Forecasting Changes in Agricultural Irrigation Demand to Support a Regional Integrated Water Resources Management Strategy

Despite being an important sector to the UK rural economy, agriculture is often excluded from strategic regional water resources management decision-making due to its low volumetric water demand compared with other sectors such as public water supply. However, the demand for water for agriculture is expected to rise significantly, driven by a changing climate with greater rainfall variability and the combined effects of socioeconomic development and population growth. These “drivers for change” contain significant elements of uncertainty which cannot be ignored. Understanding future changes in water demand also links to important policy debates regarding developing more robust multi-sectoral water strategies, identifying trade-offs between competing sectors and supporting opportunities for collaborative water infrastructure investment.

This chapter describes an approach to estimate future changes in agricultural irrigation demand under contrasting socioeconomic and climate scenarios. The work supports a regional initiative to implement integrated water resources management (IWRM) in a water-stressed region of England. The datasets and modeling routines, mapping outputs, and methodological challenges are described. The critical importance of integrating irrigated agriculture into an IWRM approach, even in a humid climate where irrigation is a relatively small component of water demand, is highlighted. The process has helped to provide stakeholders with a much deeper understanding of the agricultural sector in the region and the water risks it faces. The study has relevance to other temperate or humid countries where agricultural production is an important part of the economy and where competition for water resources is constraining socioeconomic development.