Comparing local and global water scarcity information in determining the water scarcity footprint of potato cultivation in Great Britain

Abstract

In Great Britain (GB), more water is abstracted from surface and groundwater resources for the irrigation of potatoes than for any other crop. This abstraction occurs in the driest catchments and at the driest times of year, and therefore has the potential to exacerbate pressures on water supplies and aquatic ecology. The water scarcity footprint is a metric that describes the impact of an activity on the water scarcity in a locality. In this paper, we use the concept to estimate the volume of blue water consumed in potato production in an average year for the potato growing regions of GB. This has been contextualised by weighting the water consumption according to a global map of water scarcity (Ridoutt and Pfister, 2010) and a local assessment of water resource availability (Environment Agency, 2002). Average blue water consumption for the cultivation of potatoes in Great Britain is 61 Mm3 per year, equivalent to 11 m3/t. The global map of water scarcity was shown to be insufficient for identifying “hotspots”, however the combination of water consumption estimates and local water resource availability assessments allowed the identification of catchments where potato production may be contributing to water scarcity. The East of England was identified as a “hotspot” of water related risk for potato production due to the large area of production, high irrigation need and the fact that many of the catchments are already over abstracted or over licenced.