Abstract:
The   Rongai   Valley   Irrigation   Scheme   of   Meghalaya envisages  construction  of a  barrage  founded on  firm rock.  For design   of  this barrage,   a 50-yr return period  flood peak  is required.   To   analyse  incremental  cost  and   additional   risk covered,   floods   of   various   return   periods   are needed. Probable   Maximum Flood (PMF)  peak  is  required   to   visualise potential  flood  hazard  downstream. 
Design   flood peaks  of  various  return  periods,   SPF   and PMF assessed are  presented  in  the  paper.  The  approach  adopted is  based on  the practical  view point  that : since  water   use projects   cannot be  delayed till  data of adequate quality and quantity   are  available,recourse  is  to be  taken  to arrive   at the   best   judgement   assessments   after   analysing   whatever information  is  readily available.