Brahmaputra, northern tributaries of Ganga in severe flood situation due to continuous rains
The entire Brahmaputra and northern tributaries of the Ganges, including Ghagara and Barabanki, are in severe flood situation due to continuous rains, according to the Central Water Commission (CWC).
The CWC in its Thursday flood situation report said floods in the north-east would aggravate in the coming days.
The Brahmaputra is continuing to be in floods all through its reach from Upper Assam’s Dibrugarh district to lower Assam’s Dhubri district.
Brahmaputra’s tributaries such as Jia Bharali, Dhanasiri, Desang, and Beki are also flowing in a severe flood situation.
Severe flood is declared when the water level is touching or exceeding the danger level, but below the highest flood level (HFL).
River levels in the region are likely to rise further rapidly because of a forecast for very heavy to extremely heavy rains in sub-Himalayan West Bengal, Arunachal Pradesh, Assam, Meghalaya, and Sikkim from Friday to Sunday. Several landslides were reported from Arunachal Pradesh on Thursday and Friday, where at least eight people lost their lives.
Some districts like East Siang in Arunachal Pradesh; East Khasi Hills in Meghalaya received more than 200 millimetres (mm) of rain on Thursday.
East Siang received 296.6 mm rain against a normal of 39.9 mm, a 644% excess, and east Khasi hills received 340.3 mm against normal of 63.3 mm, a 438% excess.
“There is a likelihood of flash floods in hilly regions of Arunachal Pradesh, Meghalaya and Sikkim. This combined with the existing riverine flood will further aggravate the flood situation. Since most of the catchments in north-east India, sub-Himalayan West Bengal, and Sikkim are already saturated there is a likelihood of continuation of floods in severe to extreme levels for the next three-four days. Maximum vigil has to be maintained along the banks of all rivers in these districts,” the CWC said in its report.
Very heavy rains in Uttar Pradesh (UP), Uttarakhand, Bihar from Friday to Sunday is likely to trigger a severe flood situation in many places. Ghaghra in Ayodhya and Barabanki in UP is flowing in a severe flood category.
India Meteorological Department (IMD) in its Friday bulletin said the monsoon trough is running close to the foothills of Himalayas. The combined effect of monsoon intensification in the hills and convergence of south westerly-southerly winds from the Bay of Bengal will continue over northeast & east India during the next three-four days. Under its influence, widespread and extremely heavy rain is likely over Bihar, sub-Himalayan West Bengal, Sikkim, Assam, Meghalaya and Arunachal Pradesh on Friday and Saturday and over eastern UP on Saturday and Sunday.
“Extremely heavy rains have started over the north-east and eastern India because of the shifting of the monsoon trough. Hilly areas of Uttarakhand will also receive extremely heavy rains because it is receiving moisture both from the Arabian Sea and Bay of Bengal,” said K Sathi Devi, head, National Weather Forecasting Centre (NWFC).
“The normal position of the monsoon trough is between Ganganagar in Rajasthan to the Bay of Bengal. But through the monsoon months the trough keeps shifting or oscillating,” she added.
The distribution of monsoon rains from June 1 to July 10 has been skewed with a large part of the country including Bihar, UP, Madhya Pradesh, Chhattisgarh, Maharashtra, Telangana, Andhra Pradesh, Gujarat, Jammu & Kashmir, Sikkim and Meghalaya receiving excess rains. Delhi and Himachal Pradesh have remained largely dry, according to IMD.
Earlier this week Okha in Gujarat made an all-time record with 480 mm of rain recorded on Tuesday.
On July 5, Khambala, Kalyanpur, and Porbandar recorded 490 mm, 360 mm, and 290 mm, respectively, an all-time district average record in Dwarka. Thane and Mumbai also recorded extremely heavy rains on July 3 with 170 mm at Colaba in south Mumbai and 380 mm in Thane. “The west coast had received exceptional rains. This was mainly a result of a low-pressure area formation over Saurashtra and Kutch between July 5 and 8 and another low-pressure area over the northwest Bay of Bengal off Odisha and Gangetic West Bengal coasts in the middle of the week which moved inland subsequently maintaining its intensity for about 48t hours,” said RK Jenamani, senior scientist at NWFC.