Reading the river

Part one · Set up

Before you start

River Flood Watch shows the current water height at river gauges across Queensland's catchments, arranged upstream to downstream, so you can answer one question quickly: is my street at risk?

Three things are worth knowing before you rely on it.

The readings are the Bureau's, and they arrive hourly

Every height on this site came from a Bureau of Meteorology data extract. A new file is published roughly once an hour, and the site picks it up within about fifteen minutes of it landing. Nothing here is measured by us, and nothing is smoothed, corrected or predicted: what you see is what the gauge sent.

There is no account, so nothing follows you between devices

There is no sign-up, no email address and no password. The gauges you choose are written into the browser you chose them in, and they never leave it: nothing is sent to us, and there is nothing on our side to sync.

It is stored per browser rather than per device, so one laptop running both Chrome and Firefox keeps two separate lists. Three other things will empty a list you have already made:

• Clearing your browsing data. Anything that clears cookies and site data for this site clears your gauges along with them.
• A private or incognito window. It forgets the moment you close it, every time.
• A browser that refuses storage. Some privacy settings block it outright. The site still works and you can still choose gauges for that visit; it simply will not remember them next time you come back.

It is not a warning service

That sentence is at the bottom of every screen, and the long version, what this site can and cannot tell you and who to follow instead in an emergency, is worth five minutes before you rely on any of it: read the full disclaimer.

Part one · Set up

Set it up in ten minutes

Out of the box the site shows a default set of gauges down the Brisbane River. That is a reasonable starting point and a poor finishing point: the whole value of the site comes from watching the water that actually reaches you.

1. Open the site and find the Choose gauges button. It sits in the panel just under the site's name, beside See these on a map and Save as PDF. Press it.
2. Work out which water reaches you, before you touch the list. Which river or creek runs through your area, and which way does it flow? A map will answer both in a minute: search your suburb in Google Maps and follow the blue line, or open your council's flood map. This site cannot tell you this, and it is the one thing you need before the rest is useful.
3. Get the Bureau's station numbers for that water. Google, or an AI assistant, will do this legwork if you ask it plainly: "which Bureau of Meteorology river height stations should I watch for flooding at [your suburb], and what are their station numbers?" Ask for the station numbers specifically: they are the Bureau's own IDs, they look like 540198, and the picker's search box takes them, so each one goes straight to its gauge with no hunting through headings.
4. Sanity-check whatever you were told. Trace the stations it named on the map and confirm they really are on your water and really are upstream of you (a confident wrong answer about which gauge covers you is worse than no answer, and these tools produce them). If a station number finds nothing in the picker, that is not a bad number: it means this site does not publish that station yet, and the Bureau's own site will still have it.
5. Narrow to your catchment. If the Catchment dropdown is showing, set it to your river system. If it is not showing, everything the site publishes is already in one catchment and there is nothing to narrow.
6. Work down the watercourse headings to find your gauges. The list is grouped by river and creek, and within each group it runs upstream to downstream, so find the heading for your water, then read down it to the gauge nearest you. Tick that one, then the ones above it. See Which gauges to choose, which is the part people skip and the part that gives you warning time.
7. Press ‹ Back to the river. Your list is now on the front page, in river order, and it will be there next time you open the site on this device.
8. Bookmark it. On a phone, add it to your home screen. The one time you will want this site is the one time you will not want to be searching for it.
9. Now do it again on your other devices. Your choices live in the browser you made them in and do not travel, so your phone, your tablet and each computer you use need setting up separately. See There is no account.

Part one · Set up

Choosing your gauges

The Choose gauges button opens a screen headed Choose your gauges. It lists every gauge the site publishes, grouped by catchment and then by watercourse, so the heading answers "which of these is my river" before you have read a single station name. The Brisbane River sorts to the top of its group; everything else is alphabetical.

What each row tells you

A row is a tick box with three lines of information under the name:

• the gauge name, as the Bureau names it;
• the suburb, the watercourse if it is not the Brisbane River, and the station number, the Bureau's own ID, which is what to quote if you are cross-checking against their site;
• when it was last updated, as an age: updated 12 minutes ago, updated 3 days ago, or no data yet for a station that has been switched on but has never reported.

