datum. It is important that you check which datum level is being used for each station accessed.

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Q. Why do some monitoring stations presented not have standard reference numbers?

The OPW sometimes installs monitoring stations for operational or test purposes that are not suitable for use or re-publication by third parties. See FAQ on "What are station numbers?"

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Q. What monitoring stations can be republished?

Only monitoring stations with reference numbers between 00001 and 41000 are suitable for republication, data from stations with reference numbers outside this range should not be used or republished without express permission from OPW.

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