Managing the Water Footprint of Irrigated Food Production in England and Wales
This chapter discusses the concept of a water footprint in relation to irrigated food production in England and Wales and the opportunities to reduce its environmental impact. It is split into three parts. The first considers the definition of a water footprint and how it differs from a carbon footprint. The distinction between different types of water (“blue” and “green”) commonly referred to in water footprint studies and the problems associated with interpreting the data are described. The second part reviews the current state and underlying trends in irrigated agriculture, including the volumes abstracted and water sources used. An important component of a water footprint is the environmental impact of the water abstracted. Using a geographical information system (GIS), data on the spatial distribution of irrigation abstractions is combined with information on water resource availability to identify catchments where irrigated production (footprint) is likely to be having an environmental impact. The final part assesses the options for managing water better in irrigated agriculture, both on-farm and from a catchment (water regulation) perspective. Measures to reduce the water footprint on-farm include better management (scheduling) and the adoption of new technologies to improve irrigation application uniformity and water efficiency. Water regulation measures include limiting abstractions in catchments where environmental damage is known to be occurring, using water trading to reallocate water to higher value agricultural uses and changing the timing of abstraction to encourage winter reservoir storage. Finally, there is a discussion of the implications of increasing our dependence on overseas markets for food supply and the consequences for the agricultural sector's broader role in environmental sustainability and rural employment.