Assuming that the following flood data follows a Gumbel distribution, plot the data on a Gumbel probability scale (Flood magnitude Vs Reduced Variate, y) and fit a linear trend to your plot. Determine the Flood magnitude of ARI (return period) equal to 75 years from your fitted linear trend and compare with that from the equation;

 

Year Peak flow in m3/s 2004 100.7 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 85.5 240.8 186.8 160.9 126.6 140.7 418.7 16.5 98.0 29.2 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 18.4 175.4 314.9 22.2 262.2 131.7 13.7 11.7 3.2 142.8 AEP (m-0.4)/(N +0.2) y = -ln[-In(1 - AEP)] = a = S. 6/ B=x-0.5772a x = + a.y