Tributary rivers of Sun Koshi are: Dudh Koshi(@27.15, 86.43), Likhu (@27.25, 86.20), Tamakoshi (@27.35, 85.98) , Bhote Koshi (27.73, 85.78) and Indrawati (@27.64, 85.71) ranging from east to west. Barun river (@27.69, 87.36) is the tributary of Arun.
Normal water flow of Saptakosi is 25-30 thousand cusec. In rainy season it goes upto 250 thousand cusec creating regular flood every year. Sun Kosi contributes combined 44% of the total water in the Sapta Koshi River System, whereas Arun & Tamor contributes 37% and 19 % respectively.
|Karma99- Sapta Koshi & tributaries: Tamor, Arun, Sunkohi,|
Dudh Koshi, Likhu, Tamakoshi, Bhote Koshi and Indrawati.
1897 Feb : British-Indian officials discussed about kosi flood problem and concluded to need of a dam in chatara to control kosi river. In Feb 27 rana PM bir Shamsher permitted the construction but the plan did not carried forward for some reason.
1947 Apr: Indian energy minister announced to construct a 229 meter tall high dam in barah chhetra during convention of kosi victim in India.
1953 dec 14: gulzari lal nanda presented outline of future kosi agreement in the indian parliament.
1954 Apr 25: Nepal and India signed the Kosi agreement during Martika Prasad Koirala government in Nepal and JL Nehru gov in India. Mahabir Shamsher signed for Nepal and Gulzari lal Nanda signed for India. (link)
1959 April 30: King Mahendra inaugurated the barrage. It has 56 gates and its approx 30 meter high.
1966 Dec 19: Koshi agreement revised. Signed by YP Pant (secretory, ministry of finance, Nepal) and Sriman Narayan (Indian ambassador in Nepal). (link)
1986: estimated life span 30-years of kosi barrage expired.
1987: Flood in Bihar & Nepal by Kosi river. 1399 people killed in Bihar.
1991 Dec: PM Girija P Koirala made agreement about high dam during his visit in India.
2004: Flood in Bihar by Kosi, Kamal, Bagmati, Gandaki rivers killing 885 people.
2008 Aug: Flood in Southern Nepal and Bihar, India after eastern embankments of the Koshi Barrage collapsed. 434+ died in Bihar.
2014 Aug 2: landslide after heavy rainfall blocked Sunkoshi river forming an artificial lake in Sindhupalchok District, Nepal which create serious threat of flood in Koshi river. 156 people killed in landslide. Nepal army cleared it in 45 days with small blasts creating canal to pass the water.
2015 Aug 3: Koshi Bridge in Chatara of Sunsari District inaugurated (location: 26.855, 87.152). It is 261.3-meter-long and 7.5-meter wide. (link) It can be used as the alternative for Koshi Barrage.
2017 Aug: Flood in Southern Nepal & Bihar by heavy raining through Kosi & Kamala rivers. Over 100 killed in Nepal & 517+ killed in Bihar.
2017 Aug 24: India-Nepal is said to have understanding for the construction of Kosi high dam during the visit of PM Sher B Deuba. Point 28 of joint press conference stated so. (link)
Sapt-Kosi High Dam
Uchcha bandh project is the high priority project for India for flood control in Bihar whereas Nepal is said to have less benefit from this. The proposed dam will be 269 meter high and 1 km long. But that will fill water in 200 sq km of Nepali land displacing 75,000 people.
Kamala Multi-purpose Project
diversion of sunkosi river towards Kamala river has been the priority of Nepal instead of High dam. But India favors to start High dam project before Kamala diversion.
idsa : Revisiting the Kosi Agreement: Lessons for Indo-Nepal Water Diplomacy
Kathmandu post: PM inaugurates Koshi Bridge in Sunsari
blog.com.np: THE KOSHI DELUGE: A HISTORY OF DISASTER FOR NEPAL
indian embassy: The Koshi Agreement between Nepal & India (1954 Apr 25)
The hindu: Water in India-Nepal relations