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Stochastic Reservoir Calculations

Prabhu (1958) obtained the stationary distribution of storage level $Z_{t}$ in a reservoir of finite volume $v$, given an inflow $X_{t}$ and an outflow $Y_{t}$. Time $t$ is assumed to be discrete, $X_{t} \sim$ Gamma$(p,μ)$ are independent and $p$ is a positive integer. The mean inflow is $p/μ$; the target outflow is $m$ (constant). We attempt to clarify intricate details, often omitted in the literature, by working through several examples. Of special interest are the probabilities of depletion ($Z_{t}=0$) and spillage ($Z_{t}=v$). For prescribed {$v,p,μ$}, what value of $m$ minimizes both of these?