Experts’ take on Koshi flood management
Himalayan News Service
Kathmandu, September 4:
Water resources experts pointed out that new designs and constructions, along with the review of the Koshi agreement, are needed for better control of the Himalayan river.
Efforts should also be made to ensure that breaches do not occur in the embankments of the river that resulted in flood fury. The experts were speaking at a programme organised by the Jalsrot Vikas Sanstha.
Research shows that the Saptakoshi is shifting its course. In fact, it has shifted 120 km westward over the last 200 years. “The problem to manage the river is far difficult than it actually appears,” said Dr Ananda Bahadur Thapa, an expert. Earlier the structures could easily cope with the flood discharge — estimated over 900 thousand cusec — but this time around merely 180 thousand cusec led to the change in its course." At present, the detention basin in the upstream of the barrage, at Hanuman Nagar, is full of sediments. The embankments might have been ineffective to control even relatively moderate
floods,” Thapa explained. The river originates in the Himalayas and flows into the plains at Chatara. It brings about 120 million cubic metres of sediments, along with 52 billion cubic metres of water, annually. At a conservative estimate, the volume is five times greater than the Sutlej of Bhakra and at least two times more than that of the Nile of Aswan. “Existing measures of embankments may be short-lived. It is necessary to adopt soil conservation and construction of storage reservoirs,” Thapa added.
As per the Koshi agreement in 1954, which was later revised in 1966, the 1,100-metre barrage has been built with 32-km embankment and 57 spurs to direct excess water flow towards centre of the river instead of banks — in the eastern side (read Sunsari) and another 25-km in the western side of the embankments that consist of 41 spurs. The Indian government is responsible for its maintenance and operation. “Though the length of each spur was around 200-300m at the time of the construction, it has now been reduced to less than 50m.
The condition of the embankments is very poor. Besides, river training structures were never maintained to meet the original standard,” admitted Shital Babu Regmi, joint secretary, Ministry of Water Resources (MoWR). “The breach needs to be plugged and flow of the river should be diverted through the barrage,” he explained. “Nothing could be done till the water level recedes. The government is working with India on a long-term programme. But these initiatives can only be implemented after two years,” said Shankar Prasad Koirala, secretary, MoWR.
Source: The Himalayan Times, 5 September 2008
Water resources experts pointed out that new designs and constructions, along with the review of the Koshi agreement, are needed for better control of the Himalayan river.
Efforts should also be made to ensure that breaches do not occur in the embankments of the river that resulted in flood fury. The experts were speaking at a programme organised by the Jalsrot Vikas Sanstha.
Research shows that the Saptakoshi is shifting its course. In fact, it has shifted 120 km westward over the last 200 years. “The problem to manage the river is far difficult than it actually appears,” said Dr Ananda Bahadur Thapa, an expert. Earlier the structures could easily cope with the flood discharge — estimated over 900 thousand cusec — but this time around merely 180 thousand cusec led to the change in its course." At present, the detention basin in the upstream of the barrage, at Hanuman Nagar, is full of sediments. The embankments might have been ineffective to control even relatively moderate
floods,” Thapa explained. The river originates in the Himalayas and flows into the plains at Chatara. It brings about 120 million cubic metres of sediments, along with 52 billion cubic metres of water, annually. At a conservative estimate, the volume is five times greater than the Sutlej of Bhakra and at least two times more than that of the Nile of Aswan. “Existing measures of embankments may be short-lived. It is necessary to adopt soil conservation and construction of storage reservoirs,” Thapa added.
As per the Koshi agreement in 1954, which was later revised in 1966, the 1,100-metre barrage has been built with 32-km embankment and 57 spurs to direct excess water flow towards centre of the river instead of banks — in the eastern side (read Sunsari) and another 25-km in the western side of the embankments that consist of 41 spurs. The Indian government is responsible for its maintenance and operation. “Though the length of each spur was around 200-300m at the time of the construction, it has now been reduced to less than 50m.
The condition of the embankments is very poor. Besides, river training structures were never maintained to meet the original standard,” admitted Shital Babu Regmi, joint secretary, Ministry of Water Resources (MoWR). “The breach needs to be plugged and flow of the river should be diverted through the barrage,” he explained. “Nothing could be done till the water level recedes. The government is working with India on a long-term programme. But these initiatives can only be implemented after two years,” said Shankar Prasad Koirala, secretary, MoWR.
Source: The Himalayan Times, 5 September 2008
