GATHERINGS TO MARK  DISASTER PREVENTION DAY AND KOSI RIVER

 By Dr. AB Thapa

At this time of the year we hear about the gatherings  to mark the disaster prevention day. Such gatherings have become almost a ritual.  Unfortunately it is never tried in those gatherings to create awareness about the  risk of the future Kosi floods to life and property of  innumerable people in Nepal .  The Kosi was known as the “ River of Sorrow ” in the past.  It is explained hereinafter what causes the horrific Kosi  disaster which, however, could easily be prevented  if our intellectuals and civil society took up this issue in great earnest. Similarly, various gatherings to mark the disaster prevention day could also be help to  make people aware of the great danger of the impending Kosi floods.

Past  Sufferings  of  People

All  the  elderly  people  living  in  the  Saptari  district   not   far  away   from    the  Kosi  river  would  not  have   much  difficulty   to   recall  that   some  60  years  ago   the  channel  of  the  Kosi  river   flowing  across   the   Sunsari  district  from  north  to  south   was  gradually  shifting  laterally  from  east   to  the west.   The  river  was  already  quite  close  to  Hanumannagar.   It  is  reported  that  by  that  time  the Kosi.  River  debouching  into  the  Terai  plain  at   Chatra  and   joining  the  Ganges  River near  Kursella in  India  had  already  laid  waste  about   500  square  miles  of  lands  in  Nepal  alone. People  living  in  the  eastern  part  of  the  Saptari  district  were  panic  stricken.   They  were   leaving  their  ancestral   homes  in  thousands  to find  shelter  at  safe  places  far  away  from  their  villages  carrying  with  them  whatever  few  things  they   could  take  with  them.  The  headquarter  of   the  Saptari   district  at  Hanumannagar   was   swiftly  moved   to  Rajbirag  which  was  at  a  safe  distance  away  from  the  Kosi  River.  Fortunately  the  shifting  of   the  Kosi  River  course   to  the  west   was  held  in  check  by  the  embankments  built  on  either  side  of  the  river.   Now  all  those  who  are  involved  in  the  Kosi  River  study  are  saying  that   the  embankments  built  to  protect  the  life  and  property  of  millions  in  India  and  Nepal  might  have  already  outlived  their  usefulness.  What  is  going  to  happen   the  next?  

Sediment Flow and Inland Deltas

Thirty million years ago the sea bottom that was to become the  Himalayas began to be pushed up, and  this  movement is  still in progress.  The  Himalayas continue to  rise and  so do their  peaks   including  Mount Everest . It is said that were  it not for the  strong erosion that  simultaneously  wears  down the entire Himalayan region, the  Mount  Everest  summit would now be nearly 20,000 meters  above  the  sea level. So the Kosi, rising in the  Himalayas and emptying into  the   plain  at  Chatra  after  traversing   the  mountain   region, brings with  her  every  year   an  enormous  quantity  of  sediments estimated  at  120  million  cubic  meters  along  with  52  billion    cubic  meters  of  water.  The  annual  volume  of   Kosi   sediment  is  about   5  times  greater  than   that  of  Sutlej  at  Bhakra, and two times   greater  than   that   of    Nile  at  Aswan.

Various  studies done  on  Kosi so far  come  to  one  common  conclusion - the  Kosi carries  enormous  load  of  sediments  that  it is unable to  transport   far  beyond. The river, therefore, deposits  huge  quantity of  sediments.  In  this  process  of  building  up  an  inland   delta,  the  river  shifted  over  120  km  from  east  to  west  during  the period   from  1736  to  1954.  

Lateral Movements of   the Kosi

The problem of Kosi floods has  drawn the attention since  the  late 18 th century. Major  Rennel   had  surveyed the oldest course of Kosi in 1779. Mr, James  Furguson  made  further investigation in 1863. After that many prominent  experts  have been involved in Kosi  study.

According  to Mr. Furguson there were two  earlier alignment. They were "Oldest Kosi", which flowed eastward  across the present Ganges , and eventually joined the  Brahmaputra ; and the "Old  Kosi" which flowed just west of  Purnea and joined the  Ganges    opposite  Rajmahal.

As  a result of observations of about 25 years Mr. Shilling  Feld  described  in 1893  the oscillation of  the  Kosi   river as under: (1)  The bed of the Kosi oscillates  over  a   vast  tract  of the  country from  the Brahmaputra  to  near the  mouth of   the  Gandak, the oscillation  being repeated at  long  intervals  of  time. (2) The  westward  movement  in such  oscillations  is  slow  and is  in a  series of steps  each  of  which  is  attended with  damage  to property of  temporary   nature. (3) The  eastward  movement of  the oscillation will probably   be   in one  great  swing  accompanied  with  great  loss  of life  and  property.

