Water Information Help

Water Level

Water level refers to the height in metres of the river or lake above mean sea level. Note that water level for sites in the Taieri catchment is height above mean sea level plus 100 metres (for example, a water level of 100.5 metres is actually 0.5 metres above mean sea level).

Flow

Flow refers to the volume of water in the river and is given in cumecs. One cumec equals one cubic metre of water flowing past a point in one second. One cubic metre of water equals one thousand litres and weighs one tonne.

Rainfall

Rainfall refers to the depth of rain in millimetres measured during a specific time period. The graphs for each site show hourly rainfall totals for the previous 7 days, and daily rainfall totals for the last 180 days. A total for the previous 24 hour period is also given.

Site Information

The Site Information shows detailed information about each site. Rainfall sites show the start of record, mean annual rainfall and the maximum recorded rainfall in 24 hours. Flow sites show the start of record, catchment area, 3 highest and 3 lowest flows recorded, Mean Annual Low Flow (MALF), and lowest 7 Day Low Flow. The 7 day low flow in any year is determined by calculating the average flow over 7 consecutive days for every 7 consecutive day period in the year and choosing the lowest. When this is done for every year of record, the MALF can be determined by adding the lowest 7 day low flows for every year of record and dividing by the number of years in the record.

Water Temperature

The Water Temperature graph shows the last 180 days water temperature in degrees Celsius. Not all sites have water temperature available.

Graphs

Two graphs of water level, flow and rainfall are shown for each site. The first graph displays the last 7 days of data and the second graph displays the last 180 days of data. Graphs have an extra option to overlay flood warning and minimum levels. These are activated by selecting the 'Show in Graph' box, and then selecting 'Update Graphs'.

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