LAHORE: There is a threat of very high floods in the eastern rivers over the next three days due to heavy to extremely heavy rains expected over their upper catchments by a depression from the Bay of Bengal, which is nearing Pakistan at the fag end of the monsoon season.

A warning has been issued by the Flood Forecasting Division (FFD) in Lahore, and the national and Punjab disaster management authorities, asking agencies and departments concerned to remain on their toes to meet any eventuality.

The FFD head in Lahore, Riaz Khan, told Dawn that as per the movement of the depression, which is a very strong rain-causing system, there were ample chances of torrential rains over the catchments of Sutlej, Ravi, Chenab and Jhelum rivers in the next three days. Rains were expected to start from Sunday (today) afternoon.

High flood warning issued; authorities on alert

“We are closely watching the system which is the first to come to or close to Pakistan this monsoon. The situation may change, but the system’s current movement suggests that the next three days are critical,” he added.

He further said that the division’s assessment of the weather and river flows over the next three days was based on the current environmental and meteorological conditions. The depression might weaken or get stronger because of an approaching westerly wave over Afghanistan, he said.

Mr Khan said the depression was moving towards northern India, Himachal Pradesh, which is the upper catchment area of eastern rivers of Beas, Sutlej and Ravi. As per calculations, rains in India could be very heavy to extremely heavy as a result of which these rivers would swell significantly.

But the situation in rivers Sutlej -- in which Beas merges in India -- and Ravi downstream in Pakistan depended on the extent of water released from Indian dams built over these rivers. The three dams were around 1MAF lower than their highest conservation level. India might release water from them downstream Pakistan if the inflow increases beyond capacity, he said.

Mr Khan said as the impact of the depression would be extended to Chenab and Jhelum there were chances of floods in them as well. The timing of the approaching westerly wave was very important for the rains and river flow in these two rivers. “The situation will be critical if the wave synchronises with the monsoon depression,” he added.

An FFD warning said very high flood was expected from Sunday (today) to Tuesday in Chenab at Marala and downstream, Jhelum at Mangla, Ravi and Sutlej along with the associated nullahs of rivers Chenab and Ravi. However, the scale of flood in the Ravi and Sutlej depended on release from across the border.

It also said that the depression lay over southwest Madhya Pradesh and was likely to move further northwest (towards Pakistan). The approaching westerly wave lay over northeast Afghanistan and moist current from the Bay of Bengal was penetrating northeastern parts of the country up to 10,000 feet – the strongest in many years.

These weather conditions were expected to generate widespread thunderstorm/rain with scattered heavy falls, isolated very heavy falls and one or two extremely heavy falls over upper catchments of Sutlej, Ravi and Chenab along with Gujranwala division.

Scattered thunderstorm/rain with isolated heavy falls is expected over the upper catchments of the Indus, Jhelum along with Peshawar, Kohat, Dera Ismail Khan, Bannu, Rawalpindi, Sargodha, Lahore and Sahiwal divisions.

Meanwhile, the outer shell of the monsoon depression began to develop rain in different parts of Pakistan, including Lahore on Saturday. Mangla recorded 31mm, Sialkot Cantt 21, Gujrat 18, Mandi Bahauddin 13, Parachinar 25, Peshawar 16, Risalpur 15 and Lower Dir 8.

Published in Dawn, September 23rd, 2018