Kosi the sorrow of bihar

brief introduction about kosi and their flood charecteristics

1. PRESENTED BY:-ABHISHEK VATS 18MTAESWC012

2. Starts from northern slopes of Himalayas inTibet , southern slopes in Nepal Crosses bihar from seven districts and meet ganga in kursela in katihar district

3. This river also called sapta kosi for its seven upper tributaries these are following  the  Sun Koshi , the  Indravati River , the  Bhote Koshi , the  Dudh Koshi ,  Arun River ,  Barun River , and Tamur River.

4. Tamur River  with an area of 6,053 km 2  (2,337 sq mi) in eastern Nepal.(37%) Arun River  with an area of 33,500 km 2  (12,900 sq mi), most of which is in Tibet(19%) Sun Koshi  with an area of 4,285 km 2  (1,654 sq mi) in Nepal and its northern tributaries  Dudh Koshi , Likhu Khola , Tama Koshi ,  Bhote Koshi  and  Indravati .(44%)

5. Kosi barrage

6. Between sunsari and saptari districts Constructed in 1958-1962 56 gates Eastern embankment Western embankment

7. Problem of flood Problem of river shifting Problem of heavy sediment load Problem of water logging and drainage congestion. Problems of kosi river

8. View of flooded area

9. The Kosi’s alluvial fan has fertile soil and abundant groundwater. The agricultural land in these areas is in great demand. Too high population density Why kosi floods are more dangerous

10. Kosi River is notorious for the meandering behaviour of its east-to-west course. It has a very dynamic regime; very high sediment load and frequent “ avulasive shifts”. Between 1736 and 1953 the river moved through a distance of about 112 Km. westward. shifted by 20 kms to the west in the course of single year. Kosi and its avulsive shifts

11. the bed slope of the river becomes as flat as 0.4 metre /km to 0.2 m per km. high sediment yield of 0.43 million tonnes /year/km2. The average annual sediment load of the Kosi has been assessed at 95 million cu.meter . Problem of heavy sediment load

12. in the process of shifting from east to west, has left large tracts of low land and undulating sandy tracts. Reasons for water logging and drainage congestion.

13. Birpur barrage Jacketing the river with embankments major structural measures were constructed in the past

14. Watershed management measures in the upstream catchment. the construction of a large storage dam at Chatra Recommendation