 Sir  Claude C  Inglis

In 1941, Sir Claude  Inglis,  Director, Water  Research  Station, Poona identified the  problem   of  Kosi as being due  to  an excess  charge of the  sand that Kosi  waters  carry.

In 1956, Sir  Inglis cautioned that  any  action that  leads to flood  level just  downstream of the gorge being  raised  would  reduce  the attraction  of the  right  bank at that point  which  may well  lead  to the  Kosi   being  captured  by the  left  bank  and  the  development  of  an  easterly  river  course  possibly   on  an alignment  approximately  with  the  1731 course.

  Leopold  and  Maddock

Considering  the  Kosi  behaviour, Leopold and  Maddock  stated  (1954)  that  a braided stream (like the Kosi) will tend  to  shift laterally at  a  rate  dependent  on  the rate  of  accumulation  of  materials  being  deposited.  As one  course  becomes  higher  than  possible  adjacent  paths, the  river  would shift.

Dr. A.N. Khosla's Opinion

The Government of Bihar  presented to the Central  Government  a proposal  to build embankments to  control Kosi  floods immediately  after the Second World  War.  Dr.Khosla, then Chairman of  Central  Water  Commission, gave  his opinion that  for Kosi  flood  control,  a comprehensive survey including the  study of high dam should be made. Based on his  idea  the study of  Kosi  high  dam  was initiated in 1946.

Dr. K.L. Rao

The  outline of the  present  Kosi  embankments  with  a  barrage  at  Bharda (   near  Hanumannagar)  was  drawn  up by  Dr. K.L. Rao, who  later  on became the State  Minister for  Irrigation  and Power  in the    Central  Government  of  India. He  has  explained  that  the  embankments would  provide relief  only  for  a   limited  period.   Finally  storage  dam would  be  needed.

Prof Gole CV Dr.Chitale M.

In 1966 a study of the  delta cone of the  Kosi river made by Prof Gole CV Dr. Chitale  M. appeared   in  the  ":Proceedings  of the  American  Society of  Civil  Engineers". The  study explains that  the delta building of  Kosi  was still  incomplete. The authors  have cautioned that  the  existing  measures  (embankments) may  be short  lived  and  for  effective  control  of  the  river, it  would  be   necessary  to  adopt  soil conservation   measures  and  to  construct  storage  reservoirs.

Embankments Would Soon Be Ineffective

The Kosi  shifted, as described in the preceding paragraph,  from east  to west  over  120 km  in the last  200  years.  Fortunately, embankments built  a  few  decades ago temporarily  helped  to  check   the  lateral  shifting  of  the  Kosi.   It  is quite clear that  soon  the  embankments  would be ineffective.  All past  and present  studies and  the  very  recent observations  help us to conclude  that the  Kosi, slowly  turning  into  a hanging  river,  is now on the verge of shifting to the east far away from its present course.   Thus, peoples of    Nepal and  India are heading  for a natural  disaster of   an  unprecedented scale  that would result  in  loss of life  and  property  of millions.

The  Flood  Losses

South-eastern Nepal , North-East  Bihar and North Bengal , as explained earlier,  might  again be  reeling  from  the Kosi  floods. The  eastern  and  southern  boundaries  of such  flood  affected  areas  could   extend  up to Mahananda and  the Ganges  respectively. India 's railway  and roadway  linkages with  the north-east  states  could also  be  severed.  In  a  similar  type  China's  Yellow  river  flooding  in  1938  the number  of  persons   killed   alone  was  about  half   a  million. It  was  the last  big  flood  damage.  After  this,  big  storage  dams  were  built  to control the Yellow  river   floods. The  river has  been completely  regulated. The  Yellow  river  dams  have  helped  save, as  of now,  about  50 billion  US Dollars.

In Conclusion

The Kosi known as the river of sorrow  had shifted from east to west over 12O km in the last 200 years. In the past about 10,000 sq. km. of lands had  been laid waste as a result of the sand deposit. In course of shifting, many towns and villages were wiped out, and heavy losses of property, cattle, and human life were inflicted. Fortunately the embankments built few decades ago temporarily helped to check the lateral shifting of the Kosi. Very soon the embankments would be ineffective to control the Kosi floods.  Such a grave situation must concern our intellectuals and civil society.

(Dr. Thapa writes on water resources)