Water is a scarce resource utilized by farmers, cities and industries to advance their economic activity. As population increases and the effect of climate change intensifies, competition among multiple stakeholders will exert additional pressure on already over exploited resources. According to the U.S. Government Accountability Office, four out of five states in the United States will face water scarcity somewhere in their state in the coming decade.
Historically, water scarcity has been managed by focusing on supply augmentation; either by storing excess water in reservoirs through construction of dams or by diverting water from regions with excess water to regions with water scarcity. In addition to the high infrastructure cost of building dams, they disrupt river ecology. Additionally, as dams age, there is an increased risk of failure and additional costs associated with dam removal. Even more concerning is the possibility that there may not be enough water to satisfy the demands of all users. As an example, the Colorado River Basin does not have enough water to meet the demands of all its users. The water levels in Lake Mead and Lake Powell, the two largest artificial reservoirs in the United States in terms of water capacity, have remained far below the maximum level due to a decreasing supply of rainwater and snowmelt and increasing demands. This has motivated many water researchers and practitioners to focus on demand management to tackle water scarcity.
To reduce the demand, we must understand the spectrum of water usage for different activities. My research as a civil engineering student in the lab of Dr. Landon Marston at Virginia Tech focuses on understanding water usage by agricultural crops in the United States, with the goal of reducing water usage. One of the strategies of reducing demand is “benchmarking”, where similar water users are grouped together and target benchmarks of productivity are set for each group by choosing the productivity of better than average performers. In the case of water usage, a better than average performer would utilize less water than others within their group. To ensure fair comparison, water users with similar environmental and technological profiles are compared.
The above graphic shows the water savings resulting from improved water productivity. On the left-hand side, the industry uses larger quantities of water for producing X amount of goods. If this water user’s water productivity improves to its industry-specific benchmark (as shown on the right-hand side), it could achieve a similar level of economic activity while using less water.