Reservoir Yield Using TPM Method

The use of the transition probability matrix (TPM) to estimate reservoir yield is suggested as an alternative to the generation of long sequences of simulated river flow. The theory of the TPM method is developed using the Markov process and a numerical solution of a simple case of reservoir yield is presented. This solution is compared with an analytical solution. Allowance for evaporation can be conveniently included in the TPM method if a linear relation is assumed between water in storage and water surface area. Allowance for nonuniform inflow and drawoff can also be included if constant annual hydrographs or masks are used to describe these variables.