About Flood Watch

Flood Watch provides up-to-date information about the current state of rivers and rainfall about the Marlborough District

Flood Watch is designed for flooding events and shows thresholds at all times

This enables the flooding event to be put into perspective, allowing individuals to make their own assessment on how they may be affected and decide on what appropriate action they may take.

Due to the fixed scale of the graphs, the river flows will seem rather flat during normal flows.

Flood Watch Checks for new information every 5 minutes Symbols may suddenly disappear during updating

Flood Watch Has been designed for a minimum screen resolution of 1024 x 800. You can maximize the map by hitting F11 on desktop.

Rainfall

There is no forecasting on these graphs.

Rainfall thresholds are indicated by the change in colour. See Rainfall legend information in the legnds menu.

These graphs have a fixed scale of 25mm/hour. This enables an easy visual comparison of graphs.

Rainfall Legend

The legend shows the different thresholds for rainfall levels. There are six different threshold levels, 5 which represent different return periods and one which indicated no recent data.

Statistical techniques, through a process called frequency analysis, are used to estimate the probability of the occurrence of a given precipitation event. The recurrence interval is based on the probability that the given event will be equaled or exceeded in any given year.

River Levels

Various threshold levels, appropriate to the location, appear on these graphs. Labels on the threshold lines give individuals an appreciation of what the thresholds mean.

River Flows

The 'River Flow' is measured in 'cubic metres per second' and shown as 'm3/s'.

The graphs extend over a 36 hour period. The 'blue line' traces the actual flow preceeding the 24 hours where as the red line is the forecasted flow extending for the next 6 hours.

The forecast flow is only available on graphs where there is sufficient historical information to develop a forecast. Forecasts are a guide only.

River Levels

Various threshold levels, appropriate to the location, appear on these graphs. Labels on the threshold lines give individuals an appreciation of what the thresholds mean.

Legend

  • Exceeds 50 year
  • Exceeds 10 year
  • Exceeds 2 year
  • Exceeds 50% of 2 year
  • Less than 50% of 2 year
  • No data within last 6 hours

Layers

Title Bar

Content

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