$($c$)$ i$,$ Define a flow duration curve $($FDC$)$

ii$,$ Describe how to develop a flow duration curve $($FDC$)$ from data obtained

from a stream gauging station

iii, From the flow monthly data obtained from a river gauging station $1$GD$03$ below determine $-$ the flow which can be expected $80\%$ of the time

the dependability of the flow of $40\frac{m^3}{s}$

$(7$ marks$)$

RSG $1$GD$03$ Monthly FDC for the Period $2005-2013$

$\backslash$table$[[,$Jan,Feb,Marc,April,May,June,July,Aug,Sep,Oct,Nov,Dec$],[2005,6,7\mathrm{.}35,16\mathrm{.}1,12\mathrm{.}22,51\mathrm{.}46,22\mathrm{.}64,16\mathrm{.}71,38\mathrm{.}36,42\mathrm{.}05,16\mathrm{.}03,10\mathrm{.}62,8\mathrm{.}41],[2006,8\mathrm{.}383,6\mathrm{.}97,10\mathrm{.}79,30\mathrm{.}61,28\mathrm{.}41,16\mathrm{.}09,16\mathrm{.}68,31\mathrm{.}85,20\mathrm{.}43,12\mathrm{.}33,43\mathrm{.}15,68\mathrm{.}67],[2007,40\mathrm{.}42,38\mathrm{.}18,28\mathrm{.}07,20\mathrm{.}12,36\mathrm{.}53,41\mathrm{.}01,44\mathrm{.}42,81\mathrm{.}59,84\mathrm{.}2,32\mathrm{.}98,19\mathrm{.}24,10\mathrm{.}48],[2008,8\mathrm{.}68,7\mathrm{.}48,13\mathrm{.}89,18\mathrm{.}08,11\mathrm{.}32,19\mathrm{.}95,15\mathrm{.}73,30\mathrm{.}32,33\mathrm{.}83,24\mathrm{.}1,24\mathrm{.}77,9\mathrm{.}82],[2009,15\mathrm{.}18,8\mathrm{.}23,4\mathrm{.}85,13\mathrm{.}8,12\mathrm{.}27,7\mathrm{.}65,5\mathrm{.}88,7\mathrm{.}8,12\mathrm{.}58,11\mathrm{.}44,16\mathrm{.}24,8\mathrm{.}71],[2010,20\mathrm{.}58,10\mathrm{.}56,16\mathrm{.}9,16\mathrm{.}84,76\mathrm{.}55,25\mathrm{.}85,25\mathrm{.}14,28\mathrm{.}08,45\mathrm{.}34,27\mathrm{.}39,13\mathrm{.}46,8\mathrm{.}75],[2011,14\mathrm{.}56,4\mathrm{.}59,5\mathrm{.}21,4\mathrm{.}43,10\mathrm{.}00,10\mathrm{.}87,8\mathrm{.}57,17\mathrm{.}29,40\mathrm{.}53,22\mathrm{.}17,28\mathrm{.}81,48\mathrm{.}23]]$

$\backslash$table$[[\backslash$table$[[$Distance from$],[$point $(m)$