$4.$b$)$ The annual maximum flood series for a gauging Station on the River Nore in

Kilkenny from $2006$ to $2019$ is shown in Table $2.$

Table $2$ Annual maximum river flood series for River Nore.

i$)$ Using the Gringorten Plotting position for the EV$1$ probability distribution,

prepare a flood frequency plot of the annual maximum flows $Q_T$ against the

EV$1$ reduced variate on the horizontal axis. Provide a best$-$fit linear

relationship by eye to this data and determine the $10$ and $50-$year return periods

respectively $($Graph paper is available to assist with your calculations$)$;

ii$)$ Using the ordinary Method of Moments determine the Q$-$T relationship and

compute return period flows of $10,50$ and $100$ years. Establish the respective

growth factors for these return periods.

Aide$-$m$$moire to Q$4$ included at end of paper $Fi=\frac{i-0\mathrm{.}44}{N+0\mathrm{.}12},$ where i is the index of the ranked annual maximum flow

series and N is the total number of annual maximum flows.

$Yi=-Ln(-Ln(Fi))=EV1$ Reduced Variate

and $Y_T=-Ln(-Ln(1-\frac{1}{T}))$