There is a $10,000m^2$ reservoir being built to support a rural community in Western Australia. The reservoir will have to supply at least $2\mathrm{.}5ML/$month to the community. For the reservoir, it is observed that the mean monthly rainfall is $200mm/$month$,$ mean monthly potential evaporation is $150m$m$/$month$,$ and seepage loss is $10m\frac{m}{m}$onth. The reservoir is fed by inflows from a catchment of area $110,000m^2$ that is discharging $200m$m$/$ year.

a$)$ Given the following annual variability in inflows, how reliable is the reservoir assuming constant monthly draft? You may assume the reservoir starts empty.

b$)$ Assume that the reservoir operators would like to improve the reliability of the reservoir. Explain how you would define a rule curve to help manage the reservoir