Demand Forecasting

Estimates for water abstractions are often required in drought and water resources forecasting applications. In some cases, the raw or treated water is returned to the river system, whilst consumptive use represents a more permanent loss. Water demands are typically estimated by aggregating the water demands of individual users such as households, factories and irrigation schemes or using regression relationships, econometric approaches and artificial neural network techniques. This chapter presents an introduction to these topics with examples in the areas of municipal water supply, irrigation and hydropower generation. The topics discussed include micro-component and per capita approaches, crop simulation models, and optimisation of hydropower operations. The developing area of Global Hydrological Models (GHMs) is also considered and their role in estimating water use in climate change impact assessments.