An Integrated Approach to Water Resources and Investment Planning for Water Utilities

Abstract

Traditionally, water companies in England and Wales use supply-demand modelling methods as decision-making tools for water resources evaluation and investment planning. Companies use separate models for water resources planning and for water resources investment-planning. This approach entails calculating deployable output in a water resources model, for an assumed level of service. That deployable output calculation is exported to an investment model. There is no two-way integration between the water resources model and water resources investment model in the traditional approach, hence any investments do not affect deployable output estimated first in the former model. This paper proposes a new integrated approach—where water resources modelling and investment modelling are integrated, by way of a single modelling tool. The aim of this paper is to compare and contrast traditional water resources and investment planning with the proposed new integrated approach. The new integrated model will allow for the impact of investment choices on the supply and demand position at any point over the planning horizon. The new tool is run for the baseline scenario and for climate change supply scenarios. The results from the integrated model are compared with the results presented by Bristol Water in their Water Resources Management Plan. The level of service metric is calculated in the new model for both baseline and climate change supply scenarios. Finally, this paper proposes further improvement of the integrated model, including potential multi-objective optimisation and new approach to represent uncertainty.