Will the Maha Oya at Badalgama rise in the next hour?

In the next hour the Maha Oya at Badalgama could rise to about 18.9 ft (18.7–19.4 ft). This is a forecast from the recent trend, the gauges upstream and rain, not an official warning.

What is the flood level at Badalgama?

The official marks for this gauge are alert 16.4 ft, minor flood 20.3 ft, major flood 31.5 ft. Alert means the river has reached the alert mark: move valuables up and charge your phone. Minor flood means water is spilling over low ground, and major flood means move to safety.

Where does this come from and how often does it update?

River readings come from the Department of Irrigation's gauges, roughly once an hour, and this page checks for new ones every minute. This site is independent and not an official warning service: follow the Disaster Management Centre and call 117 in an emergency.

Badalgama Maha Oya water level

As of Tue, 27 Oct, 3:03 am (Sri Lanka time), the Maha Oya at Badalgama was 18.8 ft, above the 16.4 ft alert level, and rising.

In the next hour it could rise to about 18.9 ft (18.7–19.4 ft).

Reading at 3:03 am · 29 min ago

Alert

18.8 ft

Next hour

Rising slowly

Next 24 hours

Could reach flood level in ~11 hours

Move valuables up, charge your phone

The river is above alert level and is likely to reach minor flood level around 2 pm this afternoon (in about 11 hours).

Call 117 Gampaha DMC office

Details

Above alert level now and likely to reach minor flood level around 2 pm this afternoon (in about 11 hours) (about 65% chance).

Published as 5.73 m (alert 5.0 m, minor flood 6.2 m, major flood 9.6 m)

Elevated river-flow outlook this week.

In	Level	80% range	At
1h	18.9 ft	18.7 to 19.4	4:03 am
3h	18.8 ft	18.1 to 20.5	6:03 am
6h	18.5 ft	16.5 to 21.5	9:03 am
12h	18.1 ft	14.6 to 28.4	3:03 pm
24h	17.9 ft	10.5 to 39.5	3:03 am

Minor flood (20.3 ft): likely, about 6 in 10, from about 2:03 pm
Major flood (31.5 ft): unlikely, about 3 in 10

Local trend

+0.2 ft/h

Upstream avg

-0.2 ft/h

Rain that fell: 0.0 mm in the last 3 hours, 91 mm in the last 24 hours at this gauge (heavy rain) (heavy for this river)
Rain forecast: 4.4 mm in the next 24 hours over the catchment (light rain). Forecast model estimate.

Satellite estimate of rain over the catchment: 3.7 mm in the last 6 hours, 108.4 mm in the last 24 hours (to 3:00 am). It can differ from the gauges. GSMaP data by Japan Aerospace Exploration Agency (JAXA)

Giriulla 1.2mm

· Outlook: the GloFAS global flood model has river flow at 470 m3/s in its highest member within 7 days, above the 1-in-20 level (196 m3/s). This is a heads-up only; it does not change the levels above.
· Part of the range is above the highest level this model has seen (12.3 ft); treat it as a rough guide.

How this is worked out
· Latest level at Badalgama and recent change, plus upstream gauges: Giriulla.
· Forecast model estimate of catchment rain (Open-Meteo, area average over 22 grid cells above Badalgama): 71 mm modelled for the last 24 hours, 4 mm forecast for the next 24 hours, with ECMWF ensemble spread.
· The 1, 3, 6, 12, 24 hour steps use this gauge's own recent changes and the other gauges on the river (fitted to about 11 months of hourly readings, including the November 2025 Ditwah floods); where this was tested against 'level stays the same' it missed by less.
· Heavy rain upstream is part of the 1, 3, 6, 12, 24 hour steps: rain that has fallen or is forecast over the catchment above Badalgama raises the level, and the top of the range allows for the heavier forecast rain. Tested storm by storm (leaving each storm out, Ditwah included) it was closer than the river's own trend alone.

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Water level

How this river reacts to rain

Rain close to Badalgama shows up in the river in about 10 hours.
Rain on the upper river (above Giriulla) reaches here in about 32 hours.
About 30 mm of rain over 24 hours, averaged over the catchment, has usually come before a rise of 1 ft or more.

Learned from 11 months of readings and satellite rain. A guide, not a forecast.

This gauge’s forecasts: the next hour is typically off by about 0.03 ft; 24 hours ahead, by about 1.5 ft (last 30 days, 28 checks).

When does Badalgama flood?

Flood warnings come mostly in November.

It’s October: floods are less common than in November, but they do happen.

Recent floods

27 Nov – 30 Nov 2025Major flood
21 Oct – 26 Oct 2025Major flood · estimated
27 Nov – 2 Dec 2024Major flood · estimated

Every day since 2022, year by year

Other stations

Along the Maha Oya

Arrows show the change over the last 3 hours.

Towns that depend on this gauge

Common questions

Is Badalgama flooding now?: As of Tue, 27 Oct, 3:03 am (Sri Lanka time), the Maha Oya at Badalgama was 18.8 ft, above the 16.4 ft alert level, and rising.
Will the Maha Oya at Badalgama rise in the next hour?: In the next hour the Maha Oya at Badalgama could rise to about 18.9 ft (18.7–19.4 ft). This is a forecast from the recent trend, the gauges upstream and rain, not an official warning.
What is the flood level at Badalgama?: The official marks for this gauge are alert 16.4 ft, minor flood 20.3 ft, major flood 31.5 ft. Alert means the river has reached the alert mark: move valuables up and charge your phone. Minor flood means water is spilling over low ground, and major flood means move to safety.
Where does this come from and how often does it update?: River readings come from the Department of Irrigation's gauges, roughly once an hour, and this page checks for new ones every minute. This site is independent and not an official warning service: follow the Disaster Management Centre and call 117 in an emergency.