Some rows also carry a provisional levels flag. That is important and is explained under Flood levels.

The three tools at the top

Search. One box, matching a gauge's station number, its name, its suburb, its watercourse and its catchment all at once. So Bremer finds that whole river and 540198 finds exactly one gauge. Partial station numbers narrow usefully, because the Bureau prefixes its IDs by basin.

Catchment. A dropdown that restricts the list to one catchment. It only appears when the site publishes more than one, and it composes with the search: filter to a catchment, then search within it.

Hide gauges with no reading in 5 days. A tick box, off by default, that removes stations which have gone properly silent. The catalogue contains plenty of them: published, classified, and not reporting. When you are spending ten slots, a station that has produced nothing since March is not a candidate. Two things it will never do: it never hides a gauge you have already chosen, and if the filter empties the list it says so and offers to show them anyway.

The limit is ten per catchment

The counter at the top reads 3 of 10 chosen. Ten is deliberate: it is about as many rows as fit on a phone screen without the list becoming something you scroll rather than something you scan.

The limit is per catchment, not overall. Filling the Brisbane costs you nothing on the Mary. When a catchment is full, its unticked boxes go grey and the heading tells you to untick one to make room; boxes in other catchments are unaffected.

Starting over

Use the default river forgets your choice entirely and puts back the default set of gauges. That is different from unticking everything: unticking everything gives you an empty list that says so, which is a valid thing to want, and this button undoes the whole decision.

Part one · Set up

Which gauges to choose

Most people tick the gauge nearest their house and stop. That gauge tells you what is happening now; it gives you no warning at all. A useful list has three kinds of gauge on it.

1. Your own reach

The gauge closest to you, on the water that runs past you. This is the one whose flood levels actually describe your streets. It may well be named after a suburb that is not yours, because gauges are named for where the instrument stands and there are far more suburbs than gauges. What matters is that it is on your watercourse and near you, not what it is called.

2. Two or three gauges upstream

This is where your warning time comes from. Water that is at a gauge 40 km upstream this morning is your problem this afternoon. Pick them at a spread of distances rather than clustered (one close, one middling, one well up the catchment), so you can see the shape of what is coming, not just that something is.

3. The tributary that feeds you

Rivers are not lines. If you are in Ipswich, your flood is decided by the Bremer, which is not on the Brisbane River at all, and what the Bremer does today is often what the Brisbane does tomorrow. Find the creek or river that joins upstream of you and put a gauge on it.

A last note on tributaries: a tributary is usually in the same catchment as the river it joins. The Bremer sits inside BRISBANE, so it costs one of your ten Brisbane slots and appears on the same list, which is exactly what somebody in Ipswich needs, since the two have to be read together.

Part two · Read the river

Reading the river list

The front page is your gauges, drawn down a river line, upstream at the top and downstream at the bottom. Read it in this order.

The headline sentence

One line, in plain English, describing your gauges, not the whole catchment. It is one of:

• The river is low and steady from Fernvale to the mouth.
• Levels are rising, but still below minor flood level.
• 2 gauges are at or above minor flood level.
• No gauge is reporting a reading right now.

If you read nothing else on the page, read this. It is written so that silence is never reported as calm.

The card underneath it

Everything on that card is about the list rather than on it: the catchment dropdown (only shown if you follow gauges in more than one), the two buttons for the map and the report, and a line reading something like 10 gauges · Updated 3:15 pm · next 4:15 pm.

Check that update time. It is when the readings on screen were published, and next is when the following batch is expected.

A gauge row

Illustration only: this height is invented. The vessel on the left is the height drawn as a proportion of that gauge's major flood level. The number on the right is the same fact in metres.

So a vessel that is half full means the river is halfway to major flooding at that gauge. Because each gauge has its own flood levels, two rows with similar-looking vessels are not necessarily in similar trouble, and two rows showing the same number in metres almost certainly are not. Compare vessels, not numbers.

Tap or click any row to open that gauge in full.

