Nawalapitiya Mahaweli Ganga · මහවැලි ගඟ ජල මට්ටම

Expected to stay below alert level for the next 24 hours.

ප්‍රකාශිත අගය 1.98 m (අනතුරු ඇඟවීම 3.5 m, සුළු ගංවතුර 5.0 m, ප්‍රධාන ගංවතුර 6.0 m)

මෙම සතියේ ගංගා ජල ප්‍රවාහය ඉහළ යා හැක.

• අනතුරු ඇඟවීම (11.5 ft): ඉඩ අඩුයි, 10 න් 1ක් පමණ
• සුළු ගංවතුර (16.4 ft): ඉඩ අඩුයි, 10 න් 1ක් පමණ
• ප්‍රධාන ගංවතුර (19.7 ft): ඉඩ අඩුයි, 10 න් 1ක් පමණ

වැටුණු වැසි

මෙම මාපකයේ පසුගිය පැය 3 තුළ මි.මී. 0.0, පසුගිය පැය 24 තුළ මි.මී. 81 (තද වැසි)

වැසි පුරෝකථනය

ජලඛණ්ඩය මත ඉදිරි පැය 24 තුළ මි.මී. 11 (මධ්‍යස්ථ වැසි). කාලගුණ ආකෘතියේ ඇස්තමේන්තුවකි.

ජලඛණ්ඩය මත චන්ද්‍රිකා වර්ෂාව: පසුගිය පැය 6 තුළ මි.මී. 5.4, පසුගිය පැය 24 තුළ මි.මී. 32.1 (පෙ.ව. 3:30 දක්වා). එය මානයන්ට වඩා වෙනස් විය හැක. GSMaP data by Japan Aerospace Exploration Agency (JAXA)

• · Outlook: the GloFAS global flood model has river flow at 1806 m3/s in its highest member within 7 days, above the 1-in-20 level (732 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 (9.4 ft); treat it as a rough guide.
• · At 3 h, 6 h, 12 h nothing we tested beat 'level stays the same' for this gauge, so that is the line, with a range taken from how much the gauge has really changed over that time.

• මෙය ගණනය කරන ආකාරය
• · Latest level at Nawalapitiya and recent change. No gauge sits upstream of it (or none reports in step with it), so the catchment rain is its upstream signal.
• · Forecast model estimate of catchment rain (Open-Meteo, area average over 5 grid cells above Nawalapitiya): 38 mm modelled for the last 24 hours, 11 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.
• · The 24 hour steps read the rain the satellite measured over Nawalapitiya's catchment (JAXA GSMaP, corrected for how it reads here), with rain beside the gauge and rain on the channels upstream timed separately (about 0 h from beside the gauge). Tested storm by storm it was closer than the version that reads the weather model's rain.
• · Heavy rain upstream is part of the 24 hour steps: rain that has fallen or is forecast over the catchment above Nawalapitiya 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.