Nagalagam Street Kelani Ganga · කැලණි ගඟ ජල මට්ටම

Above alert level now and expected to stay there for the next 24 hours.

මෙම සතියේ ගංගා ජල ප්‍රවාහය ඉහළ යා හැක.

• සුළු ගංවතුර (5.0 ft): ඉඩ අඩුයි, 10 න් 1ක් පමණ
• ප්‍රධාන ගංවතුර (7.0 ft): ඉඩ අඩුයි, 10 න් 1ක් පමණ

වැටුණු වැසි

මෙම මාපකයේ වැසි සංවේදකයක් නැත.ඉහළ ඇති ආසන්නතම වැසි මාපකය, Holombuwa: පැය 3 තුළ මි.මී. 0.0, පැය 24 තුළ මි.මී. 127.

වැසි පුරෝකථනය

ජලඛණ්ඩය මත ඉදිරි පැය 24 තුළ මි.මී. 15 (මධ්‍යස්ථ වැසි). කාලගුණ ආකෘතියේ ඇස්තමේන්තුවකි.

ජලඛණ්ඩය මත චන්ද්‍රිකා වර්ෂාව: පසුගිය පැය 6 තුළ මි.මී. 6.1, පසුගිය පැය 24 තුළ මි.මී. 84.8 (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 751 m3/s in its highest member within 7 days, above the 1-in-20 level (338 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 (3.2 ft); treat it as a rough guide.

• මෙය ගණනය කරන ආකාරය
• · Latest level at Nagalagam Street and recent change, plus upstream gauges: Hanwella, Glencourse.
• · Forecast model estimate of catchment rain (Open-Meteo, area average over 9 grid cells above Nagalagam Street): 63 mm modelled for the last 24 hours, 15 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 12, 24 hour steps read the rain the satellite measured over Nagalagam Street's catchment (JAXA GSMaP, corrected for how it reads here), with rain beside the gauge and rain on the channels upstream timed separately (about 6 h from beside the gauge, about 6 h from upstream). Tested storm by storm it was closer than the version that reads the weather model's rain.
• · 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 Nagalagam Street 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.