Switching catchments

The list shows one catchment at a time, and there is no "show me everything" option. That is deliberate: upstream-to-downstream only means something inside one river system, and two catchments interleaved would be a list in an order that means nothing. If you follow gauges in more than one, use the Catchment dropdown, and note that the page remembers where you were, so / next time means "the river I was reading".

Part two · Read the river

Colour, status and what each band means

Colour on this site carries flood status and nothing else. Every colour is also stated in words next to it, so nothing depends on your being able to tell orange from red.

Minor, moderate and major are the Bureau's own published classifications for that specific gauge, and the descriptions above are condensed from the Bureau's own definitions of the three bands.

Part two · Read the river

When a gauge stops reporting

Sensors go quiet. It happens on ordinary days and it happens during floods, and the site is careful to distinguish two very different kinds of silence.

One gauge has gone quiet

The row turns grey, the height is replaced by a dash, and a line appears saying No reading since 4:00 am · last 12.40 m.

Read that carefully. The last height is quoted because it is still the best information anyone has about that reach, but it is history, and the site refuses to print it where a current reading goes. A grey row with an empty vessel is not a low river.

A gauge counts as quiet after six hours without a reading. Note that some Bureau stations only transmit when the level changes, so a few hours of silence on a flat afternoon is normal rather than a fault.

The whole page has stopped updating

A separate notice appears above the readings: These readings may be out of date. It tells you when the last update arrived and how long ago that was.

This one is about the site's own data supply, not about any gauge. It appears when no new data has arrived for 90 minutes: long enough to tolerate one missed hourly file, short enough that you are told before two hours of river have gone unnoticed. The readings stay on screen underneath it, because an hour-old river is worth far more than an apology.

If you see it, go to the Bureau of Meteorology for the official heights.

Part three · Read one gauge

One gauge in detail

Tapping a row opens that gauge in full. On a phone it replaces the list: ‹ All gauges gets you back, as does the phone's own back gesture. On a wide screen it sits beside the list.

The pane has four parts, top to bottom.

The reading

The gauge's name, a large number in metres, and a status chip that says the band in words: At minor flood level, Approaching minor flood level, and so on. If the gauge is offline, the large number is a dash rather than a stale height. The last height it sent is in the paragraph below, in the past tense, with the time.

The paragraph

One short paragraph turning the number into something you can act on. For a river below minor flooding it tells you how much further the water would have to climb; for one at or above minor it tells you to check council advice and not to drive through water; for a silent gauge it says when it went quiet and what it last read.

The chart, and the flood levels

These get their own sections below; they are the two parts of this screen people most often misread.

Part three · Read one gauge

The last five days

Under the reading is a card headed Last 5 days, showing hourly readings for that gauge. The line under the heading tells you exactly what span is drawn: Hourly readings · Mon 6 am to now.

How to read it

• Vertical scale. Three labels at the top, middle and bottom of the plot, in metres. The scale fits the data, so it is not the same from gauge to gauge, and not even the same for one gauge from day to day. Always read the numbers on the axis before judging a slope.
• Horizontal rules. Where the gauge's flood levels fall inside the visible range, they are drawn as coloured lines labelled minor, moderate and major. A level well above the current river simply is not in view.
• The dot at the right-hand end is the latest reading, the same number as the big one above.
• Breaks in the line are hours the gauge did not report. The line stops and restarts rather than being drawn straight across a gap, so you can see what is measured and what is missing.

What you are looking for is the shape: rising, falling, or flat, and how steeply. Five days is long enough to show a flood peak passing, and the rise before it, and short enough to stay legible on a phone.

If the chart does not draw

You may see Loading the last 5 days…, The last 5 days couldn't be loaded just now, or No readings from this gauge in the last 5 days. None of these affects the rest of the pane: the height, the status and the flood levels come from elsewhere and are still good.

Part three · Read one gauge

Against past floods

Where the site holds historic flood peaks for a gauge, a Past floods button appears at the top of the chart card. Pressing it opens a column beside the chart headed Against past floods, ranking today's reading against the major floods on that gauge's record: 2022, 2011, 1974, and whatever else has been transcribed for it.

