Loading The Rajang at Sibu: Flood Levels…
The river's level in town against the four levels DID Sarawak publishes for that gauge — plus why Sibu only floods when upriver rain meets a king tide, and which areas the flood scheme leaves out.
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Below the alert level
Batang Rajang at 0.77 m
Sibu does not flood because of rain in Sibu. It floods when rain that fell days earlier in Kapit, Baleh, Kanowit and Song comes down the Rajang and meets a king tide holding the water back at the mouth. Either one alone the town absorbs. Together they put water into the same streets each time.
This page shows the Rajang's level at the Express Terminal in town, against the four levels the Drainage and Irrigation Department publishes for that exact gauge. Read the two things together: the level here, and whether there is heavy rain upriver.
Right now
The Batang Rajang is at 0.77 m
Against the published thresholds, that sits in: Below the alert level.
Measured 24 Aug, 9:45 am. Next threshold: 2.50 m (Waspada — Alert (2.50 m)).
The gauge is on the Rajang at the express boat terminal in the middle of town. It is tidal: the level rises and falls by up to about a metre and a half twice a day with the tide, entirely on its own, with no rain anywhere. A reading going up is not by itself a sign of a flood — what matters is how high it gets against the levels below, and whether it keeps climbing through a falling tide.
Who decides the flood degree
The flood degree actually in force is declared by Jabatan Pengairan dan Saliran (DID) Sarawak. A gauge reading passing a published threshold does not by itself mean that degree has been declared — it’s the trigger the authority weighs, not the decision. For the official current degree:
When the river rises fast, minutes matter. The surest thing you can do today is make sure the town can reach you — sign up for the alerts and keep the numbers to hand.
The body that declares a flood, opens relief centres and announces both. Its statements go out through the state government portal, local radio and the press.
The state's own gauge readings, refreshed about every fifteen minutes, with a 24-hour history per station so you can see whether the river is still climbing.
Call for help leaving a flooded house or moving someone who cannot move themselves.
The river is under 2.50 m at the Express Terminal — its ordinary range, tide included.
The river has reached the level at which the department starts watching this gauge closely.
Only 12 cm above the alert level. Low-lying areas start taking water at about this point.
The department's highest published level for this gauge. Relief centres have opened at this stage before.
The parts of town that have flooded before — worth knowing which one is yours. This is where water has reached, not a street-by-street prediction.
DID Sarawak's own flood records for Sibu keep giving the same cause, in the same words: continuous rain coinciding with a high tide, which pushes the Rajang up. That is why watching Sibu's weather is not enough. The rain that floods this town falls in Kapit, Baleh, Song and Kanowit and takes days to arrive, and it only becomes a flood if it reaches the delta while a king tide is holding the water back. So the useful question is never just "is it raining". It is: has it been raining hard upriver, and is the tide big this week.
DID Sarawak publishes an annual Sarawak King Tide Period list — 187 dated entries for 2026, each with a time. The remaining 2026 windows include 13–18 August, 27 August to 2 September, 9–15 September, and the year's biggest run from 25 October to 2 November, peaking on 27 and 28 October. One caution DID states itself: the predicted heights on that list are measured at Pending Port, Kuching, and are "valid for Kuching and its vicinity" as a general guideline. So the dates are useful here and the heights are not Sibu's. The Rajang at Sibu runs a couple of hours behind the Kuching peak.
Sibu's MP, Oscar Ling Chai Yew, has said publicly that the existing flood control plan covers the town centre and not the outskirts — specifically the west bank and the Salim areas. Those are also the places DID's own flood records name most often. If you live there, the plan that protects the shophouse blocks is not protecting you, which is the honest reason to watch this gauge yourself.
At this gauge, Alert is 2.50 m, Warning 2.62 m and Danger 2.90 m — forty centimetres from the first rung to the last. On a river that already moves more than a metre with each tide, that means the difference between watching and acting can arrive within a single tide cycle. It is a reason to act at Alert rather than wait for Warning.
This page now reads DID Sarawak's own iHydro portal rather than the national one. The national feed had been publishing a flat 0.00 for most of Sarawak's gauges, this one included, which the site refuses to show rather than print a made-up level — so for three days this page said the gauge was not reporting while the state's own portal had real readings all along. If iHydro itself goes quiet, the page will say so again: the ladder, the flooded areas and the numbers to call stay on the page either way, and a level is never invented to fill the gap.
Jabatan Pengairan dan Saliran (DID) Sarawak
DID measures the rivers, publishes the four levels used on this page, and issues the flood warnings. Whether a flood is declared, and whether relief centres open, is the district disaster committee's decision — not DID's, and not this page's.
Checked 24 Aug, 9:47 am. Live level and published alert thresholds from the Department of Irrigation and Drainage Sarawak (DID Sarawak), iHydro. Automatic telemetry, unchecked at publication.