The Irrigation Department has warned that water levels in the Kalu Ganga and the Attanagalu Oya are rising and currently approaching minor flood level at several gauging stations, NewsFirst reported.
L.S. Suriyabandara, Director of the Hydrology Division of the Irrigation Department, said the water level of the Kalu Ganga at Ratnapura and at Millakanda, along with the level of the Attanagalu Oya at Dunamale, are nearing the minor flood threshold. Residents in low-lying areas along the two river systems have been advised to take precautions.
The river-level warning is the downstream consequence of the Met Department’s 75mm rainfall forecast for the Western and Sabaragamuwa provinces issued earlier on Saturday, and pairs with the Red sea-state advisory covering the northern and western coast. The Kalu Ganga basin has been under sustained monsoon stress this cycle: minor flood thresholds at Millakanda were last crossed during the May 23 wet-zone deluge that flooded Kalutara, and the Attanagalu Oya at the Mellawagedara bridge gauging station carried a similar warning the same week.
The Ratnapura gauge sits at the upstream end of the Kalu River system and is the early-warning indicator for the lower Kalutara floodplain, while the Attanagalu Oya at Dunamale drains the Gampaha District wet-zone catchment. The current advisory falls within the four-district NBRO landslide warning area covering Kalutara, Galle, Kegalle and Ratnapura, where saturated-slope failure risk has been elevated since Thursday.
In a separate Saturday-evening notice covering a different sub-basin of the same river system, the Irrigation Department flagged the possibility of minor flooding in low-lying areas of the Kuda Ganga sub-basin of the Kalu River Basin within the next 24 hours, after significant rainfall in the upper catchment, Ada Derana reported. The department said a minor flood situation is already being observed in the Kuda Ganga sub-basin, but no significant or rapid rise in river water levels is expected during the next few hours. Residents in the floodplains of the Kuda Ganga and Magura Ganga within the Bulathsinhala, Madurawala and Palindanuwara Divisional Secretariat Divisions, as well as motorists travelling through these areas, have been asked to exercise caution. The same DSD cluster was on warning when the Kukule reservoir spill gates opened during the May 29 wet-zone deluge.
Update — June 14: Kuda Ganga remains at minor flood level at Millakanda
NewsFirst reported on Sunday morning (June 14) that the Kuda Ganga continues to remain at a minor flood level in the Millakanda area, with the Department of Irrigation maintaining its advisory for residents of the Bulathsinhala, Madurawala and Palindanuwara Divisional Secretariat divisions. Newswire confirmed the same conditions just after midnight UTC, noting that significant rainfall had been received in the upper catchment of the Kuda Ganga sub-basin and that no significant or rapid rise in river water levels was expected in the next few hours.
The National Building Research Organisation (NBRO) has separately issued early landslide warnings for Kalutara, Ratnapura and Nuwara Eliya districts, NewsFirst said. The Department of Meteorology has forecast continued showers or thundershowers in the afternoon and night over the Western, Sabaragamuwa and North Western provinces, and in the Galle, Matara, Kandy and Nuwara Eliya districts, with winds of 40–50 km/h over the western slopes of the central hills, the Northern and North Central provinces, and the Hambantota and Trincomalee districts. Sea areas off the entire western and southern coast remain under a strong-wind advisory of 50–60 km/h.
Sources: NewsFirst — Kalu Ganga and Attanagalu Oya water levels rise; Ada Derana — Minor flood warning issued for Kuda Ganga sub-basin of Kalu River; NewsFirst — Minor Flooding Continues Along Kuda Ganga; Newswire — Heavy rainfall triggers minor flood conditions in parts of Kalu River basin.