Under the column is the sentence that most people actually want: Today is 8.31 m below the Jan 1974 peak. Note that it names the highest peak on that gauge's record, which is not always 1974. Upstream of Wivenhoe it is; on the Bremer it can be an older flood still; at a gauge whose only imported flood is 2022, it is Feb 2022.

If a gauge has no Past floods button, there is nothing to show for it: either no peaks have been transcribed, or the ones that exist were recorded against a different zero point and cannot honestly share this gauge's scale. The site drops them rather than converting them.

The button is off every time you open a gauge. That is deliberate: the everyday question is "is it rising?", and the comparison is the one you go and ask for.

Part three · Read one gauge

Flood levels, and the four things this panel can say

At the bottom of each gauge is the panel that makes the height mean something: the minor, moderate and major levels for that specific location, with a one-line description of what each one does on the ground. Levels the river has already passed are tinted.

Check the heading of this panel. It is one of four, and they are not interchangeable.

Datum: why you must never compare two gauges' numbers

The last line of the panel reads Heights are metres on this gauge's own datum (LGH), or (AHD).

A datum is the fixed zero a height is measured from, and different gauges use different ones. 3.4 m at one gauge and 3.4 m at the next are not the same amount of water, and not the same amount of trouble. A height is only ever meaningful against that gauge's own flood levels.

This is also why you should be careful quoting a number you read elsewhere. If a figure from another site or a news report is on a different datum, it can be wrong by several metres in either direction, and in a flood, the direction it is wrong in is the whole question.

Part four · Share it

Seeing your gauges on a map

On the front page, See these on a map opens a picture of your chosen gauges, drawn where they actually are and coloured by flood status. It is closed until you ask for it, so it costs nothing on a phone if you never open it.

Under the picture is a numbered key. The key reads upstream to downstream like everything else, but the pin numbers count down it. The furthest-upstream gauge carries the highest number, and pin 1 is the one lowest on the river. Read the key, not the numbers, to know which dot is which.

If a gauge cannot be placed, because some stations have no coordinates in the Bureau's catalogues, the site names it underneath rather than leaving you to wonder why you counted nine dots under ten gauges.

Press the picture to open a full map you can pan and zoom, in a new tab. The pins there are the same numbers in the same colours. Your river list stays behind it, which is the point of the new tab.

Part four · Share it

Saving and sharing a report

Save as PDF on the front page builds a complete printable report of the catchment you are looking at: a cover page, a map page, and then every gauge in full, with its chart, its comparison against past floods and its flood levels, one to a page.

1. Press Save as PDF. You land on the report page and the toolbar reads Preparing… 3 of 10 gauges.
2. Wait for 10 gauges ready to save. The Save button stays disabled until every gauge and the map have finished loading: a PDF full of "Loading…" boxes is indistinguishable from a river with no data.
3. Your browser's print dialog opens by itself the moment everything is ready. Choose Save as PDF as the destination. If you dismiss it, or you opened the report from a link rather than the button, press Save as PDF on the report's own toolbar instead.

Everything on the paper carries a date, including the year: when the readings were taken, and when the report was made. Each gauge's page repeats the disclaimer and the reading time underneath it, so a single page torn off a stapled report is still safe to read on its own.

Part four · Share it

Flood alerts

The site can send your phone or computer a notification when one of your gauges passes a flood level. Press Alerts in the top-right corner. There is no account and no email address. Alerts are set up per device, so turning them on here does not turn them on anywhere else, and turning them off on your phone leaves your laptop still alerting.

