Pummeled by heavy rain over the past week, Odisha, is bracing for a "medium flood" in the Mahanadi river basin with the formation of another depression over the Bay of Bengal, the Met office said on Sunday. A well-marked low pressure system intensified into a depression over northwest Bay of Bengal and crossed the coast near Digha in West Bengal between 10.30-11.30 am, triggering downpour in many areas.

Much ahead of the anticipated flood, set to maroon areas adjoining Mundali barrage near Cuttack on Monday, over 5,500 people are already reeling under the effects of the torrential rain, with nearly 2000 stranded in six districts -- Sambalpur, Cuttack, Kandhamal, Subarnapur, Jagatsinghpur and Koraput, according to officials.

Several villages in Sambalpur lay inundated, forcing the administration to shift more than 1,500 people living in low-lying areas to safer places, they said. Special Relief Commissioner (SRC) Pradeep Kumar Jena stated that the government was apprehending a "medium flood" this time with the intensity of rain having increased in many areas, including the upper catchment of the Mahanadi.

"We expect a flow of around 10.5 lakh cusecs (cubic foot per second) of floodwater through Mundali barrage near Cuttack by Monday evening. Accordingly, we are preparing for a medium flood in the Mahanadi system," the SRC said. He underscored that there was nothing to panic for now as the administration had handled a similar situation in August 2019. Jena said 9.5 lakh cusecs of water were passing near downstream Khairmal and that would require 24 hours to reach Mundali.

"Therefore, we expect peak flood in Mahanadi by Monday evening when above 10 lakh cusecs of water will pass," the SRC said, adding that district authorities had been asked to take necessary measures. He also said that 22 rescue teams, comprising the NDRF, ODARF and Fire Services personnel, had been dispatched to Cuttack, Khurda, Puri, Kendrapara and Jagatsinghpur districts, which are "likely to get more affected" due to the possible flood situation.

Jena explained that 34 of the 98 gates of the Hirakud reservoir in Sambalpur district had been opened to discharge water into downstream Mahanadi, which spans 494 km in the state with a drainage area of 65,580 square km. Similarly, due to heavy rainfall in upper catchment area of river Baitarani, the water level is flowing above the danger level at Akhuapada. Due to rise in water level in these rivers, a flood-like situation may occur in the low-lying areas, he stated.

Collectors of Sambalpur, Subarnapur, Boudh, Nayagarh, Angul, Cuttack, Puri, Jagatsinghpur, Khurda, Kendrapara, Bhadrak, Jajpur & Keonjhar districts have been instructed to remain watchful of the situation. The river’s tributaries -- Luna, Karandia, Chitrotpala, Daya, Bhargavi, Rajua and Malaguni -- were also found to have swelled.?"Therefore, we cannot afford to open more gates of Hirakud for additional discharge," a water resources official said.

Water level has risen in most rivers, including Mahanadi, Brahmani, Rushikulya and Budhabalanga, the official said. The Jalka tributary of Subarnarekha in Balasore was flowing 0.92 metres above the danger mark of 5.5 m, a bulletin stated. Baitarani river was flowing at 17.96 m at 1 pm at Akhuapada in Bhadrak against the danger level of 17.83 m.?

Asked about the situation in other rivers, the SRC stressed that there was no reason to worry as of now. In the last 12 hours till 6 pm, Jagatsighpur recorded 132.8 mm of rain, the highest in the state, followed by 100.3 mm at Sundergarh and 92 mm at Puri.?An intense spell of 45 mm rain lashed Bhubaneswar between 8.30 am and 5.30 pm. Boudh, Dhenkanal, Jajpur, Kandhamal and Nabarangpur were pounded by downpour during the period.

The Met office issued a red alert of extremely heavy rain in 12 districts, mostly in western Odisha, and orange alert of very-heavy rain in rest of the 18 districts in coastal and southern part of the state till Monday morning.The intensity of the rain will decrease on Monday, but there will still be heavy rain in Sundargarh, Jharsuguda, Bargarh and Nuapada, it said.

Fisherfolk have been advised not to venture off the coast of Odisha, West Bengal and northern Andhra Pradesh till Monday as the sea can be very rough, with a wind speed of 45-65 kmph expected over the northern and west-central Bay of Bengal. It also sent out an alert of local cautionary signal number three (depression, squally weather) in all ports of Odisha.

Meanwhile, reports said that connectivity have been disrupted in many places with bridges and roads flooded in the districts of Boudh, Subarnapur, Sambalpur and Cuttack districts. The intense rainfall and subsequent landslide have also affected train services. Visakhapatnam-Koraput train was short-terminated at Rayagada. Similarly, Koraput-Visakhapatnam train was also short terminated at Sikharpai.

(With PTI inputs)