The EPA maintains the Register of Hydrometric Stations In Ireland. This lists all of the active and historical hydrometric stations in Ireland. An explanation of this register is outlined below.
For the purposes of hydrological activities and by agreement between the various hydrological agencies in Northern Ireland and the Republic of Ireland, Ireland was 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 was 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)).
Each individual hydrometric station number is made up of five digits where the first two digits indicate the hydrometric area in which the 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 vakue 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 12034 Kildavin is made up as follows:
12 denotes that it is in Hydrometric Area 12 (Slaney and Wexford Harbour)
034 is the unique station number within the Hydrometric Area and the digit 3 indicates that it is a station on a river
The station type describes the type of hydrometric station present at the site.
Staff Gauge Only: indicates a station fitted with a staff gauge. A staff gauge is a long metal strip with metric graduation marks to give a visual indication of water level.
Recorder: indicates a station fitted with a staff gauge and an automatic water level recorder. The aotomatic water level recorder can either be an autographic recorder or a digital datalogger. An autographic recorder is a simple float operated device that records waterlevel by activating a pen marking the water level on a chart. These charts are then digitised to convert the data to a digital format. A datalogger is a device that records water levels in digital format in equidistant time (in most cases every 15 minutes).
Measurement Site: locations where a number of spot flow measurements have been carried out. No staff gauge, autographic recorder or datalogger is present.
The EPA has classified the hydrometric stations in the local authority network into the following four categories:
Active : indicates a station where regular monitoring is carried out.
Suspended: indicates a station that was erected for a particular investigation, the purpose of which has now ceased but that may be reinstated in the future
Inactive: indicates a station that was erected for a particular investigation which has now ceased. No measurements are currently being taken.