1. Press Turn on alerts. Your browser asks permission first. Nothing is sent to us until you say yes.
2. Set a level against each gauge you want. Every gauge on your river list appears with a dropdown reading No alert. Choose Minor and above, Moderate and above or Major and above. Each takes effect straight away; there is no save button.
3. Expect every catchment here, not just the one you were reading. This is the one screen that ignores the catchment dropdown, because alerts are a standing arrangement rather than a view. If you watch more than one river system the gauges are grouped under a heading naming each catchment, with a count of how many are set in it, so you can see at a glance which river a gauge belongs to.
4. Ten gauges per device is the limit. The count above the list reads 3 of 10 set. That is the same number you may choose per catchment, so one river system in full fits, but if you watch two, you cannot be alerted about every gauge on your list. Once ten are set the dropdowns on the rest grey out; clear one and they come back.
5. Choose the level you would actually act on. Minor on a gauge that reaches minor most winters will teach you to ignore the notification, and then it is worth nothing on the day that matters.
6. Check the card at the top says Alerts are on for this device. That is the only line that means messages can reach you. If it reads Alerts are not set up on this device, your browser has allowed notifications but the device is not registered with us, so nothing would be sent whatever levels you set below — press Turn on alerts again to finish. It can say this after setting up was interrupted, or after your browser cleared the site's data.

You get one alert per crossing, not one an hour while the river stays up. The alert re-arms only once the gauge drops back below the level you chose, so a flood that sits above minor for two days sends one message, and a river that falls and rises again sends a second.

The message names the level the river has actually reached, which may be higher than the one you asked for: a gauge already at major when the alert goes out says Major flooding. A river that keeps climbing after that does not send you a second message, so once you have been told a river is up, go and look at it rather than waiting to be told again.

Part four · Share it

Links you can send someone

Every screen on this site is a real address. All of them work from cold, on a phone, pasted into a message.

Two things worth understanding about sharing:

• A gauge link always works, even if the person receiving it has never chosen that gauge. It resolves against everything the site publishes, not against their list.
• Every other link opens their gauges, not yours. Send someone /catchment/brisbane and they see their own Brisbane gauges, or, if they follow none there, a page telling them so by name. If you want them to see a specific gauge, send the gauge link.

Part five · Reference

If something looks wrong

My gauges have disappeared and the default river is back.

Your browser data was cleared, or you are on a different device or a private window. The list is stored on the device, with no account behind it. Re-choose them from Choose gauges.

I searched my suburb and got "No gauge matches".

Expected, for most suburbs: the box searches gauges, and it only matches a suburb where a gauge actually stands. It does not mean your area has no gauge covering it. Find your river or creek on a map, then search that name, or scroll to its heading in the list. If the message instead says every match has been quiet for 5 days or more, that filter is on; the message itself carries a Show all … anyway link that turns it off.

A tick box will not tick.

That catchment is full at ten. Untick something in the same catchment; the heading above the group says how many of its ten you have used.

A gauge shows a height but no colour and no status.

The site does not hold usable flood levels for it, so it will not guess what the height means. The flood levels panel at the bottom of that gauge says which of the reasons applies.

The whole river list is grey.

None of your gauges is currently reporting. Check the update line on the card and the stale-data notice; then go to the Bureau for official heights.

The heights have not moved in hours.

If the site's data supply has stopped, the notice at the top of the list says so and tells you how old the readings are. If there is no notice, the data is arriving and the river genuinely has not moved, which on a flat day is the normal state of a river.

The map is missing, or a gauge is not on it.

Some stations have no coordinates in the Bureau's catalogues. The site names them under the picture. Their heights are unaffected.

Save as PDF is greyed out.

It is still loading. The line beside it counts the gauges as they settle, and the button enables when they have all finished.

Part five · Reference

What this site will not tell you

Knowing the edges of a tool is part of using it well. This one deliberately does not do any of the following.

• It does not forecast. Every number is an observation already taken. Nothing on this site predicts a peak, a time, or a height.
• It does not issue warnings. Warnings come from the Bureau of Meteorology and your state emergency service.
• It does not know where your house is. A gauge height is the height of the river at the gauge. What that means for your street depends on ground level, and this site holds no ground levels.
• It does not tell you a road is open. The band descriptions say what typically happens at that level in general terms. Local closures are council's and the police's to publish.
• It cannot be relied on to notify you. Alerts exist (see Flood alerts), but they are hourly rather than live, they travel through your browser maker's servers, and a message that never arrives leaves no trace. Treat one as a prompt to go and look, never as the thing that tells you to act.

On the day it matters, the sequence is: look here for the shape of what is coming, then act on what the Bureau and your emergency service tell you.