Toward multi-objective optimisation for Lake Taupo water level managment

Abstract

A multi-goal optimisation strategy may provide a basis for Lake Taupō water management. This involves defining an agreed ‘optimal zone’ of lake levels which are away from both high and low levels. The aim of water releases to the Waikato River would be to maximise the duration that lake levels are within the optimal zone, while also seeking to meet other, possibly conflicting, goals such as optimal hydro power operation. A sense of how a multi-goal model could operate is given, by considering a simple dual-goal linear programming model that manages Taupō water levels on a daily time step, optimised toward (i) hydro power income and (ii) water level in the optimal zone. The model serves as an illustration only but the approach is readily capable of being expanded to a full model that includes further goals and constraints.