Agricultural water footprints, irrigation water withdrawal, and blue water scarcity in Virginia from 1985 to 2015

The United States Geological Survey (USGS) estimates that Virginia withdraws about 29.2 billion liters of water daily. However, detailed data on water availability and demand at finer scales remain limited, hindering accurate assessments of blue water footprint and scarcity. This study analyzes agricultural water demand and blue water scarcity in Virginia from 1985 to 2015, focusing on county-level crop water footprints and watershed-scale scarcity. Using data from the USGS and the United States Department of Agriculture, we estimated blue, green, and grey water footprints for 18 major crops. Blue water scarcity was defined as the ratio of total water demand (irrigation, industrial, domestic, and environmental) to available water (surface runoff plus groundwater recharge). Environmental demand was estimated using a hydrology-based method. Hotspots of agricultural water use were identified in counties such as Augusta, Rockingham, Southampton, and Suffolk. Groundwater use peaked in the mid-1990s, then declined as surface water became more dominant. A strong spatial overlap was observed between high-scarcity watersheds and high-withdrawal counties. These findings provide critical insights for targeting sustainable water management strategies and addressing emerging water stress in Virginia’s agricultural regions. This study estimates the water footprint for 18 major crops for each county in Virginia. Hotspot analysis revealed significant water footprint estimates in Northern and Eastern Virginia. Higher blue water footprint counties overlap with high water-scarce watersheds, indicating high irrigation water withdrawal.